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Breiding PS, Gomollon AMT, Martini K, Nakhostin D, Alkadhi H, Euler A. Photon-Counting Detector CT for Kidney Stone Detection in Excretory Phase CT-Comparison Between Virtual Non-contrast and Virtual Non-iodine Reconstructions in a 3D Printed Kidney Phantom. Acad Radiol 2024:S1076-6332(24)00209-5. [PMID: 38641450 DOI: 10.1016/j.acra.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 03/24/2024] [Accepted: 04/04/2024] [Indexed: 04/21/2024]
Abstract
RATIONALE AND OBJECTIVES To evaluate and compare the effectiveness of contrast media subtraction and kidney stone detection between a virtual non-iodine reconstruction algorithm (VNI; PureCalcium) and a virtual non-contrast (VNC) algorithm in excretory phase photon-counting detector computed tomography (PCD-CT), using a 3D printed kidney phantom under various tube voltages and radiation doses. MATERIALS AND METHODS A 3D-printed kidney phantom, holding Calcium Oxalate (CaOx) and uric acid stones within contrast-enhanced calyces, was created. The calyx density mirrored the average density observed in 200 excretory phase patients (916 HU at 110 kV). Imaging was conducted on a clinical dual-source PCD-CT at 120 kV and 140 kV, with radiation doses set at 5, 10, and 15 mGy. VNI and VNC algorithms were applied. Two blinded readers evaluated the image quality, along with the degree of contrast media and kidney stone subtraction, using visual scales. Krippendorff's alpha was calculated to determine inter-reader agreement, and the Chi-squared test was employed for comparing ordinal data. RESULTS Reader 2 rated overall image quality higher for VNI than VNC (4.90 vs. 4.00; P < .05), while Reader 1 found no significant difference (4.96 vs. 5.00; P > .05). Substantial agreement was observed between readers for contrast media subtraction in both VNC and VNI (Krippendorff's alpha range: 0.628-0.748). Incomplete contrast media subtraction occurred more frequently with VNI for both readers (Reader 1: 29% vs. 15%; P < .05; Reader 2: 24% vs. 20%; P > .05). Uric acid and smaller stones (<5 mm) were more likely to be subtracted than CaOx and larger stones in both VNC and VNI. Overall, a higher rate of stone subtraction was noted with VNI compared to VNC (Reader 1: 22% vs. 16%; Reader 2: 25% vs. 10%; P < .05). Neither radiation dose nor tube voltage significantly influenced stone subtraction (P > .05). CONCLUSION VNC demonstrated greater accuracy than VNI for contrast media subtraction and kidney stone visibility. Radiation dose and tube voltage had no significant impact. Nonetheless, both algorithms still exhibited frequent incomplete contrast media subtraction and partial kidney stone subtraction.
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Affiliation(s)
- Philipe S Breiding
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland; University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland
| | - Ana Maria Turrion Gomollon
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Katharina Martini
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Dominik Nakhostin
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Hatem Alkadhi
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - André Euler
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland; Department of Radiology, Kantonsspital Baden, Baden, Switzerland.
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Abu-Omar A, Murray N, Ali IT, Khosa F, Barrett S, Sheikh A, Nicolaou S, Tamburrini S, Iacobellis F, Sica G, Granata V, Saba L, Masala S, Scaglione M. Utility of Dual-Energy Computed Tomography in Clinical Conundra. Diagnostics (Basel) 2024; 14:775. [PMID: 38611688 PMCID: PMC11012177 DOI: 10.3390/diagnostics14070775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Advancing medical technology revolutionizes our ability to diagnose various disease processes. Conventional Single-Energy Computed Tomography (SECT) has multiple inherent limitations for providing definite diagnoses in certain clinical contexts. Dual-Energy Computed Tomography (DECT) has been in use since 2006 and has constantly evolved providing various applications to assist radiologists in reaching certain diagnoses SECT is rather unable to identify. DECT may also complement the role of SECT by supporting radiologists to confidently make diagnoses in certain clinically challenging scenarios. In this review article, we briefly describe the principles of X-ray attenuation. We detail principles for DECT and describe multiple systems associated with this technology. We describe various DECT techniques and algorithms including virtual monoenergetic imaging (VMI), virtual non-contrast (VNC) imaging, Iodine quantification techniques including Iodine overlay map (IOM), and two- and three-material decomposition algorithms that can be utilized to demonstrate a multitude of pathologies. Lastly, we provide our readers commentary on examples pertaining to the practical implementation of DECT's diverse techniques in the Gastrointestinal, Genitourinary, Biliary, Musculoskeletal, and Neuroradiology systems.
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Affiliation(s)
- Ahmad Abu-Omar
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Nicolas Murray
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Ismail T. Ali
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Faisal Khosa
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Sarah Barrett
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Adnan Sheikh
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Savvas Nicolaou
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Stefania Tamburrini
- Department of Radiology, Ospedale del Mare-ASL NA1 Centro, Via Enrico Russo 11, 80147 Naples, Italy
| | - Francesca Iacobellis
- Department of General and Emergency Radiology, A. Cardarelli Hospital, Via A. Cardarelli 9, 80131 Naples, Italy;
| | - Giacomo Sica
- Department of Radiology, Monaldi Hospital, Azienda Ospedaliera dei Colli, 80131 Naples, Italy;
| | - Vincenza Granata
- Division of Radiology, Istituto Nazionale Tumori IRCCS Fondazione Pascale—IRCCS Di Napoli, 80131 Naples, Italy
| | - Luca Saba
- Medical Oncology Department, AOU Cagliari, Policlinico Di Monserrato (CA), 09042 Monserrato, Italy
| | - Salvatore Masala
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Viale S. Pietro, 07100 Sassari, Italy; (S.M.)
| | - Mariano Scaglione
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Viale S. Pietro, 07100 Sassari, Italy; (S.M.)
- Department of Radiology, Pineta Grande Hospital, 81030 Castel Volturno, Italy
- Department of Radiology, James Cook University Hospital, Marton Road, Middlesbrough TS4 3BW, UK
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Liu SZ, Herbst M, Schaefer J, Weber T, Vogt S, Ritschl L, Kappler S, Kawcak CE, Stewart HL, Siewerdsen JH, Zbijewski W. Feasibility of bone marrow edema detection using dual-energy cone-beam computed tomography. Med Phys 2024; 51:1653-1673. [PMID: 38323878 DOI: 10.1002/mp.16962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 12/17/2023] [Accepted: 01/16/2024] [Indexed: 02/08/2024] Open
Abstract
BACKGROUND Dual-energy (DE) detection of bone marrow edema (BME) would be a valuable new diagnostic capability for the emerging orthopedic cone-beam computed tomography (CBCT) systems. However, this imaging task is inherently challenging because of the narrow energy separation between water (edematous fluid) and fat (health yellow marrow), requiring precise artifact correction and dedicated material decomposition approaches. PURPOSE We investigate the feasibility of BME assessment using kV-switching DE CBCT with a comprehensive CBCT artifact correction framework and a two-stage projection- and image-domain three-material decomposition algorithm. METHODS DE CBCT projections of quantitative BME phantoms (water containers 100-165 mm in size with inserts presenting various degrees of edema) and an animal cadaver model of BME were acquired on a CBCT test bench emulating the standard wrist imaging configuration of a Multitom Rax twin robotic x-ray system. The slow kV-switching scan protocol involved a 60 kV low energy (LE) beam and a 120 kV high energy (HE) beam switched every 0.5° over a 200° angular span. The DE CBCT data preprocessing and artifact correction framework consisted of (i) projection interpolation onto matched LE and HE projections views, (ii) lag and glare deconvolutions, and (iii) efficient Monte Carlo (MC)-based scatter correction. Virtual non-calcium (VNCa) images for BME detection were then generated by projection-domain decomposition into an Aluminium (Al) and polyethylene basis set (to remove beam hardening) followed by three-material image-domain decomposition into water, Ca, and fat. Feasibility of BME detection was quantified in terms of VNCa image contrast and receiver operating characteristic (ROC) curves. Robustness to object size, position in the field of view (FOV) and beam collimation (varied 20-160 mm) was investigated. RESULTS The MC-based scatter correction delivered > 69% reduction of cupping artifacts for moderate to wide collimations (> 80 mm beam width), which was essential to achieve accurate DE material decomposition. In a forearm-sized object, a 20% increase in water concentration (edema) of a trabecular bone-mimicking mixture presented as ∼15 HU VNCa contrast using 80-160 mm beam collimations. The variability with respect to object position in the FOV was modest (< 15% coefficient of variation). The areas under the ROC curve were > 0.9. A femur-sized object presented a somewhat more challenging task, resulting in increased sensitivity to object positioning at 160 mm collimation. In animal cadaver specimens, areas of VNCa enhancement consistent with BME were observed in DE CBCT images in regions of MRI-confirmed edema. CONCLUSION Our results indicate that the proposed artifact correction and material decomposition pipeline can overcome the challenges of scatter and limited spectral separation to achieve relatively accurate and sensitive BME detection in DE CBCT. This study provides an important baseline for clinical translation of musculoskeletal DE CBCT to quantitative, point-of-care bone health assessment.
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Affiliation(s)
- Stephen Z Liu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | | | | | | | | | | | | | - Christopher E Kawcak
- Department of Clinical Sciences, Colorado State University College of Veterinary Medicine and Biomedical Sciences, Fort Collins, Colorado, USA
| | - Holly L Stewart
- Department of Clinical Sciences, Colorado State University College of Veterinary Medicine and Biomedical Sciences, Fort Collins, Colorado, USA
| | - Jeffrey H Siewerdsen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Imaging Physics, MD Anderson Cancer Center, Houston, Texas, USA
| | - Wojciech Zbijewski
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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Lietz P, Brüntgens M, Wang-Leandro A, Volk HA, Meller S, Merhof K. Virtual non-contrast images of detector-based spectral computed tomography in dogs: a promising alternative to true non-contrast images in veterinary medicine. Front Vet Sci 2023; 10:1251535. [PMID: 38105773 PMCID: PMC10722308 DOI: 10.3389/fvets.2023.1251535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 10/19/2023] [Indexed: 12/19/2023] Open
Abstract
Introduction In veterinary medicine, abdominal computer tomographic (CT) examinations regularly require a minimum of two scans, with a native scan (true unenhanced, TUE) as a reference for the subsequent contrast-enhanced CT scan (CECT). Spectral detector CT (SDCT) offers the possibility to calculate virtual non-contrast (VNC) images from the post-contrast scan, but this has not yet been investigated in veterinary medicine. The purpose of this study was to assess the reliability of VNC images for abdominal organs in 44 dogs without abdominal pathologies by evaluating their quantitative and qualitative parameters compared to TUE images. We hypothesized that the subtraction of iodine is sufficient in the VNC series compared to the TUE series and that the image quality of the SDCT series is superior to conventional CT images. Methods Corresponding attenuation values in the VNC and TUE series regarding the regions of interest (ROI) in different parenchymal organs and major vessels of the abdominal cavity were assessed by means of a two one-sided t-test (TOST) and Bland-Altman plots. Additionally, the signal-to-noise ratio (SNR) was calculated for each ROI in the different series. In the second step, two board-certified veterinary radiologists made a qualitative assessment of VNC images vs. TUE images in consensus by rating the iodine subtraction, image noise, and image quality of VNC images based on a specific 5-point Likert scale. Results The difference in corresponding Hounsfield units (HUs) between TUE and VNC images was less than 10 HU in 78.67% of all ROIs. Regarding the limit of less than 10 HU, in the performed TOST, significant p-values of < 0.05 were reached for the liver, spleen, pancreas, and musculature, implying equivalence of both modalities. The quality of spectral base image (SBI) data was rated equivalent to calculated conventional images in the subjective assessment by reaching an average Likert scale score of 3.2 points. Discussion VNC images calculated from SDCT data prove a valid alternative to conventional TUE images in the abdominal organs of canine patients without abdominal pathology. VNC offers the possibility to reduce time under general anesthesia and minimize radiation exposure. Future studies are needed to prove the application of this method in clinically diseased patients.
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Cheng Y, Zhang L, Cao L, Zhang X, Qu T, Li J, Chen J, He H, Yang J, Guo J. Detection and characterization of urinary stones using material-specific images derived from contrast-enhanced dual-energy CT urography. Br J Radiol 2023; 96:20230337. [PMID: 37750853 PMCID: PMC10646646 DOI: 10.1259/bjr.20230337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 09/12/2023] [Accepted: 09/18/2023] [Indexed: 09/27/2023] Open
Abstract
OBJECTIVE To determine the accuracy of material-specific images derived from contrast-enhanced dual-energy CT urography (DECTU) in detecting and measuring urinary stones in comparison with that of unenhanced images and its utility in calcified stone differentiation. METHODS 105 patients with 202 urinary stones (121 had confirmed composition by infrared spectroscopy) underwent triphasic (unenhanced, portal venous (VP) and excretory phase (EP)) DECTU. Material-specific images were derived in VP and EP with calcium-water, calcium-iodine and CaOxalate_Dihydrate (COD)-Hydroxyapatite (HAP) as basis material pairs. Stone number and size were recorded on unenhanced images and VP and EP material-specific images, where stone densities were also measured. Material densities of calcified stones (pure calcium oxalate [pCaO, n = 34], mixed calcium oxalate [mCaO, n = 14], mixed carbonate phosphate [mCaP, n = 70]) were compared and thresholds for differentiating these stones were determined using receiver operating characteristic analysis. RESULTS All 202 urinary stones were detected on the unenhanced, calcium (water) and calcium (iodine) images in VP. While the detection rate was significantly decreased to 58 and 64% using calcium (water) and calcium (iodine) images in EP, respectively (all p < 0.001). Stone sizes measured on calcium (iodine) images in VP was similar to that of unenhanced images (10.6 vs 10.7 mm, p > 0.05). Significant differences in material densities were found among pCaO, mCaO and mCaP on COD(HAP) images with AUC of 0.72-0.74 for differentiating these stones. CONCLUSION Material-specific images in VP derived from DECTU allow reliably detecting and measuring urinary tract stones in comparison with unenhanced images and can identify calcified stones with moderate diagnostic performance to provide potential 33% dose reduction. ADVANCES IN KNOWLEDGE Material-specific images, especially the calcium (iodine) images in VP allow for reliable detection of urinary stones.Stone size measurement should be performed on the calcium (iodine) images in VP.Material density measurements on COD-HAP (VP) material decomposition images can be used to differentiate among pure calcium oxalate, mixed calcium oxalate and mixed carbonate phosphate stones with AUC of 0.72-0.74.
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Affiliation(s)
- Yannan Cheng
- Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Lu Zhang
- Department of Urology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Le Cao
- Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Xianghui Zhang
- Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Tingting Qu
- Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Jianying Li
- GE Healthcare, Computed Tomography Research Center, Beijing, PR China
| | - Jiao Chen
- Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Hui He
- Department of Urology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Jian Yang
- Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Jianxin Guo
- Department of Radiology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
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Chakravarti S, Uyeda JW. Expanding Role of Dual-Energy CT for Genitourinary Tract Assessment in the Emergency Department, From the AJR Special Series on Emergency Radiology. AJR Am J Roentgenol 2023; 221:720-730. [PMID: 37073900 DOI: 10.2214/ajr.22.27864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Among explored applications of dual-energy CT (DECT) in the abdomen and pelvis, the genitourinary (GU) tract represents an area where accumulated evidence has established the role of DECT to provide useful information that may change management. This review discusses established applications of DECT for GU tract assessment in the emergency department (ED) setting, including characterization of renal stones, evaluation of traumatic injuries and hemorrhage, and characterization of incidental renal and adrenal findings. Use of DECT for such applications can reduce the need for additional multiphase CT or MRI examinations and reduce follow-up imaging recommendations. Emerging applications are also highlighted, including use of low-energy virtual monoenergetic images (VMIs) to improve image quality and potentially reduce contrast media doses and use of high-energy VMIs to mitigate renal mass pseudoenhancement. Finally, implementation of DECT into busy ED radiology practices is presented, weighing the trade-off of additional image acquisition, processing time, and interpretation time against potential additional useful clinical information. Automatic generation of DECT-derived images with direct PACS transfer can facilitate radiologists' adoption of DECT in busy ED environments and minimize impact on interpretation times. Using the described approaches, radiologists can apply DECT technology to improve the quality and efficiency of care in the ED.
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Affiliation(s)
| | - Jennifer W Uyeda
- Department of Emergency Radiology, Brigham and Women's Hospital/Harvard Medical School, 75 Francis St, Boston, MA 02115
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Nehra AK, Dane B, Yeh BM, Fletcher JG, Leng S, Mileto A. Dual-Energy, Spectral and Photon Counting Computed Tomography for Evaluation of the Gastrointestinal Tract. Radiol Clin North Am 2023; 61:1031-1049. [PMID: 37758355 DOI: 10.1016/j.rcl.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
The use of dual-energy computed tomography (CT) allows for reconstruction of energy- and material-specific image series. The combination of low-energy monochromatic images, iodine maps, and virtual unenhanced images can improve lesion detection and disease characterization in the gastrointestinal tract in comparison with single-energy CT.
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Affiliation(s)
- Avinash K Nehra
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA.
| | - Bari Dane
- Department of Radiology, New York University Langone Medical Center, 550 First Avenue, New York, NY 10016, USA
| | - Benjamin M Yeh
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Joel G Fletcher
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Shuai Leng
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Achille Mileto
- Department of Radiology, Virginia Mason Medical Center, 1100 9th Avenue, Seattle, WA 98101, USA
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Cellina M, Cè M, Rossini N, Cacioppa LM, Ascenti V, Carrafiello G, Floridi C. Computed Tomography Urography: State of the Art and Beyond. Tomography 2023; 9:909-930. [PMID: 37218935 PMCID: PMC10204399 DOI: 10.3390/tomography9030075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/24/2023] Open
Abstract
Computed Tomography Urography (CTU) is a multiphase CT examination optimized for imaging kidneys, ureters, and bladder, complemented by post-contrast excretory phase imaging. Different protocols are available for contrast administration and image acquisition and timing, with different strengths and limits, mainly related to kidney enhancement, ureters distension and opacification, and radiation exposure. The availability of new reconstruction algorithms, such as iterative and deep-learning-based reconstruction has dramatically improved the image quality and reducing radiation exposure at the same time. Dual-Energy Computed Tomography also has an important role in this type of examination, with the possibility of renal stone characterization, the availability of synthetic unenhanced phases to reduce radiation dose, and the availability of iodine maps for a better interpretation of renal masses. We also describe the new artificial intelligence applications for CTU, focusing on radiomics to predict tumor grading and patients' outcome for a personalized therapeutic approach. In this narrative review, we provide a comprehensive overview of CTU from the traditional to the newest acquisition techniques and reconstruction algorithms, and the possibility of advanced imaging interpretation to provide an up-to-date guide for radiologists who want to better comprehend this technique.
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Affiliation(s)
- Michaela Cellina
- Radiology Department, Fatebenefratelli Hospital, ASST Fatebenefratelli Sacco, Piazza Principessa Clotilde 3, 20121 Milan, Italy
| | - Maurizio Cè
- Postgraduation School in Radiodiagnostics, Università degli Studi di Milano, Via Festa del Perdono 7, 20122 Milan, Italy
| | - Nicolo’ Rossini
- Department of Clinical, Special and Dental Sciences, University Politecnica delle Marche, 60126 Ancona, Italy
| | - Laura Maria Cacioppa
- Division of Interventional Radiology, Department of Radiological Sciences, University Politecnica delle Marche, 60126 Ancona, Italy
| | - Velio Ascenti
- Postgraduation School in Radiodiagnostics, Università degli Studi di Milano, Via Festa del Perdono 7, 20122 Milan, Italy
| | - Gianpaolo Carrafiello
- Radiology Department, Policlinico di Milano Ospedale Maggiore|Fondazione IRCCS Ca’ Granda, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Chiara Floridi
- Division of Interventional Radiology, Department of Radiological Sciences, University Politecnica delle Marche, 60126 Ancona, Italy
- Division of Special and Pediatric Radiology, Department of Radiology, University Hospital “Umberto I-Lancisi-Salesi”, 60126 Ancona, Italy
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Ascenti G, Cicero G, Cardone G, Bertelli E, Papa M, Ciccone V, Manetta R, Gentili F, Francioso AP, Mazzei MA, Floridi C, Di Cesare E, Gandolfo N, De Filippo M, Miele V, Giovagnoni A. Cornerstones of CT urography: a shared document by the Italian board of urogenital radiology. LA RADIOLOGIA MEDICA 2023; 128:601-611. [PMID: 37027091 DOI: 10.1007/s11547-023-01623-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/15/2023] [Indexed: 04/08/2023]
Abstract
CT urography is a single term used to refer to different scanning protocols that can be applied for a number of clinical indications. If, on the one hand, this highlights the role of the radiologist in deciding the most suitable technique to perform according to the patient's needs, on the other hand, a certain confusion may arise due to the different technical and clinical variables that have to be taken into account. This has been well demonstrated by a previous work based on an online questionnaire administered to a population of Italian radiologists that brought out similarities as well as differences across the national country. Defining precise guidelines for each clinical scenario, although desirable, is a difficult task to accomplish, if not even unfeasible. According to the prementioned survey, five relevant topics concerning CT urography have been identified: definition and clinical indications, opacification of the excretory system, techniques, post-processing reconstructions, and radiation dose and utility of dual-energy CT. The aim of this work is to deepen and share knowledge about these main points in order to assist the radiology in the daily practice. Moreover, a synopsis of recommendations agreed by the Italian board of genitourinary imaging is provided.
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Affiliation(s)
- Giorgio Ascenti
- Section of Radiological Sciences, Department of Biomedical Sciences and Morphological and Functional Imaging, University of Messina, Policlinico "G. Martino", Via Consolare Valeria, 1, 98100, Messina, Italy
| | - Giuseppe Cicero
- Section of Radiological Sciences, Department of Biomedical Sciences and Morphological and Functional Imaging, University of Messina, Policlinico "G. Martino", Via Consolare Valeria, 1, 98100, Messina, Italy.
| | - Gianpiero Cardone
- Diagnostic and Interventional Radiology Department, IRCCS Ospedale San Raffaele-Turro, Università Vita-Salute San Raffaele, Milan, Italy
| | - Elena Bertelli
- Department of Emergency Radiology, Careggi University Hospital, Florence, Italy
| | - Maurizio Papa
- Complex Unit of Radiology, Department of Diagnostic and Interventional Radiology, Azienda Socio Sanitaria Territoriale (ASST) Lodi, Lodi, Italy
| | - Vincenzo Ciccone
- Radiology Department, San Giovanni Di Dio E Ruggi D'Aragona Hospital, Salerno, Italy
| | - Rosa Manetta
- Radiology Unit, San Salvatore Hospital, L'Aquila, Italy
| | - Francesco Gentili
- Unit of Diagnostic Imaging, Department of Radiological Sciences, Azienda Ospedaliero-Universitaria Senese, "Santa Maria Alle Scotte" General Hospital, Viale Mario Bracci, 16, Siena, 53100, Italy
| | - Antonio Pio Francioso
- Complex Unit of Radiology, Department of Diagnostic and Interventional Radiology, Azienda Socio Sanitaria Territoriale (ASST) Lodi, Lodi, Italy
| | - Maria Antonietta Mazzei
- Unit of Diagnostic Imaging, Department of Medical, Surgical and Neuro Sciences and of Radiological Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Chiara Floridi
- Department of Radiological Sciences, Ospedali Riuniti Ancona, Università Politecnica Delle Marche - University Hospital, Via Tronto 10, 60126, Ancona, Italy
| | - Ernesto Di Cesare
- Department of Life, Health and Environmental Sciences, University of L'Aquila, 67100, L'Aquila, Italy
| | - Nicoletta Gandolfo
- Diagnostic Imaging Department, Villa Scassi Hospital-ASL 3, Corso Scassi 1, Genoa, Italy
| | - Massimo De Filippo
- University of Parma, Parma Hospital, Via Gramsci 14, 43126, Parma, Italy
| | - Vittorio Miele
- Department of Emergency Radiology, Careggi University Hospital, Florence, Italy
| | - Andrea Giovagnoni
- Department of Radiological Sciences, Ospedali Riuniti Ancona, Università Politecnica Delle Marche - University Hospital, Via Tronto 10, 60126, Ancona, Italy
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Detection and size measurements of kidney stones on virtual non-contrast reconstructions derived from dual-layer computed tomography in an ex vivo phantom setup. Eur Radiol 2023; 33:2995-3003. [PMID: 36422646 PMCID: PMC10017605 DOI: 10.1007/s00330-022-09261-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To systematically investigate the usability of virtual non-contrast reconstructions (VNC) derived from dual-layer CT (DLCT) for detection and size measurements of kidney stones with regards to different degrees of surrounding iodine-induced attenuation and radiation dose. METHODS Ninety-two kidney stones of varying size (3-14 mm) and composition were placed in a phantom filled with different contrast media/water mixtures exhibiting specific iodine-induced attenuation (0-1500 HU). DLCT-scans were acquired using CTDIvol of 2 mGy and 10 mGy. Conventional images (CI) and VNC0H-1500HU were reconstructed. Reference stone size was determined using a digital caliper (Man-M). Visibility and stone size were assessed. Statistical analysis was performed using the McNemar test, Wilcoxon test, and the coefficient of determination. RESULTS All stones were visible on CI0HU and VNC200HU. Starting at VNC400 HU, the detection rate decreased with increasing HU and was significantly lower as compared to CI0HU on VNC≥ 600HU (100.0 vs. 94.0%, p < 0.05). The overall detection rate was higher using 10 mGy as compared to 2 mGy protocol (87.9 vs. 81.8%; p < 0.001). Stone size was significantly overestimated on all VNC compared to Man-M (7.0 ± 3.5 vs. 6.6 ± 2.8 mm, p < 0.001). Again, the 10 mGy protocol tended to show a better correlation with Man-M as compared to 2 mGy protocol (R2 = 0.39-0.68 vs. R2 = 0.31-0.57). CONCLUSIONS Detection and size measurements of kidney stones surrounded by contrast media on VNC are feasible. The detection rate of kidney stones decreases with increasing iodine-induced attenuation and with decreasing radiation dose as well as stone size, while remaining comparable to CI0HU on VNC ≤ 400 HU. KEY POINTS • The detection rate of kidney stones on VNC depends on the surrounding iodine-induced attenuation, the used radiation dose, and the stone size. • The detection rate of kidney stones on VNC decreases with greater iodine-induced attenuation and with lower radiation dose, particularly in small stones. • The visibility of kidney stones on VNC ≤ 400 HU remains comparable to true-non-contrast scans even when using a low-dose technique.
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Park HY, Suh CH, Kim SO. Use of "Diagnostic Yield" in Imaging Research Reports: Results from Articles Published in Two General Radiology Journals. Korean J Radiol 2022; 23:1290-1300. [PMID: 36447417 PMCID: PMC9747267 DOI: 10.3348/kjr.2022.0741] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 10/06/2022] [Accepted: 10/10/2022] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE "Diagnostic yield," also referred to as the detection rate, is a parameter positioned between diagnostic accuracy and diagnosis-related patient outcomes in research studies that assess diagnostic tests. Unfamiliarity with the term may lead to incorrect usage and delivery of information. Herein, we evaluate the level of proper use of the term "diagnostic yield" and its related parameters in articles published in Radiology and Korean Journal of Radiology (KJR). MATERIALS AND METHODS Potentially relevant articles published since 2012 in these journals were identified using MEDLINE and PubMed Central databases. The initial search yielded 239 articles. We evaluated whether the correct definition and study setting of "diagnostic yield" or "detection rate" were used and whether the articles also reported companion parameters for false-positive results. We calculated the proportion of articles that correctly used these parameters and evaluated whether the proportion increased with time (2012-2016 vs. 2017-2022). RESULTS Among 39 eligible articles (19 from Radiology and 20 from KJR), 17 (43.6%; 11 from Radiology and 6 from KJR) correctly defined "diagnostic yield" or "detection rate." The remaining 22 articles used "diagnostic yield" or "detection rate" with incorrect meanings such as "diagnostic performance" or "sensitivity." The proportion of correctly used diagnostic terms was higher in the studies published in Radiology than in those published in KJR (57.9% vs. 30.0%). The proportion improved with time in Radiology (33.3% vs. 80.0%), whereas no improvement was observed in KJR over time (33.3% vs. 27.3%). The proportion of studies reporting companion parameters was similar between journals (72.7% vs. 66.7%), and no considerable improvement was observed over time. CONCLUSION Overall, a minority of articles accurately used "diagnostic yield" or "detection rate." Incorrect usage of the terms was more frequent without improvement over time in KJR than in Radiology. Therefore, improvements are required in the use and reporting of these parameters.
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Affiliation(s)
- Ho Young Park
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Chong Hyun Suh
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Seon-Ok Kim
- Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Cao J, Lennartz S, Pisuchpen N, Parakh A, Kambadakone A. Attenuation values on virtual unenhanced images obtained with detector-based dual-energy computed tomography: observations on single- and split-bolus contrast protocols. Abdom Radiol (NY) 2022; 47:3019-3027. [PMID: 34687325 DOI: 10.1007/s00261-021-03273-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 01/18/2023]
Abstract
PURPOSE To compare virtual unenhanced (VUE) attenuation values and their agreement with true unenhanced (TUE) images in patients who underwent dual-layer detector-based dual-energy computed tomography (dlDECT) with single- vs. split-bolus contrast media protocol. METHODS In this HIPAA-compliant, IRB-approved retrospective analysis, a total of 105 patients who underwent nephrographic phase (NP) dlDECT between 07/2018 and 11/2019 were included: 55 patients received single bolus and 50 patients split-bolus examinations. Both scan protocols comprised a TUE and 120-kVp NP acquisition from which VUE images were reconstructed. A radiologist performed ROI-based attenuation measurements of liver parenchyma, main portal vein, aorta, spleen, renal parenchyma, and pelvis on TUE and VUE images. Agreement between TUE and VUE images was determined and compared for both protocols and each anatomic region. RESULTS VUE attenuation was significantly higher than TUE attenuation in both cohorts in the liver, portal vein, spleen, and renal parenchyma (p < 0.05), while it was similar in the abdominal aorta in both cohorts (p = 0.05, 0.7522, respectively). VUE attenuation was significantly higher than TUE attenuation in the renal pelvis of the split-bolus cohort (p < 0.05). When comparing VUE images between single- and split-bolus protocols, the renal parenchyma yielded a significantly higher VUE attenuation in the single-bolus cohort (single bolus: 38.8 ± 3.3 HU vs. split bolus: 36.8 ± 3.6 HU; p < 0.05), whereas the split-bolus cohort revealed markedly higher VUE attenuation in the renal pelvis (single bolus: 2.3 ± 10.8 HU vs. split bolus: 92.3 ± 76.8; p < 0.05). Mean intra-patient differences between TUE and VUE images were comparable between single- and split-bolus cohorts (p-range 0.09-0.35) except for the renal parenchyma and pelvis: in the first, the single-bolus cohort yielded a higher VUE attenuation, while in the second, attenuation was significantly higher in the split-bolus cohort (p < 0.05). CONCLUSION VUE attenuation overestimated TUE attenuation and differed between split- and single-bolus protocols for the renal parenchyma and pelvis, while all other tissues showed comparable VUE attenuation.
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Affiliation(s)
- Jinjin Cao
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA, 02114-2696, USA
| | - Simon Lennartz
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA, 02114-2696, USA
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Nisanard Pisuchpen
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA, 02114-2696, USA
- Department of Radiology, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Anushri Parakh
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA, 02114-2696, USA
| | - Avinash Kambadakone
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA, 02114-2696, USA.
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Toshav A. Economics of Dual-Energy CT: Workflow, Costs, and Benefits. Semin Ultrasound CT MR 2022; 43:352-354. [PMID: 35738820 DOI: 10.1053/j.sult.2022.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dual-energy CT is an emerging technology which is progressively becoming more available for routine clinical applications. As practices and institutions evaluate the business case for purchase of these high-end scanners, the clinical utility and downstream costs must be determined. This article will provide an overview of the technology and will review direct and indirect costs associated with the implementation of dual-energy CT programs.
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Affiliation(s)
- Aran Toshav
- Department of Radiology, Southeast Louisiana Veterans Healthcare System, LSUHSC New Orleans, Louisiana USA.
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McCoombe K, Dobeli K, Meikle S, Llewellyn S, Kench P. Sensitivity of virtual non-contrast dual-energy CT urogram for detection of urinary calculi: a systematic review and meta-analysis. Eur Radiol 2022; 32:8588-8596. [PMID: 35763094 DOI: 10.1007/s00330-022-08939-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 05/16/2022] [Accepted: 05/30/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To determine the sensitivity of dual-energy (DE) virtual non-contrast computed tomography (vNCT), generated from the excretory phase of a CT urogram, compared to true non-contrast CT (tNCT) for the detection of urinary calculi. METHODS A search of multiple medical literature databases was performed using predetermined search terms. Inclusion and exclusion criteria were applied, and bias risk was assessed by two independent reviewers using the quality assessment of diagnostic accuracy studies (QUADAS) tool. Collated estimates of sensitivity were generated, and sources of heterogeneity were identified and reviewed. RESULTS Thirteen studies (1760 patients; 1740 urinary calculi) were included for sensitivity assessment. Pooled sensitivity for urinary calculi on vNCT was 78.1% (95% CI: 70.2 to 85.0%); however, heterogeneity between studies was very high (I2 = 92.0%). Sources of heterogeneity between studies were explored through subgroup analysis by categorising studies according to slice thickness (≥ 2 mm and < 2 mm), use of oral hydration, and use of intravenous furosemide. Pooled sensitivity for detection of urinary calculi on vNCT for studies that used oral hydration and < 2 mm slice thickness was 92.2% (95% CI: 89.5 to 94.5%). Pooled specificity was not performed as true negatives were not reported in most studies. Potential sources of bias were identified in included studies. CONCLUSION vNCT demonstrated a moderate pooled sensitivity compared to tNCT for the detection of urinary calculi in split bolus CT urogram protocols. However, subgroup analysis suggests higher sensitivity when employing oral hydration and < 2 mm slice thickness or increment. KEY POINTS • vNCT demonstrated moderate pooled sensitivity for the detection of urinary calculi in split bolus CT urogram protocols. • Subgroup analysis suggested higher sensitivity with oral hydration and < 2 mm slice thickness or increment.
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Affiliation(s)
- Katherine McCoombe
- Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales, Australia. .,Department of Medical Imaging, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.
| | - Karen Dobeli
- Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales, Australia.,Department of Medical Imaging, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Steven Meikle
- Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales, Australia
| | - Stacey Llewellyn
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Peter Kench
- Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales, Australia
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Cheng Y, Sun J, Li J, Han Y, Zhang X, Zhang L, Zheng J, He H, Yang J, Guo J. The added value of virtual unenhanced images obtained from dual-energy CT Urography in the detection and measurement of urinary stone. Urology 2022; 166:118-125. [DOI: 10.1016/j.urology.2022.02.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 10/18/2022]
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Dodig D, Solocki Matić T, Žuža I, Pavlović I, Miletić D, Markić D. Side-by-side evaluation of virtual non-contrast and post-contrast images improves detection of clinically significant urolithiasis on single-phase split bolus dual-energy CT urography. Br J Radiol 2021; 94:20210013. [PMID: 33861140 DOI: 10.1259/bjr.20210013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Studies show insufficient sensitivity of virtual non-contrast (VNC) reconstructions for stone detection in dual-energy CT urography (DE-CTU). The aim of this study was to investigate if side-by-side-evaluation of both VNC and post-contrast images could increase the sensitivity of single-phase split bolus DE-CTU. METHODS Consecutive patients with haematuria who underwent split bolus DE-CTU on the same dual-source DE-CT scanner were retrospectively enrolled in the study. Intravenous furosemide and oral hydration were employed. Two readers, independently and then jointly in two separate sessions, recorded the location and the longest axial stone diameter on three randomised sets of images: separate VNC and post-contrast images, and side-by-side-reconstructions. True non-contrast (TNC) images served as the standard of reference. RESULTS A total of 83 urinary stones were detected on TNC images. Independent reader side-by-side-evaluation of VNC and post-contrast images yielded higher stone detection sensitivity (76 and 84%, respectively) compared to evaluation of only VNC (71 and 81%, respectively) or post-contrast images (64 and 80%, respectively). The sensitivity of joint reader evaluation of side-by-side-images reached almost 86% and was not significantly different from TNC images (p = 0.77). All stones larger than 3 mm were correctly detected by side-by-side-evaluation. Dose reduction of 55% could be achieved by omitting TNC scans. CONCLUSION Side-by-side-VNC and post-contrast image evaluation enable detection of clinically significant urolithiasis on single-phase split bolus DE-CTU with significant dose reduction. ADVANCES IN KNOWLEDGE This study shows that single-phase DE-CTU is feasible if VNC imaging is simultaneously utilised with post-contrast images.
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Affiliation(s)
- Doris Dodig
- Department of Radiology, Clinical Hospital Centre Rijeka, Rijeka, Croatia
| | | | - Iva Žuža
- Department of Radiology, Clinical Hospital Centre Rijeka, Rijeka, Croatia
| | - Ivan Pavlović
- Department of Radiology, Clinical Hospital Centre Rijeka, Rijeka, Croatia
| | - Damir Miletić
- Department of Radiology, Clinical Hospital Centre Rijeka, Rijeka, Croatia.,Department of Radiology, University of Rijeka, Faculty of Medicine, Rijeka, Croatia
| | - Dean Markić
- Department of Urology, Clinical Hospital Centre Rijeka, Rijeka, Croatia
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Estimating dual-energy CT imaging from single-energy CT data with material decomposition convolutional neural network. Med Image Anal 2021; 70:102001. [PMID: 33640721 DOI: 10.1016/j.media.2021.102001] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/06/2021] [Accepted: 02/11/2021] [Indexed: 01/12/2023]
Abstract
Dual-energy computed tomography (DECT) is of great significance for clinical practice due to its huge potential to provide material-specific information. However, DECT scanners are usually more expensive than standard single-energy CT (SECT) scanners and thus are less accessible to undeveloped regions. In this paper, we show that the energy-domain correlation and anatomical consistency between standard DECT images can be harnessed by a deep learning model to provide high-performance DECT imaging from fully-sampled low-energy data together with single-view high-energy data. We demonstrate the feasibility of the approach with two independent cohorts (the first cohort including contrast-enhanced DECT scans of 5753 image slices from 22 patients and the second cohort including spectral CT scans without contrast injection of 2463 image slices from other 22 patients) and show its superior performance on DECT applications. The deep-learning-based approach could be useful to further significantly reduce the radiation dose of current premium DECT scanners and has the potential to simplify the hardware of DECT imaging systems and to enable DECT imaging using standard SECT scanners.
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18
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Xiao JM, Hippe DS, Zecevic M, Zamora DA, Cai LM, Toia GV, Chandler AG, Dighe MK, O'Malley RB, Shuman WP, Wang CL, Mileto A. Virtual Unenhanced Dual-Energy CT Images Obtained with a Multimaterial Decomposition Algorithm: Diagnostic Value for Renal Mass and Urinary Stone Evaluation. Radiology 2021; 298:611-619. [PMID: 33464180 DOI: 10.1148/radiol.2021192448] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Background Virtual unenhanced (VUE) images obtained by using a dual-energy CT (DECT) multimaterial decomposition algorithm hold promise for diagnostic use in the abdomen in lieu of true unenhanced (TUE) images. Purpose To assess VUE images obtained from a DECT multimaterial decomposition algorithm in patients undergoing renal mass and urinary stone evaluation. Materials and Methods In this retrospective Health Insurance Portability and Accountability Act-compliant study, DECT was performed in patients undergoing evaluation for renal mass or urinary stone. VUE images were compared quantitatively to TUE images and qualitatively assessed by four independent radiologists. Differences in attenuation between VUE and TUE images were summarized by using 95% limits of agreement. Diagnostic performance in urinary stone detection was summarized by using area under the receiver operating characteristic curve, sensitivity, and specificity. Results A total of 221 patients (mean age ± standard deviation, 61 years ± 14; 129 men) with 273 renal masses were evaluated. Differences in renal mass attenuation between VUE and TUE images were within 3 HU for both enhancing masses (95% limits of agreement, -3.1 HU to 2.7 HU) and nonenhancing cysts (95% limits of agreement, -2.9 HU to 2.5 HU). Renal mass classification as enhancing mass versus nonenhancing cyst did not change (reclassification rate of enhancing masses, 0% [0 of 78]; 95% CI: 0, 5; reclassification rate of nonenhancing cysts, 0% [0 of 193]; 95% CI: 0, 2) with use of VUE in lieu of TUE images. Among 166 urinary stones evaluated, diagnostic performance of VUE images for stone detection was lower compared with that of TUE images (area under the receiver operating characteristic curve, 0.79 [95% CI: 0.73, 0.84] vs 0.93 [95% CI: 0.91, 0.95]; P < .001) due to reduced sensitivity of VUE for detection of stones 3 mm in diameter or less compared with those greater than 3 mm (sensitivity, 23% [25 of 108; 95% CI: 12, 40] vs 88% [126 of 144; 95% CI: 77, 94]; P < .001). Conclusion Compared with true unenhanced images, virtual unenhanced (VUE) images were unlikely to change renal mass classification as enhancing mass versus nonenhancing cyst. Diagnostic performance of VUE images remained suboptimal for urinary stone detection due to subtraction of stones 3 mm or less in diameter. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Sosna in this issue.
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Affiliation(s)
- Jennifer M Xiao
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Daniel S Hippe
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Mladen Zecevic
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - David A Zamora
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Larry M Cai
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Giuseppe V Toia
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Adam G Chandler
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Manjiri K Dighe
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Ryan B O'Malley
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - William P Shuman
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Carolyn L Wang
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
| | - Achille Mileto
- From the Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific St, Seattle, WA 98195 (J.M.X., D.S.H., M.Z., D.A.Z., L.M.C., G.V.T., M.K.D., R.B.O., W.P.S., C.L.W., A.M.); and Global Research Organization, GE Healthcare, Houston, Tex (A.G.C.)
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Parakh A, Lennartz S, An C, Rajiah P, Yeh BM, Simeone FJ, Sahani DV, Kambadakone AR. Dual-Energy CT Images: Pearls and Pitfalls. Radiographics 2021; 41:98-119. [PMID: 33411614 PMCID: PMC7853765 DOI: 10.1148/rg.2021200102] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/10/2020] [Accepted: 07/16/2020] [Indexed: 01/10/2023]
Abstract
Dual-energy CT (DECT) is a tremendous innovation in CT technology that allows creation of numerous imaging datasets by enabling discrete acquisitions at more than one energy level. The wide range of images generated from a single DECT acquisition provides several benefits such as improved lesion detection and characterization, superior determination of material composition, reduction in the dose of iodine, and more robust quantification. Technological advances and the proliferation of various processing methods have led to the availability of diverse vendor-based DECT approaches, each with a different acquisition and image reconstruction process. The images generated from various DECT scanners differ from those from conventional single-energy CT because of differences in their acquisition techniques, material decomposition methods, image reconstruction algorithms, and postprocessing methods. DECT images such as virtual monochromatic images, material density images, and virtual unenhanced images have different imaging appearances, texture features, and quantitative capabilities. This heterogeneity creates challenges in their routine interpretation and has certain associated pitfalls. Some artifacts such as residual iodine on virtual unenhanced images and an appearance of pseudopneumatosis in a gas-distended bowel loop on material-density iodine images are specific to DECT, while others such as pseudoenhancement seen on virtual monochromatic images are also observed at single-energy CT. Recognizing the potential pitfalls associated with DECT is necessary for appropriate and accurate interpretation of the results of this increasingly important imaging tool. Online supplemental material is available for this article. ©RSNA, 2021.
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Affiliation(s)
- Anushri Parakh
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., S.L., F.J.S., A.R.K.); Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, Calif (C.A., B.M.Y.); Department of Radiology, Mayo Clinic, Rochester, Minn (P.R.); Department of Radiology, University of Washington, Seattle, Wash (D.V.S.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany (S.L.)
| | - Simon Lennartz
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., S.L., F.J.S., A.R.K.); Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, Calif (C.A., B.M.Y.); Department of Radiology, Mayo Clinic, Rochester, Minn (P.R.); Department of Radiology, University of Washington, Seattle, Wash (D.V.S.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany (S.L.)
| | - Chansik An
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., S.L., F.J.S., A.R.K.); Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, Calif (C.A., B.M.Y.); Department of Radiology, Mayo Clinic, Rochester, Minn (P.R.); Department of Radiology, University of Washington, Seattle, Wash (D.V.S.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany (S.L.)
| | - Prabhakar Rajiah
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., S.L., F.J.S., A.R.K.); Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, Calif (C.A., B.M.Y.); Department of Radiology, Mayo Clinic, Rochester, Minn (P.R.); Department of Radiology, University of Washington, Seattle, Wash (D.V.S.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany (S.L.)
| | - Benjamin M. Yeh
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., S.L., F.J.S., A.R.K.); Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, Calif (C.A., B.M.Y.); Department of Radiology, Mayo Clinic, Rochester, Minn (P.R.); Department of Radiology, University of Washington, Seattle, Wash (D.V.S.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany (S.L.)
| | - Frank J. Simeone
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., S.L., F.J.S., A.R.K.); Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, Calif (C.A., B.M.Y.); Department of Radiology, Mayo Clinic, Rochester, Minn (P.R.); Department of Radiology, University of Washington, Seattle, Wash (D.V.S.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany (S.L.)
| | - Dushyant V. Sahani
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., S.L., F.J.S., A.R.K.); Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, Calif (C.A., B.M.Y.); Department of Radiology, Mayo Clinic, Rochester, Minn (P.R.); Department of Radiology, University of Washington, Seattle, Wash (D.V.S.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany (S.L.)
| | - Avinash R. Kambadakone
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., S.L., F.J.S., A.R.K.); Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, Calif (C.A., B.M.Y.); Department of Radiology, Mayo Clinic, Rochester, Minn (P.R.); Department of Radiology, University of Washington, Seattle, Wash (D.V.S.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany (S.L.)
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Liang J, Fang Y, Jiang Y, Zhan Y, Hong G. Diagnostic accuracy of dual-energy CT virtual non-calcium images with different related contrast material values for the detection of bone marrow edema in knee. Eur J Radiol 2020; 133:109385. [PMID: 33157370 DOI: 10.1016/j.ejrad.2020.109385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 09/13/2020] [Accepted: 10/26/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of this study was to evaluate the diagnostic accuracy of different related contrast material (Rel.CM) values in dual-energy computed tomography (DECT) virtual non-calcium (VNCa) images for the detection of bone marrow edema (BME) in knee. METHOD This prospective study was approved by the institutional research ethics board, and written informed consent was obtained from all participants. Twenty-three patients (24 knees) who underwent dual-energy CT and MRI within three weeks from July 2018 to June 2019 with a definite history of trauma were enrolled. Each knee was divided into 12 regions. First, MR images served as the reference standard, Receiver operating characteristic (ROC) curve was used and diagnostic accuracy of VNCa images corresponding to different Rel.CM values (1.25, 1.35, 1.45, 1.55, 1.65, 1.75) were analyzed, aimed to select an optimal Rel.CM value of VNCa images for detecting BME. Then, CT values of the normal areas and BME areas were measured on the VNCa images corresponding to the optimal Rel.CM value for preliminary quantitative analysis. The rank-sum test was used to compare the differences of CT values between BME areas and normal bone marrow areas on the VNCa images. RESULTS The 24 knees were divided into 288 areas. MR Imaging showed BME in 121 areas. The areas under the ROC curve with different Rel.CM values (1.25, 1.35, 1.45, 1.55, 1.65, and 1.75) were 0.633, 0.674, 0.882, 0.684, 0.651, and 0.649, respectively. On the VNCa images of Rel.CM = 1.45, the diagnostic accuracy was the highest (up to 89.2 %), the CT values of the BME area and the normal area were -67.9 (1.7∼-100.1) HU and -94.5 (-69.7∼-144.9) HU, respectively, with statistical significance (Z=-9.804, P < 0.05). CONCLUSIONS The VNCa images with a Rel.CM value of 1.45 is optimal for the detection of BME in knee.
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Affiliation(s)
- Jianchao Liang
- Department of Radiology, the Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China; Department of Radiology, Zhuhai People's Hospital, Zhuhai, 519000, China
| | - Yijie Fang
- Department of Radiology, the Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Yunping Jiang
- Department of Radiology, the Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Yingying Zhan
- Department of Radiology, the Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Guobin Hong
- Department of Radiology, the Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China.
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21
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Accuracy of Dual-Energy CT Virtual Unenhanced and Material-Specific Images: A Phantom Study. AJR Am J Roentgenol 2020; 215:1146-1154. [DOI: 10.2214/ajr.19.22372] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Ma G, Han D, Dang S, Yu N, Yang Q, Yang C, Jin C, Dou Y. Replacing true unenhanced imaging in renal carcinoma with virtual unenhanced images in dual-energy spectral CT: a feasibility study. Clin Radiol 2020; 76:81.e21-81.e27. [PMID: 32993881 DOI: 10.1016/j.crad.2020.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 08/21/2020] [Indexed: 11/18/2022]
Abstract
AIM To investigate the clinical value of virtual unenhanced (VNC) spectral computed tomography (CT) images to replace the conventional true unenhanced spectral CT images (TNC) in diagnosing renal carcinoma. MATERIALS AND METHODS Fifty-six cases of renal carcinoma confirmed by histopathology underwent conventional plain CT and contrast-enhanced spectral CT at arterial phase (AP) and venous phase (VP). VNC images were generated on an AW4.6 workstation. The CT attenuation, image noise, contrast-to-noise ratio (CNR), and signal-noise-ratio (SNR) of the renal lesions and normal kidneys, long and short axis diameters of the lesion were measured from the three image sets and analysed using one-way analysis of variance (ANOVA). Two radiologists evaluated image quality subjectively using a five-point score, and lesion signature using a three-point score. Image quality scores were compared statistically and tested for consistency. RESULTS The two reviewers had good agreement for subjective evaluation (Kappa>0.70) and there was no difference in the quality of the scores among the three image groups. The lesion signature scores were all above the acceptable level. The CNR and SNR values in VNC were significantly higher than in TNC (p<0.05). VNC images had lower renal noise than in TNC (p<0.05). There was no difference in the long and short axis diameters of the lesion among the three image groups. VNC had higher CT attenuation values for the lesion and kidney than TNC (p<0.05), but the differences were <5 HU. CONCLUSION VNC images in spectral CT may be used to replace the conventional plain CT to reduce imaging duration and radiation dose in diagnosing renal carcinoma.
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Affiliation(s)
- G Ma
- Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, China
| | - D Han
- Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, China
| | - S Dang
- Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, China
| | - N Yu
- Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, China
| | - Q Yang
- Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, China
| | - C Yang
- Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, China
| | - C Jin
- Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Yanta Western Road, Xi'an, Shannxi, 710061, China
| | - Y Dou
- Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, China.
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Diamond M, Shin D, Wang J, Samuelsen B, LeBedis C. Imaging of Nontraumatic Upper Urinary Tract Emergencies. Semin Roentgenol 2020; 55:180-196. [PMID: 32438979 DOI: 10.1053/j.ro.2019.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Donghoon Shin
- Department of Radiology, Boston Medical Center, Boston, MA
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Manoharan D, Sharma S, Das CJ, Kumar R, Kumar P. Split bolus dual-energy CT urography after urine dilution: a one-stop shop for detection and characterisation of urolithiasis. Clin Radiol 2020; 75:643.e11-643.e18. [PMID: 32345438 DOI: 10.1016/j.crad.2020.03.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 03/11/2020] [Indexed: 10/24/2022]
Abstract
AIM To determine the diagnostic performance of split-bolus dual-energy computed tomography (CT) urography (SBDECTU) in the detection and characterisation of urolithiasis. MATERIALS AND METHODS This single-centre Institute Ethics Committee (IEC)-approved prospective study was conducted from April 2014 to November 2015. One hundred and thirty consenting adults with microscopic haematuria underwent dual-energy true non-enhanced CT (DETNE) of the whole abdomen followed by a SBDECTU. The SBDECTU protocol consisted of synchronous nephrogram-urogram acquisition following urine dilution by oral hydration and normal saline injection. Calculi were detected and characterised using virtual non-enhanced (VNE) images derived from SBDECT were compared with DETNE (the reference standard). The subjective image quality and radiation dose were compared. RESULTS Twenty-six participants had one or more calculi (total 129 calculi) detected on DETNE CT. The sensitivity and specificity of VNE on a per-patient basis were 100%. Of the 129 calculi, 118 were detected on VNE, with a sensitivity of 91.47% and an accuracy of 91.47%. Of the calculi, 83.9% (99/118) could be characterised on SBDECTU images. On VNE images, complete iodine subtraction was seen in 73.1% (19/26). By omitting DETNE CT, the mean dose-length product of 537.6±152.9 mGy and volume CT dose index of 10.9±2.9 mGy•cm2 could have been saved. CONCLUSION SBDECTU has high diagnostic accuracy in the detection and characterisation of clinically significant urinary calculi at potentially half the radiation dose.
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Affiliation(s)
- D Manoharan
- Department of Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110049, India
| | - S Sharma
- Department of Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110049, India.
| | - C J Das
- Department of Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110049, India
| | - R Kumar
- Department of Urology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110049, India
| | - P Kumar
- Department of Medical Physics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
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Lazar M, Ringl H, Baltzer P, Toth D, Seitz C, Krauss B, Unger E, Polanec S, Tamandl D, Herold CJ, Toepker M. Protocol analysis of dual-energy CT for optimization of kidney stone detection in virtual non-contrast reconstructions. Eur Radiol 2020; 30:4295-4305. [DOI: 10.1007/s00330-020-06806-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 03/02/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022]
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26
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Atwi NE, Sabottke CF, Pitre DM, Smith DL, Danrad R, Dharaiya E, Kambadakone A, Pandharipande PV, Toshav AM. Follow-up Recommendation Rates Associated With Spectral Detector Dual-Energy CT of the Abdomen and Pelvis: A Retrospective Comparison to Single-Energy CT. J Am Coll Radiol 2020; 17:940-950. [PMID: 32032553 DOI: 10.1016/j.jacr.2019.12.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/28/2019] [Accepted: 12/30/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND Dual-energy CT image sets have many applications in abdominopelvic imaging but no demonstrated clinical effect. PURPOSE To determine the effect of dual-energy CT iodine maps on abdominopelvic imaging follow-up recommendation rates. MATERIALS AND METHODS Retrospective study of abdominopelvic CTs acquired from April 2017 through June 2018. CT reports were analyzed for radiologic follow-up recommendation and follow-up recommendation reason. Follow-up MRI reports were analyzed for benign or nonbenign diagnosis. CT scans with iodine maps (CTIMs) and conventional CT scans (CCTs) subgroups were compared using χ2 testing. RESULTS In all, 3,221 abdominopelvic CT scans of 2,401 patients (1,326 men, 1,075 women, mean age 54.1 years) were analyzed; 1,423 were CTIMs and 1,798 were CCTs. Follow-up recommendation rates were not significantly different for CTIMs and CCTs (19.5% and 21.4%, respectively, P = .19). Follow-up recommendations because of incomplete diagnosis were significantly lower in CTIMs (9.1%) than in CCTs (11.9%, P = .01). Follow-up recommendations for MRI and PET/CT were significantly lower in CTIMs (9.6%) than CCTs (13.0%, P = .003). Follow-up MRI outcomes (n = 111) were not different between CTIMs (61.2% benign) and CCTs (59.6%, P = .87). CONCLUSION Dual-energy CT iodine maps are associated with decreased follow-up examinations because of incomplete diagnosis and decreased recommendations for follow-up MRI, suggesting that abdominopelvic iodine maps may benefit patient care and decrease institutional cost.
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Affiliation(s)
- Noah E Atwi
- Department of Radiology, LSU Health Sciences Center New Orleans, New Orleans, Louisiana
| | - Carl F Sabottke
- School of Medicine, LSU Health Sciences Center New Orleans, New Orleans, Louisiana
| | - David M Pitre
- School of Medicine, LSU Health Sciences Center New Orleans, New Orleans, Louisiana
| | - David L Smith
- Department of Radiology, LSU Health Sciences Center New Orleans, New Orleans, Louisiana
| | - Raman Danrad
- Clinical Director of MRI, Academic Director of Cardiac Imaging, Department of Radiology, LSU Health Sciences Center New Orleans, New Orleans, Louisiana
| | - Ekta Dharaiya
- Head of CT Clinical Marketing, Philips Healthcare, Cleveland, Ohio
| | - Avinash Kambadakone
- Medical Director, Martha's Vineyard Hospital Imaging, Chief of CT, Massachusetts General Hospital, Boston, Massachusetts
| | - Pari V Pandharipande
- Director, MGH Institute for Technology Assessment; Associate Chair, Integrated Imaging & Imaging Sciences, MGH Radiology; Executive Director, Clinical Enterprise Integration, Mass General Brigham (MGB) Radiology; Associate Professor of Radiology Harvard Medical School; Radiologist, Abdominal Imaging, Massachusetts General Hospital, Boston, Massachusetts
| | - Aran M Toshav
- Program Director of the diagnostic residency, Department of Radiology, LSU Health Sciences Center, New Orleans, Louisiana.
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Siegel MJ, Ramirez-Giraldo JC. Dual-Energy CT in Children: Imaging Algorithms and Clinical Applications. Radiology 2019; 291:286-297. [PMID: 30912717 DOI: 10.1148/radiol.2019182289] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Dual-energy CT enables the simultaneous acquisition of CT images at two different x-ray energy spectra. By acquiring high- and low-energy spectral data, dual-energy CT can provide unique qualitative and quantitative information about tissue composition, allowing differentiation of multiple materials including iodinated contrast agents. The two dual-energy CT postprocessing techniques that best exploit the advantages of dual-energy CT in children are the material-decomposition images (which include virtual nonenhanced, iodine, perfused lung blood volume, lung vessel, automated bone removal, and renal stone characterization images) and virtual monoenergetic images. Clinical applications include assessment of the arterial system, lung perfusion, neoplasm, bowel diseases, renal calculi, tumor response to treatment, and metal implants. Of importance, the radiation exposure level of dual-energy CT is equivalent to or less than that of conventional single-energy CT. In this review, the authors discuss the basic principles of the dual-energy CT technologies and postprocessing techniques and review current clinical applications in the pediatric chest and abdomen.
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Affiliation(s)
- Marilyn J Siegel
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, Mo 63110 (M.J.S.); and Siemens Healthineers, Malvern, Pa (J.C.R.G.)
| | - Juan Carlos Ramirez-Giraldo
- From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, Mo 63110 (M.J.S.); and Siemens Healthineers, Malvern, Pa (J.C.R.G.)
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Odenrick A, Kartalis N, Voulgarakis N, Morsbach F, Loizou L. The role of contrast-enhanced computed tomography to detect renal stones. Abdom Radiol (NY) 2019; 44:652-660. [PMID: 30225609 DOI: 10.1007/s00261-018-1778-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE To investigate the detectability of renal stones in corticomedullary and nephrographic phases on contrast-enhanced computed tomography (CT). METHODS All consecutive patients between January 2012 and February 2016 undergoing CT of the kidneys according to our department's standard four-phase protocol and having at least one stone in the NC-phase (NCP) were included. Fifty patients with altogether 136 stones were eligible. Two radiologists in consensus evaluated the NCP from each examination and documented the number, location, and size of stones. Three abdominal radiologists blinded to the findings of the NCP reviewed independently the corticomedullary and nephrographic phases on two different occasions. They reported the number and location of stones in each kidney. For the inter-observer agreement the intra-class correlation coefficient (ICC) was estimated. The detection rate of renal stones was calculated for the three radiologists and compared between the two contrast-enhanced phases and the results were analyzed with concern to the size of the stones. RESULTS The ICC was 0.86. There was no statistically significant difference between corticomedullary and nephrographic phases (p = 0.94). The detection rate for stones measuring 3-5 mm was 82-88% and 98% for stones ≥ 6 mm. CONCLUSION The detectability of renal stones ≥ 6 mm on contrast-enhanced CT is extremely high. This means that stones with a higher risk of not passing spontaneously can be safely diagnosed.
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Affiliation(s)
- Alice Odenrick
- Division of Radiology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 14186, Stockholm, Sweden.
- Department of Abdominal Radiology, Karolinska University Hospital, Huddinge, 14186, Stockholm, Sweden.
| | - Nikolaos Kartalis
- Division of Radiology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 14186, Stockholm, Sweden
- Department of Abdominal Radiology, Karolinska University Hospital, Huddinge, 14186, Stockholm, Sweden
| | - Nikolaos Voulgarakis
- Division of Radiology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 14186, Stockholm, Sweden
- Department of Abdominal Radiology, Karolinska University Hospital, Huddinge, 14186, Stockholm, Sweden
| | - Fabian Morsbach
- Division of Radiology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 14186, Stockholm, Sweden
- Department of Abdominal Radiology, Karolinska University Hospital, Huddinge, 14186, Stockholm, Sweden
| | - Louiza Loizou
- Division of Radiology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 14186, Stockholm, Sweden
- Department of Abdominal Radiology, Karolinska University Hospital, Huddinge, 14186, Stockholm, Sweden
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Initial exploration of coronary stent image subtraction using dual-layer spectral CT. Eur Radiol 2019; 29:4239-4248. [PMID: 30666447 DOI: 10.1007/s00330-018-5990-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/11/2018] [Accepted: 12/19/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVES This study aimed to investigate the feasibility of coronary stent image subtraction using spectral tools derived from dual-layer spectral computed tomography (CT). METHODS Forty-three patients (65 stents) who underwent coronary CT angiography using dual-layer spectral CT were included. Conventional, 50-keV (kilo electron-volt), 100-keV, and virtual non-contrast (VNC) images were reconstructed from the same cardiac phase. Stents were subtracted on VNC images from conventional (convsub), 100-keV (100-keVsub), and 50-keV (50-keVsub) images. The in-stent lumen diameters were measured on subtraction, conventional, and 100-keV images. Subjective evaluation of reader confidence and subtractive quality was evaluated. Friedman tests were performed to compare in-stent lumen diameters and subjective evaluation among different images. Correlation between stent diameter and subjective evaluation was expressed as Spearman's rank correlation coefficient (rs). The diagnostic accuracy was assessed according to invasive coronary angiography (ICA) performed in 11 patients (20 stents). RESULTS In-stent lumen diameters were significantly larger on subtraction images than those on conventional and 100-keV images (p < 0.05). Higher reader confidence was found on 100-keV, convsub, 100-keVsub, and 50-keVsub images compared with conventional images (p < 0.05). Subtractive quality of 100-keVsub images was better than that of convsub images (p = 0.037). A moderate-to-strong correlation between stent diameter and subjective evaluation was found (rs = 0.527~0.790, p < 0.05). Higher specificity, positive predictive value, and negative predictive value of subtraction images were shown by ICA results. CONCLUSIONS Subtraction images derived from dual-layer spectral CT enhanced in-stent lumen visibility and could potentially improve diagnostic performance for evaluating coronary stents. KEY POINTS • Dual-layer spectral CT enabled good subtractive quality of coronary stents without misregistration artifacts. • Subtraction images could improve in-stent lumen visibility. • Reader confidence and diagnostic performance were enhanced with subtraction images.
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Murray N, Darras KE, Walstra FE, Mohammed MF, McLaughlin PD, Nicolaou S. Dual-Energy CT in Evaluation of the Acute Abdomen. Radiographics 2019; 39:264-286. [DOI: 10.1148/rg.2019180087] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Nicolas Murray
- From the Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 W 12th Ave, Vancouver, BC, Canada V5Z 1M9 (N.M., K.E.D., F.E.W., P.D.M., S.N.); and the Medical Imaging Department, King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Ministry of the National Guard, Health Affairs, Riyadh, Saudi Arabia (M.F.M.)
| | - Kathryn E. Darras
- From the Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 W 12th Ave, Vancouver, BC, Canada V5Z 1M9 (N.M., K.E.D., F.E.W., P.D.M., S.N.); and the Medical Imaging Department, King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Ministry of the National Guard, Health Affairs, Riyadh, Saudi Arabia (M.F.M.)
| | - Frances E. Walstra
- From the Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 W 12th Ave, Vancouver, BC, Canada V5Z 1M9 (N.M., K.E.D., F.E.W., P.D.M., S.N.); and the Medical Imaging Department, King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Ministry of the National Guard, Health Affairs, Riyadh, Saudi Arabia (M.F.M.)
| | - Mohammed F. Mohammed
- From the Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 W 12th Ave, Vancouver, BC, Canada V5Z 1M9 (N.M., K.E.D., F.E.W., P.D.M., S.N.); and the Medical Imaging Department, King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Ministry of the National Guard, Health Affairs, Riyadh, Saudi Arabia (M.F.M.)
| | - Patrick D. McLaughlin
- From the Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 W 12th Ave, Vancouver, BC, Canada V5Z 1M9 (N.M., K.E.D., F.E.W., P.D.M., S.N.); and the Medical Imaging Department, King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Ministry of the National Guard, Health Affairs, Riyadh, Saudi Arabia (M.F.M.)
| | - Savvas Nicolaou
- From the Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 W 12th Ave, Vancouver, BC, Canada V5Z 1M9 (N.M., K.E.D., F.E.W., P.D.M., S.N.); and the Medical Imaging Department, King Saud bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Ministry of the National Guard, Health Affairs, Riyadh, Saudi Arabia (M.F.M.)
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Quantification of Cisplatin Using a Modified 3-Material Decomposition Algorithm at Third-Generation Dual-Source Dual-Energy Computed Tomography. Invest Radiol 2018; 53:673-680. [DOI: 10.1097/rli.0000000000000491] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Li B, Shen C, Chi Y, Yang M, Lou Y, Zhou L, Jia X. MULTI-ENERGY CONE-BEAM CT RECONSTRUCTION WITH A SPATIAL SPECTRAL NONLOCAL MEANS ALGORITHM. SIAM JOURNAL ON IMAGING SCIENCES 2018; 11:1205-1229. [PMID: 30298098 PMCID: PMC6173488 DOI: 10.1137/17m1123237] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Multi-energy computed tomography (CT) is an emerging medical image modality with a number of potential applications in diagnosis and therapy. However, high system cost and technical barriers obstruct its step into routine clinical practice. In this study, we propose a framework to realize multi-energy cone beam CT (ME-CBCT) on the CBCT system that is widely available and has been routinely used for radiotherapy image guidance. In our method, a kVp switching technique is realized, which acquires x-ray projections with kVp levels cycling through a number of values. For this kVp-switching based ME-CBCT acquisition, x-ray projections of each energy channel are only a subset of all the acquired projections. This leads to an undersampling issue, posing challenges to the reconstruction problem. We propose a spatial spectral non-local means (ssNLM) method to reconstruct ME-CBCT, which employs image correlations along both spatial and spectral directions to suppress noisy and streak artifacts. To address the intensity scale difference at different energy channels, a histogram matching method is incorporated. Our method is different from conventionally used NLM methods in that spectral dimension is included, which helps to effectively remove streak artifacts appearing at different directions in images with different energy channels. Convergence analysis of our algorithm is provided. A comprehensive set of simulation and real experimental studies demonstrate feasibility of our ME-CBCT scheme and the capability of achieving superior image quality compared to conventional filtered backprojection-type (FBP) and NLM reconstruction methods.
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Affiliation(s)
- Bin Li
- Department of Biomedical Engineering, Southern Medical University, GuangZhou, Guangdong 510515, China
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Chenyang Shen
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Yujie Chi
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Ming Yang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Yifei Lou
- Department of Mathematical Science, University of Texas at Dallas, Dallas, TX 75080, USA
| | - Linghong Zhou
- Department of Biomedical Engineering, Southern Medical University, GuangZhou, Guangdong 510515, China
| | - Xun Jia
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
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Kosmala A, Weng AM, Heidemeier A, Krauss B, Knop S, Bley TA, Petritsch B. Multiple Myeloma and Dual-Energy CT: Diagnostic Accuracy of Virtual Noncalcium Technique for Detection of Bone Marrow Infiltration of the Spine and Pelvis. Radiology 2017; 286:205-213. [PMID: 28799843 DOI: 10.1148/radiol.2017170281] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To determine the diagnostic performance of dual-energy computed tomography (CT) for detection of bone marrow (BM) infiltration in patients with multiple myeloma by using a virtual noncalcium (VNCa) technique. Materials and Methods In this prospective study, 34 consecutive patients with multiple myeloma or monoclonal gammopathy of unknown significance sequentially underwent dual-energy CT and magnetic resonance (MR) imaging of the axial skeleton. Two independent readers visually evaluated standard CT and color-coded VNCa images for the presence of BM involvement. MR imaging served as the reference standard. Analysis on the basis of the region of interest (ROI) of VNCa CT numbers of infiltrated (n = 75) and normal (n = 170) BM was performed and CT numbers were subjected to receiver operating characteristic analysis to calculate cutoff values. Results In the visual analysis, VNCa images had an overall sensitivity of 91.3% (21 of 23), specificity of 90.9% (10 of 11), accuracy of 91.2% (31 of 34), positive predictive value of 95.5% (21 of 22), and a negative predictive value of 83.3% (10 of 12). ROI-based analysis of VNCa CT numbers showed a significant difference between infiltrated and normal BM (P < .001). Receiver operating characteristic analysis revealed an area under the curve of 0.978. A cutoff of -44.9 HU provided a sensitivity of 93.3% (70 of 75), specificity of 92.4% (157 of 170), accuracy of 92.7% (227 of 245), positive predictive value of 84.3% (70 of 83), and negative predictive value of 96.9% (157 of 162) for the detection of BM infiltration. Conclusion Visual and ROI-based analyses of dual-energy VNCa images had excellent diagnostic performance for assessing BM infiltration in patients with multiple myeloma with precision comparable to that of MR imaging. © RSNA, 2017 Online supplemental material is available for this article.
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Affiliation(s)
- Aleksander Kosmala
- From the Departments of Diagnostic and Interventional Radiology (A.K., A.M.W., A.H., T.A.B., B.P.) and Internal Medicine II (S.K.), University Hospital Würzburg, Oberdürrbacherstr 6, 97080 Würzburg, Germany; and Department of Diagnostic Imaging, Siemens Healthcare, Forchheim, Germany (B.K.)
| | - Andreas Max Weng
- From the Departments of Diagnostic and Interventional Radiology (A.K., A.M.W., A.H., T.A.B., B.P.) and Internal Medicine II (S.K.), University Hospital Würzburg, Oberdürrbacherstr 6, 97080 Würzburg, Germany; and Department of Diagnostic Imaging, Siemens Healthcare, Forchheim, Germany (B.K.)
| | - Anke Heidemeier
- From the Departments of Diagnostic and Interventional Radiology (A.K., A.M.W., A.H., T.A.B., B.P.) and Internal Medicine II (S.K.), University Hospital Würzburg, Oberdürrbacherstr 6, 97080 Würzburg, Germany; and Department of Diagnostic Imaging, Siemens Healthcare, Forchheim, Germany (B.K.)
| | - Bernhard Krauss
- From the Departments of Diagnostic and Interventional Radiology (A.K., A.M.W., A.H., T.A.B., B.P.) and Internal Medicine II (S.K.), University Hospital Würzburg, Oberdürrbacherstr 6, 97080 Würzburg, Germany; and Department of Diagnostic Imaging, Siemens Healthcare, Forchheim, Germany (B.K.)
| | - Stefan Knop
- From the Departments of Diagnostic and Interventional Radiology (A.K., A.M.W., A.H., T.A.B., B.P.) and Internal Medicine II (S.K.), University Hospital Würzburg, Oberdürrbacherstr 6, 97080 Würzburg, Germany; and Department of Diagnostic Imaging, Siemens Healthcare, Forchheim, Germany (B.K.)
| | - Thorsten Alexander Bley
- From the Departments of Diagnostic and Interventional Radiology (A.K., A.M.W., A.H., T.A.B., B.P.) and Internal Medicine II (S.K.), University Hospital Würzburg, Oberdürrbacherstr 6, 97080 Würzburg, Germany; and Department of Diagnostic Imaging, Siemens Healthcare, Forchheim, Germany (B.K.)
| | - Bernhard Petritsch
- From the Departments of Diagnostic and Interventional Radiology (A.K., A.M.W., A.H., T.A.B., B.P.) and Internal Medicine II (S.K.), University Hospital Würzburg, Oberdürrbacherstr 6, 97080 Würzburg, Germany; and Department of Diagnostic Imaging, Siemens Healthcare, Forchheim, Germany (B.K.)
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Abstract
The prevalence of urinary stones in the United States has been described as 1 in 11 persons reporting a history of stones. Imaging plays a crucial role in diagnosis, management, and follow-up for these patients and imaging technology over the last 100 years has advanced as the disease prevalence has increased. CT remains the gold standard for imaging urolithiasis and changes in this technology, with the addition of multidetector CT and dual-energy CT, as well as the changes in utilization of CT, have decreased the radiation dose encountered by patients and allowed for improved stone detection. The use of digital tomography has been introduced for follow-up of recurrent stone formers offering the potential to lower radiation exposure over the course of a patient's lifelong treatment. However, there is still a demand for improved imaging techniques to detect smaller stones and stones in larger patients at lower radiation doses as well as the continued need for the judicious use of all imaging modalities for healthcare cost containment and patient safety.
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Affiliation(s)
- Joanne Dale
- 1 Department of Urology, Duke University Medical Center , Durham, North Carolina
| | - Rajan T Gupta
- 1 Department of Urology, Duke University Medical Center , Durham, North Carolina.,2 Department of Radiology, Duke University Medical Center , Durham, North Carolina
| | - Daniele Marin
- 2 Department of Radiology, Duke University Medical Center , Durham, North Carolina
| | - Michael Lipkin
- 1 Department of Urology, Duke University Medical Center , Durham, North Carolina
| | - Glenn Preminger
- 1 Department of Urology, Duke University Medical Center , Durham, North Carolina
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Patino M, Prochowski A, Agrawal MD, Simeone FJ, Gupta R, Hahn PF, Sahani DV. Material Separation Using Dual-Energy CT: Current and Emerging Applications. Radiographics 2017; 36:1087-105. [PMID: 27399237 DOI: 10.1148/rg.2016150220] [Citation(s) in RCA: 187] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Dual-energy (DE) computed tomography (CT) offers the opportunity to generate material-specific images on the basis of the atomic number Z and the unique mass attenuation coefficient of a particular material at different x-ray energies. Material-specific images provide qualitative and quantitative information about tissue composition and contrast media distribution. The most significant contribution of DE CT-based material characterization comes from the capability to assess iodine distribution through the creation of an image that exclusively shows iodine. These iodine-specific images increase tissue contrast and amplify subtle differences in attenuation between normal and abnormal tissues, improving lesion detection and characterization in the abdomen. In addition, DE CT enables computational removal of iodine influence from a CT image, generating virtual noncontrast images. Several additional materials, including calcium, fat, and uric acid, can be separated, permitting imaging assessment of metabolic imbalances, elemental deficiencies, and abnormal deposition of materials within tissues. The ability to obtain material-specific images from a single, contrast-enhanced CT acquisition can complement the anatomic knowledge with functional information, and may be used to reduce the radiation dose by decreasing the number of phases in a multiphasic CT examination. DE CT also enables generation of energy-specific and virtual monochromatic images. Clinical applications of DE CT leverage both material-specific images and virtual monochromatic images to expand the current role of CT and overcome several limitations of single-energy CT. (©)RSNA, 2016.
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Affiliation(s)
- Manuel Patino
- From the Division of Abdominal Imaging, Department of Radiology (M.P., A.P., M.D.A., F.J.S., R.G., D.V.S.), and Department of Abdominal Imaging and Intervention (P.F.H.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114
| | - Andrea Prochowski
- From the Division of Abdominal Imaging, Department of Radiology (M.P., A.P., M.D.A., F.J.S., R.G., D.V.S.), and Department of Abdominal Imaging and Intervention (P.F.H.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114
| | - Mukta D Agrawal
- From the Division of Abdominal Imaging, Department of Radiology (M.P., A.P., M.D.A., F.J.S., R.G., D.V.S.), and Department of Abdominal Imaging and Intervention (P.F.H.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114
| | - Frank J Simeone
- From the Division of Abdominal Imaging, Department of Radiology (M.P., A.P., M.D.A., F.J.S., R.G., D.V.S.), and Department of Abdominal Imaging and Intervention (P.F.H.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114
| | - Rajiv Gupta
- From the Division of Abdominal Imaging, Department of Radiology (M.P., A.P., M.D.A., F.J.S., R.G., D.V.S.), and Department of Abdominal Imaging and Intervention (P.F.H.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114
| | - Peter F Hahn
- From the Division of Abdominal Imaging, Department of Radiology (M.P., A.P., M.D.A., F.J.S., R.G., D.V.S.), and Department of Abdominal Imaging and Intervention (P.F.H.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114
| | - Dushyant V Sahani
- From the Division of Abdominal Imaging, Department of Radiology (M.P., A.P., M.D.A., F.J.S., R.G., D.V.S.), and Department of Abdominal Imaging and Intervention (P.F.H.), Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114
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Ananthakrishnan L, Rajiah P, Ahn R, Rassouli N, Xi Y, Soesbe TC, Lewis MA, Lenkinski RE, Leyendecker JR, Abbara S. Spectral detector CT-derived virtual non-contrast images: comparison of attenuation values with unenhanced CT. Abdom Radiol (NY) 2017; 42:702-709. [PMID: 28084546 DOI: 10.1007/s00261-016-1036-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE To assess virtual non-contrast (VNC) images obtained on a detection-based spectral detector CT scanner and determine how attenuation on VNC images derived from various phases of enhanced CT compare to those obtained from true unenhanced images. METHODS In this HIPAA compliant, IRB approved prospective multi-institutional study, 46 patients underwent pre- and post-contrast imaging on a prototype dual-layer spectral detector CT between October 2013 and November 2015, yielding 84 unenhanced and VNC pairs (25 arterial, 39 portal venous/nephrographic, 20 urographic). Mean attenuation was measured by one of three readers in the liver, spleen, kidneys, psoas muscle, abdominal aorta, and subcutaneous fat. Equivalence testing was used to determine if the mean difference between unenhanced and VNC attenuation was less than 5, 10, or 15 HU. VNC image quality was assessed on a 5 point scale. RESULTS Mean difference between unenhanced and VNC attenuation was <15 HU in 92.6%, <10 HU in 75.2%, and <5 HU in 44.4% of all measurements. Unenhanced and VNC attenuation were equivalent in all tissues except fat using a threshold of <10 HU difference (p < 0.05). No significant variation was seen between phases. In fat, VNC overestimated the HU relative to unenhanced images. VNC image quality was rated as excellent or good in 84% of arterial phase and 85% of nephrographic phase cases, but only 40% of urographic phase. CONCLUSION VNC images derived from novel dual layer spectral detector CT demonstrate attenuation values similar to unenhanced images in all tissues evaluated except for subcutaneous fat. Further study is needed to determine if attenuation thresholds currently used clinically for common pathology should be adjusted, particularly for lesions containing fat.
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White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 4: Abdominal and Pelvic Applications. J Comput Assist Tomogr 2017; 41:8-14. [PMID: 27824670 DOI: 10.1097/rct.0000000000000546] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This is the fourth of a series of 4 white papers that represent expert consensus documents developed by the Society of Computed Body Tomography and Magnetic Resonance through its task force on dual-energy computed tomography. This article, part 4, discusses DECT for abdominal and pelvic applications and, at the end of each, will offer our consensus opinions on the current clinical utility of the application and opportunities for further research.
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Abstract
Dual-energy CT is being increasingly used for abdominal imaging due to its incremental benefit of material characterization without significant increase in radiation dose. Knowledge of the different dual-energy CT acquisition techniques and image processing algorithms is essential to optimize imaging protocols and understand potential limitations while using dual-energy CT renal imaging such as urinary calculi characterization, assessment of renal masses and in CT urography. This review article provides an overview of the current dual-energy CT techniques and use of dual-energy CT in renal imaging.
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Single- and dual-energy CT of the abdomen: comparison of radiation dose and image quality of 2nd and 3rd generation dual-source CT. Eur Radiol 2016; 27:642-650. [PMID: 27165140 DOI: 10.1007/s00330-016-4383-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 02/10/2016] [Accepted: 04/25/2016] [Indexed: 12/12/2022]
Abstract
OBJECTIVES To compare single-energy (SECT) and dual-energy (DECT) abdominal CT examinations in matched patient cohorts regarding differences in radiation dose and image quality performed with second- and third-generation dual-source CT (DSCT). METHODS We retrospectively analysed 200 patients (100 male, 100 female; mean age 61.2 ± 13.5 years, mean body mass index 27.5 ± 3.8 kg/m2) equally divided into four groups matched by gender and body mass index, who had undergone portal venous phase abdominal CT with second-generation (group A, 120-kV-SECT; group B, 80/140-kV-DECT) and third-generation DSCT (group C, 100-kV-SECT; group D, 90/150-kV-DECT). The radiation dose was normalised for 40-cm scan length. Dose-independent figure-of-merit (FOM) contrast-to-noise ratios (CNRs) were calculated for various organs and vessels. Subjective overall image quality and reader confidence were assessed. RESULTS The effective normalised radiation dose was significantly lower (P < 0.001) in groups C (6.2 ± 2.0 mSv) and D (5.3 ± 1.9 mSv, P = 0.103) compared to groups A (8.8 ± 2.3 mSv) and B (9.7 ± 2.4 mSv, P = 0.102). Dose-independent FOM-CNR peaked for liver, kidney, and portal vein measurements (all P ≤ 0.0285) in group D. Subjective image quality and reader confidence were consistently rated as excellent in all groups (all ≥1.53 out of 5). CONCLUSIONS With both DSCT generations, abdominal DECT can be routinely performed without radiation dose penalty compared to SECT, while third-generation DSCT shows improved dose efficiency. KEY POINTS • Dual-source CT (DSCT) allows for single- and dual-energy image acquisition. • Dual-energy acquisition does not increase the radiation dose in abdominal DSCT. • Third-generation DSCT shows improved dose efficiency compared to second-generation DSCT. • Dose-independent figure-of-merit image contrast was highest with third-generation dual-energy DSCT. • Third-generation DSCT shows improved dose efficiency for SECT and DECT.
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Diagnostic Performance of Split-Bolus Portal Venous Phase Dual-Energy CT Urography in Patients With Hematuria. AJR Am J Roentgenol 2016; 206:1013-22. [DOI: 10.2214/ajr.15.15112] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Single-phase DECT with VNCT compared with three-phase CTU in patients with haematuria. Eur Radiol 2016; 26:3550-7. [DOI: 10.1007/s00330-016-4206-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 12/29/2015] [Accepted: 01/08/2016] [Indexed: 10/22/2022]
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Split-Bolus Portal Venous Phase Dual-Energy CT Urography: Protocol Design, Image Quality, and Dose Reduction. AJR Am J Roentgenol 2016; 205:W492-501. [PMID: 26496571 DOI: 10.2214/ajr.14.13687] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE The purpose of this study is to evaluate the image quality of split-bolus portal venous phase urography and the potential reduction of radiation dose by using a second-generation dual-source dual-energy CT (DECT) scanner. MATERIALS AND METHODS DECT urography was performed in 84 patients. Unenhanced CT was performed 20 minutes after drinking 800 mL of water. The split-bolus protocol consisted of a sequence of injections, as follows: 200 mL of normal saline (2.0 mL/s), 50 mL of contrast medium (2.5 mL/s) at 0 second, 70 mL of contrast medium (2.5 mL/s) at 360 seconds, and a saline flush of 25 mL. The scan was started at 420 seconds. Virtual unenhanced images were reconstructed from contrast-enhanced images. The mean CT density and signal-to-noise ratio (SNR) of the renal parenchyma, vessels, upper urinary tract, normal reference tissues, and tumors were measured for image quantitative analysis. Image quality and opacification of the collecting systems were rated by two radiologists using 3- or 4-point scales. RESULTS The SNR of all measured sites, except the renal pelvis, showed a statistically significant correlation (p < 0.001) between the true unenhanced and virtual unenhanced images. The overall sensitivity of stone detection was 87.5% (28/32) in virtual unenhanced images. Image quality of the renal parenchyma, arteries, and veins was excellent in 59.5%, 75.0%, and 97.6% of cases, respectively. Opacification of the intrarenal collecting systems, proximal, middle, and distal ureters, and bladder was complete in 92.9%, 83.9%, 78.6%, 77.4%, and 26.2% of patients, respectively. Omitting the unenhanced scan can reduce the mean radiation dose from 15.6 to 6.7 mSv. CONCLUSION Portal venous phase split-bolus DECT urography provides sufficient image quality with potential to reduce radiation exposure.
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McCollough CH, Leng S, Yu L, Fletcher JG. Dual- and Multi-Energy CT: Principles, Technical Approaches, and Clinical Applications. Radiology 2015; 276:637-53. [PMID: 26302388 DOI: 10.1148/radiol.2015142631] [Citation(s) in RCA: 922] [Impact Index Per Article: 102.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In x-ray computed tomography (CT), materials having different elemental compositions can be represented by identical pixel values on a CT image (ie, CT numbers), depending on the mass density of the material. Thus, the differentiation and classification of different tissue types and contrast agents can be extremely challenging. In dual-energy CT, an additional attenuation measurement is obtained with a second x-ray spectrum (ie, a second "energy"), allowing the differentiation of multiple materials. Alternatively, this allows quantification of the mass density of two or three materials in a mixture with known elemental composition. Recent advances in the use of energy-resolving, photon-counting detectors for CT imaging suggest the ability to acquire data in multiple energy bins, which is expected to further improve the signal-to-noise ratio for material-specific imaging. In this review, the underlying motivation and physical principles of dual- or multi-energy CT are reviewed and each of the current technical approaches is described. In addition, current and evolving clinical applications are introduced.
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Affiliation(s)
- Cynthia H McCollough
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Shuai Leng
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Lifeng Yu
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Joel G Fletcher
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
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McLaughlin PD, Mallinson P, Lourenco P, Nicolaou S. Dual-Energy Computed Tomography: Advantages in the Acute Setting. Radiol Clin North Am 2015; 53:619-38, vii. [PMID: 26046502 DOI: 10.1016/j.rcl.2015.02.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The aim of this article is to inform and update emergency radiologists in respect of the clinically relevant benefits that dual-energy computed tomography (CT) contributes over conventional single-energy CT in the emergency setting using practical imaging examples. Particular emphasis will be placed on acute gout, bone marrow edema, acute renal colic, acute cardiovascular and neurovascular emergencies aswell as characterization of abdominal incidentalomas. The relevant scientific literature will be summarized and limitations of the technique also will be emphasized to provide the reader with a rounded concept of the current state of technology.
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Affiliation(s)
- Patrick D McLaughlin
- Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 West 12th Avenue, Vancouver V5Z 1M9, Canada.
| | - Paul Mallinson
- Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 West 12th Avenue, Vancouver V5Z 1M9, Canada
| | - Pedro Lourenco
- Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 West 12th Avenue, Vancouver V5Z 1M9, Canada
| | - Savvas Nicolaou
- Department of Radiology, Vancouver General Hospital, University of British Columbia, 899 West 12th Avenue, Vancouver V5Z 1M9, Canada
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Low KTA, Teh HS. CT Urography: An Update in Imaging Technique. CURRENT RADIOLOGY REPORTS 2015. [DOI: 10.1007/s40134-015-0110-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Diagnostic efficiency of split-bolus dual-energy computed tomography for patients with suspected urinary stones. J Comput Assist Tomogr 2015; 39:25-31. [PMID: 25247691 DOI: 10.1097/rct.0000000000000151] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The objective of this study was to evaluate the efficiency of virtual noncontrast image (VNCI) generated from dual-energy split-bolus computed tomographic urography (DE-SBCTU) for urinary stones detection. METHODS Three hundred fifty-six patients underwent true noncontrast image (TNCI) and DE-SBCTU. Two radiologists evaluated opacification scores of DE-SBCTU as well as iodine subtractions and image noise on VNCI. Diagnostic performance of the VNCI was evaluated using TNCI as a reference standard, according to diameter and image quality. The results were compared between patient groups with body mass index of less than 25 and 25 kg/m2 or greater. RESULTS Agreements for opacification, iodine subtraction, and image noise between the radiologists were excellent, and there were no significant difference in the 2 patients groups. A total of 499 stones were detected on VNCI, with a sensitivity and diagnostic accuracy of 95.1% (468/492) and 92.9% (499/537). Mean (SD) diameter was significantly smaller on VNCI (3.6 [2.3] mm) than on TNCI (4.4 [2.0] mm) (P = 0.01). The stone diameter with false interpretation was less than 4 mm in 48 of 51 patients. The diameter and image quality on VNCI had no significant difference between the 2 patients groups. CONCLUSIONS Virtual noncontrast image displays high accuracy for detecting urinary stones, regardless of body mass index.
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