How accurate is dimercaptosuccinic acid scintigraphy for the diagnosis of acute pyelonephritis? A meta-analysis of experimental studies

The purpose of this study was to evaluate the performance of dimercaptosucc inic acid (DMSA) scintigraphy in the diagnosis of acute pyelonephritis and to compare the test performance of the standard technique, planar DMSA, wit h the newly introduced technique. SPECT DMSA. Methods: All published animal studies in which DMSA scintigraphy was compared with histopathology, the r eference standard for acute pyelonephritis, were identified using a compreh ensive search strategy with the MEDLINE and EMBASE databases. Test performa nces of ail DMSA methods and SPECT versus planar DMSA were analyzed using s ummary receiver operating characteristic (sROC) curves. Results: Seven stud ies were identified, including 2 of SPECT DMSA. Problems in study design or reporting were common, with numerical errors in 4 studies. Overall, at a s ensitivity of 86%, specificity was estimated to be 91%. Detection of acute pyelonephritis was at a lower threshold for SPECT than for planar DMSA (sen sitivity/specificity values of 97%/66% compared with 82%/ 97%), and the ove rall test performance of SPECT was not demonstrably better than that of pla nar DMSA. When applied to a group of children with a prevalence of renal da mage of 40%, this means that 98% of children with abnormal planar DMSA scan s will have renal damage, whereas only 65% of those with abnormal SPECT sca ns wilt have renal damage. Planar and SPECT DMSA will miss 11% and 3% of ch ildren with renal damage, respectively. Out of 100 children in the hypothet ical group with 40% experiencing renal damage, SPECT will identify 6 extra true cases of renal damage at the expense of 19 extra false positives, when compared with planar DMSA. Conclusion: Published studies of DMSA test perf ormance are few in number and have significant methodologic problems that s hould be avoided in future studies. DMSA, particularly the planar technique , performs well for the diagnosis of acute pyelonephritis. Using test perfo rmance criteria, SPECT DMSA alone has not been shown to be preferable to th e established planar method and will result in a small number of true-posit ives at the expense of a larger number of false-positives.