Comparison of MRI and renal cortical scintigraphy findings in childhood acute pyelonephritis: preliminary experience.

OBJECTIVE: The diagnosis of acute pyelonephritis in children remains a clinical challenge. It may cause permanent renal scar formation and results in the chronic renal failure if prompt diagnosis and treatment are delayed. The purpose of this study is to compare magnetic resonance imaging (MRI) and renal cortical scintigraphy (RCS) findings in childhood acute pyelonephritis and to determine pyelonephritic foci in the acute phase.

MATERIALS AND METHOD: Twenty children (15 females and five males) with symptoms dysuria, enuresis, costovertebral pain, fever of 37.5 degrees C or more and/or positive urine culture were imaged by unenhanced turbo spin echo T2, spin echo T1-weighted, pre- and post-gadolinium inversion recovery MRI and RCS. Both imaging techniques were read independently by two radiologists and nuclear medicine specialists. Sensitivity and specificity of MRI in detecting acute pyelonephritic foci and scar lesions were calculated. Furthermore, in order to calculate the reliability of MRI over RCS in differentiating scar tissue and acute pyelonephritic foci, follow-up MRI studies were done in six patients after treatment of acute pyelonephritis.

RESULTS: Sensitivity and specificity of MRI in the detection of pyelonephritic lesions were found to be 90.9 and 88.8%, respectively. There is no statistically significant difference in lesion detection between the two diagnostic modalities (P>0.05).

CONCLUSION: Post-gadolinium MR images show significant correlation with RCS in the determination of renal pathology. Moreover, the ability of discriminating acute pyelonephritic foci and renal scar in early stages of disease is the superiority of MRI.