1
|
Hou J, Zhang Y, Yan J, Zhang T, Xia W, Zhu Y, Liu W. Clinical application of the contrast-enhancement boost technique in computed tomography angiography of the portal vein. Abdom Radiol (NY) 2023; 48:806-815. [PMID: 36471003 PMCID: PMC9902311 DOI: 10.1007/s00261-022-03754-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2022] [Indexed: 12/12/2022]
Abstract
PURPOSE The aim of this study was to explore the improved image quality of the portal vein using the contrast-enhancement boost (CE-boost) technique for the improved visibility of abdominal-enhanced computed tomography (CT) scans in clinical practice. METHODS This retrospective study included 50 patients in Group A who underwent routine abdominal-enhanced CT and 50 patients in Group B who underwent abdominal computed tomography angiography (CTA) with matched body mass index, age, and sex. Images in Group A were postprocessed with the CE-boost technique for further enhanced visibility of the portal vein. Both subjective and objective assessments of different branches of the portal vein in three types of images (i.e., Group A with CE-boost and without CE-boost, Group B) were statistically analyzed. RESULTS The subjective scores of two experienced radiologists showed good consistency (kappa value > 0.624, p < 0.001), and the score of Group A with CE-boost (mean, 4.64) was significantly higher than that of the others (p < 0.001). The liver parenchyma and most target veins in Group A with CE-boost showed the highest CT, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) values and the lowest standard deviation (SD), while the CNR of most portal veins in Group A without CE-boost had the lowest CNR (p < 0.001). There were no differences in the SNR of the portal vein in Group A without CE-Boost and Group B (p > 0.05). CONCLUSION CE-boost can significantly improve image quality in portal vein imaging without any additional scanning settings or changes in the clinical workflow.
Collapse
Affiliation(s)
- Juan Hou
- Imaging Center, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 Xinjiang China
| | - Yuan Zhang
- Imaging Center, The Fourth Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 Xinjiang China
| | - Jing Yan
- Canon Medical Systems (China), Co., Ltd., Room 1004-1006, City Point, NO 666 West Huaihai Rd, Changning District, 200052 Shanghai China
| | - Tieliang Zhang
- Imaging Center, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 Xinjiang China
| | - Wenwen Xia
- Imaging Center, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 Xinjiang China
| | - Yucai Zhu
- Imaging Center, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 Xinjiang China
| | - Wenya Liu
- Imaging Center, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China.
| |
Collapse
|
2
|
|
3
|
Kanii Y, Ichikawa Y, Nakayama R, Nagata M, Ishida M, Kitagawa K, Murashima S, Sakuma H. Usefulness of dictionary learning-based processing for improving image quality of sub-millisievert low-dose chest CT: initial experience. Jpn J Radiol 2019; 38:215-221. [PMID: 31863329 DOI: 10.1007/s11604-019-00912-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/14/2019] [Indexed: 11/29/2022]
Abstract
PURPOSE To develop a dictionary learning (DL)-based processing technique for improving the image quality of sub-millisievert chest computed tomography (CT). MATERIALS AND METHODS Standard-dose and sub-millisievert chest CT were acquired in 12 patients. Dictionaries including standard- and low-dose image patches were generated from the CT datasets. For each patient, DL-based processing was performed for low-dose CT using the dictionaries generated from the remaining 11 patients. This procedure was repeated for all 12 patients. Image quality of normal thoracic structures on the processed sub-millisievert CT images was assessed with a 5-point scale (5 = excellent, 1 = very poor). Lung lesion conspicuity was also assessed on a 5-point scale. RESULTS Image noise on sub-millisievert CT was significantly decreased with DL-based image processing (48.5 ± 13.7 HU vs 20.4 ± 7.9 HU, p = 0.0005). Image quality of lung structures was significantly improved with DL-based method (middle level of lung, 2.25 ± 0.75 vs 2.92 ± 0.79, p = 0.0078). Lung lesion conspicuity was also significantly improved with DL-based technique (solid nodules, 3.4 ± 0.6 vs 2.7 ± 0.6, p = 0.0273). CONCLUSION Image quality and lesion conspicuity on sub-millisievert chest CT images may be improved by DL-based post-processing.
Collapse
Affiliation(s)
- Yoshinori Kanii
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Yasutaka Ichikawa
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
| | - Ryohei Nakayama
- Department of Electronic and Computer Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Motonori Nagata
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Masaki Ishida
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Kakuya Kitagawa
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Shuichi Murashima
- Department of Radiology, Matsusaka Chuo General Hospital, 102 Kobou, Kawai, Matsusaka, Mie, 515-8566, Japan
| | - Hajime Sakuma
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| |
Collapse
|
4
|
Camera L, Pezzullo F, Acampora A, Liuzzi R, Rispo A, Nardone OM, Luglio G, Bucci L, Castiglione F, Brunetti A. Multi-detector CT enterography in active inflammatory bowel disease: Image quality and diagnostic efficacy of a low-radiation high contrast protocol. Clin Imaging 2019; 58:27-33. [PMID: 31228828 DOI: 10.1016/j.clinimag.2019.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/20/2019] [Accepted: 06/13/2019] [Indexed: 12/13/2022]
Abstract
PURPOSE To prospectively evaluate image quality and diagnostic efficacy of a low radiation-high contrast (LR-HC) CT Enterography (CTE) in active Inflammatory Bowel Disease (IBD). MATERIALS AND METHODS Eighty-five (36M; 49F; 17-75 yrs) patients with active IBD underwent contrast-enhanced CTE and were stratified in two groups according to age (< or ≥45 yrs): Group A (N = 45; 32 ± 9 yrs; 58 ± 10 kg) and Group B (N = 40; 58 ± 10 yrs; 61 ± 13 kg). Each group received a different amount of radiation (Noise Index, NI) and non-ionic iodinated contrast media (LOCM) as follows: Group A (NI = 15; 2.5 ml/kg) and Group B (NI = 12.5; 2 ml/kg). Thyroid functional tests were performed in all patients of group A at 4-6 wks. Signal- and contrast-to-noise ratios were calculated for liver (L) and abdominal aorta (A). Statistical analysis was performed by Student's t- or Chi-square test for continuous and categorical data, respectively. RESULTS No patient of Group A developed signs of thyrotoxicosis. SNRL, CNRL and diagnostic accuracy of CTE were 8.4 ± 1.7 vs 8.9 ± 2.1 (p = 0.256), 5.4 ± 1.5 vs 5.6 ± 1.7 (p = 0.486) and 91.1 vs 92.5% (p = 0.764) whereas the effective dose and the LOCM administered were 6.7 ± 2.2 vs 13.9 ± 6.0 mSv (p < 0.001) and 144 ± 25 vs 122 ± 25 ml (p < 0.001) for Group A and B, respectively. CONCLUSION LR-HC CTE is a dose-effective protocol in the evaluation of active IBD in young patients.
Collapse
Affiliation(s)
- Luigi Camera
- Department of Advanced Biomedical Sciences - Section of Diagnostic Imaging, University "Federico II", Naples, Italy.
| | - Filomena Pezzullo
- Department of Advanced Biomedical Sciences - Section of Diagnostic Imaging, University "Federico II", Naples, Italy
| | - Angela Acampora
- Department of Advanced Biomedical Sciences - Section of Diagnostic Imaging, University "Federico II", Naples, Italy
| | - Raffaele Liuzzi
- Institute of Biostructures and Bioimaging, National Research Council, University "Federico II", Naples, Italy
| | - Antonio Rispo
- Department of Clinical Medicine and Surgery - Sections of Gastroenterology, University "Federico II", Naples, Italy
| | - Olga Maria Nardone
- Department of Clinical Medicine and Surgery - Sections of Gastroenterology, University "Federico II", Naples, Italy
| | - Gaetano Luglio
- Colo-rectal Surgery, University "Federico II", Naples, Italy
| | - Luigi Bucci
- Colo-rectal Surgery, University "Federico II", Naples, Italy
| | - Fabiana Castiglione
- Department of Clinical Medicine and Surgery - Sections of Gastroenterology, University "Federico II", Naples, Italy
| | - Arturo Brunetti
- Department of Advanced Biomedical Sciences - Section of Diagnostic Imaging, University "Federico II", Naples, Italy
| |
Collapse
|
5
|
Denoising of low-dose CT images via low-rank tensor modeling and total variation regularization. Artif Intell Med 2019; 94:1-17. [DOI: 10.1016/j.artmed.2018.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/24/2018] [Accepted: 12/27/2018] [Indexed: 11/23/2022]
|
6
|
Aschoff AJ, Catalano C, Kirchin MA, Krix M, Albrecht T. Low radiation dose in computed tomography: the role of iodine. Br J Radiol 2017; 90:20170079. [PMID: 28471242 PMCID: PMC5603952 DOI: 10.1259/bjr.20170079] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Recent approaches to reducing radiation exposure during CT examinations typically utilize automated dose modulation strategies on the basis of lower tube voltage combined with iterative reconstruction and other dose-saving techniques. Less clearly appreciated is the potentially substantial role that iodinated contrast media (CM) can play in low-radiation-dose CT examinations. Herein we discuss the role of iodinated CM in low-radiation-dose examinations and describe approaches for the optimization of CM administration protocols to further reduce radiation dose and/or CM dose while maintaining image quality for accurate diagnosis. Similar to the higher iodine attenuation obtained at low-tube-voltage settings, high-iodine-signal protocols may permit radiation dose reduction by permitting a lowering of mAs while maintaining the signal-to-noise ratio. This is particularly feasible in first pass examinations where high iodine signal can be achieved by injecting iodine more rapidly. The combination of low kV and IR can also be used to reduce the iodine dose. Here, in optimum contrast injection protocols, the volume of CM administered rather than the iodine concentration should be reduced, since with high-iodine-concentration CM further reductions of iodine dose are achievable for modern first pass examinations. Moreover, higher concentrations of CM more readily allow reductions of both flow rate and volume, thereby improving the tolerability of contrast administration.
Collapse
Affiliation(s)
- Andrik J Aschoff
- 1 Department for Diagnostic and Interventional Radiology and Neuroradiology, Klinikum Kempten, Kempten, Germany
| | - Carlo Catalano
- 2 Department of Radiological Sciences, University of Rome "La Sapienza", Rome, Italy
| | - Miles A Kirchin
- 3 Bracco Imaging SpA, Global Medical & Regulatory Affairs, Milan, Italy
| | - Martin Krix
- 4 Bracco Imaging Germany, Global Medical & Regulatory Affairs, Konstanz, Germany
| | - Thomas Albrecht
- 5 Institut für Radiologie und Interventionelle Therapie, Vivantes-Klinikum Neukölln, Berlin, Germany
| |
Collapse
|
7
|
Chen Y, Liu J, Hu Y, Yang J, Shi L, Shu H, Gui Z, Coatrieux G, Luo L. Discriminative feature representation: an effective postprocessing solution to low dose CT imaging. Phys Med Biol 2017; 62:2103-2131. [PMID: 28212114 DOI: 10.1088/1361-6560/aa5c24] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This paper proposes a concise and effective approach termed discriminative feature representation (DFR) for low dose computerized tomography (LDCT) image processing, which is currently a challenging problem in medical imaging field. This DFR method assumes LDCT images as the superposition of desirable high dose CT (HDCT) 3D features and undesirable noise-artifact 3D features (the combined term of noise and artifact features induced by low dose scan protocols), and the decomposed HDCT features are used to provide the processed LDCT images with higher quality. The target HDCT features are solved via the DFR algorithm using a featured dictionary composed by atoms representing HDCT features and noise-artifact features. In this study, the featured dictionary is efficiently built using physical phantom images collected from the same CT scanner as the target clinical LDCT images to process. The proposed DFR method also has good robustness in parameter setting for different CT scanner types. This DFR method can be directly applied to process DICOM formatted LDCT images, and has good applicability to current CT systems. Comparative experiments with abdomen LDCT data validate the good performance of the proposed approach.
Collapse
Affiliation(s)
- Yang Chen
- Laboratory of Image Science and Technology, Southeast University, Nanjing 210096, People's Republic of China. Centre de Recherche en Information Biomedicale Sino-Francais (LIA CRIBs), Rennes, France. Key Laboratory of Computer Network and Information Integration (Southeast University), Ministry of Education, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Camera L, Liccardo I, Romano F, Liuzzi R, Rispo A, Imbriaco M, Testa A, Luglio G, De Fronzo S, Castiglione F, Bucci L, Brunetti A. Diagnostic efficacy of single-pass abdominal multidetector-row CT: prospective evaluation of a low dose protocol. Br J Radiol 2016; 90:20160612. [PMID: 27826994 DOI: 10.1259/bjr.20160612] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE To evaluate the diagnostic efficacy of single-pass contrast-enhanced multidetector CT (CE-MDCT) performed with a low-radiation high-contrast (LR-HC) dose protocol in selected patients with non-traumatic acute bowel disease. METHODS 65 (32 males, 33 females; aged 20-67 years) consecutive patients with non-traumatic acute bowel disease underwent single-pass CE-MDCT performed 70-100 s after i.v. bolus injection of a non-ionic iodinated contrast medium (CM) (370 mgI ml-1). In 46 (70%) patients with a clinical and/or ultrasonographic suspicion of inflammatory bowel disease, up to 1.2-1.4 l of a 7% polyethylene-glycol solution was orally administered 45-60 mins prior to the CT examination. Patients were then divided into two groups according to age: Group A (20-44 years; n = 34) and Group B (45-70 years; n = 31). Noise index (NI) and CM dose were selected as follows: Group A (NI = 15; 2.5 ml kg-1) and Group B (NI = 12.5; 2 ml kg-1). All patients of Group A underwent thyroid functional tests at 4-6 weeks. Final diagnoses were obtained by open (n = 12) or laparoscopic surgery (n = 4), endoscopy w/without biopsy (n = 24) and clinical (n = 19) and/or instrumental (ultrasonography) (n = 6) follow-up at 11 ± 4 months (range 6-18 mo.). Statistical analysis was performed by χ2 and Student's t-test for categorical and continuous variables, respectively. RESULTS Sensitivity and specificity were 91.3 vs 95.4% (p = 0.905) and 90.9 vs 88.8% (p = 0.998) with an overall diagnostic accuracy of 91.1 vs 93.5% (p = 0.756), whereas the radiation (in millisievert) and CM dose (in millilitre) were 7.5 ± 2.8 mSv and 155 ± 30 ml for Group A and 14.1 ± 5.3 mSv and 130 ± 24 ml for Group B (p < 0.001), respectively. No patients of Group A showed laboratory signs of thyrotoxicosis at follow-up. CONCLUSION The LR-HC has proved to be a safe and a dose-effective protocol in the evaluation of selected young patients with non-traumatic acute bowel disease. Advances in knowledge: (1) As reaching the highest diagnostic benefit to risk ratio (AHARA) appears to be the current principle of MDCT imaging, an increased amount of iodinated CM (0.7-0.9 gI ml-1) can be safely administered to young patients (<40 years) with normal thyroid and renal function to compensate for the lower image quality resulting from low-dose CT protocols performed with the standard filter back-projection algorithm. Such an approach will result in a significant reduction of the radiation dose, which could be otherwise achieved only using iterative reconstruction algorithms combined with either low tube voltage and/or low tube current protocols. (2) An optimal scan delay (Tdelay) for a venous phase caudocranial acquisition can be calculated by the following formula: Tdelay = CI + 25 - TSD, where CI is the duration of the contrast injection, 25 is the average of the sum of abdominal aortic and peak hepatic arrival times and TSD is the scan duration. With such an approach, the radiation exposure resulting from bolus tracking, albeit performed with low-dose scans, can be spared in patients with normal transit times.
Collapse
Affiliation(s)
- Luigi Camera
- 1 Section of Diagnostic Imaging, Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy.,2 National Research Council (CNR), Institute of Biostructures and Bioimaging, Naples, Italy
| | - Immacolata Liccardo
- 1 Section of Diagnostic Imaging, Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy
| | - Federica Romano
- 1 Section of Diagnostic Imaging, Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy
| | - Raffaele Liuzzi
- 2 National Research Council (CNR), Institute of Biostructures and Bioimaging, Naples, Italy
| | - Antonio Rispo
- 3 Section of Gastroenterology, Department of Clinical Medicine and Surgery, University "Federico ll", Naples, Italy
| | - Massimo Imbriaco
- 1 Section of Diagnostic Imaging, Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy
| | - Anna Testa
- 3 Section of Gastroenterology, Department of Clinical Medicine and Surgery, University "Federico ll", Naples, Italy
| | - Gaetano Luglio
- 4 Section of Colo-rectal Surgery, Department of Clinical Medicine and Surgery, University "Federico ll", Naples, Italy
| | - Simona De Fronzo
- 1 Section of Diagnostic Imaging, Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy
| | - Fabiana Castiglione
- 3 Section of Gastroenterology, Department of Clinical Medicine and Surgery, University "Federico ll", Naples, Italy
| | - Luigi Bucci
- 4 Section of Colo-rectal Surgery, Department of Clinical Medicine and Surgery, University "Federico ll", Naples, Italy
| | - Arturo Brunetti
- 1 Section of Diagnostic Imaging, Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy
| |
Collapse
|
9
|
Improving Low-dose Cardiac CT Images based on 3D Sparse Representation. Sci Rep 2016; 6:22804. [PMID: 26980176 PMCID: PMC4793253 DOI: 10.1038/srep22804] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 02/19/2016] [Indexed: 11/08/2022] Open
Abstract
Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.
Collapse
|
10
|
Balancing Radiation and Contrast Media Dose in Single-Pass Abdominal Multidetector CT: Prospective Evaluation of Image Quality. Acad Radiol 2015; 22:1419-26. [PMID: 26264765 DOI: 10.1016/j.acra.2015.06.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 01/29/2023]
Abstract
RATIONALE AND OBJECTIVES As both contrast and radiation dose affect the quality of CT images, a constant image quality in abdominal contrast-enhanced multidetector computed tomography (CE-MDCT) could be obtained balancing radiation and contrast media dose according to the age of the patients. MATERIALS AND METHODS Seventy-two (38 Men; 34 women; aged 20-83 years) patients underwent a single-pass abdominal CE-MDCT. Patients were divided into three different age groups: A (20-44 years); B (45-65 years); and C (>65 years). For each group, a different noise index (NI) and contrast media dose (370 mgI/mL) was selected as follows: A (NI, 15; 2.5 mL/kg), B (NI, 12.5; 2 mL/kg), and C (NI, 10; 1.5 mL/kg). Radiation exposure was reported as dose-length product (DLP) in mGy × cm. For quantitative analysis, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated for both the liver (L) and the abdominal aorta (A). Statistical analysis was performed with a one-way analysis of variance. Standard imaging criteria were used for qualitative analysis. RESULTS Although peak hepatic enhancement was 152 ± 16, 128 ± 12, and 101 ± 14 Hounsfield units (P < .001) for groups A, B, and C, respectively, no significant differences were observed in the corresponding SNRL with 9.2 ± 1.4, 9.1 ± 1.2, and 9.2 ± 3. Radiation (mGy × cm) and contrast media dose (mL) administered were 476 ± 147 and 155 ± 27 for group A, 926 ± 291 and 130 ± 16 for group B, and 1981 ± 451 and 106 ± 15 for group C, respectively (P < .001). None of the studies was graded as poor or inadequate by both readers, and the prevalence-adjusted bias-adjusted kappa ranged between 0.48 and 0.93 for all but one criteria. CONCLUSIONS A constant image quality in CE-MDCT can be obtained balancing radiation and contrast media dose administered to patients of different age.
Collapse
|
11
|
Yi-Qun X, Wei L, Xin-Ye N. Spectral Imaging Technology-Based Evaluation of Radiation Treatment Planning to Remove Contrast Agent Artifacts. Technol Cancer Res Treat 2015. [PMID: 26208836 DOI: 10.1177/1533034615595902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE This study employs dual-source computed tomography single-spectrum imaging to evaluate the effects of contrast agent artifact removal and the computational accuracy of radiotherapy treatment planning improvement. METHOD The phantom, including the contrast agent, was used in all experiments. The amounts of iodine in the contrast agent were 30, 15, 7.5, and 0.75 g/100 mL. Two images with different energy values were scanned and captured using dual-source computed tomography (80 and 140 kV). To obtain a fused image, 2 groups of images were processed using single-energy spectrum imaging technology. The Pinnacle planning system was used to measure the computed tomography values of the contrast agent and the surrounding phantom tissue. The difference between radiotherapy treatment planning based on 80 kV, 140 kV, and energy spectrum image was analyzed. RESULTS For the image with high iodine concentration, the quality of the energy spectrum-fused image was the highest, followed by that of the 140-kV image. That of the 80-kV image was the worst. The difference in the radiotherapy treatment results among the 3 models was significant. When the concentration of iodine was 30 g/100 mL and the distance from the contrast agent at the dose measurement point was 1 cm, the deviation values (P) were 5.95% and 2.20% when image treatment planning was based on 80 and 140 kV, respectively. When the concentration of iodine was 15 g/100 mL, deviation values (P) were -2.64% and -1.69%. CONCLUSION Dual-source computed tomography single-energy spectral imaging technology can remove contrast agent artifacts to improve the calculated dose accuracy in radiotherapy treatment planning.
Collapse
Affiliation(s)
- Xu Yi-Qun
- Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, China
| | - Liu Wei
- Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, China
| | - Ni Xin-Ye
- Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, China
| |
Collapse
|
12
|
He J, Wang Q, Ma X, Sun Z. Dual-energy CT angiography of abdomen with routine concentration contrast agent in comparison with conventional single-energy CT with high concentration contrast agent. Eur J Radiol 2015; 84:221-7. [DOI: 10.1016/j.ejrad.2014.11.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/14/2014] [Accepted: 11/18/2014] [Indexed: 10/24/2022]
|
13
|
Chen Y, Shi L, Feng Q, Yang J, Shu H, Luo L, Coatrieux JL, Chen W. Artifact suppressed dictionary learning for low-dose CT image processing. IEEE TRANSACTIONS ON MEDICAL IMAGING 2014; 33:2271-92. [PMID: 25029378 DOI: 10.1109/tmi.2014.2336860] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Low-dose computed tomography (LDCT) images are often severely degraded by amplified mottle noise and streak artifacts. These artifacts are often hard to suppress without introducing tissue blurring effects. In this paper, we propose to process LDCT images using a novel image-domain algorithm called "artifact suppressed dictionary learning (ASDL)." In this ASDL method, orientation and scale information on artifacts is exploited to train artifact atoms, which are then combined with tissue feature atoms to build three discriminative dictionaries. The streak artifacts are cancelled via a discriminative sparse representation operation based on these dictionaries. Then, a general dictionary learning processing is applied to further reduce the noise and residual artifacts. Qualitative and quantitative evaluations on a large set of abdominal and mediastinum CT images are carried out and the results show that the proposed method can be efficiently applied in most current CT systems.
Collapse
|
14
|
Low-dose abdominal CT protocols with a tube voltage setting of 100 kVp or 80 kVp: Performance of radiation dose reduction and influence on visual contrast. Clin Radiol 2014; 69:804-11. [DOI: 10.1016/j.crad.2014.03.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 03/10/2014] [Accepted: 03/20/2014] [Indexed: 11/18/2022]
|
15
|
Spectral CT Imaging in Patients with Budd-Chiari Syndrome: Investigation of Image Quality. Cell Biochem Biophys 2014; 70:1043-9. [PMID: 24833430 DOI: 10.1007/s12013-014-0021-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
16
|
Whole-Body CT Angiography With Low Tube Voltage and Low-Concentration Contrast Material to Reduce Radiation Dose and Iodine Load. AJR Am J Roentgenol 2014; 202:W106-16. [PMID: 24370154 DOI: 10.2214/ajr.13.10720] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
17
|
Chen Y, Yu F, Luo L, Toumoulin C. Improving abdomen tumor low-dose CT images using dictionary learning based patch processing and unsharp filtering. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:4014-7. [PMID: 24110612 DOI: 10.1109/embc.2013.6610425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Reducing patient radiation dose, while maintaining a high-quality image, is a major challenge in Computed Tomography (CT). The purpose of this work is to improve abdomen tumor low-dose CT (LDCT) image quality by using a two-step strategy: a first patch-wise non linear processing is first applied to suppress the noise and artifacts, that is based on a sparsity prior in term of a learned dictionary, then an unsharp filtering aiming to enhance the contrast of tissues and compensate the contrast loss caused by the DL processing. Preliminary results show that the proposed method is effective in suppressing mottled noise as well as improving tumor detectability.
Collapse
|
18
|
Chen CM, Chu SY, Hsu MY, Liao YL, Tsai HY. Low-tube-voltage (80 kVp) CT aortography using 320-row volume CT with adaptive iterative reconstruction: lower contrast medium and radiation dose. Eur Radiol 2013; 24:460-8. [PMID: 24081645 DOI: 10.1007/s00330-013-3027-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 08/14/2013] [Accepted: 09/08/2013] [Indexed: 01/03/2023]
Abstract
OBJECTIVES To evaluate CT aortography at reduced tube voltage and contrast medium dose while maintaining image quality through iterative reconstruction (IR). METHODS The Institutional Review Board approved a prospective study of 48 patients who underwent follow-up CT aortography. We performed intra-individual comparisons of arterial phase images using 120 kVp (standard tube voltage) and 80 kVp (low tube voltage). Low-tube-voltage imaging was performed on a 320-detector CT with IR following injection of 40 ml of contrast medium. We assessed aortic attenuation, aortic attenuation gradient, image noise, contrast-to-noise ratio (CNR), volume CT dose index (CTDIvol), and figure of merit (FOM) of image noise and CNR. Two readers assessed images for diagnostic quality, image noise, and artefacts. RESULTS The low-tube-voltage protocol showed 23-31% higher mean aortic attenuation and image noise (both P < 0.01) than the standard-tube-voltage protocol, but no significant difference in the CNR and aortic attenuation gradients. The low-tube-voltage protocol showed a 48% reduction in CTDIvol and an 80% increase in FOM of CNR. Subjective diagnostic quality was similar for both protocols, but low-tube-voltage images showed greater image noise (P = 0.01). CONCLUSIONS Application of IR to an 80-kVp CT aortography protocol allows radiation dose and contrast medium reduction without affecting image quality. KEY POINTS • CT aortography at 80 kVp allows a significant reduction in radiation dose. • Addition of iterative reconstruction reduces image noise and improves image quality. • The injected contrast medium dose can be substantially reduced at 80 kVp. • Aortic enhancement is uniform despite a reduced volume of contrast medium.
Collapse
Affiliation(s)
- Chien-Ming Chen
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital Linkou, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | | | | | | | | |
Collapse
|
19
|
Chen Y, Yin X, Shi L, Shu H, Luo L, Coatrieux JL, Toumoulin C. Improving abdomen tumor low-dose CT images using a fast dictionary learning based processing. Phys Med Biol 2013; 58:5803-20. [PMID: 23917704 DOI: 10.1088/0031-9155/58/16/5803] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In abdomen computed tomography (CT), repeated radiation exposures are often inevitable for cancer patients who receive surgery or radiotherapy guided by CT images. Low-dose scans should thus be considered in order to avoid the harm of accumulative x-ray radiation. This work is aimed at improving abdomen tumor CT images from low-dose scans by using a fast dictionary learning (DL) based processing. Stemming from sparse representation theory, the proposed patch-based DL approach allows effective suppression of both mottled noise and streak artifacts. The experiments carried out on clinical data show that the proposed method brings encouraging improvements in abdomen low-dose CT images with tumors.
Collapse
Affiliation(s)
- Yang Chen
- Laboratory of Image Science and Technology, Southeast University, 210096, Nanjing, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
20
|
Seesaw balancing radiation dose and i.v. contrast dose: evaluation of a new abdominal CT protocol for reducing age-specific risk. AJR Am J Roentgenol 2013; 200:383-8. [PMID: 23345361 DOI: 10.2214/ajr.12.8534] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate an abdominal CT protocol in which radiation dose was reduced and i.v. contrast dose increased for young patients and radiation dose was increased and i.v. medium dose decreased for elderly patients. The hypothesis was that these adjustments would result in constant image quality and a reduction in age-specific risk. MATERIALS AND METHODS Patients were divided into four age groups of 25 patients each: group 1, 16-25 years; group 2, 26-50 years; group 3, 51-75 years; and group 4, older than 75 years. The quality reference tube load ranged from 100 to 300 mAs, and the i.v. contrast dose ranged from 600 to 350 mg I/kg. Group 3 was the reference group. Signal-to-noise and contrast-to-noise ratios for a hypothetical hypovascular liver metastatic lesion were calculated. Subjective image quality was evaluated by visual grading characteristic analysis in which four readers assessed the reproduction of seven image-quality criteria. RESULTS Radiation dose was reduced 57% in the youngest group, and the i.v. contrast dose was reduced 18% in elderly patients. There were no statistically significant differences between the groups with respect to signal-to-noise and contrast-to-noise ratios. Subjective image quality was graded significantly lower for four criteria in group 1 compared with group 3. No significant difference was found in comparisons of groups 2 (except for one criterion) and 4 with group 3. CONCLUSION It is possible to balance radiation dose and contrast dose against each other and maintain signal-to-noise and contrast-to-noise ratios. Subjective image quality was affected by increased noise level on the images but was judged acceptable in all groups except the one with the lowest radiation dose.
Collapse
|
21
|
|
22
|
CT enterography at 80 kVp with adaptive statistical iterative reconstruction versus at 120 kVp with standard reconstruction: image quality, diagnostic adequacy, and dose reduction. AJR Am J Roentgenol 2012; 198:1084-92. [PMID: 22528897 DOI: 10.2214/ajr.11.6597] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE The objective of our study was to evaluate the image quality and diagnostic adequacy of the following two CT enterography protocols in patients weighing less than 160 lb (72 kg): 80-kVp imaging with the adaptive statistical iterative reconstruction (ASIR) in comparison with 120-kVp imaging with the filtered back projection reconstruction. MATERIALS AND METHODS We retrospectively reviewed 133 CT enterography examinations of 127 patients weighing less than 160 lb, 64 80-kVp examinations, and 69 120-kVp examinations. Image quality for evaluation of the bowel wall, mesenteric vessels, and hepatic parenchyma and the overall image quality were graded on a scale of 1-5 (1 = poor, 2 = acceptable, 3 = good, 4 = very good, 5 = excellent). Diagnostic accuracy for the detection of inflammatory bowel disease was evaluated. The volume CT dose index (CTDI(vol)) was recorded and effective dose was calculated from scanner-generated dose-length product. RESULTS There was a statistically significant decrease in the mean image quality scores for 80-kVp examinations compared with 120-kVp examinations for evaluation of the bowel wall (3.19 vs 3.70, respectively) and liver (3.12 vs 3.81) and for overall image quality (3.23 vs 3.68), but there was no significant decrease in score for evaluation of the mesenteric vessels (3.63 vs 3.67). None of the 80-kVp examinations was graded as poor, and all were considered to be of acceptable quality. Both techniques had comparable diagnostic accuracy for the detection of inflammatory bowel disease. Interobserver agreement was fair to moderate for qualitative image grading and was substantial for the detection of features of inflammatory bowel disease. The mean CTDI(vol) and effective dose for the 80-kVp examinations were 6.15 mGy and 4.60 mSv, respectively, and for the 120-kVp examinations, 20.79 mGy and 15.81 mSv. CONCLUSION In patients weighing less than 160 lb, CT enterography examinations at 80 kVp with 30% ASIR produce diagnostically acceptable image quality with an average CTDI(vol) of 6.15 mGy and an average effective dose of 4.60 mSv.
Collapse
|
23
|
A Simple QI Project to Improve Practice Quality in Neuroradiological CT Angiography. J Med Imaging Radiat Sci 2012; 43:103-107. [PMID: 31052025 DOI: 10.1016/j.jmir.2012.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 01/08/2012] [Accepted: 01/13/2012] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The purpose of this study was continuous quality improvement (CQI) of head and neck CT angiography (CTA) in the neuroradiology practice of a tertiary care medical center. MATERIALS AND METHODS We conducted baseline quality audits of 50 consecutive head or neck CTAs, including referrals for a variety of indications from emergency department, ambulatory, and inpatient settings. Neuroradiologists as a group used Likert-type questionnaire items to assess scan quality. Based on identified opportunities for CQI, the group evaluated alternative scanning methods, proposed action items, and implemented changes in scanning methods. After implementing the changes, the group performed follow-up quality audits of 61 consecutive CTAs. Quality of scans was compared for baseline and postimplementation patients using chi-square or McNemar tests. RESULTS Several key opportunities for CQI were identified, namely related to coverage levels and timing. These opportunities were translated into protocol changes, standardization of methods, and in-service sessions to implement specific process changes. Using a Likert-type scale with 1 anchored at "excellent" and 5 at "poor," the overall quality of CTAs improved from 2.46 at baseline to 1.64 after implementation of QI measures (P < .01). There were significant improvements in timing and coverage, and fewer scans required quality disclaimers after CQI implementation. CONCLUSION Using basic CQI techniques of assessment, analysis, change implementation, and reassessment, the quality of CTA scans in a busy neuroradiology clinical practice can be improved. These techniques are amenable to repeated use, so that CQI can be a routine practice to help optimize the quality of care in radiology.
Collapse
|
24
|
Goo HW. CT radiation dose optimization and estimation: an update for radiologists. Korean J Radiol 2011; 13:1-11. [PMID: 22247630 PMCID: PMC3253393 DOI: 10.3348/kjr.2012.13.1.1] [Citation(s) in RCA: 143] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 10/18/2011] [Indexed: 11/29/2022] Open
Abstract
In keeping with the increasing utilization of CT examinations, the greater concern about radiation hazards from examinations has been addressed. In this regard, CT radiation dose optimization has been given a great deal of attention by radiologists, referring physicians, technologists, and physicists. Dose-saving strategies are continuously evolving in terms of imaging techniques as well as dose management. Consequently, regular updates of this issue are necessary especially for radiologists who play a pivotal role in this activity. This review article will provide an update on how we can optimize CT dose in order to maximize the benefit-to-risk ratio of this clinically useful diagnostic imaging method.
Collapse
Affiliation(s)
- Hyun Woo Goo
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
| |
Collapse
|
25
|
Peng SSF, Chan PC, Chang YC, Shih TTF. Computed tomography of children with pulmonary Mycobacterium tuberculosis infection. J Formos Med Assoc 2011; 110:744-9. [DOI: 10.1016/j.jfma.2011.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 11/10/2011] [Accepted: 11/21/2011] [Indexed: 10/24/2022] Open
|
26
|
Goo HW. Individualized volume CT dose index determined by cross-sectional area and mean density of the body to achieve uniform image noise of contrast-enhanced pediatric chest CT obtained at variable kV levels and with combined tube current modulation. Pediatr Radiol 2011; 41:839-47. [PMID: 21656275 DOI: 10.1007/s00247-011-2121-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 12/15/2010] [Accepted: 01/02/2011] [Indexed: 01/09/2023]
Abstract
BACKGROUND A practical body-size adaptive protocol providing uniform image noise at various kV levels is not available for pediatric CT. OBJECTIVE To develop a practical contrast-enhanced pediatric chest CT protocol providing uniform image noise by using an individualized volume CT dose index (CTDIvol) determined by the cross-sectional area and density of the body at variable kV levels and with combined tube current modulation. MATERIALS AND METHODS A total of 137 patients (mean age, 7.6 years) underwent contrast-enhanced pediatric chest CT based on body weight. From the CTDIvol, image noise, and area and mean density of the cross-section at the lung base in the weight-based group, the best fit equation was estimated with a very high correlation coefficient (γ(2) = 0.86, P < 0.001). For the next study, 177 patients (mean age, 7.9 years; the CTDIvol group) underwent contrast-enhanced pediatric chest CT with the CTDIvol determined individually by the best fit equation. CTDIvol values on the dose report after CT scanning, noise differences from the target noise, areas, and mean densities were compared between these two groups. RESULTS The CTDIvol values (mean ± standard deviation, 1.6 ± 0.7 mGy) and the noise differences from the target noise (1.1 ± 0.9 HU) of the CTDIvol group were significantly lower than those of the weight-based group (2.0 ± 1.0 mGy, 1.8 ± 1.4 HU) (P < 0.001). In contrast, no statistically significant difference was found in area (317.0 ± 136.8 cm(2) vs. 326.3 ± 124.8 cm(2)), mean density (-212.9 ± 53.1 HU vs. -221.1 ± 56.3 HU), and image noise (13.8 ± 2.3 vs. 13.6 ± 1.7 HU) between the weight-based and the CTDIvol groups (P > 0.05). CONCLUSION Contrast-enhanced pediatric chest CT with the CTDIvol determined individually by the cross-sectional area and density of the body provides more uniform noise and better dose adaptation to body habitus than does weight-based CT at variable kV levels and with combined tube current modulation.
Collapse
Affiliation(s)
- Hyun Woo Goo
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asanbyeongwon-gil 86, Songpa-gu, Seoul, 138-736, Korea.
| |
Collapse
|
27
|
Beitzke D, Wolf F, Edelhauser G, Plank C, Schernthaner R, Weber M, Nolz R, Lammer J, Loewe C. Computed tomography angiography of the carotid arteries at low kV settings: a prospective randomised trial assessing radiation dose and diagnostic confidence. Eur Radiol 2011; 21:2434-44. [PMID: 21710265 DOI: 10.1007/s00330-011-2188-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Revised: 04/08/2011] [Accepted: 05/15/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To assess radiation dose and diagnostic image quality of a low-dose (80 kV) versus a standard-dose (120 kV) protocol for computed tomography angiography (CTA) of the supra-aortic arteries. METHODS 64-slice CTA of the supra-aortic arteries was performed in 42 consecutive patients using randomly either 80 or 120 kV at 300 absolute mAs. Intravascular attenuation values, contrast-to-noise (CNR) and signal-to-noise ratio (SNR) measurements were performed at three levels. Two readers assessed image quality by using a four-point scale. The effective dose (ED) was calculated to assess the differences in radiation exposure. RESULTS Intravascular attenuation values at 80 kV were higher in the common carotid artery, the carotid bifurcation and the internal carotid artery (p < 0.001). CNR and SNR differed at the internal carotid artery, with higher values in the 80-kV group (p > 0.05). Both readers revealed a significantly better image quality at 120 kV only at the common carotid artery (p < 0.001; p = 0.007). Mean ED was significantly lower at 80-kV (1.23 ± 0.09 vs. 3.99 ± 0.33 mSv; p < 0.001). CONCLUSION Tube voltage reduction to 80 kV in CTA of the supra-aortic arteries allows for significant radiation dose reduction but has limitations at the level of the common carotid artery.
Collapse
Affiliation(s)
- Dietrich Beitzke
- Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Low-Kilovoltage, High-Tube-Current MDCT of Liver in Thin Adults: Pilot Study Evaluating Radiation Dose, Image Quality, and Display Settings. AJR Am J Roentgenol 2011; 196:1332-8. [PMID: 21606297 DOI: 10.2214/ajr.10.5698] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
29
|
Improving image quality in portal venography with spectral CT imaging. Eur J Radiol 2011; 81:1677-81. [PMID: 21444170 DOI: 10.1016/j.ejrad.2011.02.063] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 02/28/2011] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To investigate the effect of energy spectral CT on the image quality of CT portal venography in cirrhosis patients. MATERIALS AND METHODS 30 portal hypertension patients underwent spectral CT examination using a single-tube, fast dual tube voltage switching technique. 101 sets of monochromatic images were generated from 40keV to 140keV. Image noise and contrast-to-noise ratio (CNR) for portal veins from the monochromatic images were measured. An optimal monochromatic image set was selected for obtaining the best CNR for portal veins. The image noise and CNR of the intra-hepatic portal vein and extra-hepatic main stem at the selected monochromatic level were compared with those from the conventional polychromatic images. Image quality was also assessed and compared. RESULTS The monochromatic images at 51keV were found to provide the best CNR for both the intra-hepatic and extra-hepatic portal veins. At this energy level, the monochromatic images had about 100% higher CNR than the polychromatic images with a moderate 30% noise increase. The qualitative image quality assessment was also statistically higher with monochromatic images at 51keV. CONCLUSION Monochromatic images at 51keV for CT portal venography could improve CNR for displaying hepatic portal veins and improve the overall image quality.
Collapse
|