Feasibility of gamma camera-based GFR measurement using renal depth evaluated by lateral scan of 99mTc-DTPA renography.

OBJECTIVE: Gamma camera-based measurement of glomerular filtration rate (GFR) with 99mTc-diethylenetriaminepentaacetic acid (DTPA) is an established non-invasive measurement of split renal function; however, it is not as accurate as the plasma sample method. Therefore, study into improving the accuracy of such method is clinically relevant. The aim of this study was to elucidate the feasibility of gamma camera-based GFR measurement using renal depth evaluated by lateral scan of 99mTc-DTPA renography and comparing the results with those of GFR using renal depth measured by CT, and three representative formulas. METHODS: The study population comprised 38 patients (median, 69 years; male 28, female 10; median estimated GFR, 67.4 ml/min) with renourinary disorders. Scintigraphy was performed after intravenous injection of 370 MBq 99mTc-DTPA by dynamic data acquisition for 20 min, followed by a bilateral static scan of the abdomen for 3 min. All patients underwent computed tomography (CT) within 2 months from renography. GFR was calculated by renography using renal depth determined in five ways; lateral scan of 99mTc-DTPA, CT, and three formulas previously created with using weight, height and age. GFRs were compared with estimated GFR (eGFR). The depth of both kidneys measured as described above was compared and evaluated the laterality of the renal depth. RESULTS: The median values of GFR calculated with renal depth determined by 99mTc-DTPA renography, CT, and the three formulas were 87.3, 83.9, 67.8, 68.3, and 71.5 ml/min, respectively. All of them correlated significantly with eGFR (r = 0.734, r = 0.687, r = 0.728, r = 0.726, and r = 0.686, respectively), however, no significant difference was observed among five correlation coefficients. Bland-Altman plot revealed that eGFR had error and fixed bias when compared with GFRs calculated using renal depth determined by renography, CT, and Taylor's formula. The depth of both kidneys measured by 99mTc-DTPA renography was equivalent to that measured by CT, however, those measured by the three formulas were significantly smaller than that measured by 99mTc-DTPA renography. The depth of the right kidney was larger than that of the left kidney using all three formulas in all patients. However, CT detected only 66% of patients to have a deeper right kidney than left kidney. CONCLUSION: Lateral scanning is a feasible procedure to measure renal depth for accurate and reasonable split GFR measurements using 99mTc-DTPA renography.

Effect of Verapamil on Kidney Function Using Radionuclide Imaging.

BACKGROUND AND OBJECTIVE: Calcium channel blockers (CCBs) are among the most widely used prescribed drugs for the treatment of cardiovascular diseases. The present study investigates the effect of verapamil, which is most commonly used as a CCB, on kidney function using radionuclide imaging. METHODS: Ten New Zealand white rabbits were used in vitro (4) and in vivo (6) studies. Isometric tensions were recorded for isolated renal artery ring segments, while renographic studies were performed using Technetium-99m mercaptoacetyltriglycine and Gamma camera. Time to peak activity (Tmax) and time from peak to 50% activity (T1/2), were calculated from the renograms for control and treated rabbits with verapamil. RESULTS: In vitro, verapamil shifted the curve of phenylephrine concentration-dependent contraction on renal artery to the right, and decrease the highest contraction by 30 ± 3%. In vivo, the average values of Tmax for control and treated rabbits were 2.8 ± 0.1 and 2.2 ± 0.2 min respectively. The T1/2 for control and treated rabbits were 4.7 ± 0.05 and 4.2 ± 0.08 min respectively. The differences were statistically significant: p < 0.05. There is 30 ± 4% decrease in the 2 values. This indicates that there is a rapid renal uptake of the tracer and clearance of the radioactivity after verapamil. CONCLUSION: Verapamil dilates the renal artery and accelerates both the Tmax and T1/2 in the renogram. It increases renal blood perfusion and protects kidney function and therefore improves its work. However, verapamil should not be used while performing renograms to avoid misleading results.

REPEATABILITY AND RELIABILITY OF GLOMERULAR FILTRATION RATE DETERMINATION VIA GAMMA CAMERA UPTAKE OF TC-99M-DTPA IN CATS WITH CHRONIC KIDNEY DISEASE.

Measurement of glomerular filtration rate (GFR) via gamma camera uptake of 99mTc-diethylenetriaminepentaacetic acid is a standard method for quantifying renal function. Aims of this retrospective, observer agreement study were to determine intra- and interobserver variation in GFR values for cats with chronic kidney disease and to determine whether renal insufficiency classification changed between observers. Guideline cut-points were established for the difference in repeated GFRs to differentiate changes caused by therapeutic effect vs. inherent variation. Included cats had a diagnosis of chronic kidney disease and had undergone GFR examinations between the years of 2010 and 2013. Twenty-nine GFR studies were sampled. Each study was read twice, 6 months apart, by two veterinary radiologists and one radiology resident. Modified Bland-Altman plots were used to investigate differences between readings 1 and 2 by observer and between pairs of observers by reading. Reliability of clinical classification was assessed through comparisons between readings and observers. Measurements were not systematically different between readings for the experienced observers but were higher in reading 1 than reading 2 for the inexperienced observer. Measurements were not systematically different between the experienced observers in reading 1 or between any two observers in reading 2. Reliability for GFR measurements was high among experienced observers; variations in GFR measurements rarely led to differences in clinical classification. Results suggested that, for experienced observers, changes in GFR values following treatment in cats with chronic kidney disease between -0.4 and 0.4 mL/min/kg may be due to inherent variability rather than treatment effect.

The accuracy of quantitative parameters in (99m) Tc-MAG3 dynamic renography: a national audit based on virtual image data.

Assessment of image analysis methods and computer software used in (99m) Tc-MAG3 dynamic renography is important to ensure reliable study results and ultimately the best possible care for patients. In this work, we present a national multicentre study of the quantification accuracy in (99m) Tc-MAG3 renography, utilizing virtual dynamic scintigraphic data obtained by Monte Carlo-simulated scintillation camera imaging of digital phantoms with time-varying activity distributions. Three digital phantom studies were distributed to the participating departments, and quantitative evaluation was performed with standard clinical software according to local routines. The differential renal function (DRF) and time to maximum renal activity (Tmax ) were reported by 21 of the 28 Swedish departments performing (99m) Tc-MAG3 studies as of 2012. The reported DRF estimates showed a significantly lower precision for the phantom with impaired renal uptake than for the phantom with normal uptake. The Tmax estimates showed a similar trend, but the difference was only significant for the right kidney. There was a significant bias in the measured DRF for all phantoms caused by different positions of the left and right kidney in the anterior-posterior direction. In conclusion, this study shows that virtual scintigraphic studies are applicable for quality assurance and that there is a considerable uncertainty associated with standard quantitative parameters in dynamic (99m) Tc-MAG3 renography, especially for patients with impaired renal function.

A new quantitative method for estimating glomerular filtration rate and its clinical value.

BACKGROUND AND AIM: The estimation of the glomerular filtration rate (GFR) is essential for the renal function. However, all estimation methods for GFR have advantages and disadvantages. The aim of this study was to develop a new quantitative method for estimating GFR and evaluate its clinical value. METHODS: The new GFR was estimated by quantifying the accumulation of Tc-99m DTPA in the dual kidneys and bladder during a gamma camera renogram study in 116 patients with chronic kidney disease. GFR was determined by this new method (nGFR), Gates' gamma camera technique (gGFR), a two-plasma sampling method (tGFR) and creatinine-based clearance as estimated by Cockcroft-Gault (cGFR) and abbreviated MDRD (aGFR) formulae. The correlation analysis, Bland-Altman analysis and receiver-operating characteristic (ROC) plots were carried out among above methods. RESULTS: The nGFR value has significant correlation with tGRF (r = 0·827, P<0·01). The nGFR had the best overall performances with a lowest bias deviation (3·1 ml min(-1) /1·73 m(2) ), better precision (53·0 ml min(-1) /1·73 m(2) ), narrowest interquartile range (13·5 ml min(-1) /1·73 m(2) ) and best accuracy (68·1%) within 30% of the tGFR, compared with those of gGFR, cGFR and aGFR. The new method had the similar maximum accuracy with the Gates' method and creatinine clearance as estimated by Cockcroft-Gault and abbreviated modification of diet in renal disease (MDRD) method. The new method had better repeatability characteristic compared with the Gates' method. CONCLUSIONS: The new method for estimating GFR had the better performances compared with the Gates' method and creatinine clearance as estimated by Cockcroft-Gault and MDRD method.

Multicenter evaluation of renography with an automated physical phantom.

PURPOSE: The diversity of the dynamic radionuclide renal imaging (renography) study protocols sets challenges for the overall study quality, therefore raising a need for national quality control. The aim of this study was to encourage the standardization of renography in Finland and to evaluate the development after a previous study performed in 1997. METHODS: The new Heikkinen phantom was imaged in each of the 20 participating nuclear medicine laboratories. The results were interpreted in the manner of a regular patient study, and reconstructions and printouts were made according to the clinical routines of each laboratory. Four quantitative parameters were calculated and compared between laboratories. The reports were also assessed in a blind test. RESULTS: The average error in T(max) values ranged from -5 to 7% (-29 to +18% in 1997), in T(1/2) from 0 to 35% (-43 to +66%), in RCA20 from -20 to +28% (-50 to +82%) and in relative uptake from -3 to 5%. The difference from average in relative uptake ranged from -4 to 5% (-21 to +36%). CONCLUSION: The results showed that the errors in T(max) and relative uptake were generally within quite acceptable margins, and the variation in quantitative parameters between laboratories was shown to be smaller than 14 years earlier. The reason might be the use of new software packages as well as increased efforts to improve the quality of the studies.

UK audit of analysis of quantitative parameters from renography data generated using a physical phantom.

BACKGROUND: In this second UK audit of quantitative parameters obtained from renography, phantom simulations were used in cases in which the 'true' values could be estimated, allowing the accuracy of the parameters measured to be assessed. MATERIALS AND METHODS: A renal physical phantom was used to generate a set of three phantom simulations (six kidney functions) acquired on three different gamma camera systems. A total of nine phantom simulations and three real patient studies were distributed to UK hospitals participating in the audit. Centres were asked to provide results for the following parameters: relative function and time-to-peak (whole kidney and cortical region). As with previous audits, a questionnaire collated information on methodology. Errors were assessed as the root mean square deviation from the true value. RESULTS: Sixty-one centres responded to the audit, with some hospitals providing multiple sets of results. Twenty-one centres provided a complete set of parameter measurements. Relative function and time-to-peak showed a reasonable degree of accuracy and precision in most UK centres. The overall average root mean squared deviation of the results for (i) the time-to-peak measurement for the whole kidney and (ii) the relative function measurement from the true value was 7.7 and 4.5%, respectively. These results showed a measure of consistency in the relative function and time-to-peak that was similar to the results reported in a previous renogram audit by our group. CONCLUSION: Analysis of audit data suggests a reasonable degree of accuracy in the quantification of renography function using relative function and time-to-peak measurements. However, it is reasonable to conclude that the objectives of the audit could not be fully realized because of the limitations of the mechanical phantom in providing true values for renal parameters.

Dynamic (99m)Tc-MAG3 renography: images for quality control obtained by combining pharmacokinetic modelling, an anthropomorphic computer phantom and Monte Carlo simulated scintillation camera imaging.

In dynamic renal scintigraphy, the main interest is the radiopharmaceutical redistribution as a function of time. Quality control (QC) of renal procedures often relies on phantom experiments to compare image-based results with the measurement setup. A phantom with a realistic anatomy and time-varying activity distribution is therefore desirable. This work describes a pharmacokinetic (PK) compartment model for (99m)Tc-MAG3, used for defining a dynamic whole-body activity distribution within a digital phantom (XCAT) for accurate Monte Carlo (MC)-based images for QC. Each phantom structure is assigned a time-activity curve provided by the PK model, employing parameter values consistent with MAG3 pharmacokinetics. This approach ensures that the total amount of tracer in the phantom is preserved between time points, and it allows for modifications of the pharmacokinetics in a controlled fashion. By adjusting parameter values in the PK model, different clinically realistic scenarios can be mimicked, regarding, e.g., the relative renal uptake and renal transit time. Using the MC code SIMIND, a complete set of renography images including effects of photon attenuation, scattering, limited spatial resolution and noise, are simulated. The obtained image data can be used to evaluate quantitative techniques and computer software in clinical renography.

Determination of kidney function with 99mTc-DTPA renography using a dual-head camera.

OBJECTIVE: Single-head gamma camera renography has been used for decades to estimate kidney function. An estimate of the glomerular filtration rate (GFR) can be obtained using Tc-diethylenetriaminepentaacetic acid (Tc-DTPA). However, because of differing attenuation, an error is introduced when the kidney depth or kidney size is unequal. This error can be reduced using geometric mean data obtained from dual-head renography. The aim of this study was to compare single-head versus dual-head assessment of single kidney function. METHODS: Thirty-four patients were examined with (a) single-head renography, acquiring counts from the left ventricle and kidneys from a posterior projection, and simultaneously with (b) dual-head renography, acquiring counts from the left ventricle from an anterior projection and kidneys from both anterior and posterior projections using geometric mean values. Single kidney GFR from both models was estimated (GFRcam1 and GFRcam2, respectively) and compared with GFR determined with plasma samples of Tc-DTPA (GFRps). RESULTS: The prediction intervals of GFRcam1 and GFRcam2 compared with GFRps did not differ significantly (SD of GFRcam1-GFRps=17.6 ml/min and SD of GFR2-GFRps=15.5 ml/min; P=0.48). The corresponding coefficients of variation were 16.5 and 14.7%, respectively. CONCLUSION: There is no difference in variance between GFR estimated from single-head renography and that estimated using dual-head renography. Hence, dual-head camera renography might be useful in daily practice with the potential to provide a better estimate of absolute function in each kidney and the relative kidney function in patients with differing kidney depths and/or malformed kidneys.

Monitoring of renal function using 99mTc-DMSA and 99mTc-DTPA scintigraphy in patients with spinal cord injury

Objetivo. El objetivo de este estudio fue evaluar el grado de alteración funcional renal mediante el estudio gammagráfico con 99mTc-ácido demercaptosuccínico (99mTc-DMSA) y 99mTc-ácido dietilentriaminopentaacético (99mTc-DTPA) en pacientes con lesión de médula espinal (SCI). Material y métodos. Estudio prospectivo que incluye a 22 pacientes consecutivos con SCI (15 parapléjicos y 7 tetrapléjicos) (media de edad: 49,1±13,4 años) sin síntomas urinarios. La lesión medular se había producido hacía, 45,6±48,8 meses. Dieciséis pacientes tenían al menos historia de infección del tracto urinario. La gammagrafía renal con 99mTc-DMSA, el renograma con 99mTc-DTPA y la ecografía renal se realizaron en un periodo de 2 semanas. Resultados. En la gammagrafía cortical con 99mTc-DMSA 4 pacientes (18%) presentaron alteraciones severas, unilaterales o bilaterales, en el parénquima renal y aumento de la captación de fondo. Dos de ellos tenían ectasia pielocalicial grado 3-4 en la ecografía. Además, 2 de los 18 pacientes restantes tenían ectasia pielocalicial grado 2 en la ecografía. En el renograma con 99mTc-DTPA 16 pacientes (73%) presentaron retraso, o retraso y disminución de la función, en uno o en los 2 riñones. Sin embargo, solo 4 pacientes tenían ectasia pélvica grado 2 a 4 y ninguno de ellos, cicatrices corticales. Conclusión. El uso combinado de la gammagrafía cortical renal y el renograma con radiotrazadores puede contribuir, junto con la ecografía, en el seguimiento a largo plazo de pacientes con SCI. Los casos con alteraciones en la gammagrafía o en el renograma deben tener un seguimiento más estrecho; de este modo, un tratamiento adecuado precoz puede reducir la morbilidad y la mortalidad en este tipo de pacientes(AU)

Aim. The aim of this study was to assess the degree of alterations of renal function by using 99m-technetium dimercaptosuccinic acid (99mTc-DMSA) and 99m-technetium diethylenetriaminepentaacetic acid (99mTc-DTPA) scintigraphy in spinal cord injury (SCI) patients. Material and methods. Twenty-two consecutive SCI (15 paraplegic and 7 tetraplegic) patients (mean age: 49.1±13.4 years) who had no urinary symptoms participated in this prospective study. The mean duration of injury was 45.6±48.8 months before. Sixteen patients had at least one urinary tract infection history. Renal cortical scintigraphy with 99mTc-DMSA, radionuclide renography with 99mTc-DTPA and renal ultrasound were performed within 2-week period. Results. Four (18%) patients had serious pathology on their kidneys such as unilateral or bilateral parenchymal scarring and increased background uptake in their renal cortical scintigraphy with 99mTc-DMSA. Two of them had grade 3-4 pelvicaliceal ectasia on ultrasound. Additionally, 2 of 18 remaining patients had grade 2 pelvicaliceal ectasia on ultrasound. Sixteen (73%) patients had markedly delayed or delayed and decreased functions of one or both of kidneys on radionuclide renography. However, only four patients had grade 2-4 pelvicaliceal ectasia and none of them had a finding of loosening of renal parenchyma. Conclusion. Combined use of renal cortical scintigraphy and radionuclide renography appears to be contributive to renal ultrasound in the long-term follow-up of patients with SCI. Patients with abnormal findings should be closely followed, and early therapeutic interventions may enable lower morbidity and mortality rates in these patients(AU)

Estimation of Tc-99m MAG3 clearance using camera-based methods without blood sampling.

PURPOSE: To establish camera-based methods for estimating Tc-99m mercaptoacetyltriglycine (MAG3) clearance without blood sampling. MATERIALS AND METHODS: The results of renal scintigraphy with Tc-99m MAG3 obtained from 160 patients were analyzed retrospectively. Eight renogram parameters were calculated for each patient based on the area under the renogram (area method) and slope of the renogram (slope method) using different periods for analysis (1-2 and 1-2.5 minutes for the area method; 0.5-1.5 and 0.5-2 minutes for the slope method) and different backgrounds for subtraction (perirenal and subrenal backgrounds). The 8 parameters were then correlated with MAG3 clearance measured by the single-sample methods proposed by Russell et al and Bubeck et al to determine the equation for the conversion of renogram parameters to clearance. RESULTS: All 8 renogram parameters were highly correlated with clearance measured by the single-sample methods, and the obtained equations enabled the estimation of clearance from image data. Selection between the area and slope methods, between different periods for analysis, or between perirenal and subrenal backgrounds did not cause large differences in the estimation. CONCLUSION: The camera-based methods determined in the present study allow the estimation of MAG3 clearance with acceptable accuracy.

Guidelines for standard and diuretic renogram in children.

Special consideration needs to be given to children who undergo dynamic renography. The Paediatric Committee of the European Association of Nuclear Medicine has updated the previous guidelines. Details are provided on how to manage the child, the equipment, and the acquisition and processing protocols. The pitfalls, difficulties and controversies that are encountered are also discussed, as well as the interpretation of the results.

Captopril renography as a prognostic factor in obstructive hydronephrosis with preserved renal function

El riñón hidronefrótico con una función renal diferencial mayor del 55% se define como supranormal. El significado de este hallazgo sigue siendo controvertido. En este artículo, los autores comunican un caso de función supranormal dentro de una hidronefrosis obstructiva. Se evaluaron las funciones diferenciales del riñón después de la administración de captropril y después de una pieloplastia. Se examina el papel de la renografía con captopril como un factor de prognosis para la cirugía(AU)

Hydronephrotic kidney with a differential renal function greater than 55% is defined as supranormal. The signification of this finding remains controversial. In this article, the authors reported a case of supranormal function in obstructive hydronephrosis. Differential renal functions were evaluated after administration of captopril and after pyeloplasty. The role of captopril renography as a prognostic factor for surgery is discussed(AU)

Trombosis arterial del injerto renal diagnosticada con renograma 99mTc-MAG3 en un paciente con poliquistosis / Arterial thrombosis of the renal graft diagnosed with 99mTc-MAG3 renogram in a female

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Seguimiento a largo plazo de la endopielotomía anterógrada. Factores que influyen en el resultado / Long-term follow-up of antegrade endopyelotomy. Factors that influence the outcome

Objetivo: Conocer los resultados de la endopielotomía con un seguimiento a largo plazo y determinar las variables que influyen en los mismos. Material y Métodos: Se revisan los resultados de la endopielotomía anterógrada realizada en 77 pacientes con obstrucción de la unión pieloureteral (OUPU) con un seguimiento superior a 10 años. Se utilizó la curva de Kaplan-Meier para conocer la probabilidad de fracaso en un determinado momento. Se realizó planimetría del área pielocalicial y se estudio su factor de forma para conocer la influencia de la hidronefrosis en el resultado. Se estudiaron otras variables como el grado de función renal, cirugía previa, coexistencia de litiasis y malformación renal asociada. Resultados: El seguimiento medio fue de 149,26 meses. La probabilidad de fracaso fue de 26,9%, 34,5% y 36,8% al año, 5 años y 10 años respectivamente. La mayor concentración de fracasos se produjo dentro de los 20 primeros meses. El área pielocalicial media en los éxitos fue de 19,70±8,32 cm2 vs 30,19±11,07 cm2 en los fracasos, (p=0,018).No hubo diferencias entre los valores del factor de forma en los éxitos y en los fracasos (0,87 vs 0,88, p= 0,135, respectivamente). La función renal (45,1% en éxitos vs 40,9% en fracasos, p=0,625), la cirugía previa (62% de éxito con cirugía previa vs 64,7% en primarias, p=0,843), y la asociación con litiasis (69,3% éxito con litiasis vs 61,1% sin litiasis, p=0,541) no influyeron el resultado. La concomitancia de hidronefrosis y malformación renal afectó negativamente el resultado. Conclusión: La tasa de éxito de la endopielotomía disminuye en seguimientos a largo plazo, si bien a partir del quinto año se mantiene estable. Seleccionar casos para esta técnica de acuerdo al área de la hidronefrosis podría mejorar el resultado (AU)

Objective: To find out the outcomes of endopyelotomy alter a long-term follow-up and determine the variables that may influence the results. Material and Methods: We review the results obtained in 77 patients that underwent antegrade endopyelotomy with ureteropelvic junction obstruction, after 10- year follow-up. We used the Kaplan-Meier curve in order to determine the probable failure rate at a certain point. We took measurements of the pyelocalix area and studied its shape to find out the influence of hydronephrosis in the outcomes. Other variables, such as renal function, previous surgery, lithiasis and renal malformation associated, were analysed. Results: Mean follow-up was 149.26 months. Faliure rate probability was 26.9, 34.5 and 36.8% a year, 5 years and 10 years later, respectively. Major failure concentration occurred in the first 20 months. Mean pyelocalix area success was 19.70±8.32 cm2 vs 30.19±11.07 cm2 of failure, (p=0,018). There were no differences between the values of the shape factor in either success and failure. (0, 87 vs 0.88, p= 0.135, respectively). Renal function (45.1% success vs 40,9% failure, p=0,625), previous surgery (62% success after previous surgery vs 64.7% first procedure, p=0.843), and lithiasis associated (69.3% success through lithiasis vs 61.1% without lithiasis, p=0.541) did not affect the outcomes. Concomitance of hydronephrosis and renal malformation affected the outcomes negatively. Conclusion: Endopyelotomy success rate reduces long-term follow-up, however, after the fifth year it becomes stable. Selecting cases to apply this technique according to the value of hydronephrosis area could improve the results (AU)

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.