Multidetector CT angiography for preoperative evaluation of living laparoscopic kidney donors

OBJECTIVE: The purpose of this study was to determine the accuracy of multidetector CT (MDCT) angiography as the primary imaging technique in the evaluation of living kidney donors. SUBJECTS AND METHODS: Seventy-four consecutive living kidney donors (30 men, 44 women; mean age, 41.7 years) who underwent MDCT were evaluated. CT examination was performed with 120 mL of IV contrast material at an injection rate of 3 mL/sec and a pitch of 6. In every case, arterial and venous phase volumetric data sets were acquired at 25 and 55 sec, respectively. Scans were reconstructed at 1-mm intervals for three-dimensional (3D) imaging using a volume-rendering technique. Axial CT images and 3D CT angiography were evaluated prospectively by one reviewer and retrospectively by two reviewers who had no knowledge of surgical results. Surgical correlation for the location of primary and accessory renal arteries, early branching of the renal arteries, and renal vein anomalies was made. RESULTS: Seventy-two subjects underwent left nephrectomy, and two subjects underwent right nephrectomy because supernumerary left renal arteries were detected on preoperative CT angiography. Eighteen supernumerary renal arteries (two arteries to 16 kidneys and three arteries to one kidney) to 74 kidneys underwent nephrectomy. CT and surgical findings agreed in 93% of subjects (the average of three reviewers; range, 89-97%). Two small accessory renal arteries were missed by all three reviewers. Those arteries were diminutive and were thought to be insignificant by the surgeons. Early branching of the renal arteries was shown in 14 arteries, and CT and surgical findings agreed in 96% (the average of three reviewers; range, 93-97%). Renal vein anomalies were present in eight subjects, and CT and surgical findings agreed in 99% of the cases (range, 96-100%). CONCLUSION: MDCT angiography is highly accurate for detecting vascular anomalies and providing anatomic information for laparoscopic living donor nephrectomy.     

Evaluation of renal arteries in living renal donors: comparison between MDCT angiography and gadolinium-enhanced 3D MR angiography

Purpose The purpose of this study was to clarify and compare the accuracy of contrast-enhanced computed tomography (CT) angiography using multidetector-row helical CT (MDCT angiography) and gadolinium-enhanced MR angiography using three-dimensional Fourier transformation gradient-echo sequence (3D MR angiography) for preoperative evaluation of renal arteries in living renal donors. Materials and methods A total of 42 living renal donor candidates underwent both MDCT angiography and 3D MR angiography before digital subtraction angiography (DSA). Each MDCT angiogram and 3D MR angiogram was prospectively interpreted, and the findings were compared with the DSA results. Results MDCT angiography identified all of the 12 supernumerary arteries detected by DSA, whereas 3D MR angiography identified only 8. MDCT angiography identified all of the 19 proximal arterial branches detected by DSA, whereas 3D MR angiography identified only 16. Conclusion A more accurate depiction of renal arteries in living renal donors can be achieved with MDCT angiography than with 3D MR angiography.     

US, CT, and MR evaluation of accessory renal arteries and proximal renal arterial branches

RATIONALE AND OBJECTIVES: The purpose of this study was to compare color Doppler ultrasound (US), computed tomographic (CT) angiography, and magnetic resonance (MR) angiography for the evaluation of accessory renal arteries and proximal branches of the main renal artery. MATERIALS AND METHODS: Fifty-six subjects who had undergone conventional arteriography of the renal arteries participated in a prospective comparison of Doppler US (45 patients), CT angiography (52 patients), and nonenhanced MR angiography (28 patients). Conventional arteriography depicted 28 accessory renal arteries and 21 proximal branches of the main renal artery within 2 cm of the aorta. RESULTS: US depicted five of 24 accessory renal arteries seen at arteriography but no proximal arterial branches. CT angiography depicted 24 of 26 accessory renal arteries and 13 of 17 proximal arterial branches, as well as 15 additional accessory renal arteries not seen at conventional arteriography. MR demonstrated 11 of 15 accessory arteries, as well as four additional accessory arteries not seen at conventional arteriography. MR did not depict any of nine proximal arterial branches seen at conventional arteriography. CONCLUSION: When compared with US or nonenhanced MR angiography, CT is the preferred method for evaluation of accessory renal arteries and proximal branches of the renal artery.     

Noninvasive imaging of living related kidney donors: evaluation with CT angiography and gadolinium-enhanced MR angiography.

OBJECTIVE: This study was performed to determine whether noninvasive imaging with CT angiography and MR angiography in the preoperative investigation of living, related kidney donors provides sufficient information for the surgeon. MATERIALS AND METHODS: Eighty consecutive potential living kidney donors were investigated. Fifty patients underwent CT angiography and 30 underwent MR angiography before donor nephrectomy. CT was performed using 3-mm collimation with a pitch of 1.6 after the injection of 150 mL of nonionic contrast medium. The axial data, multiplanar reconstructions, and maximum intensity projections were reviewed. MR angiography was performed on a 1-T magnet using a contrast-enhanced three-dimensional gradient echo technique. Maximum intensity projections and axial reformations were reviewed. Imaging findings were compared with the surgical results in 54 patients. RESULTS: CT angiography and MR angiography were 100% sensitive in identifying the main renal arteries and renal veins. CT angiography visualized 37 of the 40 arteries identified at surgery, for a detection rate of 93%. MR angiography visualized 18 of the 20 arteries identified at surgery, a detection rate of 90%. CONCLUSION: CT angiography and MR angiography are suitable for the noninvasive investigation of living kidney donors and provide all the information required by the surgeon. Both methods may miss small accessory renal arteries. MR angiography does not use potentially toxic contrast material or radiation and is the preferred investigation, with CT angiography reserved for patients unable to tolerate MR imaging.     

Living donor kidneys: usefulness of multi-detector row CT for comprehensive evaluation

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.     

64层CT肾血管成像在肾移植供体评价中的临床应用价值

目的:评价64层螺旋CT肾血管成像技术在肾移植供体评价中的临床应用价值。方法:对40例亲属供肾者行64层螺旋CT肾血管成像,应用容积再现(VR)、最大密度投影(MIP)、多平面重组(MPR)等技术进行肾血管重建,评价供肾血管情况,将影像学表现与术中所见进行对照。结果:40例供肾者1次屏气完成扫描,均获得满意的轴面图像,应用VR、MIP、MPR等后处理技术重建肾血管,可清晰显示肾动脉主干及其2～4级分支。9例单侧肾由副肾动脉供血,其中8例单侧肾见单支副肾动脉,1例双侧肾各见1支副肾动脉;9例存在肾动脉分支过早,其中1例双肾动脉均为肾动脉分支过早,共10支血管距离肾动脉开口在1.5cm以内;2例显示肾静脉解剖变异。CT血管成像对供肾动静脉主干、副肾动脉、肾动脉分支过早、肾静脉主干变异的显示与术中所见一致。结论:64层螺旋CT肾血管成像是肾移植术前评价活体供肾血管的一种无创、安全、经济、有效的检查方法。     

Ureteropelvic junction obstruction: use of helical CT for preoperative assessment--comparison with intraarterial angiography

PURPOSE: To evaluate helical computed tomography (CT) in the preoperative assessment of crossing arteries in kidneys with ureteropelvic junction (UPJ) obstruction and to compare the results with those obtained by means of angiography. MATERIALS AND METHODS: Forty-one consecutive patients with symptomatic UPJ obstruction in 42 obstructed kidneys underwent renal helical CT and renal intraarterial digital subtraction angiography (DSA; flush aortography and bilateral selective renal injections). The helical CT and DSA images were interpreted in a blinded manner by two readers, and the results were compared. RESULTS: DSA showed 126 renal arteries in the 41 patients; 56% of patients had supernumerary renal arteries. Helical CT depicted 121 (96%) of these 126 renal arteries prospectively. Retrospectively, 124 (98%) renal arteries were visible on CT images. Twelve (29%) of the 42 kidneys with UPJ obstruction had identifiable arteries crossing the UPJ on DSA images. If DSA is used as the standard of reference, CT angiography was 100% sensitive and 96.6% specific for depicting these crossing arteries. CONCLUSION: Renal helical CT seems suitable to replace intraarterial DSA in the preoperative assessment of crossing arteries in kidneys with UPJ obstruction.     

Aortoiliac and renal arteries: prospective intraindividual comparison of contrast-enhanced three-dimensional MR angiography and multi-detector row CT angiography

PURPOSE: To compare contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography and multi-detector row computed tomographic (CT) angiography in the same patients for assessment of the aortoiliac and renal arteries, with digital subtraction angiography (DSA) as the standard of reference. MATERIALS AND METHODS: DSA, 3D MR angiography, and multi-detector row CT angiography were performed in 46 consecutive patients. A total of 769 arterial segments were analyzed for arterial stenosis by using a four-point grading system. Aneurysmal changes were noted. The time required for performing 3D reconstructions and image analysis of both MR and CT data sets was measured. Patient acceptance for each modality was assessed with a visual analogue scale. Statistical analysis of data was performed. RESULTS: Sensitivity of MR angiography for detection of hemodynamically significant arterial stenosis was 92% for reader 1 and 93% for reader 2, and specificity was 100% and 99%, respectively. Sensitivity of CT angiography was 91% for reader 1 and 92% for reader 2, and specificity was 99% and 99%, respectively. Differences between the two modalities were not significant. Interobserver and intermodality agreement was excellent (kappa = 0.88-0.90). The time for performance of 3D reconstruction and image analysis of CT data sets was significantly longer than that for MR data sets (P <.001). Patient acceptance was best for CT angiography (P =.016). CONCLUSION: There is no statistically significant difference between 3D MR angiography and multi-detector row CT angiography in the detection of hemodynamically significant arterial stenosis of the aortoiliac and renal arteries.     

Comparing contrast-enhanced breath-hold MR angiography and conventional angiography in the evaluation of mesenteric circulation

OBJECTIVE: Our aim was to compare the results of gadolinium-enhanced breath-hold MR angiography with those of conventional angiography for the study of mesenteric circulation. SUBJECTS AND METHODS: MR angiography and digital subtraction angiography were prospectively performed in 33 patients referred for hepatic, pancreatic, or mesenteric disease. MR angiography was performed with four three-dimensional acquisitions at 0, 30, 60, and 90 sec after injection of 0.1 mmol/kg of gadolinium. Selective conventional angiography was used as the standard of reference. RESULTS: A pure arterial angiogram (one on which veins could not be visualized) was obtained in 27 patients during the second or third acquisition. By subtracting the arterial phase from an arteriovenous phase (third or fourth acquisition) we obtained a pure venous angiogram (one on which arteries could not be visualized) in 28 patients. Agreement was good or excellent for the hepatic artery (kappa = 0.78), the superior mesenteric artery (kappa = 0.65), the splenic artery (kappa = 0.70), the portal vein (kappa = 1.0), the superior mesenteric vein (kappa = 0.88), and the splenic vein (kappa = 0.75). Agreement was poor, and vessels were better shown by conventional angiography, for the intrahepatic arteries (kappa = 0.006) and the branches of the superior mesenteric artery (kappa = 0.14). MR angiography and conventional angiography revealed 29 and 27 portosystemic collaterals, respectively. CONCLUSION: Dynamic breath-hold contrast-enhanced MR angiography compared favorably with conventional angiography in preoperative assessment of the proximal mesenteric arteries and in the evaluation of portal hypertension; however, conventional angiography is still necessary to evaluate distal arteries.     

Preoperative evaluation of potential living related kidney donors with high-spatial-resolution magnetic resonance (MR) angiography at 3 Tesla: comparison with intraoperative findings

PURPOSE: The purpose of this prospective study was to determine the feasibility and accuracy of high-spatial-resolution MR imaging at 3 Tesla (T) in the preoperative evaluation of potential living related kidney donors. MATERIALS AND METHODS: Eighteen potential donors (8 men, 10 women; mean age, 50.1 +/- 14.2 years) for renal transplantation were evaluated with 3 T MR imaging. A high-spatial-resolution 3-dimensional (3D) gradient-echo MR angiography (repetition time/echo time, 3.0/1.14 ms; flip, 19-23 degrees; matrix, 512; slice thickness, 1.0 mm) using parallel acquisition technique (GRAPPA) with an acceleration factor of 3 was performed on a whole body scanner. Images were evaluated in a prospective and blinded fashion by 2 MR radiologists. The number of renal arteries, presence of early branches (defined as a branch arising within 2 cm of the main renal ostium), and renal artery stenosis were analyzed. The renal parenchyma, collecting system and ureters, were evaluated on the MR urograms. Interpretation of MR images were compared with surgical findings. RESULTS: Based on MR angiography data sets, a total of 36 main and 9 accessory renal arteries was found. There were 5 renal arteries presenting an early branching (相似文献   

Preoperative evaluation of live renal donors using multislice CT angiography

AIM: To determine the accuracy of multidetector row CT renal angiography in the preoperative evaluation of live kidney donors, and to identify potential pitfalls when reporting. METHODS: Between July 1998 and June 2003, 74 consecutive live renal donors underwent contrast-enhanced multidetector row CT renal angiography before donor nephrectomy. The operative notes and radiological reports of all cases were reviewed retrospectively. Where a significant discrepancy was identified, the archived images were reviewed by two radiologists in the light of the intraoperative findings. RESULTS: A total of 12 discrepancies were identified in 11 of the 74 cases (15%). In the preoperative CT angiography reports, 4 accessory arteries, 6 early-branching renal arteries, 1 duplicated renal vein and 1 accessory ureter were not identified; 9 of these were evident on review, but were not detected at the time of reporting. In 3 cases (1 accessory artery, the duplicated renal vein and the accessory ureter), the anomaly was not visible on review of the CT angiographic data, even with the benefit of hindsight. Surgical feedback during the study period resulted in modifications to CT technique and improved performance. CONCLUSION: In the majority of cases, there was good correlation between preoperative CT renal angiography and operative findings. Most discrepancies were due either to an oversight by the reporting radiologist, or failure to fully appreciate the potential surgical significance of certain findings. Regular surgical feedback plays a valuable role in improving reporting accuracy and maintaining imaging standards.     

Assessment of aortoiliac and renal arteries: MR angiography with parallel acquisition versus conventional MR angiography and digital subtraction angiography

PURPOSE: To prospectively compare the image quality, sensitivity, and specificity of three-dimensional gadolinium-enhanced magnetic resonance (MR) angiography accelerated by parallel acquisition (ie, fast MR angiography) with MR angiography not accelerated by parallel acquisition (ie, conventional MR angiography) for assessment of aortoiliac and renal arteries, with digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: The study was approved by the institutional review board; informed consent was obtained from all patients. Forty consecutive patients (33 men, seven women; mean age, 63 years) suspected of having aortoiliac and renal arterial stenoses and thus examined with DSA underwent both fast (mean imaging time, 17 seconds) and conventional (mean imaging time, 29 seconds) MR angiography. The arterial tree was divided into segments for image analysis. Two readers independently evaluated all MR angiograms for image quality, presence of arterial stenosis, and renal arterial variants. Image quality, sensitivity, and specificity were analyzed on per-patient and per-segment bases for multiple comparisons (with Bonferroni correction) and for dependencies between segments (with patient as the primary sample unit). Interobserver agreement was evaluated by using kappa statistics. RESULTS: Overall, the image quality with fast MR angiography was significantly better (P=.001) than that with conventional MR angiography. At per-segment analysis, the image quality of fast MR angiograms of the distal renal artery tended to be better than that of conventional MR angiograms of these vessels. Differences in sensitivity for the detection of arterial stenosis between the two MR angiography techniques were not significant for either reader. Interobserver agreement in the detection of variant renal artery anatomy was excellent with both conventional and fast MR angiography (kappa=1.00). CONCLUSION: Fast MR angiography and conventional MR angiography do not differ significantly in terms of arterial stenosis grading or renal arterial variant detection.     

Hepatic arteries in potential donors for living related liver transplantation: evaluation with multi-detector row CT angiography

PURPOSE: To assess the accuracy of multi-detector row computed tomographic (CT) angiography in the evaluation of hepatic arterial anatomy in living related liver transplantation (LRLT) donors. MATERIALS AND METHODS: During a 10-month period, 62 potential LRLT donors were evaluated with CT and conventional angiography. Multi-detector row CT was performed after intravenous injection of 150 mL of contrast material at 3 mL/sec. CT angiograms of the hepatic arteries were generated by a radiologist who used volume rendering and maximum intensity projection techniques without knowledge of results of conventional angiography. Two reviewers reviewed CT and conventional angiograms retrospectively in consensus. The results of the two examinations were then compared. RESULTS: CT examinations were technically adequate in 56 (90%) donors. Respiratory motion artifact compromised detailed hepatic artery analysis in six donors (10%). Second-order branches of right hepatic arteries were visualized in 58 donors (94%), and second-order branches of left hepatic arteries were visualized in 51 (82%). A total of 27 hepatic arterial anatomic variations were detected in 22 donors at conventional angiography. CT angiography accurately depicted 25 (93%) anatomic variations in 20 donors (91%). CT angiography did not depict an accessory right hepatic artery in two donors. The number and origins of dominant arteries supplying segment IV were accurately identified at CT angiography in 51 donors (82%). Hepatic arterial anatomy depicted at CT angiography was identical to that at conventional angiography in 50 donors (81%). CONCLUSION: Multi-detector row CT angiography is useful but limited in its ability to depict the dominant artery supplying segment IV and small accessory hepatic arteries.     

Time-resolved contrast-enhanced MR angiography of renal artery stenosis: diagnostic accuracy and interobserver variability

OBJECTIVE: The purpose of this study was to evaluate diagnostic accuracy and interobserver variability of time-resolved three-dimensional gadolinium-enhanced MR angiography in the detection of renal artery stenosis in comparison with intraarterial digital subtraction angiography as the standard of reference. SUBJECTS AND METHODS: Forty consecutive patients (age range, 25-81 years; mean, 62.9 +/- 11.9 years) with suspected renal artery stenosis underwent intraarterial digital subtraction angiography and gadolinium-enhanced MR angiography, performed on a 1.5-T system with fast low-angle shot three-dimensional imaging (3.8/1.49 [TR/TE], 25 degrees flip angle, 10-sec acquisition time, and 1.5-mm partition thickness). Three time-resolved phases were obtained in a single breath-hold. Digital subtraction angiography and gadolinium-enhanced MR angiography were evaluated by four observers who studied 80 main renal arteries and 19 accessory vessels to evaluate the degree of stenosis. A stenosis reducing the intraarterial diameter by more than 50% was regarded as hemodynamically significant. Interobserver variability was calculated. RESULTS: Only one gadolinium-enhanced MR angiography study was not of diagnostic quality, as a result of failure of the power injector. All main branches were of diagnostic quality in 38 (97.4%) of the remaining 39 gadolinium-enhanced MR angiography studies. Seventeen (89.5%) of 19 accessory renal arteries were depicted with gadolinium-enhanced MR angiography. The overall sensitivity for significant stenoses was 92.9%. The overall specificity was 83.4%, and the overall accuracy was 85.9%. Interobserver variability of gadolinium-enhanced MR angiography exceeded that of digital subtraction angiography. CONCLUSION: Time-resolved three-dimensional gadolinium-enhanced MR angiography is a useful noninvasive method of screening suspected renal artery stenosis because of its easy application, short examination time, and high sensitivity despite of its higher interobserver variability.     

Prospective blinded evaluation of Gd-DOTA- versus Gd-BOPTA-enhanced peripheral MR angiography,as compared with digital subtraction angiography

PURPOSE: To compare the diagnostic accuracy of gadobenate dimeglumine (Gd-BOPTA)-enhanced versus gadoterate meglumine (Gd-DOTA)-enhanced magnetic resonance (MR) angiography in patients with peripheral arterial occlusive disease (PAOD). MATERIALS AND METHODS: Fifty-six patients underwent MR angiography enhanced with either Gd-DOTA (28 patients) or Gd-BOPTA (28 patients). All arterial segments from the renal arteries to the distal run-off vessels were evaluated for disease severity. The sensitivity, specificity, and accuracy of MR angiography enhanced with both agents separately were evaluated with a paired t test; digital subtraction angiography was the reference standard. Interobserver variability was assessed by using the Cohen test. RESULTS: Diagnostic MR angiograms were obtained in all 56 patients. Overall, sensitivity and specificity of Gd-DOTA-enhanced MR angiography were 96% and 93%, respectively, for observer 1 and 96% and 85%, respectively, for observer 2 (kappa = 0.82). Corresponding values for Gd-BOPTA-enhanced MR angiography were 94% and 93%, respectively, for observer 1 and 94% and 89%, respectively, for observer 2 (kappa = 0.78). No consistent differences between the two contrast materials in assessment of PAOD in the renal to popliteal arteries were observed. For assessment below the knee, specificity was slightly higher in the Gd-BOPTA group-91% and 84% for observers 1 and 2, respectively-than in the Gd-DOTA group-89% and 77%, respectively (P <.01). The number of nonassessable below-the-knee segments was significantly lower in the Gd-BOPTA group: nine of 299 segments versus 25 of 312 segments in the Gd-DOTA group (P <.01). CONCLUSION: At MR angiography of the distal run-off vessels, Gd-BOPTA yielded higher specificity and a significantly smaller number of nonassessable segments than Gd-DOTA. The diagnostic accuracy of the two gadolinium chelates at peripheral MR angiography was comparable in the renal to popliteal arteries.     

动态增强MR血管成像对活体肾移植供体术前的评估

目的 探讨动态增强MRA对活体肾移植供体血管解剖的显示情况.方法 35名肾移植供体,术前行MRA检查.首先经静脉注入1 ml对比剂Gd-DTPA,测出循环至肾动脉时间.然后行冠状面3D T1加权快速扰相小角度梯度回波(3D FLASH)序列扫描.自动脉期开始连续扫描4期,每期间隔10 s,获得肾动脉、肾静脉、集合系统等各期图像.2名放射科医师观察原始图像及MIP重组后图像,观察肾动脉、肾静脉及其分支的显示情况,确定血管的走形及有无变异.并把MRA图像质量确定为5级,与32名手术结果进行比较.结果 MRA对于肾动脉、肾静脉系统的显示质量均较好.35名供者70个肾脏中发现5支左肾副动脉,9支右副肾动脉.3支左肾动脉过早分支,6只右肾动脉过早分支,其中1支右侧双肾静脉,2例左侧精索静脉粗大.1例右肾副上极动脉MRA术前未发现.结论 动态增强MRA安全无创,对肾动脉、肾静脉显示清楚,诊断变异准确度高,是术前肾移植供体血管评价较好的影像检查手段.     

动态增强MR血管成像对活体肾移植供体术前的评估

目的 探讨动态增强MRA对活体肾移植供体血管解剖的显示情况.方法 35名肾移植供体,术前行MRA检查.首先经静脉注入1 ml对比剂Gd-DTPA,测出循环至肾动脉时间.然后行冠状面3D T1加权快速扰相小角度梯度回波(3D FLASH)序列扫描.自动脉期开始连续扫描4期,每期间隔10 s,获得肾动脉、肾静脉、集合系统等各期图像.2名放射科医师观察原始图像及MIP重组后图像,观察肾动脉、肾静脉及其分支的显示情况,确定血管的走形及有无变异.并把MRA图像质量确定为5级,与32名手术结果进行比较.结果 MRA对于肾动脉、肾静脉系统的显示质量均较好.35名供者70个肾脏中发现5支左肾副动脉,9支右副肾动脉.3支左肾动脉过早分支,6只右肾动脉过早分支,其中1支右侧双肾静脉,2例左侧精索静脉粗大.1例右肾副上极动脉MRA术前未发现.结论 动态增强MRA安全无创,对肾动脉、肾静脉显示清楚,诊断变异准确度高,是术前肾移植供体血管评价较好的影像检查手段.     

动态增强MR血管成像对活体肾移植供体术前的评估

目的 探讨动态增强MRA对活体肾移植供体血管解剖的显示情况.方法 35名肾移植供体,术前行MRA检查.首先经静脉注入1 ml对比剂Gd-DTPA,测出循环至肾动脉时间.然后行冠状面3D T1加权快速扰相小角度梯度回波(3D FLASH)序列扫描.自动脉期开始连续扫描4期,每期间隔10 s,获得肾动脉、肾静脉、集合系统等各期图像.2名放射科医师观察原始图像及MIP重组后图像,观察肾动脉、肾静脉及其分支的显示情况,确定血管的走形及有无变异.并把MRA图像质量确定为5级,与32名手术结果进行比较.结果 MRA对于肾动脉、肾静脉系统的显示质量均较好.35名供者70个肾脏中发现5支左肾副动脉,9支右副肾动脉.3支左肾动脉过早分支,6只右肾动脉过早分支,其中1支右侧双肾静脉,2例左侧精索静脉粗大.1例右肾副上极动脉MRA术前未发现.结论 动态增强MRA安全无创,对肾动脉、肾静脉显示清楚,诊断变异准确度高,是术前肾移植供体血管评价较好的影像检查手段.     

Accuracy of normal-dose contrast-enhanced MR angiography in assessing renal artery stenosis and accessory renal arteries

OBJECTIVE: The purpose of this study was to evaluate the accuracy of breath-hold contrast-enhanced MR angiography in the assessment of renal artery stenosis and accessory renal arteries using a standard dose of gadolinium. SUBJECTS AND METHODS: Thirty-eight patients suspected of having renal artery stenosis underwent MR angiography and intraarterial digital subtraction angiography, which was the method of reference. Three-dimensional gradient-echo MR subtraction angiography (TR/TE, 5.8/1.8 msec) was performed on a 1.5-T imager using a phased array body coil. Before imaging, a separate timing bolus sequence was used, administering 1.0 ml of contrast agent. Gadopentetate dimeglumine (15 ml) was injected using an MR power injector. Two observers, who were unaware of each other's interpretation and of MR findings, assessed digital subtraction angiography. Likewise, two other observers assessed MR angiography. RESULTS: Digital subtraction angiography depicted 75 main and 17 accessory renal arteries (n = 92). All main renal arteries and 13 accessory renal arteries were identified on MR angiography. Compared with digital subtraction angiography, MR imaging correctly classified 57 of 66 arteries without a hemodynamically significant stenosis (0-49%), 22 of 22 arteries as significantly stenotic (50-99%), and four of four occluded arteries; five stenoses were overestimated. There was one false-positive finding of an accessory renal artery on MR angiography that was identified retrospectively on digital subtraction angiography. Interobserver agreement was high. Sensitivity and specificity for grading significant stenosis were 100% and 85%, respectively. CONCLUSION: Contrast-enhanced MR angiography, using +/-0.1 mmol/kg of gadolinium, is an accurate method in the assessment of renal artery stenosis and accessory renal arteries.     

CT angiography for evaluation of living renal donors: comparison of four reconstruction methods

OBJECTIVE: We sought to compare various reconstruction methods for CT angiographic images in evaluating living renal donors. MATERIALS AND METHODS: In 76 patients who underwent donor nephrectomy, vascular phase CT data were obtained using an MDCT scanner (detector array, 1.25 mm x 4; beam pitch, 1.5). Two radiologists independently reconstructed CT angiographic images using thick-slab volume rendering, thick-slab maximum intensity projection (MIP), sliding thin-slab volume rendering, and sliding thin-slab MIP. The radiologists counted the number of renal arteries, early branching arteries, and renal veins. We compared the accuracy rates for the detection of vessels achieved with the four types of reconstructed images, using the surgical findings as the gold standard. Agreement between the two observers and between the surgical and CT angiographic findings was evaluated. RESULTS: The sensitivity for detecting the supernumerary artery was significantly greater with sliding thin-slab volume rendering and sliding thin-slab MIP (97%) than with thick-slab volume rendering (59%) (p = 0.039). No significant difference between the other comparison pairs of reconstruction methods was found. The interobserver agreement for detecting supernumerary and early branching arteries with sliding thin-slab volume rendering and MIP was excellent (kappa = 0.820-0.859) and good for renal veins (kappa = 0.698-0.724), whereas the agreement of thick-slab volume rendering and MIP was good for arteries (kappa = 0.706-0.791) and moderate for veins (kappa = 0.443-0.579). The agreement between CT angiographic reconstructed images and surgical findings for detection of vessels was better with sliding thin-slab volume rendering and MIP (kappa = 0.793-1.000) than in thick-slab volume rendering and MIP (kappa = 0.306-0.613). CONCLUSION: For CT angiographic evaluation of living renal donors, sliding thin-slab reconstruction is superior to thick-slab reconstruction.