RT Journal Article SR Electronic T1 Quantitative Analysis of 99mTc-DMSA During Acute Pyelonephritis for Prediction of Long-Term Renal Scarring JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 285 OP 289 VO 45 IS 2 A1 Hitzel, Anne A1 Liard, Agnès A1 Dacher, Jean-Nicolas A1 Gardin, Isabelle A1 Ménard, Jean-François A1 Manrique, Alain A1 Véra, Pierre YR 2004 UL http://jnm.snmjournals.org/content/45/2/285.abstract AB This study was performed to evaluate a quantitative method based on 99mTc-DMSA renal planar scintigraphy performed during acute pyelonephritis (APN) to detect kidneys at risk of scarring. Methods: A total of 43 children (5.8 ± 3.6 y old [mean ± SD]) were examined by 99mTc-DMSA scintigraphy during (DMSA 1) and 8 ± 2 mo after (DMSA 2) APN. Two levels of interpretation were performed independently: first, a semiquantitative analysis to classify the kidneys by considering the evolution between DMSA 1 and DMSA 2 (i.e., to determine which kidneys had developed scarring), and second, an automatic quantitative analysis of DMSA 1 to define and to evaluate a predictive index for kidney evolution from DMSA 1 to DMAS 2. The method consisted of determining an automatic threshold for the kidney and then calculating ratios of the count density in a given isocount n% (region of interest containing all the pixels with a value ≥ n% of the value of the pixel with the maximal activity value) to the count density in a 20% isocount (Cn%) and the number of pixels in a given isocount to the number of pixels in a 20% isocount (Sn%). Results: All kidneys normal at DMSA 1 remained normal at DMSA 2. For the automatic index, the C70% ratio was considered the best index for the prediction of scarring. When this C70% ratio was used, a cutoff value of 0.45 was able to predict scarring with a sensitivity of 0.83, a specificity of 0.78, a positive predictive value of 0.85, and a negative predictive value of 0.77. Conclusion: A cutoff value of 0.45 for the C70% ratio calculated for 99mTc-DMSA scintigraphy performed during APN may be useful for detecting kidneys at risk of scarring.