How to cite: Vargas A. Best Use of MRI for Focal Therapy. Grand Rounds in Urology. October 23, 2025. Accessed Apr 2026. https://grandroundsinurology.com/best-use-of-mri-for-focal-therapy/
Summary
Alberto Vargas, MD, Vice Chair of Oncology Imaging and Strategy, and Professor, Department of Radiology, New York University, New York, New York, provides a radiologist’s perspective on the optimal use of magnetic resonance imaging (MRI) in the setting of focal therapy for prostate cancer, with emphasis on post-treatment assessment. He clarifies that an MRI performed before focal therapy follows the same principles as any pretreatment prostate MRI and is interpreted using the prostate imaging reporting and data system (PI-RADS) to define eligibility, disease extent, lesion visibility, laterality, and location.
The primary focus of the talk is MRI after focal therapy, an area characterized by limited evidence and significant interpretive challenges. Dr. Vargas reviews a recent meta-analysis evaluating MRI performance for detecting recurrence after focal therapy, noting wide variability in reported sensitivity and specificity across studies. This variability reflects differences in patient populations, treatment types, and reference standards, limiting the ability to generalize diagnostic performance.
Dr. Vargas explains that post-focal therapy MRI interpretation is inherently more difficult than pretreatment imaging. Treatment-related artifacts, patient motion, metallic implants, and diffusion-weighted image distortion frequently limit diagnostic confidence. Absolute prostate-specific antigen (PSA) values are unreliable in this setting, and PI-RADS is inapplicable after treatment.
Dr. Vargas discusses efforts to standardize post-treatment MRI reporting, specifically prostate imaging after focal ablation (PI-FAB) system. This framework integrates findings from T2-weighted and diffusion-weighted imaging and dynamic contrast enhancement, with greater emphasis on contrast enhancement for detecting recurrence. The clinical application of PI-FAB scores remains an area of ongoing debate.
Temporal changes after focal therapy further complicate interpretation, as hemorrhage, edema, necrosis, fibrosis, and contrast enhancement evolve over time. Early MRI may be primarily useful for establishing a baseline rather than detecting recurrence, whereas delayed imaging may better distinguish fibrosis from viable tumor. Dr. Vargas also addresses unresolved questions regarding the timing of imaging, the duration of surveillance, and the emerging but limited role of prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT).
Overall, Dr. Vargas provides a practical radiology-focused perspective on the strengths, limitations, and future directions of MRI in focal therapy.
About the 28th Annual Southwest Prostate Cancer Symposium:
Presented by Program Chairs Nelson N. Stone, MD, Richard G. Stock, MD, and William K. Oh, MD, this conference educated attendees about advances in the management of localized and advanced prostate cancer, with a focus on imaging, technology, and training in the related devices. It included a scientific session, as well as live demonstrations of surgical techniques. You can learn more about the conference here.
ABOUT THE AUTHOR
Alberto Vargas, MD, is Vice Chair of Oncology Imaging and Strategy, and a Professor within the Department of Radiology at New York University in New York City. Dr. Vargas specializes in oncological and molecular imaging. His clinical and research interests focus on the use of advanced-imaging modalities, including diffusion-weighted and dynamic contrast-enhanced magnetic resonance imaging and novel positron emission tomography tracers for the non-invasive diagnosis, staging, treatment response assessment, and follow-up of patients with cancer. Dr. Vargas is especially interested in imaging patients with cancers involving the urinary system and the female reproductive organs.
