MRI for risk stratification of muscle invasion by upper tract urothelial carcinoma: a feasibility study.

• Muscle invasion is a crucial information for tailored treatments of upper tract urothelial carcinomas. • CT does not distinguish ureter wall layers, making muscle invasion risk assessment not feasible. • MRI was shown to reliably diagnose muscle-layer invasion by upper tract urothelial carcinomas (sensitivity 95%, specificity 71%).