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

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 (ADC20HZ), OGSE at 40 HZ (ADC40HZ), and PGSE (ADCPGSE), and MR cytometry-derived microstructural parameters (cell diameter [ d ], intracellular volume fraction [ v in ], extracellular diffusivity [ D ex ], and cellularity [ ρ ]) 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 v in (median: 0.31 vs. 0.20), ρ (1.97 vs. 1.33 × 10-2 μm-1), and lower ADCs than low-grade tumors while d (p = 0.85, 95% confidence interval [CI] of mean difference: -0.822 to -0.820) and D ex (p = 0.053, 95% CI of mean difference: 0.025 to 0.352) were not different. v in demonstrated the highest AUC (0.89; 95% CI: 0.80-0.97) among single parameters, and the combined model of v in , D ex , and ADCPGSE 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. v in showed good discriminatory performance, and combining v in , D ex , and ADCPGSE further improves preoperative assessment.

EVIDENCE LEVEL: 1.

TECHNICAL EFFICACY: Stage 3: Diagnostic Thinking.