Optimizing Multi-b-Value DWI Quantitative Parameters for Assessing Detrusor Muscle Invasion and Histological Grade in Bladder Tumors
Author Block: Y. Wu, X. Zhu, Y. Shang, C. Liu, Y. Tong, L. Ai, Z. Xiaolong; Kunming/CN
Purpose: Given bladder tumors' high incidence, malignancy, and invasiveness, traditional VI-RADS scoring, based on morphology, inadequately captures tumor microstructure. This study innovatively evaluates MRI multi-b-value DWI parameters' predictive power for muscular invasion and histological grading in bladder urothelial carcinoma, exploring their synergy with VI-RADS.
Methods or Background: Prospectively, 160 patients with suspected bladder masses underwent conventional MRI and multi-b-value DWI (11 b-values, 0-2000 s/mm²). Among them, 106 pathologically confirmed cases (age 68±11 years, 84.9% male) were analyzed. Using iCareSpinx software, entire lesion volumes were delineated to compute 15 diffusion parameters from six non-Gaussian models (CTRW, DKI, FROC, IVIM, SEM, SE). Statistical tests compared parameter differences between groups with varying muscular invasion and pathological grades. Binary logistic regression constructed combined diagnostic models, and ROC curves with AUC values evaluated diagnostic performance.
Results or Findings: Significant differences were observed in CTRW-ADC, DKI-ADC, IVIM-D slow, SEM-ADC, SM-ADC, SM-Theta, and monoADC for discriminating muscular invasion and pathological grading (all P < 0.05). Individually, these parameters showed moderate AUCs (0.704-0.779 for invasion, 0.629-0.712 for grading). VI-RADS alone had AUCs of 0.774 (95% CI: 0.681-0.867) for invasion and 0.720 (95% CI: 0.621-0.818) for grading. Combining parameters with VI-RADS improved AUCs (e.g., 0.870 for invasion with four parameters, outperforming traditional monoADC-VI-RADS combination's 0.845; 0.849 for grading, outperforming 0.765).
Conclusion: MRI multi-b-value DWI quantitative parameters offer clinical value in assessing bladder urothelial tumor invasiveness and grading. While their individual efficacy is limited, their combination with VI-RADS significantly enhances diagnostic performance, providing a more reliable tool.
Limitations: Firstly, the single-center study has a relatively small sample size. Secondly, not delineating smaller or unclear-boundary lesions may omit some. However, volume-based delineation minimizes this bias. Additionally, post-processing times for some models are lengthy, necessitating further optimization to enhance clinical practicality.
Funding for this study: Yunnan Provincial Education Department Project: Research on Predicting Pathological Grading of Bladder Cancer Based on MRI Radiomics Model (2024J03480)
General Project of Yunnan Provincial Science and Technology Department: Comprehensive Study on Assessing Bladder Cancer Aggressiveness, Prognosis, and Therapeutic Efficacy Using MRI-Based Deep Learning Models (202401AY070001-337)
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: None