Potential of Perfusion Magnetic Resonance Imaging to Predict Residual Renal Function after Radical Nephroureterectomy

Abstract

Introduction: The diffusion-weighted imaging (DWI) technique with intravoxel incoherent motion model enables the estimation of capillary blood volume as a perfusion-related parameter- (PP-) value. Therefore, the PP-value of the kidney theoretically reflects renal capillary blood volume. We analyzed the usefulness of the PP-value in estimating postoperative renal function in upper-tract urothelial carcinoma (UTUC) patients. Methods: Forty-eight consecutive patients who underwent magnetic resonance imaging before radical nephroureterectomy from 2011 to 2018 were analyzed. A PP-map displaying PP-values on a pixel-by-pixel basis was created from DWI signals (b-values of 0, 500, and 1,000 s/mm2). Two readers independently analyzed the renal PP-value. DWI-based split renal function (SRF) of the intact kidney was calculated by splitting serum Cr-based preoperative estimated glomerular filtration rates (eGFRs). The predictive accuracy of the method was evaluated using renography as the reference standard. Results: Interobserver analysis revealed an excellent correlation value of 0.97. The SRF value showed a good linear correlation with the observed postoperative eGFR (r = 0.76, p < 0.001). The predictive accuracy of the DWI-based method was similar to that of the nuclear-based method. Conclusion: This DWI-based evaluation of capillary blood volume provides a noninvasive tool for predicting the postoperative renal function, thereby facilitating the management of UTUC patients.

Patterns of recurrence in genuine and induced oligometastatic castration‐resistant prostate cancer treated with progressive site‐directed therapy

“…Diagnosis was made according to the MET‐RADS‐P criteria, and any discrepancy in diagnosis between the readers was resolved by consensus 18 . If necessary, computed DWI of the prostate with a b‐value of 2000 s/mm 2 was used 19–21 . The treatment effect of PSDT was rated on a scale of 1 to 5 using the response assessment category (RAC).…”

“…18 If necessary, computed DWI of the prostate with a b-value of 2000 s/mm 2 was used. [19][20][21] The treatment effect of PSDT was rated on a scale of 1 to 5 using the response assessment category (RAC). When there was discrepancy in the assessment of response by lesion, the assessment of the most advanced lesion was considered for evaluation.…”