Reliability of 99Tcm-DMSA scintigraphy for the diagnosis of kidney damage in children

Full text: The aim of this study was to evaluate the variability of dimercaptosuccinic acid (DMSA) scintigraphy interpretation by four nuclear medicine physicians for the diagnosis of renal parenchymal abnormality and compare the variability among three different DMSA methods in clinical use: planar alone, SPET alone and planar with SPET. One hundred DMSA scans were independently interpreted by four specialists from different departments and in random order. All scans were classified by whether renal parenchymal abnormality was present or absent and a modified 4 level grading system of Goldraich. Indices of agreement were the percentage of agreement and kappa. Disagreement was analysed for children, kidneys, and kidney zones. For patients, agreement for planar alone and planar with SPET was 86-87% (kappa 74%) for normal-abnormal scan classification. Agreement for SPET alone was 78% (kappa 57%). The frequency of substantial disagreement occurred in 2.5% and 1.3% of comparisons between observers for planar alone and planar with SPET, but in 5.2% of comparisons for SPET alone (X2= 15.4; P < 0.0001). These results did not vary appreciably whether interpretation of patients, kidneys or zones was compared. In conclusion, there was excellent agreement in the interpretation of planar alone and planar with SPET DMSA scintigraphy. Interpretation of SPET DMSA studies, without planar, was significantly more variable than the other two methods used. SPET DMSA scintigraphy, when used without planar images, does not provide a firm basis for clinical decision making in the case of children who may have renal damage