The Performance of MR Cytometry Imaging in Differentiating High‐ and Low‐Grade Bladder Cancer

ABSTRACT Background Accurate preoperative grading of bladder cancer is important for determining treatment and prognosis. Purpose To investigate the diagnostic efficacy of MR cytometry imaging in differentiating high‐ and low‐grade bladder cancer. Study Type Prospective. Population Sixty‐participants (male: 27, mean age: 65 years) with pathologically confirmed bladder cancer (37 high‐grade, 23 low‐grade). Field Strength/Sequence 3.0 T, pulsed gradient spin‐echo ( PGSE ) and oscillating gradient spin‐echo ( OGSE , 20 and 40 Hz) diffusion‐weighted imaging. Assessment All tumors were manually delineated independently by two radiologists, and inter‐observer agreement was assessed using intraclass correlation coefficient (ICC). Time‐dependent apparent diffusion coefficients (ADCs), including OGSE at 20 HZ (ADC 20HZ ), OGSE at 40 HZ (ADC 40HZ ), and PGSE (ADC PGSE ), and MR cytometry‐derived microstructural parameters (cell diameter , intracellular volume fraction , extracellular diffusivity , and cellularity ) were calculated. Histopathological examination of surgical specimens served as the reference standard for tumor grading. Statistical Tests Mann–Whitney U test was used for group comparisons. Diagnostic performance was evaluated by logistic regression and receiver operating characteristic (ROC) analysis; area under the ROC curve (AUCs) was compared with the DeLong test. Statistical significance was set at p < 0.05. Results High‐grade tumors showed significantly higher (median: 0.31 vs. 0.20), (1.97 vs. 1.33 × 10 −2 μm −1 ), and lower ADCs than low‐grade tumors while ( p = 0.85, 95% confidence interval CI of mean difference: −0.822 to −0.820) and ( p = 0.053, 95% CI of mean difference: 0.025 to 0.352) were not different. demonstrated the highest AUC (0.89; 95% CI: 0.80–0.97) among single parameters, and the combined model of , , and ADC PGSE achieved the highest diagnostic accuracy (AUC = 0.92; 95% CI: 0.86–0.99). Data Conclusion MR cytometry noninvasively differentiates high‐ from low‐grade bladder cancer. showed good discriminatory performance, and combining , , and ADC PGSE further improves preoperative assessment. Evidence Level 1. Technical Efficacy Stage 3: Diagnostic Thinking.