Using intravoxel incoherent motion MR imaging to evaluate cortical defects in the first episode of upper urinary tract infections: Preliminary results

Purpose To compare intravoxel incoherent motion diffusion weight imaging IVIM-DWI MRI with DMSA for the evaluation of cortical defect in pediatric upper urinary tract infection (UTI) patients. Materials and Methods Forty-three kidneys of 22 pediatric patients with the first episode of febrile upper UTI were evaluated. DWI using IVIM model was performed with eight b factors. The presence of cortical defect was evaluated on apparent diffusion coefficient (ADC) map. DMSA was used as the standard of reference. ADC, true diffusion coefficient (D), pseudo-diffusion coefficient (D), and perfusion fraction (F) in both defect and nondefect area were calculated and compared. Results Cortical defects were detected in 14 kidneys by IVIM-DWI. The sensitivity, specificity, positive predictive value, and negative predictive value of IVIM-DWI MRI for the detection of defects was 93.3%, 100%, 100%, and 96.5%, respectively. Mean values of ADC, D, D, and F were 1.12 ± 0.15, 1.05 ± 0.10, 33 ± 17 (× 10^-3 mm²/s), and 0.14 ± 0.09 in the defect foci. In normal foci, ADC, D, D, and F were 1.37 ± 0.09, 1.31 ± 0.10, 43 ± 19 (× 10^-3 mm²/s), and 0.12 ± 0.04, respectively. ADC and D were significantly lower in defect group than nondefect group (P < 0.01). Conclusion IVIM-DWI can allow both direct visualization and quantitative measurement of cortical defects.