Practical Guide to VI-RADS: MRI Protocols, Lesion Characterization, and Pitfalls.

Urothelial carcinoma is the most common type of bladder cancer (BC), accounting for approximately 90% of all cases. Evaluating the depth of tumor invasion in the bladder wall (tumor staging) is essential for determining the treatment and prognosis in patients with BC. Neoadjuvant therapy followed by radical cystectomy is the most common treatment of localized muscle-invasive BC (MIBC). Therefore, it is vital to differentiate non-MIBC from MIBC. Transurethral resection of bladder tumor (TURBT) is the reference standard to determine the extent of tumor invasion into the bladder wall through tissue sampling. However, this diagnostic and therapeutic method may not adequately sample the muscularis propria, leading to a higher risk of residual disease, early recurrence, and tumor understaging in approximately 50% of patients during the initial TURBT. Multiparametric MRI can overcome some of the limitations of TURBT when evaluating BC, particularly regarding tumor staging. In this context, the Vesical Imaging Reporting and Data System (VI-RADS) classification was developed to establish standards for bladder multiparametric MRI and interpretation. It uses a 5-point scale to assess the likelihood of detrusor muscle invasion. T2-weighted MR images are particularly useful as an initial guide, especially for categories 1-3, while the presence of muscular invasion is determined with diffusion-weighted and dynamic contrast-enhanced sequences. Diffusion-weighted imaging takes precedence as the dominant method when optimal image quality is achieved. The presence of a stalk or a thickened inner layer and no evidence of interruption of the signal intensity of the muscular layer are central for predicting a low likelihood of muscle invasion. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Hoegger in this issue.

Prostate imaging reporting and data system correlation with Gleason score: Pathological aspects of magnetic resonance imaging findings.

OBJECTIVE: Prostate cancer has a high prevalence and mortality, being the most diagnosed urologic cancer. Prostatic magnetic resonance imaging showed high sensitivity in the detection of clinically significant neoplasia and agreement with the Gleason score. Therefore, we attempted to evaluate the diagnostic accuracy of the prostate imaging reporting and data system, using biopsy and prostatectomy as the reference standard. The secondary goal of correlating prostatic magnetic resonance imaging findings and anatomopathological samples is obtained. MATERIALS AND METHODS: We retrospectively analyzed seventy-nine 1.5 Tesla prostatic magnetic resonance imaging scans in patients aged 31 to 86 years, performed at the Clinical Hospital of the Federal University of Paraná between January 2015 and February 2018. RESULTS: Considering all 79 patients, prostatic magnetic resonance imaging was able to diagnose tumor in 47 patients (59.4%). Considering the peripheral zone, the prostatic magnetic resonance imaging had a sensitivity of 75.0% (95% confidence interval: 52.1%-98.0%), specificity of 89.5% (95% confidence interval: 66.0%-100%), 94.4% positive predictive value (95% confidence interval: 71.0%-100%), 66.7% negative predictive value (95% confidence interval: 43.0%-69.0%), 83.8% Positive Likelihood Ratio (PVR) (95% confidence interval: 60.0%-100%), 27.9% Negative Likelihood Ratio (RVN) (95% confidence interval: 5.0%-50.0 %), and accuracy of 86.3% (95% confidence interval: 63.0%-100%). The receiver operating characteristic curve obtained demonstrated the sensitivity variation according to the prostate imaging reporting and data system score of the patients, obtaining an area under the curve of 84.8 for a prostate imaging reporting and data system cutoff of 3. CONCLUSION: The use of the prostate imaging reporting and data system score is useful for the screening and classification of prostate cancer, due to its easy reproducibility, even in a population with an unknown prostate cancer prevalence, which can be easily correlated with biopsy studies and/or radical prostatectomy.