Preoperative evaluation of hilar vessel anatomy with 3-D computerized tomography in living kidney donors

OBJECTIVES: Digital subtract angiography is the gold standard for anatomic assessment of renal vasculature for living renal donors. However, multidetector-row computerized tomography (MDCT) is less invasive than digital subtract angiography and provides information of kidney stones and other intra-abdominal organs. In this study, preoperative MDCT angiography results were compared with the peroperative findings to evaluate the accuracy of MDCT for the evaluation of renal anatomy. METHODS: From December 2002 to May 2007, all 60 consecutive living kidney donors were evaluated with MDCT angiography preoperatively. We reported the number and origin of renal arteries, presence of early branching arteries, and any intrinsic renal artery disease. Renal venous anatomy was evaluated for the presence of accessory, retroaortic, and circumaortic veins using venous phase axial images. The calyces and ureters were assessed with delayed topograms. The results of the MDCT angiography were compared with the peroperative findings. RESULTS: A total of 67 renal arteries were seen peroperatively in 60 renal units. Preoperative MDCT angiography detected 64 of them. The two arteries not detected by MDCT had diameters less than 3 mm. Anatomic variations were present in nine veins, five of which were detected by CT angiography. Sensitivity of MDCT angiography for arteries and veins was 95% and 93%, respectively. Positive predictive values were 100% for both arteries and veins. CONCLUSION: MDCT angiography offers a less invasive, rapid, and accurate preoperative investigation modality for vascular anatomy in living kidney donors. It also provides sufficient information about extrarenal anatomy important for donor surgery.     

Utility of 16-multidetector CT angiography in the preoperative evaluation of vascular and ureteral anatomy of donor nephrectomy

ObjectiveTo evaluate the accuracy of 16-section multi-detector row computed tomography (MDCT) angiography in the preoperative evaluation of renal transplant donors in comparison with intra-operative findings.Patients and methodsIn this prospective study 89 consecutive renal donors (69 men and 20 women) underwent 16-MDCT angiography followed by open surgical donor nephrectomy from January 2008 to March 2010. We reported the number and origin of renal arteries and the presence of early branching arteries. Renal venous anatomy was evaluated for the presence of major and minor venous anomalies. The renal calyces and ureters were assessed with delayed excretory phase images. On a 3D workstation, images were evaluated by the radiologist and the urologist. These CT angiography results were compared with surgical findings.ResultsThe mean age of the donors was 31 years. Open donor nephrectomy was performed on the left in 52 and on the right in 37 subjects. At surgery, accessory renal arteries were found in 14 kidneys (double arteries to 13 kidneys and triple arteries to one kidney). CT and surgical findings agreed in 92% of subjects. Seven small accessory renal arteries in seven donors were missed by radiology reviewers. Early branching of the renal arteries was shown in 5 arteries, and CT matched surgical findings in 88 cases (99%). Renal vein anomalies were present in six subjects, three of them were missed with the preoperative CT. The major shortcoming of MDCT angiography was noted in identifying minor venous anatomy. The presence of discrepancies between pre-operative MDCT and the findings at surgery did not affect the clinical outcome of transplantation, except in one case where intra-operative surgical distress was noted due to failure in identifying multiple major renal veins.Conclusions16-MDCT angiography is a good modality in the pre-operative evaluation of live renal donors. However, it provides suboptimal information on renal vascular anatomy, particularly complex venous patterns. Surgeons should not rely fully on pre-operative CT angiography while performing donor nephrectomy.     

Pre-operative evaluation of living kidney donors using computerized tomographic angiography (CTA) and conventional angiography: comparison with intraoperative findings

This study was undertaken to assess the accuracy of computerized tomographic angiography (CTA) for the evaluation of renal vascular anatomy for pre-operative donor assessment in living kidney transplantation and to compare it with conventional angiography. CTA of 70 living donor kidney donors were analyzed by two blinded observers and compared with the intraoperative findings. Similarly, findings of formal angiography of 30 living donor kidney donors were compared with the intraoperative observations. In the CTA group, there were two patients each with two main renal veins discovered during surgery that had not been recorded on CTA. In the second group, there was one patient with unrevealed two main renal veins before surgery. In both groups, accessory renal arteries were diagnosed. Overall, the accuracy for renal main artery anatomy was 100% for both CTA and conventional angiography. Accuracy for renal main vein anatomy was 97.1% and 96.6% for CTA and conventional angiography, respectively. Hence, these two modalities had comparable results for assessment of main renal vasculature anatomy.     

活体供肾术前评估中16层螺旋CT的价值

目的：评价16层螺旋CT三维重建在活体供肾血管、肾实质、泌尿系统评估中的实际应用价值.方法：回顾2004年以来41例活体肾移植供体临床资料,术前均行16层螺旋CT扫描,采集肾动脉期、静脉期以及排泄期的影像数据,采用MIP、VR、MPR和CRP等三维图像后处理技术,评估供体肾动脉、肾静脉、泌尿集合系统和肾实质情况,与术中所见相对照.结果：41例供肾动脉显示,34例双肾单支动脉供血,其中2例左肾动脉、3例右肾动脉分支较早;4例右肾见一支副肾动脉,3例左肾见一支副肾动脉;术中证实有1例右副肾动脉,1例左肾动脉早期分支未能在影像中显示清楚,准确率95.1%.41例供肾静脉显示,37例双肾静脉为单支,4例右侧双支肾静脉;术中证实5例右侧双支肾静脉未能在影像中显示,准确率87.8%;泌尿集合系统显影满意,1例左侧双肾盂双输尿管畸形.结论：16层螺旋CT三维重建能准确显示供体肾脏血管、泌尿集合系统、肾实质解剖及可能的病理情况,给临床肾移植术前评估提供有价值的帮助,可作为供体术前检查的首选方法.     

Diagnostic accuracy of 64-MDCT angiography in the preoperative evaluation of renal vessels and compared with laparotomy findings in living donor kidney

Introduction: Multidetector-row computed tomography (MDCT) angiography is a reliable technique in preoperative renal anatomy evaluation in live renal donors. Objectives: To investigate the accuracy of early arterial phase findings and compares them with intraoperative findings. Methods: In this prospective study, 100 potential live donors undergoing preoperative MDCT and nephrectomy during 2010–2013 were included. The examination was performed with a 64-detector scanner including early arterial and venous phase. MDCT angiography started by bolus tracking and venous phase was acquired 9?s after arterial phase. Anatomical findings and vein and artery attenuation values were recorded and arterial phase findings were compared with intraoperative findings. Results: All anatomical findings reported by MDCT in early arterial phase were confirmed by intraoperative findings with sensitivity of 100%. Right renal vein was supernumerary in 17 cases and left renal vein was circumaortic in 3 and retroaortic in 5 cases. Renal arteries had early branching in 13, two arteries in 12 and accessory in 8 cases. Vein and artery attenuation values had significant difference between early arterial and venous phase (p?0.001). Conclusion: Early arterial phase has similar results to venous phase in preoperative evaluation and intraoperative findings and could be used alone to reduce radiation dose.     

Multidetector CT angiography in living donor renal transplantation: accuracy and discrepancies in right venous anatomy

Kulkarni S, Emre S, Arvelakis A, Asch W, Bia M, Formica R, Israel G. Multidetector CT angiography in living donor renal transplantation: accuracy and discrepancies in right venous anatomy.
Clin Transplant 2011: 25: 77–82. © 2010 John Wiley & Sons A/S. Abstract: Multidetector computed tomography (MDCT) angiography is a reliable technique for assessing pre‐operative renal anatomy in living kidney donors. The method has largely evolved into protocols that eliminate dedicated venous phase and instead utilize a combined arterial/venous phase to delineate arterial and venous anatomy simultaneously. Despite adoption of this protocol, there has been no study to assess its accuracy. To assess whether or not MDCT angiography compares favorably to intra‐operative findings, 102 donors underwent MDCT angiography without a dedicated venous phase with surgical interpretation of renal anatomy. Anatomical variants included multiple arteries (12%), multiple veins (7%), early arterial bifurcation (13%), late venous confluence (5%), circumaortic renal veins (5%), retroaortic vein (1%), and ureteral duplication (2%). The sensitivity and specificity of multiple arterial anomalies were 100% and 97%, respectively. The sensitivity and specificity of multiple venous anomalies were 92% and 98%, respectively. The most common discrepancy was noted exclusively in the interpretation of right venous anatomy as it pertained to the renal vein/vena cava confluence (3%). MDCT angiography using a combined arterial/venous contrast‐enhanced phase provides suitable depiction of renal donor anatomy. Careful consideration should be given when planning a right donor nephrectomy whether the radiographic interpretation is suggestive of a late confluence.     

Magnetic resonance angiography for preoperative evaluation of potential kidney donors

BACKGROUND: Careful evaluation of the renovascular anatomy for living kidney donors is essential to optimize donor and recipient outcomes. Arteriography has been the standard for delineating the renovascular anatomy. However, this procedure is invasive. Magnetic resonance angiography (MRA) is an attractive, noninvasive alternative. The aim of this study was to evaluate the accuracy of MRA in potential living kidney donors. METHODS: A retrospective comparison of the preoperative MRA results with the intraoperative anatomy was performed in 189 living kidney donors. RESULTS: MRA interpretations correctly identified the vascular anatomy of the donor kidneys in 173 donors (91.5%). In the remaining 16 patients (8.5%), the MRA interpretation was inaccurate. In 10 patients, the MRA reported fewer arteries than the number encountered during the donor operation, whereas in six patients MRA reported more arteries than what found during operation. In seven patients, MRA supplied additional important anatomical information, including kidney size disparity, the presence of nephrolithiasis, the presence of a renal cyst, and renal artery stenosis. All kidneys were successfully transplanted. The misinterpretation of the MRA did not adversely affect the recipient outcome. CONCLUSION: The noninvasive MRA evaluation of donor renovascular anatomy is an acceptable substitute for traditional angiography.     

Role of multidetector-row computed tomography in evaluation of living renal donors

Objectives

To assess the value of multidetector-row computed tomography (MDCT) in evaluation of the anatomy of living kidney donors and to reveal the prevalence of renal vascular variations in a Chinese population.

Patients and Methods

One hundred four potential donors underwent MDCT, and the data sets were postprocessed for reformatted images using maximum intensity projection, a volume-rendering technique, and multiplanar re-formation. Nephrectomy was performed in 97 donors, which enabled correlation of MDCT evaluation with the actual anatomy at surgery as the standard of reference.

Results

The MDCT images accurately demonstrated the anatomical structure of the main renal arteries and veins and the upper part of the ureters. The prevalence of accessory arteries was 41.7% (43 of 103), and of early branching was 12.6% (13 of 103). Compared with findings during surgery, the detection rate of accessory arteries on MDCT images was 91.3% (21 of 23), of larger accessory arteries (>1.5 mm in diameter) was 100%, and of early branching was 100%.

Conclusion

Multidetector-row computed tomography is helpful in accurately evaluating the renal anatomy of potential donors, thus facilitating planning of surgery.     

Preoperative evaluation of living renal donors with gadolinium-enhanced magnetic resonance angiography

BACKGROUND: Preoperative evaluation of living renal donors includes an intra-arterial digital subtraction angiography (DSA). Inasmuch as this technique is invasive, uses radiation and an iodine-containing contrast medium, an alternative technique would be preferable. The purpose of this study was to determine the accuracy of gadolinium-enhanced magnetic resonance (MR) angiography in the visualization of renovascular anatomy for the preoperative evaluation of renal donors. METHODS: Twenty-four consecutive potential renal donors underwent gadolinium-enhanced MR angiography before the standard of reference, intra-arterial DSA. Both modalities were evaluated in a blinded manner. The results were correlated with the surgical findings. RESULTS: Three MR angiograms were technically unacceptable because of inadequate breath-hold. The remaining 21 donors had 47 renal arteries, including 5 accessory renal arteries, which were all visualized by MR angiography. MR angiography failed to visualize one case of subtle fibromuscular dysplasia in the distal part of a renal artery. In one donor, a small accessory renal artery, which had not been visualized on DSA, was encountered during nephrectomy. CONCLUSION: Gadolinium-enhanced MR angiography is an accurate minimally invasive method for the detection of accessory renal arteries in the preoperative evaluation of potential renal donors. The accuracy for excluding stenosis in general is high; however, the depiction of stenosis that are located far distally, or in the branch vessels, is less accurate. Advantages of gadolinium-enhanced MR angiography over the currently used method, intra-arterial DSA, are the minimal invasive nature, lower costs, and superiority in detecting venous anomalies, renal cysts, and tumors.     

Prospective study comparing three-dimensional computed tomography and magnetic resonance imaging for evaluating the renal vascular anatomy in potential living renal donors

OBJECTIVE: To prospectively compare the accuracy of multislice spiral computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) in evaluating the renal vascular anatomy in potential living renal donors. SUBJECTS AND METHODS: Thirty-one donors underwent multislice spiral CTA and gadolinium-enhanced MRA. In addition to axial images, multiplanar reconstruction and maximum intensity projections were used to display the renal vascular anatomy. Twenty-four donors had a left laparoscopic donor nephrectomy (LDN), whereas seven had right open donor nephrectomy (ODN); LDN was only considered if the renal vascular anatomy was favourable on the left. CTA and MRA images were analysed by two radiologists independently. The radiological and surgical findings were correlated after the surgery. RESULTS: CTA showed 33 arteries and 32 veins (100% sensitivity) whereas MRA showed 32 arteries and 31 veins (97% sensitivity). CTA detected all five accessory renal arteries whereas MRA only detected one. CTA also identified all three accessory renal veins whereas MRA identified two. CTA had a sensitivity of 97% and 47% for left lumbar and left gonadal veins, whereas MRA had a sensitivity of 74% and 46%, respectively. CONCLUSION: Multislice spiral CTA with three-dimensional reconstruction was more accurate than MRA for both renal arterial and venous anatomy.     

多层螺旋CT在活体肾移植供者术前评估中的作用

目的 探讨多层螺旋CT(MELt)在活体肾移植供者术前评估中的作用.方法 对104名活体供肾者术前肾脏MDCT检查的资料进行回顾性分析.均采用64层螺旋CT检查,对双肾进行非增强扫描,注射造影剂后分别行动脉、静脉和排泄期增强扫描,扫描范围从膈顶到耻骨联合.扫描完后重建MDCT图像.根据MDCT图像,记录供者肾脏、输尿管、肾动脉及肾静脉的解剖结构和变异情况,并以供肾切取术中被证实的情况作为标准,对比分析术前MDCT检查对供肾的评估作用.结果 104名供者成功完成MDCT检查,肾脏和输尿管异常者8例.除外1例蹄铁型肾,副肾动脉和肾动脉过早分支的发生率分别为27.2%(28/103)和12.6%(13/103),有双肾静脉者3例,左肾静脉位于腹主动脉之后者3例.共有93名供者成功接受供肾切取术,术中证实,术侧供肾和输尿管异常与术前MDCT检查结果一致;术侧副肾动脉的检出率为80%.直径大于1 mm的副肾动脉和肾动脉过早分支术前均被MDCF检出;肾静脉均与术前MDCT检查结果一致.结论 活体供肾切取前采用MDCT检查能准确显示肾脏的解剖结构和血管变异情况,对供者选择及手术方案的制定具有重要意义.     

Evaluation of the vascular anatomy in potential living kidney donors with gadolinium‐enhanced magnetic resonance angiography: comparison with digital subtraction angiography and intraoperative findings

Asgari MA, Dadkhah F, Ghadian AR, Razzaghi MR, Noorbala MH, Amini E. Evaluation of the vascular anatomy in potential living kidney donors with gadolinium‐enhanced magnetic resonance angiography: comparison with digital subtraction angiography and intraoperative findings.
Clin Transplant 2011: 25: 481–485. © 2010 John Wiley & Sons A/S. Abstract: Background: X‐ray contrast arteriography has traditionally been used for pre‐operative evaluation in living kidney donors. However, magnetic resonance angiography (MRA) offers a non‐invasive alternative, which has been considered to be less accurate. This study was performed to determine whether MRA in the pre‐operative investigation of living kidney donors provides sufficient information. Methods: From December 2005 to December 2007, 173 potential live donors were evaluated in this study. Donors performed digital subtraction angiography (DSA) and those with one or more accessory arteries at least on one side recruited for further evaluation with three‐dimensional gadolinium‐enhanced MRA. Results: A total of 30 donors constituted the study population. When compared with DSA as the reference method, MRA detected 20 of 36 renal accessory arteries which indicates a sensitivity of 55.6%. The difference between MRA and DSA in identifying accessory renal arteries was significant (p‐value <0.001). Considering intraoperative findings as the standard of reference, MRA depicted correctly four of six (66.7%) accessory arteries on the transplanted kidneys. Conclusions: MRA has the advantage of avoiding exposure to ionizing radiation and is non‐invasive. These are important considerations in pre‐operative evaluation of a generally healthy donor population. However, MRA provides suboptimal accuracy in detecting small accessory arteries.     

Multi-detector row CT scanner angiography in the evaluation of living kidney donors

Renal vascular anomalies are frequent and are not usually problematic, especially when they have been identified and localised with preoperative imaging; computed tomography angiography is a fast and minimally invasive procedure that may afford accurate visualisation of arterial and venous anatomy. We report on our experience with the utilisation of multi-detector row angiography in the preoperative evaluation of living kidney donors. Nineteen living kidney donors underwent multidetector row scan angiography with 3D post-processing. The subjects were 12 male and 7 female donors with a mean age of 60 years. Renal vascular anomalies were identified in 52.6% of donors. A total of 10 supernumerary arteries were identified. Surgical correlation was available for 19 kidneys (17 left and 2 right). The donated kidneys were selected on the basis of CT scan and renal function. CT scan identified all 29 arteries including 10 double right or left arteries (100% specificity and sensitivity). Dual multi-phase multi-detector row CT angiography is a minimally invasive and highly accurate method for preoperative evaluation of renal donors. It affords comprehensive depiction of the arterial and venous anatomy of the kidney, which is particularly critical for planning and performing the donor nephrectomy, especially via a laparoscopic approach.     

Gadolinium-enhanced three-dimensional magnetic resonance angiography versus conventional digital subtraction angiography: which modality is superior in evaluating living kidney donors?

This study evaluates the correlation of magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) with the operative vessel findings in living kidney donors. The intraoperative vessel findings of 52 living renal donors were compared with the preoperative diagnoses of each imaging technique. Sixty-seven arteries were found during explantation. Forty kidneys showed a single arterial blood supply, and 12 kidneys showed a multiple arterial blood supply. No advantage of either imaging method was found for arterial imaging. There were 55 veins identified during organ harvesting. MRA could not determine the venous system in one donor (1.9%) and failed to detect one small pole vein in another. DSA did not yield a venous diagnosis in seven patients (13.5%) and yielded misdiagnoses in four patients. The correct diagnosis of renal donor veins differed significantly in favor of MRA (kappa 0.79 vs. 0.45; P=0.008). MRA is superior to DSA in assessing the renal vasculature in living kidney donors.     

Assessment of the arteries in living kidney donors: correlation of magnetic resonance angiography with intraoperative findings

Comprehensive imaging evaluation of kidney donor anatomy is crucial for selecting candidates for living kidney transplantation and for determining the surgical technique to procure the renal graft. In 76 living renal donors we compared the results of preoperative magnetic resonance angiography (MRA) with the intraoperative findings of arterial anatomy. Donors were evaluated for the number of main renal arteries and the presence of any polar arteries. A total of 80 main renal arteries and five polar arteries were observed at MRA. At surgery, 90 main renal arteries and eight polar arteries were identified. MRA demonstrated a sensitivity, specificity, and overall accuracy of 18%, 98%, and 87%, respectively, for main arteries and 25%, 96%, and 88% for polar arteries. Eleven (14.5%) kidneys displayed more than one main artery and MRA only detected two cases. Eight kidneys had polar arteries and MRA only detected two cases. MRA is a reliable method for presurgical evaluation of renal arteries in potential donors, providing valuable information required by the surgeon. But, as the technique misses small-diameter vessels, it cannot be recommended as the sole diagnostic tool in unclear cases.     

Digital subtraction angiography for renal donor evaluation

A consecutive series of 52 living related renal donors were evaluated preoperatively by angiography. The preoperative angiographic interpretation was compared with the anatomy found at donor nephrectomy. Standard selective renal arteriography was found to be 100 per cent accurate in defining single (25) or multiple (1) renal arteries. Digital subtraction angiography (DSA) alone performed with an intra-arterial injection of contrast material was found to be 82 per cent accurate in determining the number of renal arteries. In five kidneys with multiple renal arteries, only two had the correct number of vessels identified. The errors are inherent in the DSA technology. DSA at the present time is not accurate enough to replace the standard arteriogram in the evaluation of the donor nephrectomy patient.     

Renal Vascular and Ureteral Anatomic Variations in 1859 Potential Living Renal Donors

BackgroundRenal vascular and ureteral anomalies detected by preoperative computed tomography angiography (CTA) are important for determining the side of the donor nephrectomy and the optimal surgical technique. In the present study, we aimed to examine the renal vascular and ureteral variations in living kidney donor candidates.MethodsA retrospective analysis was made of 1859 patients who were examined in our clinic as donor nephrectomy candidates between November 2008 and December 2019. Renal CTA images were acquired using a 64-channel multidetector computed tomography scanner, and renal vascular and ureteral variations were evaluated.ResultsThe prevalence rates of multiple renal arteries on the right and left sides were 18.3% and 22.6%, respectively. The prevalence rates of early branching of the renal arteries, in turn, were 6.3% on the right side and 6.5% on the left side. The overall rate of renal artery variations on both the right and left sides was significantly higher in male individuals than in female individuals (P < .001). Multiple renal veins rates were 28.2% and 2.3% on the right and left sides, respectively, and the short renal veins rates on the right and left sides were 10.1% and 4.35%, respectively. Among the 941 cases undergoing donor nephrectomy, the procedure was completed by laparoscopy in 815 and by conversion from laparoscopic to open surgery in 36. The rate of vascular variations was higher in the conversion to open surgery group than in the laparoscopy group (P = .015).ConclusionsCareful preoperative assessments of donor renal vascular and ureteral anatomy and variations in CTA are essential for successful and safe renal transplant.     

Utility of CT angiography for evaluation of living kidney donors

We reviewed our initial experience with helical computed tomography (CT) angiography in the evaluation of living kidney donors which, until now, has necessitated arteriography. Nineteen donors (12 women, 7 men) have had their renal anatomy evaluated solely by CT angiography preoperatively.All scans demonstrated normal collecting systems and single ureters. Five donors (26%) had supernumerary renal arteries. Fourteen donors had single, 4 donors had two, and 1 donor had three renal arteries. Helical CT demonstrated small polar vessels in several donors. Two donors (10%) had supernumerary renal veins. Accuracy of vascular anatomy defined on CT was 90% when confirmed at operation. Anatomically all CT findings were consistent with operative findings except in 1 donor who was found to have a 0.8 cm lesion near the renal hilum.At our institution, the total charges for selective renal arteriography are $3845 and for helical CT with three-dimensional (3-D) reconstruction are $1546. The amount of contrast dye (approximately 100 mL) is equivalent. Patients uniformly reported that the CT scan was a convenient and painless procedure.The accuracy of helical CT angiography is equivalent to arteriography in assessing renal vascular anatomy (with the additional benefit of imaging venous and parenchymal anatomy). Charges for helical CT are 59% less. There is greater patient acceptance and potentially less morbidity associated with the non-invasive nature of helical CT. We believe that CT angiography is the radiologic procedure of choice for the assessment of renal anatomy in potential living kidney donors.     

Can magnetic resonance angiogram be a reliable alternative for donor evaluation for laparoscopic nephrectomy?

BACKGROUND: While hand-assisted laparoscopic donor nephrectomy (HLDN) is less invasive, which can encourage kidney donation, it requires more exact information about the renal vascular anatomy because of its limited visual field during nephrectomy. MRA is also an attractive choice because of its minimal invasiveness; further, it is an outpatient-based procedure, it uses non-nephrotoxic contrast material and it has no radiation. The aim of our study was to evaluate the effectiveness of gadolinium enhanced three-dimensional MRA (GdE-3D MRA) in a group of potential live donors who were candidates for HLDN. METHODS: From September 2002 to December 2004, 40 potential live renal donors were evaluated prospectively with GdE-3D MRA, and this imaging modality was performed before the gold standard, the intra-arterial digital subtraction angiogram (IA-DSA), was carried out. All the images were reviewed in a blinded manner by the attending vascular radiologist. The MRA findings were compared with the DSA findings and the surgical findings as the reference methods. We evaluated the accuracy of MRA for imaging the renal architectures, and especially for imaging the renal accessory arteries and the early branching arteries that are important determinants for selection of the donor kidney. RESULTS: Both the MRA and DSA images showed consistent findings with the surgical findings in 92.5% of the 40 donors. There were no discrepant cases in depicting the main renal artery. MRA showed 100% specificity for imaging both the renal accessory arteries and the early branching arteries, when compared with the surgical findings. The kappa values for the MRA and DSA for the accessory arteries were all 0.66 compared with the intraoperative findings. MRA also depicted one huge renal cyst in one donor and many small renal cysts in the other donors that could not be imaged by DSA. There were no adverse events during the MRA procedure. None of the findings missed by MRA resulted in deleterious consequences at laparoscopic nephrectomy for the donor and graft. CONCLUSIONS: Our limited experience with GdE-3D MRA for imaging the renal structures in kidney donor evaluation for HLDN has been quite satisfactory.     

Imaging Modalities for Renal Artery Stenosis in Suspected Renovascular Hypertension: Prospective Intraindividual Comparison of Color Doppler US,CT Angiography,GD-Enhanced MR Angiography,and Digital Substraction Angiography

The aim of the study was to evaluate the diagnostic accuracy of Color Doppler US, CT Angiography (CTA), and GD-enhanced MR Angiography (MRA) compared with digital subtraction angiography (DSA) for the detection of renal artery stenosis in patients with clinically suspected renovascular hypertension. Fifty-eight patients with suspected renovascular hypertension were enrolled in the study. All patients underwent Color Doppler US, CTA and GD-enhanced MRA. DSA was the gold standard method for the number of renal arteries, existence and degree of stenosis, or evidence of fibromuscular dysplasia. DSA depicted 132 renal arteries, 16 stenoses, and 4 arteries with fibromuscular dysplasia. Color Doppler US failed to detect 1 main and 14 polar arteries. CTA depicted all main renal arteries and 7/16 polar arteries, but failed to detect stenosis in two accessory vessels. Likewise, MRA did not detect stenotic accessory renal arteries, depicted 9/16 polar renal arteries, but missed two main renal arteries. All methods depicted the four main renal arteries with fibromuscular dysplasia. The overall sensitivity, specificity, and positive and negative predictive accuracy were 75%, 89.6%, 60% and 94.6%, respectively, for color Doppler US; 94%, 93%, 71%, and 99%, respectively, for CTA; and 90%, 94.1%, 75%, and 98%, respectively, for GD-enhanced MRA. CTA and GD-enhanced MRA have comparable and satisfactory results with respect to the negative predictive accuracy of the suspected renal artery stenosis. The concept of an imaging algorithm including US as screening test when appropriate and CTA or MRA as the second step-procedure is suggested. Therefore, DSA may be reserved for cases with major discrepancies or therapeutic interventions.