Development and Validation of a Contrast-Enhanced US VI-RADS for Evaluating Muscle Invasion in Bladder Cancer

Area of Science:

• Urology
• Oncologic Imaging
• Medical Devices and Instrumentation

Background:

• Contrast-enhanced ultrasound (CEUS) is valuable for preoperative assessment of muscle invasion in bladder cancer, crucial for treatment planning.
• Standardized diagnostic criteria for CEUS in evaluating bladder cancer muscle invasion are currently lacking.

Purpose of the Study:

• To develop and validate a CEUS Vesical Imaging Reporting and Data System (VI-RADS) for standardized assessment of muscle invasion in bladder cancer.
• To establish optimal criteria and evaluate the diagnostic performance and interreader agreement of the CEUS VI-RADS.

Main Methods:

• A prospective, single-center study enrolled patients with suspected bladder cancer undergoing CEUS.
• A training set (2:1 ratio) was used to develop CEUS VI-RADS criteria, identifying key imaging features and determining the optimal cutoff for muscle invasion.
• A validation set was used by novice and expert readers to assess diagnostic performance and interreader agreement against a pathologic reference standard.

Main Results:

• The optimal cutoff for muscle invasion in the training set was CEUS VI-RADS category 4 or higher (Youden index, 0.77).
• In the validation set, CEUS VI-RADS showed good diagnostic performance for both novice and expert readers (AUCs 0.80 and 0.88, respectively).
• Interreader agreement for CEUS VI-RADS categorization was substantial, ranging from 0.77 to 0.87 across reader groups.

Conclusions:

• The developed CEUS VI-RADS provides a standardized approach for evaluating muscle invasion in bladder cancer.
• The system demonstrates good diagnostic accuracy and reliable interreader agreement, aiding in preoperative assessment and treatment decisions.