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Wells ML, Froemming AT, Kawashima A, Vrtiska TJ, Kim B, Hartman RP, Holmes DR, Carter RE, Bartley AC, Leng S, McCollough CH, Fletcher JG. A multi-reader in vitro study using porcine kidneys to determine the impact of integrated circuit detectors and iterative reconstruction on the detection accuracy, size measurement, and radiation dose for small (<4 mm) renal stones. Acta Radiol 2017; 58:1012-1019. [PMID: 28273736 DOI: 10.1177/0284185116682382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background Detection of small renal calculi has benefitted from recent advances in computed tomography (CT) scanner design. Information regarding observer performance when using state-of-the-art CT scanners for this application is needed. Purpose To assess observer performance and the impact of radiation dose for detection and size measurement of <4 mm renal stones using CT with integrated circuit detectors and iterative reconstruction. Material and Methods Twenty-nine <4 mm calcium oxalate stones were randomly placed in 20 porcine kidneys in an anthropomorphic phantom. Four radiologists used a workstation to record each calculus detection and size. JAFROC Figure of Merit (FOM), sensitivity, false positive detections, and calculus size were calculated. Results Mean calculus size was 2.2 ± 0.7 mm. The CTDIvol values corresponding to the automatic exposure control settings of 160, 80, 40, 25, and 10 Quality Reference mAs (QRM) were 15.2, 7.9, 4.2, 2.7, and 1.3 mGy, respectively. JAFROC FOM was ≥ 0.97 at ≥ 80 QRM, ≥ 0.89 at ≥ 25 QRM, and was inferior to routine dose (160 QRM) at 10 QRM (0.72, P < 0.05). Per-calculus sensitivity remained ≥ 85% for every reader at ≥ 25 QRM. Mean total false positive detections per reader were ≤ 3 at ≥ 80 QRM, but increased substantially for two readers ( ≥ 12) at ≤ 40 QRM. Measured calculus size significantly decreased at ≤ 25 QRM ( P ≤ 0.01). Conclusion Using low dose renal CT with iterative reconstruction and ≥ 25 QRM results in high sensitivity, but false positive detections increase for some readers at very low dose levels (≤ 40 QRM). At very low doses with iterative reconstruction, measured calculus size will artifactually decrease.
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Affiliation(s)
| | | | | | | | - Bohyun Kim
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - David R Holmes
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Rickey E Carter
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA
| | - Adam C Bartley
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA
| | - Shuai Leng
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
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Song I, Yi JG, Park JH, Ko SM. Indirect CT Venography at 80 kVp with Sinogram-Affirmed Iterative Reconstruction Compared to 120 kVp with Filtered Back Projection: Assessment of Image Quality and Radiation Dose. PLoS One 2016; 11:e0163416. [PMID: 27662618 PMCID: PMC5035093 DOI: 10.1371/journal.pone.0163416] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/08/2016] [Indexed: 11/30/2022] Open
Abstract
Objective To evaluate the image quality and radiation dose of indirect computed tomographic venography (CTV) using 80 kVp with sinogram-affirmed iterative reconstruction (SAFIRE) and 120 kVp with filtered back projection (FBP). Materials and Methods This retrospective study was approved by our institution and informed consent was waived. Sixty-one consecutive patients (M: F = 27: 34, mean age 60 ± 16, mean BMI 23.6 ± 3.6 kg/m2) underwent pelvic and lower extremity CTVs [group A (n = 31, 120 kVp, reconstructed with FBP) vs. group B (n = 30, 80 kVp, reconstructed with SAFIRE)]. The vascular enhancement, image noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were compared. Subjective image analysis for image quality and noise was performed by two radiologists. Radiation dose was compared between the two groups. Results Compared with group A, higher mean vascular enhancement was observed in the group B (group A vs. B, 118.8 ± 15.7 HU vs. 178.6 ± 39.6 HU, p < 0.001), as well as image noise (12.0 ± 3.8 HU vs. 17.9 ± 6.1 HU, p < 0.001) and CNR (5.1 ± 1.9 vs. 7.6 ± 3.0, p < 0.001). The SNRs were not significantly different in both groups (11.2 ± 4.8 vs. 10.8 ± 3.7, p = 0.617). There was no significant difference in subjective image quality between the two groups (all p > 0.05). The subjective image noise was higher in the group B (p = 0.036 in reader 1, p = 0.005 in reader 2). The inter-observer reliability for assessing subjective image quality was good (ICC 0.746~0.784, p < 0.001). The mean CT dose index volume (CTDIvol) and mean dose length product (DLP) were significantly lower in group B than group A [CTDIvol, 6.4 ± 1.3 vs. 2.2 ± 2.2 mGy (p < 0.001); DLP, 499.1 ± 116.0 vs. 133.1 ± 45.7 mGy × cm (p < 0.001)]. Conclusions CTV using 80 kVp combined with SAFIRE provides lower radiation dose and improved CNR compared to CTV using 120 kVp with FBP.
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Affiliation(s)
- Inyoung Song
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, 143–729, Korea
| | - Jeong Geun Yi
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, 143–729, Korea
- * E-mail:
| | - Jeong Hee Park
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, 143–729, Korea
| | - Sung Min Ko
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, 143–729, Korea
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Tarzamni MK, Nezami N, Zomorrodi A, Fathi-Noroozlou S, Piri R, Naghavi-Behzad M, Mojadidi MK, Bijan B. Renal Collecting System Anatomy in Living Kidney Donors by Computed Tomographic Urography: Protocol Accuracy Compared to Intravenous Pyelographic and Surgical Findings. J Clin Imaging Sci 2016; 6:1. [PMID: 26958431 PMCID: PMC4766870 DOI: 10.4103/2156-7514.175079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 12/25/2015] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES To evaluate the accuracy of triple-bolus computed tomography urography (CTU) as a surrogate of intravenous pyelography (IVP) for determining the anatomy of the urinary collecting system in living kidney donors. MATERIALS AND METHODS In an analytic descriptive cross-sectional study, 36 healthy kidney donors were recruited during 12 months. Preoperative IVP and CTU were utilized to evaluate kidneys' anatomy; major and minor calyces and variation were used as anatomical indices to compare the accuracy of CTU and IVP; the images were then compared to surgical findings. RESULTS Thirty-six kidney donors (92% male; mean age: 28 ± 6 years) were enrolled in this study. The kappa coefficient value was significant and almost perfect for the CTU and IVP findings in detecting the pattern of calyces (kappa coefficient 0.92, asymptotic 95% confidence interval 0.86-0.97). Anatomic variations or anomalies of the urinary collecting system included the bifid pelvis (5.6%), duplication (8.3%), and extra-renal pelvis (2.8%). Both the sensitivity and specificity of CTU in the detection of the anatomy and variations were 100%; the sensitivity and specificity of IVP were 83.3% and 100%, respectively. CONCLUSIONS The triple-bolus preoperative CTU can be considered an alternative to IVP for assessing the anatomy of the urinary collecting system.
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Affiliation(s)
| | - Nariman Nezami
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Afshar Zomorrodi
- Department of Urology and Transplantation, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Reza Piri
- Student's Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran; Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Naghavi-Behzad
- Medical Philosophy and History Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran; Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Khalid Mojadidi
- Department of Medicine, Division of Cardiology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Bijan Bijan
- Department of Diagnostic Radiology and Nuclear Medicine, University of California Davis Medical Center, Sacramento, CA, USA
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Role of Imaging in Musculoskeletal Care. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2016. [DOI: 10.1007/s40141-016-0106-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Zhu X, Shi Z, Zhu Y, Liu W, Yang G, Yu T, Tang L, Xu Y. Individually adapted tube current selection and contrast medium injection protocol of coronary CT angiography based on test bolus parameters: a feasibility study. Acta Radiol 2015; 56:666-72. [PMID: 24938658 DOI: 10.1177/0284185114536156] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 04/28/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND Test bolus is mostly used to determine the starting point of a full cardiac scanning with respect to injection of a larger bolus of contrast material. So far there are limited data demonstrating the feasibility of using information obtained from a test bolus to adjust contrast delivery protocols and tube current individually during coronary computed tomography angiography (CCTA). PURPOSE To evaluate the feasibility of individually adapted tube current selection and contrast injection protocols of CCTA based on test bolus parameters. MATERIAL AND METHODS Test bolus followed by CCTA was performed in 93 patients at 100 kV and in 81 patients at 120 kV, respectively. Simulated attenuation of the descending aorta (SimDA) of CCTA was calculated at a fixed contrast injection rate of 4 mL/s. Univariate and multivariate comparisons were performed to identify associations of SimDA and image noise of CCTA (NoiseCCTA) with test bolus information and patient-related factors including body weight (BW), body mass index (BMI), and body surface area (BSA). RESULTS Compared with BW, BMI, and BSA, SimDA was more closely related to the peak time of left ventricle and peak enhancement of right ventricle obtained from test bolus (r = 0.495 and r = 0.642 for 100 and 120 kV protocol, respectively). Similarly, NoiseTB was much more closely related to NoiseCCTA (r = 0.740 and r = 0.630 for 100 and 120 kV protocol, respectively) when compared with BW, BMI, and BSA. CONCLUSION It is feasible to individually adapt tube current and contrast injection protocol of CCTA based on the information of test bolus.
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Affiliation(s)
- Xiaomei Zhu
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Zhaofei Shi
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Yinsu Zhu
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Wangyan Liu
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Guanyu Yang
- Laboratory of Image Science & Technology, School of Computer Science and Engineering, Southeast University, Nanjing, Jiangsu, PR China
| | - Tongfu Yu
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Lijun Tang
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Yi Xu
- Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China
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Bae KT. Intravenous contrast medium administration and scan timing at CT: considerations and approaches. Radiology 2010; 256:32-61. [PMID: 20574084 DOI: 10.1148/radiol.10090908] [Citation(s) in RCA: 646] [Impact Index Per Article: 46.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The continuing advances in computed tomographic (CT) technology in the past decades have provided ongoing opportunities to improve CT image quality and clinical practice and discover new clinical CT imaging applications. New CT technology, however, has introduced new challenges in clinical radiology practice. One of the challenges is with intravenous contrast medium administration and scan timing. In this article, contrast medium pharmacokinetics and patient, contrast medium, and CT scanning factors associated with contrast enhancement and scan timing are presented and discussed. Published data from clinical studies of contrast medium and physiology are reviewed and interpreted. Computer simulation data are analyzed to provide an in-depth analysis of various factors associated with contrast enhancement and scan timing. On the basis of basic principles and analysis of the factors, clinical considerations and modifications to protocol design that are necessary to optimize contrast enhancement for common clinical CT applications are proposed.
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Affiliation(s)
- Kyongtae T Bae
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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Kekelidze M, Dwarkasing RS, Dijkshoorn ML, Sikorska K, Verhagen PCMS, Krestin GP. Kidney and urinary tract imaging: triple-bolus multidetector CT urography as a one-stop shop--protocol design, opacification, and image quality analysis. Radiology 2010; 255:508-16. [PMID: 20160002 DOI: 10.1148/radiol.09082074] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE To retrospectively evaluate renal, vascular, and urinary tract visualization following a single postcontrast multidetector computed tomographic (CT) urographic sequence performed with three limited-volume bolus injections. MATERIALS AND METHODS The institutional review board approved this retrospective study. Patient informed consent was waived. Triple-bolus multidetector CT urography was performed in 110 patients. Triple-bolus protocol consisted of 30 mL of contrast material at 2 mL/sec at 0 seconds, 50 mL at 1.5 mL/sec at 435 seconds, 65 mL at 3 mL/sec at 488 seconds, with total abdominal scanning time of 510 seconds. Two independent readers rated urinary tract opacification and qualitatively and quantitatively assessed renal parenchymal and vascular contrast enhancement. Upper urinary tract (UUT) distention was measured by one reader. Interobserver agreement was assessed by using kappa statistics. RESULTS Complete opacification of the intrarenal collecting system and proximal ureter was achieved in 91% (184 of 202) (kappa = 0.62) and 82% (166 of 202) (kappa = 0.94) of segments, respectively. The distal ureter was not opacified in 21% of the cases (kappa = 0.92), and the bladder was not opacified in 20% of the cases. Mean distention was higher for proximal (3.9 mm) than for distal (3.7 mm) segments. Image quality of renal parenchymal enhancement was excellent in 76% of cases. Arteries showed better contrast enhancement than veins (excellent rating in 89% vs 59% of the cases). Radiation dose calculated for triple-bolus acquisition was 9.8 mSv. CONCLUSION Triple-bolus multidetector CT urography is a dose-efficient protocol acquiring corticomedullary-nephrographic-excretory and vascular enhancement phases in a single acquisition and provides sufficient opacification and distention of the UUT. Simultaneously, adequate image quality of renal parenchyma and vascular anatomy is achieved.
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Affiliation(s)
- Maka Kekelidze
- Department of Radiology, Erasmus Medical Center Rotterdam, 's-Gravendijkwal 230, 3015 CE Rotterdam, the Netherlands.
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Silverman SG, Leyendecker JR, Amis ES. What Is the Current Role of CT Urography and MR Urography in the Evaluation of the Urinary Tract? Radiology 2009; 250:309-23. [DOI: 10.1148/radiol.2502080534] [Citation(s) in RCA: 218] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Chow LC, Kwan SW, Olcott EW, Sommer G. Split-bolus MDCT urography with synchronous nephrographic and excretory phase enhancement. AJR Am J Roentgenol 2007; 189:314-22. [PMID: 17646456 DOI: 10.2214/ajr.07.2288] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Our purpose was to evaluate the utility of CT urography performed using a split contrast bolus that yields synchronous nephrographic and excretory phase enhancement. MATERIALS AND METHODS Five hundred consecutive patients referred for evaluation of possible urinary tract abnormalities (327 for painless hematuria) underwent CT urography with unenhanced scanning of the abdomen and pelvis and scanning during concurrent nephrographic and excretory phase enhancement produced by administration of a split contrast bolus. The enhanced abdomen scan was obtained with abdominal compression; the enhanced pelvis scan was obtained after release of compression. Findings from axial sections and coronal maximum intensity projections were correlated with clinical follow-up and, as available, with laboratory and other imaging studies including cystoscopy, ureteroscopy, urine cytology, surgery, and pathology. Follow-up management for each patient was determined by the clinical judgment of the referring physician. RESULTS CT urography identified 100% of pathologically confirmed renal cell carcinomas (n = 10) and uroepithelial malignancies involving the renal collecting system or ureter (n = 8). An additional nine renal masses were identified for which no pathologic proof has yet been obtained, including eight subcentimeter solid renal masses and one multiloculated lesion. Fourteen of 19 confirmed cases of uroepithelial neoplasm involving the bladder were identified. CT urography yielded one false-positive for bladder tumor, two false-positives for ureteral tumor, and one patient with a bladder mass who refused further evaluation. CT urography yielded sensitivity and specificity of 100% and 99% and 74% and 99% and positive predictive value and negative predictive value of 80% and 100% and 93% and 99% for the renal collecting system and ureter and bladder, respectively. CT urography was ineffective in identifying 11 cases of noninfectious cystitis. CT urography also depicted numerous other congenital and acquired abnormalities of the urinary tract. CONCLUSION Split-bolus MDCT urography detected all proven cases of tumors of the upper urinary tract, yielding high sensitivity and specificity. The split-bolus technique has the potential to reduce both radiation dose and the number of images generated by MDCT urography.
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Affiliation(s)
- Lawrence C Chow
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA.
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Roy C, Jeantroux J, Irani FG, Sauer B, Lang H, Saussine C. Accuracy of intermediate dose of furosemide injection to improve multidetector row CT urography. Eur J Radiol 2007; 66:253-61. [PMID: 17646072 DOI: 10.1016/j.ejrad.2007.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 05/09/2007] [Accepted: 06/04/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Evaluate the usefulness of intermediate dose furosemide to improve visualization of the intrarenal collecting system and ureter using MDCTU. MATERIALS AND METHODS Two groups of 100 patients without urinary tract disease or major abdominal pathology underwent MDCTU. Group I (various abdominal indications) was performed without any additional preparation and Group II (suspicion of urinary tract disease) 10 min after injection of furosemide (20mg). MIP images of the excretory phase were post-processed. Maximal short-axis diameter of the pelvis and ureter were measured on axial images for all phases. Visualization of the collecting system wall and the identification of the whole ureter were assessed. RESULTS Mean pelvic diameter before contrast was (7.4mm, S.D.+/-2.7; 13.4mm, S.D.+/-4.1), on cortico-medullary phase (8.4mm, S.D.+/-4.2; 14.3mm, S.D.+/-4), on nephrographic phase (8.1mm, S.D.+/-2.5; 14.8mm, S.D.+/-4) and on excretory phase (9.7 mm, S.D.+/-3.4; 14.9 mm, S.D.+/-4.5), respectively, for Groups I and II. Intrarenal collecting system wall was clearly identified on both corticomedullary and nephrographic phases in 91% of Group II against 20% of Group I. Opacification of the entire ureter was excellent on excretory phase in 96% of Group II against 13% of Group I. The difference between the mean values for the two groups was statistically significant for all phases (p<10(-9)). CONCLUSION Intermediate-dose furosemide (20mg) before MDCTU is a very simple add-on for accurate depiction of pelvicalyceal details and collecting system wall without artefacts. The procedure is associated with a constant and complete visualisation of the entire urete.
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Affiliation(s)
- Catherine Roy
- Department of Radiology B, Universitary Hospital of Strasbourg-Civil Hospital, 1, Place de l'Hopital BP 426, 67091 Strasbourg Cedex, France.
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Nolte-Ernsting C, Cowan N. Understanding multislice CT urography techniques: many roads lead to Rome. Eur Radiol 2006; 16:2670-86. [PMID: 16953373 DOI: 10.1007/s00330-006-0386-z] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 05/10/2006] [Accepted: 06/27/2006] [Indexed: 11/30/2022]
Abstract
CT urography has emerged as a serious alternative to conventional urography by utilizing the advantages of modern multislice CT techniques for the visualization of the entire upper urinary tract. Several different examination techniques have been developed in multislice CT (MSCT) urography for improving the opacification and distension of the urinary tract. All efforts in performing MSCT urography have to compromise between the best possible image quality and a reasonably low radiation exposure. Initial low-dose examination protocols are already available. Operating modern MSCT urography properly is not difficult, but it presupposes basic knowledge on the variety of current MSCT urography techniques, including such issues as present-day indications, split-bolus injection, compression, saline infusion, low-dose diuretic administration, hybrid scanning, timing of the acquisition delay, examination protocols, postprocessing, image analysis, and radiation exposure. This article is not intended to provide guidelines of how to conduct MSCT urography, but everyone will be able to understand the functionality of several robust operating MSCT urography techniques, which helps making an individual selection for the clinical practice. In the near future, systematic studies are awaited evaluating the morphologic and diagnostic accuracy of MSCT urography regarding diverse urinary tract disorders.
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Affiliation(s)
- Claus Nolte-Ernsting
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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12
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Coppenrath E, Meindl T, Herzog P, Khalil R, Mueller-Lisse U, Krenn L, Reiser M, Mueller-Lisse UG. Dose reduction in multidetector CT of the urinary tract. Studies in a phantom model. Eur Radiol 2006; 16:1982-9. [PMID: 16568267 DOI: 10.1007/s00330-005-0138-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 10/16/2005] [Accepted: 12/16/2005] [Indexed: 10/24/2022]
Abstract
A novel ureter phantom was developed for investigations of image quality and dose in CT urography. The ureter phantom consisted of a water box (14 cm x 32 cm x 42 cm) with five parallel plastic tubes (diameter 2.7 mm) filled with different concentrations of contrast media (1.88-30 mg iodine/ml). CT density of the tubes and noise of the surrounding water were determined using two multidetector scanners (Philips MX8000 with four rows, Siemens Sensation 16 with 16 rows) with varying tube current-time product (15-100 mAs per slice), voltage (90 kV, 100 kV, 120 kV), pitch (0.875-1.75), and slice thickness (1 mm, 2 mm, 3.2 mm). Contrast-to-noise ratio as a parameter of image quality was correlated with dose (CTDI) and was compared with image evaluation by two radiologists. The CT densities of different concentrations of contrast media and contrast-to-noise ratio were significantly higher when low voltages (90 kV versus 120 kV, 100 kV versus 120 kV) were applied. Smaller slice thickness (1 mm versus 2 mm) did not change CT density but decreased contrast-to-noise ratio due to increased noise. Contrast phantom studies showed favourable effects of low tube voltage on image quality in the low dose range. This may facilitate substantial dose reduction in CT urography.
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Affiliation(s)
- E Coppenrath
- Clinical Radiology, Ludwig-Maximilians University of Munich, Ziemssenstrasse 1, 80336, Munich, Germany.
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Sudakoff GS, Dunn DP, Hellman RS, Laguna MA, Wilson CR, Prost RW, Eastwood DC, Lim HJ. Opacification of the genitourinary collecting system during MDCT urography with enhanced CT digital radiography: nonsaline versus saline bolus. AJR Am J Roentgenol 2006; 186:122-9. [PMID: 16357390 DOI: 10.2214/ajr.04.1835] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to determine whether a saline bolus during CT urography improves urinary collecting system opacification and whether the addition of enhanced CT digital radiography (CTDR) improves urinary collecting system visualization with or without a saline bolus. MATERIALS AND METHODS One hundred eight CT urography and enhanced CTDR examinations were reviewed. Fifty-four patients were given a saline bolus during CT urography, and 54 patients underwent CT urography without a saline bolus. Urinary collecting system opacification was evaluated by group (saline vs nonsaline), imaging technique (CT urography alone vs CT urography plus enhanced CTDR), number of enhanced CTDR images, and site of nonopacified urinary segments. Using a multivariate logistic regression model, we determined significance of variables and odds of complete opacification. RESULTS In the saline group, 248 nonopacified sites were identified on CT urography alone and 95 sites with CT urography plus enhanced CTDR. In the nonsaline group, 185 nonopacified sites were identified on CT urography alone and 59 sites with CT urography plus enhanced CTDR. Combining both groups, 433 nonopacified sites were identified with CT urography alone and 154 sites with CT urography plus enhanced CTDR. Multivariate logistic regression showed significance for group (p = 0.010), imaging method (p < 0.0001), number of enhanced CTDR images (p = 0.048), and site of segment opacification (p < 0.0001). The renal pelvis shows the greatest odds and the distal ureter the lowest odds for complete opacification by group or imaging method. CONCLUSION The addition of a saline bolus offers no improvement, whereas the addition of enhanced CTDR offers significant improvement in collecting system opacification during CT urography.
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Affiliation(s)
- Gary S Sudakoff
- Department of Radiology, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, 9200 W. Wisconsin Avenue, Milwaukee, WI 53226, USA.
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Huang J, Kim YH, Shankar S, Tyagi G, Baker SP. Multidetector CT urography: comparison of two different scanning protocols for improved visualization of the urinary tract. J Comput Assist Tomogr 2006; 30:33-6. [PMID: 16365569 DOI: 10.1097/01.rct.0000191682.13097.6d] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The goal of this study was to evaluate different CT scanning protocols on the depiction of the urinary tract by multidetector CT. The authors retrospectively reviewed 55 consecutive patients who underwent CT scanograms. Two groups of patients were included: renal donors (n=29) and hematuria patients (n=26). For the renal donor protocol, 120 mL of iodinated contrast was injected and a CT scanogram was obtained after a 5-minute delay. For the hematuria CT urography protocol, 100 mL of contrast was followed by a 250 mL normal saline drip and CT scanograms acquired after an 8-minute delay. Urinary tracts from both imaging protocols were then divided into four segments and evaluated by consensus reading of two experienced radiologists rated on a scale of 0 to 2. Complete visualization of the renal pelvis and the proximal, middle, and distal ureter for the renal donor protocol was noted to be 86%, 57%, 45%, and 52% and for that of the CT urography protocol to be 75%, 65%, 40%, and 44%, respectively. Comparing scanograms of the renal donor protocol and the CT urography protocol, there was no statistically significant difference in the depiction of renal pelvis or the proximal, middle or distal ureteral region (P=0.1625, 0.3226, 0.8636, and 0.6145, respectively). The study demonstrates that there is no significant difference between the CT urography protocol and the renal donor protocol in the depiction of the urinary tract.
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Affiliation(s)
- Jiayi Huang
- University of Massachusetts Medical School, and Department of Radiology, UMass Memorial Health Care, Worcester, MA 01655, USA
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15
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Kemper J, Adam G, Nolte-Ernsting C. [Multislice CT urography Aspects for technical management and clinical application]. Radiologe 2006; 45:905-14. [PMID: 16021410 DOI: 10.1007/s00117-005-1210-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The introduction of multislice computed tomography with its well-known advantages has made it possible to visualize the entire urinary tract with thin collimation during a breath-holding phase. CT data acquisition during urographic contrast enhancement for contiguous imaging of the entire upper urinary tract is termed "multislice CT urography" (MSCTU). Multiplanar reconstructions, maximum intensity projections, and average intensity projections can be rendered from the volume datasets to view the urogenital tract. MSCTU will play an important role in the future of modern uroradiology. This article describes the technical aspects involved in the course of the MSCTU examination and identifies additional potential indications for clinical application.
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Affiliation(s)
- J Kemper
- Radiologisches Zentrum, Klinik für Diagnostische und Interventionelle Radiologie, Universitätsklinikum Hamburg-Eppendorf.
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16
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Abstract
Multidetector row CT is the most recent advance in CT technology. An increased number of detector rows and more powerful x-ray tubes result in faster scanning time, increased volume coverage, and improved spatial and temporal resolution. MDCT technology allows superior image quality, decreased examination time, and the ability to perform complex multiphase vascular and three-dimensional examinations.
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Affiliation(s)
- Ercan Kocakoc
- Department of Radiology, Faculty of Medicine, Firat University, Elazig, Turkey
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17
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Raptopoulos V, McNamara A. Improved pelvicalyceal visualization with multidetector computed tomography urography; comparison with helical computed tomography. Eur Radiol 2005; 15:1834-40. [PMID: 15761715 DOI: 10.1007/s00330-005-2699-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Revised: 01/10/2005] [Accepted: 01/18/2005] [Indexed: 11/24/2022]
Abstract
Our aim was to compare the quality of pelvicalyceal visualization on computed tomography (CT) urography using a small intravenous contrast material dose, hydration, and high-resolution multidetector CT (MDCT) with that of conventional helical CT. The test (MDCT) group (49 consecutive patients, 98 kidneys) was scanned 5 min following an intravenous bolus of 30 ml of iodinated contrast material. The control (helical CT) group (50 consecutive patients, 95 kidneys) was scanned 5 min following injection of 120-150 ml of intravenous contrast material. Enhancement and quality of calyceal detail were measured using a five-scale grading system (1 for no detail, 5 for cupped calyces). Calyceal attenuation was substantial in both groups (more than 220 Hounsfield units, HU) but less in the test group compared with the control group (mean 475 and 920 HU, respectively), p<0.0001. In the test group, the calyceal attenuation was less than 500 HU in the majority of cases (65/98 kidneys), while the opposite was true for the control group, where calyceal attenuation was more than 750 HU in 50/95 kidneys (p<0.001). The quality of calyceal detail was 3.4/5 in the test group compared with 1.8/5 in the control group (p<0.0001). The combination of hydration, low-contrast dose, and the high image resolution achieved with MDCT significantly improves calyceal visualization in CT urography.
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Affiliation(s)
- V Raptopoulos
- Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, USA.
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18
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Norrman E, Persliden J. A factorial experiment on image quality and radiation dose. RADIATION PROTECTION DOSIMETRY 2005; 114:246-52. [PMID: 15933116 DOI: 10.1093/rpd/nch557] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
To find if factorial experiments can be used in the optimisation of diagnostic imaging, a factorial experiment was performed to investigate some of the factors that influence image quality, kerma area product (KAP) and effective dose (E). In a factorial experiment the factors are varied together instead of one at a time, making it possible to discover interactions between the factors as well as major effects. The factors studied were tube potential, tube loading, focus size and filtration. Each factor was set to two levels (low and high). The influence of the factors on the response variables (image quality, KAP and E) was studied using a direct digital detector. The major effects of each factor on the response variables were estimated as well as the interaction effects between factors. The image quality, KAP and E were mainly influenced by tube loading, tube potential and filtration. There were some active interactions, for example, between tube potential and filtration and between tube loading and filtration. The study shows that factorial experiments can be used to predict the influence of various parameters on image quality and radiation dose.
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Affiliation(s)
- Eva Norrman
- Department of Natural Sciences, Orebro University, S-70182 Orebro, Sweden.
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Noroozian M, Cohan RH, Caoili EM, Cowan NC, Ellis JH. Multislice CT urography: state of the art. Br J Radiol 2004; 77 Spec No 1:S74-86. [PMID: 15546844 DOI: 10.1259/bjr/13478281] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Recent improvements in helical CT hardware and software have provided imagers with the tools to obtain an increasingly large number of very thin axial images. As a result, a number of new applications for multislice CT have recently been developed, one of which is CT urography. The motivation for performing CT urography is the desire to create a single imaging test that can completely assess the kidneys and urinary tract for urolithiasis, renal masses and mucosal abnormalities of the renal collecting system, ureters and bladder. Although the preferred technique for performing multislice CT urography has not yet been determined and results are preliminary, early indications suggest that this examination can detect even subtle benign and malignant urothelial abnormalities and that it has the potential to completely replace excretory urography within the next several years. An important limitation of multislice CT urography is increased patient radiation exposure encountered when some of the more thorough recommended techniques are utilized.
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Affiliation(s)
- M Noroozian
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109, USA
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20
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Burgess K, Slovis TL. The gold standard: PACS alchemy and the gold standard. Pediatr Radiol 2004; 34:931-2. [PMID: 15517237 DOI: 10.1007/s00247-004-1296-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 06/25/2004] [Indexed: 11/26/2022]
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Kawashima A, Vrtiska TJ, LeRoy AJ, Hartman RP, McCollough CH, King BF. CT Urography. Radiographics 2004; 24 Suppl 1:S35-54; discussion S55-8. [PMID: 15486248 DOI: 10.1148/rg.24si045513] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
With the recent introduction of multi-detector row helical computed tomography (CT), the radiologic evaluation of patients with urologic disease has changed rapidly. Two major approaches to CT urography have been developed. The first approach combines axial CT with timed excretory urography (EU) performed by using conventional radiography, digital radiography, or CT scanned projection radiography (SPR). This approach produces traditional projection urograms, and the timed imaging technique is familiar to radiologists and clinicians. Additional excretory phase CT can be performed when the EU findings are positive or indeterminate. Improved CT SPR processing technology produces radiographlike images, thus eliminating patient transportation between the CT and urography suites or the necessity for a CT suite with a ceiling-mounted x-ray tube and a modified CT tabletop for performance of EU. The second approach to CT urography combines axial CT with thin-section excretory phase CT. The near-isotropic volume data set enables creation of high-resolution two- and three-dimensional reformatted images. However, the increased amount of radiation and the time required for data manipulation are concerns. Further studies evaluating large numbers of patients with various urothelial abnormalities will be necessary to determine the optimal CT urography technique for clinical practice.
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Affiliation(s)
- Akira Kawashima
- Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
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Nawfel RD, Judy PF, Schleipman AR, Silverman SG. Patient radiation dose at CT urography and conventional urography. Radiology 2004; 232:126-32. [PMID: 15220498 DOI: 10.1148/radiol.2321030222] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE To measure and compare patient radiation dose from computed tomographic (CT) urography and conventional urography and to compare these doses with dose estimates determined from phantom measurements. MATERIALS AND METHODS Patient skin doses were determined by placing a thermoluminescent dosimeter (TLD) strip (six TLD chips) on the abdomen of eight patients examined with CT urography and 11 patients examined with conventional urography. CT urography group consisted of two women and six men (mean age, 55.5 years), and conventional urography group consisted of six women and five men (mean age, 58.9 years). CT urography protocol included three volumetric acquisitions of the abdomen and pelvis. Conventional urography protocol consisted of acquisition of several images involving full nephrotomography and oblique projections. Mean and SD of measured patient doses were compared with corresponding calculated doses and with dose measured on a Lucite pelvic-torso phantom. Correlation coefficient (R(2)) was calculated to compare measured and calculated skin doses for conventional urography examination, and two-tailed P value significance test was used to evaluate variation in effective dose with patient size. Radiation risk was calculated from effective dose estimates. RESULTS Mean patient skin doses for CT urography measured with TLD strips and calculated from phantom data (CT dose index) were 56.3 mGy +/- 11.5 and 54.6 mGy +/- 4.1, respectively. Mean patient skin doses for conventional urography measured with TLD strips and calculated as entrance skin dose were 151 mGy +/- 90 and 145 mGy +/- 76, respectively. Correlation coefficient between measured and calculated skin doses for conventional urography examinations was 0.95. Mean effective dose estimates for CT urography and conventional urography were 14.8 mSv +/- 90.0 and 9.7 mSv +/- 3.0, respectively. Mean effective doses estimated for the pelvic-torso phantom were 15.9 mSv (CT urography) and 7.8 mSv (conventional urography). CONCLUSION Standard protocol for CT urography led to higher mean effective dose, approximately 1.5 times the radiation risk for conventional urography. Patient dose estimates should be taken into consideration when imaging protocols are established for CT urography.
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Affiliation(s)
- Richard D Nawfel
- Department of Radiology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA.
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Akbar SA, Mortele KJ, Baeyens K, Kekelidze M, Silverman SG. Multidetector CT urography: techniques, clinical applications, and pitfalls. Semin Ultrasound CT MR 2004; 25:41-54. [PMID: 15035531 DOI: 10.1053/j.sult.2003.11.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
For two decades, computed tomography (CT) has challenged intravenous urography (IVU) in the evaluation of urinary tract abnormalities. Compared with IVU, CT is more sensitive and specific in the detection and characterization of a variety of urinary tract disorders, including renal masses and urolithiasis. The last purported advantage of IVU has been its ability to depict subtle and mucosal abnormalities of the urothelium. Now, using multidetector CT (MDCT), this challenge has been overcome. In this article, we review the current role of MDCT urography in the evaluation of the urinary tract.
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Affiliation(s)
- Syed A Akbar
- Division of Abdominal Imaging and Intervention, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
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Kim JK, Park SY, Kim HJ, Kim CS, Ahn HJ, Ahn TY, Cho KS. Living donor kidneys: usefulness of multi-detector row CT for comprehensive evaluation. Radiology 2003; 229:869-76. [PMID: 14593192 DOI: 10.1148/radiol.2293021098] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate in living renal donors the usefulness of multi-detector row computed tomography (CT) in the assessment of renal vasculature and the upper urinary tract. MATERIALS AND METHODS Four-channel multi-detector row CT scans were obtained in 77 patients. Vascular phase scans were used for CT angiography; excretory phase scans, for CT urography. At CT angiography, two independent observers evaluated the number of arteries and veins and the presence of early-branching arteries. CT urographic images were evaluated with regard to the opacification of the urinary tract and for abnormalities. Findings of CT angiography and urography were compared with surgical findings. Interobserver agreement between CT angiographic and surgical findings was quantified with weighted kappa statistics. Sensitivity and specificity of CT angiography in identifying supernumerary vessels and early-branching arteries were also evaluated. To evaluate the radiation dose to patients, weighted CT dose index (DI) was assessed for each scan. RESULTS Agreement between CT angiographic and surgical findings was excellent for the number of renal arteries (kappa = 0.896) and veins (kappa = 0.843). Detection rate of CT angiography was 98% (89 of 91) for arteries and 98% (83 of 85) for veins. The respective sensitivity and specificity of CT angiography were 86% (12 of 14) and 100% (65 of 65) for supernumerary arteries, 100% (11 of 11) and 100% (66 of 66) for early-branching arteries, and 75% (six of eight) and 100% (69 of 69) for supernumerary veins. At CT urography, collecting systems and proximal ureters were well opacified in all patients; two patients had underrotated kidneys without obstruction. The weighted CT DI was 10.19 mGy for unenhanced and excretory phase scans and 12.88 mGy for the vascular phase scan. CONCLUSION Multi-detector row CT can help assess well the renal vasculature and the urinary tract of living renal donors.
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Affiliation(s)
- Jeong-Kon Kim
- Departments of Radiology and Urology, Asan Medical Center, University of Ulsan, 388-1 Poongnap-dong, Songpa-gu, Seoul 138-736, Korea
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25
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Abstract
CT urography and MR urography are an evolving concept and developing technique. As the technology matures, CT urography will combine the ultimate diagnostic capabilities of intravenous urography and CT. In the near future, many intravenous urograms will be replaced by CT urography to evaluate patients with hematuria and other genitourinary conditions. MR urography currently serves as an alternative imaging technique to intravenous urography and CT urography for children and pregnant women and for patients with contraindications to iodinated contrast media.
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Affiliation(s)
- Akira Kawashima
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA.
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