Preoperative Evaluation of Upper Urinary Tract Urothelial Carcinoma Pathological Grade Using Volumetric ADC Histogram Analysis

Motivation: Upper urinary tract urothelial carcinoma (UTUC) shows varying aggressiveness across tumor grades, making accurate preoperative grading essential for treatment planning. Goal(s): To assess the effectiveness of volumetric apparent diffusion coefficient (ADC) histogram metrics in preoperatively evaluating UTUC pathological grade. Approach: Magnetic Resonance Imaging (MRI) data from 225 UTUC patients were analyzed using volumetric ADC histogram metrics, with area under the curve (AUC) from receiver operating characteristic (ROC) curves assessing predictive accuracy. Results: The best model (10th percentile ADC + smoking status) achieved an AUC of 0.835, with 83.3% sensitivity and 68.9% specificity. Impact: Volumetric ADC histogram parameters hold promise for the preoperative differentiation of UTUC grades. When combined with clinical factors, these metrics provide a noninvasive approach to UTUC grading that exceeds the predictive accuracy of ADC histogram parameters alone.