Influence of CT-based depth correction of renal scintigraphy in evaluation of living kidney donors on side selection and postoperative renal function: is it necessary to know the relative renal function?

PURPOSE: To analyse the influence of CT-based depth correction in the assessment of split renal function in potential living kidney donors. METHODS: In 116 consecutive living kidney donors preoperative split renal function was assessed using the CT-based depth correction. Influence on donor side selection and postoperative renal function of the living kidney donors were analyzed. Linear regression analysis was performed to identify predictors of postoperative renal function. RESULTS: A left versus right kidney depth variation of more than 1 cm was found in 40/114 donors (35%). 11 patients (10%) had a difference of more than 5% in relative renal function after depth correction. Kidney depth variation and changes in relative renal function after depth correction would have had influence on side selection in 30 of 114 living kidney donors. CT depth correction did not improve the predictability of postoperative renal function of the living kidney donor. In general, it was not possible to predict the postoperative renal function from preoperative total and relative renal function. In multivariate linear regression analysis, age and BMI were identified as most important predictors for postoperative renal function of the living kidney donors. CONCLUSIONS: Our results clearly indicate that concerning the postoperative renal function of living kidney donors, the relative renal function of the donated kidney seems to be less important than other factors. A multimodal assessment with consideration of all available results including kidney size, location of the kidney and split renal function remains necessary.

THE POWER COLLECTION METHOD FOR CONNECTION RELATIONS: MEIXNER POLYNOMIALS.

We introduce the power collection method for easily deriving connection relations for certain hypergeometric orthogonal polynomials in the (q-)Askey scheme. We summarize the full-extent to which the power collection method may be used. As an example, we use the power collection method to derive connection and connection-type relations for Meixner and Krawtchouk polynomials. These relations are then used to derive generalizations of generating functions for these orthogonal polynomials. The coefficients of these generalized generating functions are in general, given in terms of multiple hypergeometric functions. From derived generalized generating functions, we deduce corresponding contour integral and infinite series expressions by using orthogonality.

Optimizing scintigraphic evaluation of split renal function in living kidney donors using the geometric mean method: a preliminary retrospective study.

BACKGROUND: Accurate assessment of pre-transplant split renal function in candidates for living kidney donation is indispensable for side-selection and a sufficient long-term residual renal function. OBJECTIVE: To analyse the need of depth correction in the assessment of split renal function in potential living kidney donors. METHODS: In 13 consecutive patients screened for living kidney donation split renal function was measured with four different methods including conventional posterior MAG-3-scintigraphy, the geometric mean method in MAG-3-scintigraphy, MAG-3-scintigraphy with CT-based depth correction and CT-volumetry. Correlation and agreement of methods were analyzed using Spearman's rho correlation coefficient and the Bland-Altman method. RESULTS: Despite good correlation and agreement between the different radioisotopic methods there were clinically relevant differences in split renal function in 2/13 patients (15 %) between conventional posterior MAG-3 scan and the geometric mean method. The best correlation was found between the two scintigraphic methods with depth correction. Comparing radioisotopic methods with CT-volumetry, significant differences were found in up to 6/13 patients (46 %). CONCLUSIONS: Our results clearly indicate that in the case of living kidney donation further assessment concerning the accuracy and reliability of measuring split renal function is necessary. As there are no differences in duration of examination, costs and radiation exposure between techniques with and without depth correction, but clinically relevant differences in up to 46 % of patients, kidney depth should be incorporated in daily clinical practice of living kidney donor evaluation. The geometric mean method could significantly improve future patient assessment in cases of living kidney donation.