Vol. 7, Issue 12, Part E (2021)

a)To estimate relative renal function by four different methods in live voluntary kidney donors using computed tomography. 1. Semi-automated volume method; 2. Attenuation capacity method; 3. Modified ellipsoid method; 4. Parenchymal area method.

b)To compare the results of relative renal function estimated by the four CT methods with that estimated by Tc99m DTPA renal scintigraphy to identify the best fit CT method to determine split renal function.

Methodology: A prospective study on patients who were potential voluntary kidney donors who attended the Nephrology Out Patient Clinics for a potential renal donation.

1.All consecutive voluntary kidney donors who attended the Nephrology out Patient Clinics of S.P.Medical College from December 2020 to October 2021.

2.Those of the above who underwent contrast enhanced computed tomography as a part of preoperative workup in Department of Radiology in our institution.

3.Those of the above who underwent nuclear scintigraphy as a part of preoperative workup in Department of Nuclear Medicine in neighbouring nuclear medicine lab.

Results: The mean time taken was the maximum for methods 1 and 2 (Relative Renal Volume and Relative Renal Attenuation Capacity methods), which may be attributed to the relative technical difficulty in drawing manually corrected region of interests on each slice. Based on these findings we infer that Method 3 or Relative Mean Ellipsoid Volume Method in terms of its highest correlation coefficient, very good agreement with the reference standard, technical simplicity and least time taken among the other CT methods is the best among the four CT methods to assess relative renal function. In view of the simplicity we recommend that this test can in fact be performed by the referring physician itself.

We also infer that methods 1 and 2 (Relative Renal Volume and Relative Renal Attenuation Capacity methods), though have a very good correlation with the reference standard are limited due to the technical complexity requiring a workstation monitor and increased time consumption

Conclusion: Computed tomography (CT) due to its excellent anatomical information is an established imaging modality in the pre-operative evaluation of live potential voluntary kidney donors. Intravenous non-iodinated contrast enhanced CT of the abdomen is the current radiological investigation of choice in planning for surgery in such patients.

2. When it comes to functional assessment of live potential voluntary kidney donors renal Tc99m DTPA scintigraphy is considered a reference standard though not the gold standard. A difference of up to 7% of relative renal function does not necessarily mean significant renal functional loss. A functional difference of20% is needed to label a kidney as dominant as compared to the other kidney.