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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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Shibata H, Matsubara K, Asada Y, Takemura A, Kozawa I. Physical and visual evaluations of CT image quality of large low-contrast objects with visual model-based iterative reconstruction technique: a phantom study. Phys Eng Sci Med 2023; 46:141-150. [PMID: 36508073 DOI: 10.1007/s13246-022-01205-4] [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: 12/30/2021] [Accepted: 11/30/2022] [Indexed: 12/14/2022]
Abstract
We aimed to verify whether the image quality of large low-contrast objects can be improved using visual model-based iterative reconstruction (VMR) while maintaining the visibility of conventional filtered back projection (FBP) and reducing radiation dose through physical and visual evaluation. A 64-row multi-slice CT system with SCENARIA View (FUJIFILM healthcare Corp. Tokyo, Japan) was used. The noise power spectrum (NPS), task-based transfer function (TTF), and signal-to-noise ratio (SNR) were physically evaluated. A low contrast object as a substitute for a liver mass was visually evaluated. In the noise measurement, STD1 showed an 18% lower noise compared to FBP. STR4 was able to reduce noise by 58% compared to FBP. The NPS of VMR was similar to those of FBP from low to high spatial frequency. The NPS of VMR reconstructions showed a similar variation with frequency as FBP reconstructions. STD1 showed the highest 10% TTF, and higher 10% TTF was observed with lower VMR level. The SNR of VMR was close to that of FBP, and higher SNR was observed with higher VMR level. In the results of the visual evaluation, there was no significant difference in visual evaluation between STD1 and FBP (p = 0.99) and between STD2 and FBP (p = 0.56). We found that the NPS of VMR images was similar to that of FBP images, and it can reduce noise and radiation dose by 25% and 50%, respectively, without decreasing the visual image quality compared to FBP.
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Affiliation(s)
- Hideki Shibata
- Department of Radiological Technology, Toyota Kosei Hospital, 500-1 Ibobara Josui, Toyota, Aichi, 470-0396, Japan.
- Department of Quantum Medical Technology, Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 920-0942, Japan.
| | - Kosuke Matsubara
- Department of Quantum Medical Technology, Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 920-0942, Japan
| | - Yasuki Asada
- School of Health Sciences, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Akihiro Takemura
- Department of Quantum Medical Technology, Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 920-0942, Japan
| | - Isao Kozawa
- Department of Radiological Technology, Toyota Kosei Hospital, 500-1 Ibobara Josui, Toyota, Aichi, 470-0396, Japan
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Dahm P, Koziarz A, Gerardo CJ, Nishijima DK, Jung JH, Benipal S, Raja AS. A systematic review and meta‐analysis of clinical signs, symptoms, and imaging findings in patients with suspected renal colic. J Am Coll Emerg Physicians Open 2022; 3:e12831. [DOI: 10.1002/emp2.12831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 09/18/2022] [Accepted: 09/22/2022] [Indexed: 12/04/2022] Open
Affiliation(s)
- Philipp Dahm
- Urology Section Minneapolis VA Medical Center and Department of Urology University of Minnesota Minneapolis Minnesota USA
| | - Alex Koziarz
- Faculty of Medicine University of Toronto Toronto Ontario Canada
| | - Charles J. Gerardo
- Department of Emergency Medicine Duke University Medical Center Durham North Carolina USA
| | - Daniel K. Nishijima
- Department of Emergency Medicine Davis School of Medicine University of California Sacramento California USA
| | - Jae Hung Jung
- Department of Urology Yonsei University Wonju College of Medicine Wonju Gangwon‐do South Korea
| | - Simranjeet Benipal
- College of Medicine California Northstate University Elk Grove California USA
| | - Ali S. Raja
- Department of Emergency Medicine Massachusetts General Hospital and Harvard Medical School Boston Massachusetts USA
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Xu J, Wang S, Wang X, Wang Y, Xue H, Yan J, Xu M, Jin Z. Effects of contrast enhancement boost postprocessing technique in combination with different reconstruction algorithms on the image quality of abdominal CT angiography. Eur J Radiol 2022; 154:110388. [DOI: 10.1016/j.ejrad.2022.110388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 05/22/2022] [Accepted: 05/30/2022] [Indexed: 12/24/2022]
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Value of deep learning reconstruction at ultra-low-dose CT for evaluation of urolithiasis. Eur Radiol 2022; 32:5954-5963. [PMID: 35357541 DOI: 10.1007/s00330-022-08739-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 12/31/2022]
Abstract
OBJECTIVES To determine the diagnostic accuracy and image quality of ultra-low-dose computed tomography (ULDCT) with deep learning reconstruction (DLR) to evaluate patients with suspected urolithiasis, compared with ULDCT with hybrid iterative reconstruction (HIR) by using low-dose CT (LDCT) with HIR as the reference standard. METHODS Patients with suspected urolithiasis were prospectively enrolled and underwent abdominopelvic LDCT, followed by ULDCT if any urinary stone was observed. Radiation exposure, stone characteristics, image noise, signal-to-noise ratio (SNR), and subjective image quality on a 5-point Likert scale were evaluated and compared. RESULTS The average effective radiation dose of ULDCT was significantly lower than that of LDCT (1.28 ± 0.34 vs. 5.49 ± 1.00 mSv, p < 0.001). According to the reference standard (LDCT-HIR), 148 urinary stones were observed in 85.0% (51/60) of patients. ULDCT-DLR detected 143 stones with a rate of 96.6%, and ULDCT-HIR detected 142 stones with a rate of 95.9%. The urinary stones that were not observed with ULDCT-DLR or ULDCT-HIR were renal calculi smaller than 3 mm. There were no significant differences in the detection of clinically significant calculi (≥ 3 mm) or stone size estimation among ULDCT-DLR, ULDCT-HIR, and LDCT-HIR. The image quality of ULDCT-DLR was better than that of ULDCT-HIR and LDCT-HIR with lower image noise, higher SNR, and higher average subjective score. CONCLUSIONS ULDCT-DLR performed comparably to LDCT-HIR in urinary stone detection and size estimation with better image quality and decreased radiation exposure. ULDCT-DLR may have potential to be considered the first-line choice to evaluate urolithiasis in practice. KEY POINTS • Ultra-low-dose computed tomography (ULDCT) has been investigated for diagnosis of urolithiasis, but stone evaluation may be adversely impacted by compromised image quality. • This study evaluated the value of novel deep learning reconstruction (DLR) at ULDCT by comparing the stone evaluation and image quality of ULDCT-DLR to the reference standard of low-dose CT (LDCT) with hybrid iterative reconstruction (HIR). • ULDCT-DLR performed comparably to LDCT-HIR in urinary stone detection and size estimation with better image quality and reduced radiation exposure.
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Lee YJ, Hwang JY, Ryu H, Kim TU, Kim YW, Park JH, Choo KS, Nam KJ, Roh J. Image quality and diagnostic accuracy of reduced-dose computed tomography enterography with model-based iterative reconstruction in pediatric Crohn's disease patients. Sci Rep 2022; 12:2147. [PMID: 35140296 PMCID: PMC8828853 DOI: 10.1038/s41598-022-06246-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 01/18/2022] [Indexed: 11/09/2022] Open
Abstract
This study assessed the image quality and diagnostic accuracy in determining disease activity of the terminal ileum of the reduced-dose computed tomography enterography using model-based iterative reconstruction in pediatric patients with Crohn's disease (CD). Eighteen patients were prospectively enrolled and allocated to the standard-dose (SD) and reduced-dose (RD) computed tomography enterography (CTE) groups (n = 9 per group). Image quality, reader confidence in interpreting bowel findings, accuracy in determining active CD in the terminal ileum, and radiation dose were evaluated. Objective image quality did not show intergroup differences, except for image sharpness. Although reader confidence in detecting mural stratification, ulcer, and perienteric fat stranding of the RD-CTE were inferior to SD-CTE, RD-CTE correctly diagnosed active disease in all patients. The mean values of radiation dose metrics (SD-CTE vs. RD-CTE) were 4.3 versus 0.74 mGy, 6.1 versus 1.1 mGy, 211.9 versus 34.5 mGy∙cm, and 4.4 versus 0.7 mSv mGy∙cm for CTDIvol, size-specific dose estimation, dose-length product, and effective dose, respectively. RD-CTE showed comparable diagnostic accuracy to SD-CTE in determining active disease of the terminal ileum in pediatric CD patients. However, image quality and reader confidence in detecting ulcer and perienteric fat stranding was compromised.
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Affiliation(s)
- Yeoun Joo Lee
- Department of Pediatrics, Pusan National University Children's Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea
| | - Jae-Yeon Hwang
- Department of Radiology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea.
| | - Hwaseong Ryu
- Department of Radiology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea
| | - Tae Un Kim
- Department of Radiology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea
| | - Yong-Woo Kim
- Department of Radiology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea
| | - Jae Hong Park
- Department of Pediatrics, Pusan National University Children's Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea
| | - Ki Seok Choo
- Department of Radiology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea
| | - Kyung Jin Nam
- Department of Radiology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea
| | - Jieun Roh
- Department of Radiology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, College of Medicine, Pusan National University, Yangsan, 50612, Republic of Korea
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Reimer RP, Klein K, Rinneburger M, Zopfs D, Lennartz S, Salem J, Heidenreich A, Maintz D, Haneder S, Große Hokamp N. Manual kidney stone size measurements in computed tomography are most accurate using multiplanar image reformatations and bone window settings. Sci Rep 2021; 11:16437. [PMID: 34385563 PMCID: PMC8361194 DOI: 10.1038/s41598-021-95962-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 07/19/2021] [Indexed: 12/26/2022] Open
Abstract
Computed tomography in suspected urolithiasis provides information about the presence, location and size of stones. Particularly stone size is a key parameter in treatment decision; however, data on impact of reformatation and measurement strategies is sparse. This study aimed to investigate the influence of different image reformatations, slice thicknesses and window settings on stone size measurements. Reference stone sizes of 47 kidney stones representative for clinically encountered compositions were measured manually using a digital caliper (Man-M). Afterwards stones were placed in a 3D-printed, semi-anthropomorphic phantom, and scanned using a low dose protocol (CTDIvol 2 mGy). Images were reconstructed using hybrid-iterative and model-based iterative reconstruction algorithms (HIR, MBIR) with different slice thicknesses. Two independent readers measured largest stone diameter on axial (2 mm and 5 mm) and multiplanar reformatations (based upon 0.67 mm reconstructions) using different window settings (soft-tissue and bone). Statistics were conducted using ANOVA ± correction for multiple comparisons. Overall stone size in CT was underestimated compared to Man-M (8.8 ± 2.9 vs. 7.7 ± 2.7 mm, p < 0.05), yet closely correlated (r = 0.70). Reconstruction algorithm and slice thickness did not significantly impact measurements (p > 0.05), while image reformatations and window settings did (p < 0.05). CT measurements using multiplanar reformatation with a bone window setting showed closest agreement with Man-M (8.7 ± 3.1 vs. 8.8 ± 2.9 mm, p < 0.05, r = 0.83). Manual CT-based stone size measurements are most accurate using multiplanar image reformatation with a bone window setting, while measurements on axial planes with different slice thicknesses underestimate true stone size. Therefore, this procedure is recommended when impacting treatment decision.
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Affiliation(s)
- Robert Peter Reimer
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
| | - Konstantin Klein
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Miriam Rinneburger
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - David Zopfs
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Simon Lennartz
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
- Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA, 02114, USA
| | - Johannes Salem
- Department of Urology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Axel Heidenreich
- Department of Urology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - David Maintz
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Stefan Haneder
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Nils Große Hokamp
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
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Papadakis AE, Damilakis J. The effect of tube focal spot size and acquisition mode on task-based image quality performance of a GE revolution HD dual energy CT scanner. Phys Med 2021; 86:75-81. [PMID: 34062336 DOI: 10.1016/j.ejmp.2021.05.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/05/2021] [Accepted: 05/17/2021] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To assess the task-based performance of images obtained under different focal spot size and acquisition mode on a dual-energy CT scanner. METHODS Axial CT image series of the Catphan phantom were obtained using a tube focus at different sizes. Acquisitions were performed in standard single-energy, high resolution (HR) and dual-energy modes. Images were reconstructed using conventional and high definition (HD) kernels. Task-based transfer function at the 50% level (TTF50%) for teflon, delrin, low density polyethylene (LDPE) and acrylic, as well as image noise and noise texture, were assessed across all focal spots and acquisition modes using Noise Power Spectrum (NPS) analysis. A non-prewhitening mathematical observer model was used to calculate detectability index (dNPW'). RESULTS TTF50% degraded with increasing focal spot size. TTF50% ranged from 0.67 mm-1 for teflon to 0.25 mm-1 for acrylic. For standard kernel, image noise and NPS-determined average spatial frequency were 8.3 HU and 0.29 mm-1, respectively in single-energy, 12.0 HU and 0.37 mm-1 in HR, and 7.9 HU and 0.26 mm-1 in dual-energy mode. For standard kernel, dNPW' was 61 in single-energy and HR mode and reduced to 56 in dual-energy mode. CONCLUSIONS The task-based image quality assessment metrics have shown that spatial resolution is higher for higher image contrast materials and detectability is higher in the standard single-energy mode compared to HR and dual-energy mode. The results of the current study provide CT operators the required knowledge to characterize their CT system towards the optimization of its clinical performance.
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Affiliation(s)
- Antonios E Papadakis
- Medical Physics Department, University General Hospital of Heraklion, Stavrakia 71110, Crete, Greece.
| | - John Damilakis
- Medical Physics Department, University General Hospital of Heraklion, Stavrakia 71110, Crete, Greece
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Eddy FK, Ngano SO, Jervé FA, Serge A. Optimization of the scan length of head traumas on the pediatric and adult CT scan and proposition of a new acquisition limit. Sci Rep 2021; 11:10958. [PMID: 34040095 PMCID: PMC8155083 DOI: 10.1038/s41598-021-90529-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 05/10/2021] [Indexed: 11/15/2022] Open
Abstract
To propose a new method of reducing the scan length of head trauma while keeping the diagnostic efficiency of the examination in order to develop DRL in an African context. This is a retrospective single-center study including 145 patients who had cranial examinations on a 64-barettes scanner. All head trauma cases were selected. The interpretations of these CT scanners by the three radiologists of the service were noted to determine the acquisition limit. All patient acquisition lengths have been recorded. The acquisition limit for head trauma ended in clinical routine at cervical spine 4 (C4). The average scan length was 23.03 cm. Out of the CT scan results for 145 patients, only 2 (1.37%) had a C3 level cervical spine fracture and 2 (1.37%) at C4. By respecting the principles of radiation protection, this result has shown us that it is possible to limit the acquisition length of the CT scanners indicated for head trauma. The limit of the optimized scan length that we proposed is at cervical spine 2 (98.62%). Now, all head trauma are limited on cervical vertebra 2 in our hospital. The use of this new method is beneficial when the clinical indication of the examination and the type of trauma (multi-trauma) are taken into account. Based on the principles of radiation protection and the clinical indication for the examination, reducing the scan length from C4 to C2 is an effective way to reduce the dose absorbed by the patient.
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Affiliation(s)
- Fotso Kamdem Eddy
- Unité de Recherche de la Matière Condensée, d'Electronique et de Traitement du Signal, Department of Physics, Faculty of Science, University of Dschang, Dschang, Cameroon.
| | - Samba Odette Ngano
- Unité de Recherche de la Matière Condensée, d'Electronique et de Traitement du Signal, Department of Physics, Faculty of Science, University of Dschang, Dschang, Cameroon
- Department of Radiography, Yaoundé General Hospital, Yaoundé, Cameroon
| | - Fotue Alain Jervé
- Unité de Recherche de la Matière Condensée, d'Electronique et de Traitement du Signal, Department of Physics, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Abogo Serge
- Department of Radiology, National Social Insurance Fund Hospital, Yaoundé, Cameroon
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Deep learning-based denoising algorithm in comparison to iterative reconstruction and filtered back projection: a 12-reader phantom study. Eur Radiol 2021; 31:8755-8764. [PMID: 33885958 DOI: 10.1007/s00330-021-07810-3] [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: 09/25/2020] [Revised: 01/02/2021] [Accepted: 02/17/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES (1) To compare low-contrast detectability of a deep learning-based denoising algorithm (DLA) with ADMIRE and FBP, and (2) to compare image quality parameters of DLA with those of reconstruction methods from two different CT vendors (ADMIRE, IMR, and FBP). MATERIALS AND METHODS Using abdominal CT images of 100 patients reconstructed via ADMIRE and FBP, we trained DLA by feeding FBP images as input and ADMIRE images as the ground truth. To measure the low-contrast detectability, the randomized repeat scans of Catphan® phantom were performed under various conditions of radiation exposures. Twelve radiologists evaluated the presence/absence of a target on a five-point confidence scale. The multi-reader multi-case area under the receiver operating characteristic curve (AUC) was calculated, and non-inferiority tests were performed. Using American College of Radiology CT accreditation phantom, contrast-to-noise ratio, target transfer function, noise magnitude, and detectability index (d') of DLA, ADMIRE, IMR, and FBPs were computed. RESULTS The AUC of DLA in low-contrast detectability was non-inferior to that of ADMIRE (p < .001) and superior to that of FBP (p < .001). DLA improved the image quality in terms of all physical measurements compared to FBPs from both CT vendors and showed profiles of physical measurements similar to those of ADMIRE. CONCLUSIONS The low-contrast detectability of the proposed deep learning-based denoising algorithm was non-inferior to that of ADMIRE and superior to that of FBP. The DLA could successfully improve image quality compared with FBP while showing the similar physical profiles of ADMIRE. KEY POINTS • Low-contrast detectability in the images denoised using the deep learning algorithm was non-inferior to that in the images reconstructed using standard algorithms. • The proposed deep learning algorithm showed similar profiles of physical measurements to advanced iterative reconstruction algorithm (ADMIRE).
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Papadakis AE, Damilakis J. Technical Note: Quality assessment of virtual monochromatic spectral images on a dual energy CT scanner. Phys Med 2021; 82:114-121. [DOI: 10.1016/j.ejmp.2021.01.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/26/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022] Open
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Effect of New Model-Based Iterative Reconstruction on Quantitative Analysis of Airway Tree by Computer-Aided Detection Software in Chest Computed Tomography. J Comput Assist Tomogr 2021; 45:166-170. [PMID: 31929380 DOI: 10.1097/rct.0000000000000975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Compared the performance of computer-aided detection (CAD) software for quantitative analysis of airway using computed tomography (CT) images reconstructed with versions of model-based iterative reconstruction (MBIR) that either balances spatial and density resolution (MBIRSTND) or prefers spatial resolution (MBIRRP20), and adaptive statistical iterative reconstruction (ASIR) with lung kernel. METHODS Thirty patients were included who were scanned for pulmonary disease using a routine dose multidetector CT system. Data were reconstructed with ASIR, MBIRSTND, and MBIRRP20. Airway dimensions from the 3 reconstructions were measured using an automated, quantitative CAD software designed to segment and quantify the bronchial tree automatically using a skeletonization algorithm. For each patient and reconstruction algorithm, the right middle lobe bronchus was selected as a representative for measuring the bronchial length of the matched airways. Two radiologists used a semiquantitative 5-point scale to rate the subjective image quality of MBIRSTND and MBIRRP20 reconstructions on airway trees analysis. RESULTS Algorithm impacts the measurement variability of bronchus length in chest CT, MBIRRP20 were the best, whereas ASIR were the worst (P < 0.05). In addition, the optimal reconstruction algorithm was found to be MBIRSTND for the airway trees being assessed about subjective noise and MBIRRP20 about bronchial end shows, and there were no significant differences in the continuity and completeness of bronchial wall, whereas ASIR performed inferiorly compared with them (P < 0.05). CONCLUSIONS Compared with ASIR, MBIRSTND, and MBIRRP20 from MBIRn algorithm potentially allow the desired airway quantification accuracy to be achieved on the performance of CAD, especially for MBIRRP20.
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Diagnostic value of deep learning reconstruction for radiation dose reduction at abdominal ultra-high-resolution CT. Eur Radiol 2021; 31:4700-4709. [PMID: 33389036 DOI: 10.1007/s00330-020-07566-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/01/2020] [Accepted: 11/26/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVES We evaluated lower dose (LD) hepatic dynamic ultra-high-resolution computed tomography (U-HRCT) images reconstructed with deep learning reconstruction (DLR), hybrid iterative reconstruction (hybrid-IR), or model-based IR (MBIR) in comparison with standard-dose (SD) U-HRCT images reconstructed with hybrid-IR as the reference standard to identify the method that allowed for the greatest radiation dose reduction while preserving the diagnostic value. METHODS Evaluated were 72 patients who had undergone hepatic dynamic U-HRCT; 36 were scanned with the standard radiation dose (SD group) and 36 with 70% of the SD (lower dose [LD] group). Hepatic arterial and equilibrium phase (HAP, EP) images were reconstructed with hybrid-IR in the SD group, and with hybrid-IR, MBIR, and DLR in the LD group. One radiologist recorded the standard deviation of attenuation in the paraspinal muscle as the image noise. The overall image quality was assessed by 3 other radiologists; they used a 5-point confidence scale ranging from 1 (unacceptable) to 5 (excellent). Superiority and equivalence with prespecified margins were assessed. RESULTS With respect to the image noise, in the HAP and EP, LD DLR and LD MBIR images were superior to SD hybrid-IR images; LD hybrid-IR images were neither superior nor equivalent to SD hybrid-IR images. With respect to the quality scores, only LD DLR images were superior to SD hybrid-IR images. CONCLUSIONS DLR preserved the quality of abdominal U-HRCT images even when scanned with a reduced radiation dose. KEY POINTS • Lower dose DLR images were superior to the standard-dose hybrid-IR images quantitatively and qualitatively at abdominal U-HRCT. • Neither hybrid-IR nor MBIR may allow for a radiation dose reduction at abdominal U-HRCT without compromising the image quality. • Because DLR allows for a reduction in the radiation dose and maintains the image quality even at the thinnest slice section, DLR should be applied to abdominal U-HRCT scans.
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Size and volume of kidney stones in computed tomography: Influence of acquisition techniques and image reconstruction parameters. Eur J Radiol 2020; 132:109267. [PMID: 32949914 DOI: 10.1016/j.ejrad.2020.109267] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/31/2022]
Abstract
PURPOSE Computed tomography (CT) is routinely used to assess suspected urolithiasis. Information obtained from CT include presence, location and size of stones, with the latter frequently determining treatment strategy. While there is consensus regarding measurements procedures of kidney stones, influence of radiation dose and reconstruction techniques on stone measurements are unknown. The purpose of this study was to systematically evaluate the influence of these technical determinants on kidney stone size measurements. METHOD 47 kidney stones of different composition were scanned using a 64-row-multi-detector CT in a 3D-printed, semi-anthropomorphic phantom. Reference stone sizes were measured manually with a digital caliper (Man-M). Stones were imaged with 2 and 10 mGy CTDI. Images were reconstructed using filtered-back-projection, hybrid-iterative and model-based-iterative reconstruction algorithms (FBP, HIR, MBIR) in combination with different kernels and denoising levels. All stones underwent semi-automatic, threshold-based segmentation for computation of maximum diameter and volume. Statistics were conducted using ANOVA ± correction for multiple comparisons. RESULTS Overall stone size as compared to manual measurements was overestimated in CT (10.0 ± 3.1 vs. 8.8 ± 2.9 mm, p < 0.05) yet showing a good correlation (R2 = 0.66). Radiation dose and denoising levels did not significantly influence measurements (p > 0.05). MBIR and sharp kernels showed closest agreement with Man-M (9.3 ± 3.1 vs. 8.8 ± 2.9 mm, p < 0.05). Differences within single stones were as high as 40 % (e.g. Man-M: 5.9 mm, CT: 7.3-12.0 mm). CONCLUSIONS CT-based measurements of kidney stone size appear unaffected by radiation dose and denoising technique, whereas reconstruction algorithms and kernels demonstrate a relevant impact on size measurements. Smallest differences were found using MBIR with a sharp kernel.
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Uldin H, McGlynn E, Cleasby M. Using the T11 vertebra to minimise the CT-KUB scan field. Br J Radiol 2020; 93:20190771. [PMID: 32208971 PMCID: PMC10993226 DOI: 10.1259/bjr.20190771] [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: 09/06/2019] [Revised: 03/12/2020] [Accepted: 03/16/2020] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Computed tomography scans of the kidney, ureters, and bladder (CT-KUB) are crucial in investigating urinary calculi but impart a substantial radiation doses. Radiation can be limited by minimising the scanning field to the necessary area (i.e. from the kidneys to urethra). Before auditing, the superior limit of CT-KUB scans had not been formally clarified at our trust. Consistently ensuring the upper limit of scans is at or below T10 has been shown to be a viable method of performing CT-KUB scans. This study aimed to assess the overscan length of CT-KUB investigations and modify practice accordingly to minimise it. There were two standards that were set for CT-KUB scanning. First, the mean percentage overscan length (i.e. percentage of the scan above the kidneys) should be <15%. Second, all scans should include the superior borders of both kidneys. METHODS 90 consecutive CT-KUB scans for ureteric calculus were retrospectively investigated using IMPAX software in the first phase of data collection. After these data were analysed, a newly devised protocol using T11 as the superior scan limit was delivered to radiographers in the department. and 105 in the second phase (re-audit). The analysis parameters were: percentage overscan length, distance between diaphragm and upper border of kidneys, vertebral level at which the scan commenced, and whether both kidneys were fully included. RESULTS In the first phase, overscan of >15% was present in 94.4% of scans. The mean percentage overscan length was 28.2%. The superior vertebral limit of 59% of scans was at T10 or below and a lower superior vertebral limit correlated with decreasing overscan. 99% of scans fully included both kidneys. In the second phase (3 months later), the mean overscan percentage reduced to 10.6% (standard deviation = 4.4%). Excessive overscan affected 35.2% of scans. The superior vertebral limit of 8% of scans was at T10 or below. 100% of scans fully included both kidneys. CONCLUSION Excessive overscanning was due to inconsistent technique in capturing CT-KUB scans. Before this audit, the superior limit of CT-KUB scans had not been formally clarified at our trust. By successfully standardising the process with a reproducible method, the overscan target was comfortably met. Therefore, patient dose was minimised without compromising scan quality. ADVANCES IN KNOWLEDGE This audit has successfully shown a feasible standardised protocol for CT-KUB investigations which can be used to minimise overscanning of patients.
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Affiliation(s)
- Hasaam Uldin
- Heartlands, Good Hope, and Solihull Hospitals, University
Hospitals Birmingham NHS Foundation Trust,
Birmingham, United Kingdom
| | - Eunan McGlynn
- Heartlands, Good Hope, and Solihull Hospitals, University
Hospitals Birmingham NHS Foundation Trust,
Birmingham, United Kingdom
| | - Morgan Cleasby
- Heartlands, Good Hope, and Solihull Hospitals, University
Hospitals Birmingham NHS Foundation Trust,
Birmingham, United Kingdom
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Sun J, Yang L, Zhou Z, Zhang D, Han W, Zhang Q, Peng Y. Performance evaluation of two iterative reconstruction algorithms, MBIR and ASIR, in low radiation dose and low contrast dose abdominal CT in children. Radiol Med 2020; 125:918-925. [DOI: 10.1007/s11547-020-01191-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 03/30/2020] [Indexed: 12/21/2022]
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A New Class of Smart Gadolinium Contrast Agent for Tissue pH Probing Using Magnetic Resonance Imaging. Molecules 2020; 25:molecules25071513. [PMID: 32225079 PMCID: PMC7180778 DOI: 10.3390/molecules25071513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/13/2020] [Accepted: 03/15/2020] [Indexed: 11/17/2022] Open
Abstract
Detecting tissue pH in vivo is extremely vital for medical diagnosis and formulation of treatment decisions. To this end, many investigations have been carried out to develop an accurate and efficient method of in vivo pH measurement. Most of the techniques developed so far suffer from inadequate accuracy, due to poor sensitivity at low concentration of the target or nonspecific interactions within the tissue matrix. To overcome these issues, we describe herein the development of a simple, yet reliable, way to estimate pH with high precision using a Gd(III)-DOTA-silyl-based acid-labile group as a pH-sensitive contrast agent with Magnetic Resonance Imaging (MRI). With this method, a change in T1 weighted image intensity of the newly developed pH-sensitive contrast is directly linked to the proton concentration in the media. As a result, we were able estimate the pH of the target with 95% reliability.
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Whole-Body Computed Tomography Using Low-Dose Biphasic Injection Protocol With Adaptive Statistical Iterative Reconstruction V: Assessment of Dose Reduction and Image Quality in Trauma Patients. J Comput Assist Tomogr 2019; 43:870-876. [PMID: 31453974 DOI: 10.1097/rct.0000000000000907] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
AIM This study aimed to evaluate potential dose savings on a revised protocol for whole-body computed tomography and image quality after implementing Adaptive Statistical Iterative Reconstruction V (ASiR-V) algorism for trauma patients and compare it with routine protocol. MATERIALS AND METHODS One hundred trauma patients were classified into 2 groups using 2 different scanning protocols. Group A (n = 50; age, 32.48 ± 8.09 years) underwent routine 3-phase protocol. Group B (n = 50; age, 35.94 ± 13.57 years) underwent biphasic injection protocol including unenhanced scan for the brain and cervical spines, followed by a 1-step acquisition of the thorax, abdomen, and pelvis. The ASiR-V level was kept at 50% for all examinations, and then studies were reconstructed at 0% ASiR-V level. Radiation dose, total acquisition time, and image count were compared between groups (A and B). Two radiologists independently graded image quality and artifacts between both groups and 2 ASiR-V levels (0 and 50%). RESULTS The mean (±SD) dose-length product value for postcontrast scans in group A was 1602.3 ± 271.8 mGy · cm and higher when compared with group B (P < 0.001), which was 951.1 ± 359.6 mGy · cm. Biphasic injection protocol gave a dose reduction of 40.4% and reduced the total acquisition time by 11.4% and image count by 37.6%. There was no statistically significant difference between the image quality scores for both groups; however, group A scored higher grades (4.62 ± 0.56 and 4.56 ± 0.67). Similarly, the image quality scores for both ASiR-V levels in both groups were not significantly different. CONCLUSIONS Biphasic computed tomography protocol reduced radiation dose with maintenance of diagnostic accuracy and image quality after implementing ASiR-V algorism.
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Nakamura Y, Higaki T, Tatsugami F, Zhou J, Yu Z, Akino N, Ito Y, Iida M, Awai K. Deep Learning-based CT Image Reconstruction: Initial Evaluation Targeting Hypovascular Hepatic Metastases. Radiol Artif Intell 2019; 1:e180011. [PMID: 33937803 DOI: 10.1148/ryai.2019180011] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 06/03/2019] [Accepted: 07/05/2019] [Indexed: 02/07/2023]
Abstract
Purpose To evaluate the effect of a deep learning-based reconstruction (DLR) method on the conspicuity of hypovascular hepatic metastases on abdominal CT images. Materials and Methods This retrospective study with institutional review board approval included 58 patients with hypovascular hepatic metastases. A radiologist recorded the standard deviation of attenuation in the paraspinal muscle as the image noise and the contrast-to-noise ratio (CNR). CNR was calculated as region of interest ([ROI]L - ROIT)/N, where ROIL is the mean liver parenchyma attenuation, ROIT, the mean tumor attenuation, and N, the noise. Two other radiologists graded the conspicuity of the liver lesion on a five-point scale where 1 is unidentifiable and 5 is detected without diagnostic compromise. Only the smallest liver lesion in each patient, classified as smaller or larger than 10 mm, was evaluated. The difference between hybrid iterative reconstruction (IR) and DLR images was determined by using a two-sided Wilcoxon signed-rank test. Results The image noise was significantly lower, and the CNR was significantly higher on DLR images than hybrid IR images (median image noise: 19.2 vs 12.8 HU, P < .001; median CNR: tumors < 10 mm: 1.9 vs 2.5; tumors > 10 mm: 1.7 vs 2.2, both P < .001). The scores for liver lesions were significantly higher for DLR images than hybrid IR images (P < .01 for both in tumors smaller or larger than 10 mm). Conclusion DLR improved the quality of abdominal CT images for the evaluation of hypovascular hepatic metastases.© RSNA, 2019Supplemental material is available for this article.
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Affiliation(s)
- Yuko Nakamura
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Toru Higaki
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Fuminari Tatsugami
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Jian Zhou
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Zhou Yu
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Naruomi Akino
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Yuya Ito
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Makoto Iida
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Kazuo Awai
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
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Akagi M, Nakamura Y, Higaki T, Narita K, Honda Y, Zhou J, Yu Z, Akino N, Awai K. Deep learning reconstruction improves image quality of abdominal ultra-high-resolution CT. Eur Radiol 2019; 29:6163-6171. [PMID: 30976831 DOI: 10.1007/s00330-019-06170-3] [Citation(s) in RCA: 217] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 02/22/2019] [Accepted: 03/14/2019] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Deep learning reconstruction (DLR) is a new reconstruction method; it introduces deep convolutional neural networks into the reconstruction flow. This study was conducted in order to examine the clinical applicability of abdominal ultra-high-resolution CT (U-HRCT) exams reconstructed with a new DLR in comparison to hybrid and model-based iterative reconstruction (hybrid-IR, MBIR). METHODS Our retrospective study included 46 patients seen between December 2017 and April 2018. A radiologist recorded the standard deviation of attenuation in the paraspinal muscle as the image noise and calculated the contrast-to-noise ratio (CNR) for the aorta, portal vein, and liver. The overall image quality was assessed by two other radiologists and graded on a 5-point confidence scale ranging from 1 (unacceptable) to 5 (excellent). The difference between CT images subjected to hybrid-IR, MBIR, and DLR was compared. RESULTS The image noise was significantly lower and the CNR was significantly higher on DLR than hybrid-IR and MBIR images (p < 0.01). DLR images received the highest and MBIR images the lowest scores for overall image quality. CONCLUSIONS DLR improved the quality of abdominal U-HRCT images. KEY POINTS • The potential degradation due to increased noise may prevent implementation of ultra-high-resolution CT in the abdomen. • Image noise and overall image quality for hepatic ultra-high-resolution CT images improved with deep learning reconstruction as compared to hybrid- and model-based iterative reconstruction.
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Affiliation(s)
- Motonori Akagi
- Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Yuko Nakamura
- Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan.
| | - Toru Higaki
- Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Keigo Narita
- Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Yukiko Honda
- Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Jian Zhou
- Canon Medical Research USA, Inc., Vernon Hills, IL, USA
| | - Zhou Yu
- Canon Medical Research USA, Inc., Vernon Hills, IL, USA
| | | | - Kazuo Awai
- Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
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Jia Y, Ji X, He T, Yu Y, Yu N, Duan H, Guo Y. Quantitative Analysis of Airway Tree in Low-dose Chest CT with a New Model-based Iterative Reconstruction Algorithm: Comparison to Adaptive Statistical Iterative Reconstruction in Routine-dose CT. Acad Radiol 2018; 25:1526-1532. [PMID: 30017502 DOI: 10.1016/j.acra.2018.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/12/2018] [Accepted: 03/19/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVE We aimed to evaluate a new model-based iterative reconstruction (MBIRn) algorithm either with spatial resolution and noise reduction balance (MBIRSTND) or spatial resolution preference (MBIRRP20) for quantitative analysis of airway in low-dose chest computed tomography (CT) with a computer-aided detection (CAD) software, in comparison to adaptive statistical iterative reconstruction (ASIR) in routine-dose CT. METHODS Thirty patients who underwent both the routine-dose (noise index [NI] = 14 HU) and low-dose (at 30% level with NI = 28 HU) CT examination for pulmonary disease were included. Image acquisition was performed with 120 kVp tube voltage and automatic tube current modulation. Routine-dose scans were reconstructed with ASIR, whereas low-dose scans were reconstructed with ASIR, MBIRSTND, and MBIRRP20. Airway dimensions of the right middle lobe bronchus from the four reconstructions were measured using CAD software. Two radiologists used a semiquantitative 5 scoring criteria (-2, inferior to; +2, superior to; -1 slightly inferior to; +1, slightly superior to; and 0, equal to ASIR in routine-dose CT) to rate the subjective image quality of MBIRSTND and MBIRRP20 of airway trees. The paired t test and Wilcoxon signed-rank test were used for statistical comparison. RESULTS The low-dose CT provided 70.76% dose reduction compared to the routine-dose CT (0.88 ± 0.83 mSv vs 3.01 ± 1.89 mSv). MBIRSTND and MBIRRP20 with low-dose CT provided longer bronchial length measurements and were better in measurement variability and continuity and completeness of bronchial walls than ASIR in routine-dose CT (P < .05). MBIRSTND was better for subjective noise and MBIRRP20 for showing distal branches. CONCLUSIONS: MBIRSTND and MBIRRP20 algorithms provide better airway quantification at 30% of the radiation dose, compared to ASIR at routine-dose CT.
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Affiliation(s)
- Yongjun Jia
- Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Yanta Western Road, Xi'an, Shannxi 710061, China; Department of Radiology, Affiliated Hospital of Shaanxi Chinese Medicine University, Xianyang 712000, China
| | - Xing Ji
- Department of Radiology, Affiliated Hospital of Yan'an University, Yan'an 716000, China
| | - Taiping He
- Department of Radiology, Affiliated Hospital of Shaanxi Chinese Medicine University, Xianyang 712000, China
| | - Yong Yu
- Department of Radiology, Affiliated Hospital of Shaanxi Chinese Medicine University, Xianyang 712000, China
| | - Nan Yu
- Department of Radiology, Affiliated Hospital of Shaanxi Chinese Medicine University, Xianyang 712000, China
| | - Haifeng Duan
- Department of Radiology, Affiliated Hospital of Shaanxi Chinese Medicine University, Xianyang 712000, China
| | - Youmin Guo
- Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Yanta Western Road, Xi'an, Shannxi 710061, China.
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Lee RK, Sun JY, Lockerby S, Soltycki E, Matalon T. Reducing Variability of Radiation Dose in CT: The New Frontier in Patient Safety. J Am Coll Radiol 2018; 15:1633-1641. [DOI: 10.1016/j.jacr.2017.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/20/2017] [Accepted: 10/03/2017] [Indexed: 10/18/2022]
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Yan C, Xu J, Liang C, Wei Q, Wu Y, Xiong W, Zheng H, Xu Y. Radiation Dose Reduction by Using CT with Iterative Model Reconstruction in Patients with Pulmonary Invasive Fungal Infection. Radiology 2018; 288:285-292. [DOI: 10.1148/radiol.2018172107] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Chenggong Yan
- From the Department of Medical Imaging Center (C.Y., C.L., Y.W., W.X., H.Z., Y.X.) and Department of Hematology (J.X., Q.W.), Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou 510515, Guangdong, People’s Republic of China
| | - Jun Xu
- From the Department of Medical Imaging Center (C.Y., C.L., Y.W., W.X., H.Z., Y.X.) and Department of Hematology (J.X., Q.W.), Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou 510515, Guangdong, People’s Republic of China
| | - Chunyi Liang
- From the Department of Medical Imaging Center (C.Y., C.L., Y.W., W.X., H.Z., Y.X.) and Department of Hematology (J.X., Q.W.), Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou 510515, Guangdong, People’s Republic of China
| | - Qi Wei
- From the Department of Medical Imaging Center (C.Y., C.L., Y.W., W.X., H.Z., Y.X.) and Department of Hematology (J.X., Q.W.), Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou 510515, Guangdong, People’s Republic of China
| | - Yuankui Wu
- From the Department of Medical Imaging Center (C.Y., C.L., Y.W., W.X., H.Z., Y.X.) and Department of Hematology (J.X., Q.W.), Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou 510515, Guangdong, People’s Republic of China
| | - Wei Xiong
- From the Department of Medical Imaging Center (C.Y., C.L., Y.W., W.X., H.Z., Y.X.) and Department of Hematology (J.X., Q.W.), Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou 510515, Guangdong, People’s Republic of China
| | - Huan Zheng
- From the Department of Medical Imaging Center (C.Y., C.L., Y.W., W.X., H.Z., Y.X.) and Department of Hematology (J.X., Q.W.), Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou 510515, Guangdong, People’s Republic of China
| | - Yikai Xu
- From the Department of Medical Imaging Center (C.Y., C.L., Y.W., W.X., H.Z., Y.X.) and Department of Hematology (J.X., Q.W.), Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou 510515, Guangdong, People’s Republic of China
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Noda Y, Goshima S, Nagata S, Miyoshi T, Kawada H, Kawai N, Tanahashi Y, Matsuo M. Right adrenal vein: comparison between adaptive statistical iterative reconstruction and model-based iterative reconstruction. Clin Radiol 2018; 73:594.e1-594.e6. [DOI: 10.1016/j.crad.2018.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/15/2018] [Indexed: 11/29/2022]
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Rodger F, Roditi G, Aboumarzouk O. Diagnostic Accuracy of Low and Ultra-Low Dose CT for Identification of Urinary Tract Stones: A Systematic Review. Urol Int 2018; 100:375-385. [DOI: 10.1159/000488062] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/01/2018] [Indexed: 12/27/2022]
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Adaptive Statistical Iterative Reconstruction–V Versus Adaptive Statistical Iterative Reconstruction. J Comput Assist Tomogr 2018; 42:191-196. [PMID: 28937493 DOI: 10.1097/rct.0000000000000677] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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den Harder AM, Willemink MJ, van Doormaal PJ, Wessels FJ, Lock MTWT, Schilham AMR, Budde RPJ, Leiner T, de Jong PA. Radiation dose reduction for CT assessment of urolithiasis using iterative reconstruction: A prospective intra-individual study. Eur Radiol 2018; 28:143-150. [PMID: 28695359 PMCID: PMC5717126 DOI: 10.1007/s00330-017-4929-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/05/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To assess the performance of hybrid (HIR) and model-based iterative reconstruction (MIR) in patients with urolithiasis at reduced-dose computed tomography (CT). METHODS Twenty patients scheduled for unenhanced abdominal CT for follow-up of urolithiasis were prospectively included. Routine dose acquisition was followed by three low-dose acquisitions at 40%, 60% and 80% reduced doses. All images were reconstructed with filtered back projection (FBP), HIR and MIR. Urolithiasis detection rates, gall bladder, appendix and rectosigmoid evaluation and overall subjective image quality were evaluated by two observers. RESULTS 74 stones were present in 17 patients. Half the stones were not detected on FBP at the lowest dose level, but this improved with MIR to a sensitivity of 100%. HIR resulted in a slight decrease in sensitivity at the lowest dose to 72%, but outperformed FBP. Evaluation of other structures with HIR at 40% and with MIR at 60% dose reductions was comparable to FBP at routine dose, but 80% dose reduction resulted in non-evaluable images. CONCLUSIONS CT radiation dose for urolithiasis detection can be safely reduced by 40 (HIR)-60 (MIR) % without affecting assessment of urolithiasis, possible extra-urinary tract pathology or overall image quality. KEY POINTS • Iterative reconstruction can be used to substantially lower the radiation dose. • This allows for radiation reduction without affecting sensitivity of stone detection. • Possible extra-urinary tract pathology evaluation is feasible at 40-60% reduced dose.
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Affiliation(s)
- Annemarie M den Harder
- Department of Radiology, Utrecht University Medical Center, P.O. Box 85500, E01.132, 3508GA, Utrecht, The Netherlands.
| | - Martin J Willemink
- Department of Radiology, Utrecht University Medical Center, P.O. Box 85500, E01.132, 3508GA, Utrecht, The Netherlands
| | - Pieter J van Doormaal
- Department of Radiology, Erasmus Medical Center, P.O. Box 2040, 3000CA, Rotterdam, The Netherlands
| | - Frank J Wessels
- Department of Radiology, Utrecht University Medical Center, P.O. Box 85500, E01.132, 3508GA, Utrecht, The Netherlands
| | - M T W T Lock
- Department of Urology, University Medical Center, P.O. Box 85500, 3508GA, Utrecht, The Netherlands
| | - Arnold M R Schilham
- Department of Radiology, Utrecht University Medical Center, P.O. Box 85500, E01.132, 3508GA, Utrecht, The Netherlands
| | - Ricardo P J Budde
- Department of Radiology, Erasmus Medical Center, P.O. Box 2040, 3000CA, Rotterdam, The Netherlands
| | - Tim Leiner
- Department of Radiology, Utrecht University Medical Center, P.O. Box 85500, E01.132, 3508GA, Utrecht, The Netherlands
| | - Pim A de Jong
- Department of Radiology, Utrecht University Medical Center, P.O. Box 85500, E01.132, 3508GA, Utrecht, The Netherlands
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Park JH, Jeon JJ, Lee SS, Dhanantwari AC, Sim JY, Kim HY, Lee KH. Can We Perform CT of the Appendix with Less Than 1 mSv? A De-escalating Dose-simulation Study. Eur Radiol 2017; 28:1826-1834. [DOI: 10.1007/s00330-017-5159-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/13/2017] [Accepted: 10/27/2017] [Indexed: 12/19/2022]
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Iterative Reconstructions in Reduced-Dose CT: Which Type Ensures Diagnostic Image Quality in Young Oncology Patients? Acad Radiol 2017; 24:1114-1124. [PMID: 28365232 DOI: 10.1016/j.acra.2017.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 02/24/2017] [Accepted: 02/24/2017] [Indexed: 12/11/2022]
Abstract
RATIONALE AND OBJECTIVES To compare adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) algorithms for reduced-dose computed tomography (CT). MATERIALS AND METHODS Forty-four young oncology patients (mean age 30 ± 9 years) were included. After routine thoraco-abdominal CT (dose 100%, average CTDIvol 9.1 ± 2.4 mGy, range 4.4-16.9 mGy), follow-up CT was acquired at 50% (average CTDIvol 4.5 ± 1.2 mGy, range 2.2-8.4 mGy) in 29 patients additionally at 20% dose (average CTDIvol 1.9 ± 0.5 mGy, range 0.9-3.4 mGy). Each reduced-dose CT was reconstructed using both ASIR and MBIR. Four radiologists (two juniors and two seniors) blinded to dose and technique read each set of CT images regarding objective and subjective image qualities (high- or low-contrast structures), subjective noise or pixilated appearance, diagnostic confidence, and lesion detection. RESULTS At all dose levels, objective image noise was significantly lower with MBIR than with ASIR (P < 0.001). The subjective image quality for low-contrast structures was significantly higher with MBIR than with ASIR (P < 0.001). Reduced-dose abdominal CT images of patients with higher body mass index (BMI) were read with significantly higher diagnostic confidence than images of slimmer patients (P < 0.001) and had higher subjective image quality, regardless of technique. Although MBIR images appeared significantly more pixilated than ASIR images, they were read with higher diagnostic confidence, especially by juniors (P < 0.001). CONCLUSIONS Reduced-dose CT during the follow-up of young oncology patients should be reconstructed with MBIR to ensure diagnostic quality. Elevated body mass index does not hamper the quality of reduced-dose CT.
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Weisenthal K, Karthik P, Shaw M, Sengupta D, Bhargavan-Chatfield M, Burleson J, Mustafa A, Kalra M, Moore C. Evaluation of Kidney Stones with Reduced-Radiation Dose CT: Progress from 2011-2012 to 2015-2016-Not There Yet. Radiology 2017; 286:581-589. [PMID: 28858562 DOI: 10.1148/radiol.2017170285] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Purpose To determine if the use of reduced-dose computed tomography (CT) for evaluation of kidney stones increased in 2015-2016 compared with that in 2011-2012, to determine variability in radiation exposure according to facility for this indication, and to establish a current average radiation dose for CT evaluation for kidney stones by querying a national dose registry. Materials and Methods This cross-sectional study was exempt from institutional review board approval. Data were obtained from the American College of Radiology dose registry for CT examinations submitted from July 2015 to June 2016. Study descriptors consistent with single-phase unenhanced CT for evaluation of kidney stones and associated RadLex® Playbook identifiers (RPIDs) were retrospectively identified. Facilities actively submitting data on kidney stone-specific CT examinations were included. Dose metrics including volumetric CT dose index, dose-length product, and size-specific dose estimate, when available, were reported, and a random effects model was run to account for clustering of CT examinations at facilities. A z-ratio was calculated to test for a significant difference between the proportion of reduced-radiation dose CT examinations (defined as those with a dose-length product of 200 mGy · cm or less) performed in 2015-2016 and the proportion performed in 2011-2012. Results Three hundred four study descriptors for kidney stone CT corresponding to data from 328 facilities that submitted 105 334 kidney stone CT examinations were identified. Reduced-dose CT examinations accounted for 8040 of 105 334 (7.6%) CT examinations, a 5.6% increase from the 1010 of 49 903 (2%) examinations in 2011-2012 (P < .001). Mean overall dose-length product was 689 mGy · cm (95% confidence interval: 667, 712), decreased from the mean of 746 mGy · cm observed in 2011-2012. Median facility dose-length product varied up to sevenfold, from less than 200 mGy · cm to greater than 1600 mGy · cm. Conclusion Use of reduced-radiation dose CT for evaluation of kidney stones has increased since 2011-2012, but remains low; variability of radiation dose according to facility continues to be wide. National mean CT radiation exposure for evaluation of renal colic during 2015-2016 decreased relative to 2011-2012 values, but remained well above what is reasonably achievable. © RSNA, 2017.
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Affiliation(s)
- Karrin Weisenthal
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
| | - Priyadarshini Karthik
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
| | - Melissa Shaw
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
| | - Debapriya Sengupta
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
| | - Mythreyi Bhargavan-Chatfield
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
| | - Judy Burleson
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
| | - Adel Mustafa
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
| | - Mannudeep Kalra
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
| | - Christopher Moore
- From the Departments of Emergency Medicine, (K.W., M.S., C.M.) and Radiology and Biomedical Imaging (A.M.), Yale School of Medicine, 464 Congress Ave, Suite 273, New Haven, CT 06510; Department of Quality and Safety, American College of Radiology, Reston, Va (P.K., D.S., M.B.C., J.B.); and Department of Radiology, Massachusetts General Hospital, Boston, Mass (M.K.)
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Impact of model-based iterative reconstruction on low-contrast lesion detection and image quality in abdominal CT: a 12-reader-based comparative phantom study with filtered back projection at different tube voltages. Eur Radiol 2017; 27:5252-5259. [DOI: 10.1007/s00330-017-4825-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 02/08/2017] [Accepted: 03/20/2017] [Indexed: 12/21/2022]
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Tenant S, Pang CL, Dissanayake P, Vardhanabhuti V, Stuckey C, Gutteridge C, Hyde C, Roobottom C. Intra-patient comparison of reduced-dose model-based iterative reconstruction with standard-dose adaptive statistical iterative reconstruction in the CT diagnosis and follow-up of urolithiasis. Eur Radiol 2017; 27:4163-4172. [DOI: 10.1007/s00330-017-4783-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/13/2017] [Accepted: 02/16/2017] [Indexed: 01/24/2023]
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Poletti PA, Becker M, Becker CD, Halfon Poletti A, Rutschmann OT, Zaidi H, Perneger T, Platon A. Emergency assessment of patients with acute abdominal pain using low-dose CT with iterative reconstruction: a comparative study. Eur Radiol 2017; 27:3300-3309. [PMID: 28083698 DOI: 10.1007/s00330-016-4712-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/15/2016] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To determine if radiation dose delivered by contrast-enhanced CT (CECT) for acute abdominal pain can be reduced to the dose administered in abdominal radiography (<2.5 mSv) using low-dose CT (LDCT) with iterative reconstruction algorithms. METHODS One hundred and fifty-one consecutive patients requiring CECT for acute abdominal pain were included, and their body mass index (BMI) was calculated. CECT was immediately followed by LDCT. LDCT series was processed using 1) 40% iterative reconstruction algorithm blended with filtered back projection (LDCT-IR-FBP) and 2) model-based iterative reconstruction algorithm (LDCT-MBIR). LDCT-IR-FBP and LDCT-MBIR images were reviewed independently by two board-certified radiologists (Raters 1 and 2). RESULTS Abdominal pathology was revealed on CECT in 120 (79%) patients. In those with BMI <30, accuracies for correct diagnosis by Rater 1 with LDCT-IR-FBP and LDCT-MBIR, when compared to CECT, were 95.4% (104/109) and 99% (108/109), respectively, and 92.7% (101/109) and 100% (109/109) for Rater 2. In patients with BMI ≥30, accuracies with LDCT-IR-FBP and LDCT-MBIR were 88.1% (37/42) and 90.5% (38/42) for Rater 1 and 78.6% (33/42) and 92.9% (39/42) for Rater 2. CONCLUSIONS The radiation dose delivered by CT to non-obese patients with acute abdominal pain can be safely reduced to levels close to standard radiography using LDCT-MBIR. KEY POINTS • LDCT-MBIR (<2.5 mSv) can be used to assess acute abdominal pain. • LDCT-MBIR (<2.5 mSv) cannot safely assess acute abdominal pain in obese patients. • LDCT-IR-FBP (<2.5 mSv) cannot safely assess patients with acute abdominal pain.
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Affiliation(s)
- Pierre-Alexandre Poletti
- Department of Radiology, University Hospital of Geneva, 4 rue Gabrielle Perret-Gentil, 1211, Geneva, Switzerland.
| | - Minerva Becker
- Department of Radiology, University Hospital of Geneva, 4 rue Gabrielle Perret-Gentil, 1211, Geneva, Switzerland
| | - Christoph D Becker
- Department of Radiology, University Hospital of Geneva, 4 rue Gabrielle Perret-Gentil, 1211, Geneva, Switzerland
| | - Alice Halfon Poletti
- Department of Community, Primary Care and Emergency Medicine, University Hospital of Geneva, Geneva, Switzerland
| | - Olivier T Rutschmann
- Department of Community, Primary Care and Emergency Medicine, University Hospital of Geneva, Geneva, Switzerland
| | - Habib Zaidi
- Department of Radiology, University Hospital of Geneva, 4 rue Gabrielle Perret-Gentil, 1211, Geneva, Switzerland
| | - Thomas Perneger
- Division of Clinical Epidemiology, University Hospital of Geneva, Geneva, Switzerland
| | - Alexandra Platon
- Department of Radiology, University Hospital of Geneva, 4 rue Gabrielle Perret-Gentil, 1211, Geneva, Switzerland
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Cha MJ, Jeong WK, Choi D, Kim YK, Lim S, Choi SY, Lee WJ. Iterative reconstruction: comparison of techniques for reduced-dose liver computed tomography following transarterial chemoembolization for hepatocellular carcinoma. Acta Radiol 2016; 57:1429-1437. [PMID: 26792822 DOI: 10.1177/0284185115626472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Background Adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) algorithms have the potential to reduce dose while maintaining image quality. Purpose To compare computed tomography (CT) image quality and diagnostic performance among three reconstruction techniques - ASIR, MBIR, and filtered back projection (FBP) - after transcatheter arterial chemoembolization (TACE) of hepatocellular carcinomas (HCC). Material and Methods Of 60 patients that underwent initial TACE for HCCs, half underwent dynamic liver CT with conventional scanning protocol, and the other half with dose reduction to approximately 60% of conventional exposure. All images were reconstructed using three algorithms: FBP, ASIR, and MBIR. For objective analysis, image noise and signal-to-noise ratio (SNR) were compared. For subjective analysis, three radiologists independently assessed image quality. Ability to detect viable HCCs was also evaluated. Results MBIR and ASIR produced images with less noise and higher SNR compared with FBP regardless of radiation dosage ( P < 0.017). However, in terms of subjective parameters, such as image blotchiness, artifacts, and overall quality, MBIR was inferior to FBP and ASIR ( P < 0.001). Regarding diagnostic performance, there were no significant differences among reviewers in the detection of viable HCCs depending on the reconstruction algorithm, regardless of the dose reduction protocol ( P > 0.017). Conclusion Although subjective evaluations suggest that MBIR images are of lower quality compared with FBP and ASIR regardless of radiation dosage, there were no significant differences among reconstruction algorithms in diagnosis of viable HCC after TACE.
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Affiliation(s)
- Min Jae Cha
- Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Woo Kyoung Jeong
- Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Dongil Choi
- Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Young Kon Kim
- Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Sanghyeok Lim
- Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
- Department of Radiology, Hanyang University College of Medicine, Hanyang University Guri Hospital, Gyeonggi-do, Republic of Korea
| | - Seo-Youn Choi
- Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
- Department of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Gyeonggi-do, Republic of Korea
| | - Won Jae Lee
- Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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Takagi S, Koyama M, Hayashi K, Kawauchi T. Image Quality Required for the Diagnosis of Skull Fractures Using Head CT: A Comparison of Conventional and Improved Reconstruction Kernels. AJNR Am J Neuroradiol 2016; 37:1992-1995. [PMID: 27418472 DOI: 10.3174/ajnr.a4861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 05/05/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Although skull fractures are generally assessed on bone images obtained by using head CT, the combined multikernel technique that enables evaluation of both brain and bone through a change in the window settings of an image set has been reported. The purpose of this retrospective study was to determine the image quality required for the accurate assessment of skull fractures by using head CT. MATERIALS AND METHODS A random sample of 50 patients (25 nonfracture and 25 simple nondisplaced skull fractures) was selected, and sets of conventional brain and bone images and improved combined multikernel images were reconstructed (4614 images). Three radiologists indicated their confidence levels regarding the presence of skull fractures by marking on a continuous scale for each image set. The mean area under the receiver operating characteristic curve was calculated for each kernel, and the statistical significance of differences was tested by using the Dorfman-Berbaum-Metz method. RESULTS Although a difference in the diagnostic performance of the 3 radiologists was suggested, the mean area under the curve value showed no significant differences among the 3 reconstruction kernels (P = .95 [bone versus combined]), P = .91 [bone versus brain]), and P = .88 [brain versus combined]). However, the quality of brain images was distinctly poorer than the quality of the other 2 images. CONCLUSIONS There was no significant difference in the diagnostic performance of brain, bone, and combined multikernel images for skull fractures. Skull fracture diagnosis is made possible by brain image assessments. Combined multikernel images offer the advantage of high-quality brain and bone images.
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Affiliation(s)
- S Takagi
- From the Faculty of Health Sciences (S.T.), Hokkaido University, Hokkaido, Japan
| | - M Koyama
- Radiological Center (M.K.), National Defense Medical College Hospital, Saitama, Japan
| | - K Hayashi
- Department of Radiology (K.H., T.K.), National Defense Medical College, Saitama, Japan
| | - T Kawauchi
- Department of Radiology (K.H., T.K.), National Defense Medical College, Saitama, Japan
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Gervaise A, Teixeira P, Hossu G, Blum A, Lapierre-Combes M. Optimizing z-axis coverage of abdominal CT scans of the urinary tract: a proposed alternative proximal landmark for acquisition planning. Br J Radiol 2016; 89:20160197. [PMID: 27653843 DOI: 10.1259/bjr.20160197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate an alternative method to reduce the acquisition coverage of urinary tract CT. METHODS This retrospective study included 365 abdominopelvic CT studies. Three radiographers simulated shortened acquisition coverages using three methods to determine the upper limit of the acquisition: Method 1 used the renal contours; Method 2 used the inferior margin of the 10th thoracic vertebra; and Method 3 used the point of intersection of the left diaphragmatic dome and the anterior margin of the vertebral bodies. Reductions in acquisition coverage and number of CT scans with a portion of the kidney excluded from the simulated reduced acquisition were compared between the three methods. RESULTS The mean ± standard deviation reduction of acquisition coverage for the three readers with Methods 1, 2 and 3 were 20.5 ± 4.8, 15.1 ± 6.5 and 18.2 ± 5.3%, respectively. Compared with Method 2, Method 3 allowed a mean scan length reduction of 3.6%. The proportions of CT scans with a portion of the kidney excluded from the simulated reduced acquisition with Methods 1, 2 and 3 and averaged over the three readers were 6.7, 0.7 and 1.4%, respectively, with no significant difference between Methods 2 and 3. Interreader and intrareader agreements were excellent with all methods, but interclass correlation coefficients were higher with Method 3. CONCLUSION The method using the renal contours should not be used owing to its high proportion of kidneys with a portion excluded from the acquisition. Using the intersection of the left diaphragmatic dome and the anterior margin of the vertebral bodies for proximal landmark for urinary tract CT represents a new alternative method with a better reduction of scan length compared with the method using the inferior margin of T10 and with no significant increase in the number of kidneys with a portion excluded from the reduced acquisition. Advances in knowledge: A new method using the point of intersection of the left diaphragmatic dome and the anterior border of the vertebral bodies on the lateral scout radiograph is introduced to reduce the z-axis coverage of urinary tract CT scans.
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Affiliation(s)
- Alban Gervaise
- 1 Service d'Imagerie Médicale, HIA Legouest, Metz, France.,2 Service d'Imagerie Guilloz, Hôpital Central, CHRU Nancy, Nancy, France.,3 U947, INSERM, Nancy, France.,4 IADI, Université de Lorraine, Nancy, France
| | - Pedro Teixeira
- 2 Service d'Imagerie Guilloz, Hôpital Central, CHRU Nancy, Nancy, France.,3 U947, INSERM, Nancy, France.,4 IADI, Université de Lorraine, Nancy, France
| | - Gabriela Hossu
- 5 CIC-IT 1433, INSERM, Nancy, France.,6 Pôle S2R, CHRU Nancy, Nancy, France.,7 CIC-IT, Université de Lorraine, Nancy, France
| | - Alain Blum
- 2 Service d'Imagerie Guilloz, Hôpital Central, CHRU Nancy, Nancy, France
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Parakh A, Kortesniemi M, Schindera ST. CT Radiation Dose Management: A Comprehensive Optimization Process for Improving Patient Safety. Radiology 2016; 280:663-73. [DOI: 10.1148/radiol.2016151173] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Hata A, Yanagawa M, Honda O, Gyobu T, Ueda K, Tomiyama N. Submillisievert CT using model-based iterative reconstruction with lung-specific setting: An initial phantom study. Eur Radiol 2016; 26:4457-4464. [PMID: 26988356 DOI: 10.1007/s00330-016-4307-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 02/18/2016] [Accepted: 02/23/2016] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To assess image quality of filtered back-projection (FBP) and model-based iterative reconstruction (MBIR) with a conventional setting and a new lung-specific setting on submillisievert CT. METHODS A lung phantom with artificial nodules was scanned with 10 mA at 120 kVp and 80 kVp (0.14 mSv and 0.05 mSv, respectively); images were reconstructed using FBP and MBIR with conventional setting (MBIRStnd) and lung-specific settings (MBIRRP20/Tx and MBIRRP20). Three observers subjectively scored overall image quality and image findings on a 5-point scale (1 = worst, 5 = best) compared with reference standard images (50 mA-FBP at 120, 100, 80 kVp). Image noise was measured objectively. RESULTS MBIRRP20/Tx performed significantly better than MBIRStnd for overall image quality in 80-kVp images (p < 0.01), blurring of the border between lung and chest wall in 120p-kVp images (p < 0.05) and the ventral area of 80-kVp images (p < 0.001), and clarity of small vessels in the ventral area of 80-kVp images (p = 0.037). At 120 kVp, 10 mA-MBIRRP20 and 10 mA-MBIRRP20/Tx showed similar performance to 50 mA-FBP. MBIRStnd was better for noise reduction. Except for blurring in 120 kVp-MBIRStnd, MBIRs performed better than FBP. CONCLUSION Although a conventional setting was advantageous in noise reduction, a lung-specific setting can provide more appropriate image quality, even on submillisievert CT. KEY POINTS • Lung-specific submillisievert 10 mA-MBIR CT setting has similar performance to 50 mA-FBP • The new lung-specific settings improve vessel clarity and blurring of borders • The new settings may provide more appropriate images than conventional settings.
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Affiliation(s)
- Akinori Hata
- Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, Japan.
| | - Masahiro Yanagawa
- Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Osamu Honda
- Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Tomoko Gyobu
- Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Ken Ueda
- Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, Japan
| | - Noriyuki Tomiyama
- Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, Japan
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Xiao H, Liu Y, Tan H, Liang P, Wang B, Su L, Wang S, Gao J. A pilot study using low-dose Spectral CT and ASIR (Adaptive Statistical Iterative Reconstruction) algorithm to diagnose solitary pulmonary nodules. BMC Med Imaging 2015; 15:54. [PMID: 26576676 PMCID: PMC4647278 DOI: 10.1186/s12880-015-0096-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/25/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lung cancer is the most common cancer which has the highest mortality rate. With the development of computed tomography (CT) techniques, the case detection rates of solitary pulmonary nodules (SPN) has constantly increased and the diagnosis accuracy of SPN has remained a hot topic in clinical and imaging diagnosis. The aim of this study was to evaluate the combination of low-dose spectral CT and ASIR (Adaptive Statistical Iterative Reconstruction) algorithm in the diagnosis of solitary pulmonary nodules (SPN). METHODS 62 patients with SPN (42 cases of benign SPN and 20 cases of malignant SPN, pathology confirmed) were scanned by spectral CT with a dual-phase contrast-enhanced method. The iodine and water concentration (IC and WC) of the lesion and the artery in the image that had the same density were measured by the GSI (Gemstone Spectral Imaging) software. The normalized iodine and water concentration (NIC and NWC) of the lesion and the normalized iodine and water concentration difference (ICD and WCD) between the arterial and venous phases (AP and VP) were also calculated. The spectral HU (Hounsfield Unit ) curve was divided into 3 sections based on the energy (40-70, 70-100 and 100-140 keV) and the slopes (λHU) in both phases were calculated. The ICAP, ICVP, WCAP and WCVP, NIC and NWC, and the λHU in benign and malignant SPN were compared by independent sample t-test. RESULTS The iodine related parameters (ICAP, ICVP, NICAP, NICVP, and the ICD) of malignant SPN were significantly higher than that of benign SPN (t = 3.310, 1.330, 2.388, 1.669 and 3.251, respectively, P <0.05). The 3 λHU values of venous phase in malignant SPN were higher than that of benign SPN (t = 3.803, 2.846 and 3.205, P <0.05). The difference of water related parameters (WCAP, WCVP, NWCAP, NWCVP and WCD) between malignant and benign SPN were not significant (t = 0.666, 0.257, 0.104, 0.550 and 0.585, P > 0.05). CONCLUSIONS The iodine related parameters and the slope of spectral curve are useful markers to distinguish the benign from the malignant lung diseases, and its application is extremely feasible in clinical applications.
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Affiliation(s)
- Huijuan Xiao
- The Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, 450052, China.
| | - Yihe Liu
- The No.7 People's Hospital of Zhengzhou, 17 Jingnan 5th Road, Zhengzhou Economic and Technological Development Zone, Zhengzhou, Henan Province, 450000, China.
| | - Hongna Tan
- The Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, 450052, China.
| | - Pan Liang
- The Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, 450052, China.
| | - Bo Wang
- The Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, 450052, China.
| | - Lei Su
- The Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, 450052, China.
| | - Suya Wang
- The Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, 450052, China.
| | - Jianbo Gao
- The Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, 450052, China.
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