Determination of split renal function by 3D reconstruction of CT angiograms: a comparison with gamma camera renography.

OBJECTIVE: The objective of our study was to examine the correlation between CT-based and radionuclide renography-based measures of split renal function in a healthy population of live potential kidney donors using 3D models generated from CT angiography. MATERIALS AND METHODS: The records of 173 renal donor candidates who had undergone CT and radionuclide renography between March 1, 2005, and February 28, 2006, were retrospectively evaluated; of those 173 patients, 152 met study inclusion criteria. A blinded investigator using 3D models that were created semiautomatically from the unenhanced, arterial, and excretory phase data made measurements of CT renal volumes and attenuations. The mean renal attenuation and volume were used to calculate the net accumulation of contrast material and split renal function for comparison with radionuclide renography. Split function from CT was calculated in the arterial and excretory phases as well as based on split renal volume and the Patlak method. RESULTS: All four CT-based methods for the calculation of split renal function showed correlation with no significant difference from radionuclide renography (p > 0.05, Student's t test). Pearson's correlation coefficients varied from 0.36 to 0.63 (p < 0.001 for each). Difference scores revealed that the excretory and renal volume splits had the narrowest range and showed a linear, nonzero relationship to the renography splits. Bland-Altman analysis confirmed that the majority of difference scores between each CT method and the radionuclide renography were within the 95% CI of the differences. CONCLUSION: Split renal function based on 3D CT models can provide a "one-stop" evaluation of both the anatomic and the functional characteristics of the kidneys of living potential kidney donors. The excretory phase data and the split renal volume data show the best correlation and the smallest difference scores compared with radionuclide renography data.

Living renal donor allograft lithiasis: a review of stone related morbidity in donors and recipients.

PURPOSE: The use of screening computerized tomography angiography has resulted in the increased detection of incidental nephrolithiasis in potential living renal donor candidates. We reviewed current acceptance guidelines for donors with stone disease as well as data on stone related outcomes in donors with stone disease and recipients who received a kidney with a stone left in situ. MATERIALS AND METHODS: We performed a medical literature search in English using MEDLINE/PubMed that addressed renal donor allograft lithiasis. We then analyzed the literature with respect to the historical evolution of this concept, current guidelines regarding the acceptance of donors with stones and stone related morbidity in recipients and donors. RESULTS: The prevalence of asymptomatic solitary nephrolithiasis has increased with the widespread use of screening computerized tomography angiography during renal donor evaluation. Few studies have addressed the risk of stone related morbidity in donors and recipients. Short-term studies have shown little stone related morbidity in patients who donate or receive an allograft with a stone left in situ. Consensus statements from transplant societies around the world offer guidance for determining donor eligibility. CONCLUSIONS: The available literature on stone related morbidity in donors and recipients is extremely limited. It would appear that the risk of recurrence and subsequent morbidity in renal donors with a solitary kidney is low but not insignificant. Rare stone related adverse events are reported for recipients of an allograft with a stone left in situ. Renal donors and recipients should be educated regarding their unique risk perspectives. Long-term followup is mandatory.

Computerized tomographic angiography for renal donor evaluation leads to a higher exclusion rate.

PURPOSE: We compared the exclusion rate for potential living renal donors evaluated with computerized tomography angiography and radionuclide renal scintigraphy (renal scan) vs excretory urogram, renal scan and renal arteriography. MATERIALS AND METHODS: From March 2004 through February 2006, 603 consecutive patients were evaluated as potential living renal donors. From March 2004 through February 2005, 270 consecutive patients underwent evaluation with excretory urogram, renal scan and renal angiography (group 1). Of these patients 16 underwent computerized tomography to evaluate abnormalities detected on excretory urogram. From March 2005 through February 2006, 333 consecutive patients underwent evaluation with computerized tomography angiography and renal scan (group 2). The number of patients excluded for medical reasons and/or radiographic abnormalities was determined for the 2 groups. RESULTS: More than twice as many patients evaluated with computerized tomography were excluded. In group 1, 7% of patients (20 of 270) were excluded from donation due to radiographic findings vs 16% (53 of 333) in group 2 (p=0.0016). Of the patients 26% and 23% were excluded from renal donation for medical reasons in groups 1 and 2, respectively (p=0.5059). CONCLUSIONS: Multidetector row computerized tomography angiography increases the detection of incidental radiographic abnormalities as well as the renal donor exclusion rate. The increased sensitivity of computerized tomography angiography has created a dilemma for those determining patient eligibility for kidney donation because the clinical significance of many of these findings is unclear. Additional studies should address the significance of these incidental findings so that patients are not needlessly excluded from kidney donation.