Interobserver variability in 99mTc-DMSA renal scintigraphy reports: multicentric study.

Background: The aim of the study was to evaluate the interobserver variability and reproducibility of the renal scintigraphy reports.
Methods: The study was prospective performed in 60 99mTc DMSA scintigraphies (116 kidneys), done in one centre, displayed on X ray films as analogue 300 kcounts images in 4 standard projections. Six observers from 4 different centres (group A), including three observers from one institution (group B), were asked to interpret original scans. Seven parameters of scintigraphy protocol were analysed with at least two responses: kidney size (1), uptake (2), outlines (3), scars (4), SOL (5), differential function (6) and conclusion (7).
Results: Among 116 kidneys, concordant results in interpretation of seven points of report from 1 to 7, in the group A were found in 62%, 42.5%, 45%, 9%, 47%, 52% and 34%, and In the group B in 72%, 55%, 59%, 22%, 62%, 60% and 41% respectively. Some improvement in concordant reporting was noted in the group of 3 observers, in comparison of group of all, statistically significant in category of scar reports (p < 0.01).
Conclusions: Results suggest to use of standardised criteria and terminology in interpretations, to improve low interobserver reproducibility and objectivity of renal scintigraphy reports, particularly in evaluation of renal scars.