Comparison of automatic depth correction versus manual depth correction in the calculation of glomerular filtration rate in gates renal processing of diethylenetriaminepentaacetic acid renogram in prospective renal donors

Abstract

Aim: The aim of the study was to compare the glomerular filtration rate (GFR) obtained by gates method of renal processing using automated system generated method (ASGM) of depth correction with manual depth correction method (MDCM), in prospective renal donors using 99m-Tc diethylenetriaminepentaacetic acid (DTPA) scintigraphy. Materials and Methods: Prospective interventional study involving 20 voluntary renal donors of age 26–65 years were included. 99m-Tc DTPA renograms were acquired by dynamic acquisition for 30 min. Presyringe and postsyringe counts, prevoid and postvoid images, and both sides of lateral images (for manual depth correction) were acquired. GFR was calculated by Gates renal processing with the depth correction both by ASGM and MDCM methods. Results: The mean depth of right and left kidneys calculated by MDCM and ASGM were 7.2 ± 1.1 and 6.4 ± 1.1 and 7.0 ± 1.2 and 6 ± 1.2, respectively. The mean total GFR calculated by Gate's Method using MDCM and ASGM was 96.2 ± 15.4 and 82.0 ± 11.5. There was a statistically significant difference in the depth correction of both kidneys and improvement in total GFR values by MDCM methods compared to the ASGM method. Conclusion: There was a significant difference in depth and GFR values, calculated from MDCM compared to ASGM. Hence, the MDCM is better in calculating GFR for renal donors, especially when using low-energy high-resolution collimators, as full-width half-maximum varies considerably for every centimeter of the distance of the source from the collimator.

Keywords

• depth correction
• diethylenetriaminepentaacetic acid renogram
• glomerular filtration rate calculation