Transurethral ultrasound ablation for prostate cancer: MRI-based pre-treatment planning and post-treatment assessment-what the radiologist needs to know.

Transurethral ultrasound ablation (TULSA) is an MRI-guided thermal therapy that enables focal or whole-gland ablation of prostate tissue using real-time MR thermometry and feedback control. It is an emerging treatment option for carefully selected patients with localized prostate cancer, particularly when preservation of urinary and sexual function is an important clinical priority. However, TULSA is not yet an established equivalent to radical prostatectomy or radiation therapy, because available clinical data on long-term oncologic control remain limited. Radiologists should therefore understand both its potential role and the limitations of the current evidence. Multiparametric MRI plays a central role throughout the TULSA workflow, including lesion localization, assessment of extraprostatic extension and seminal vesicle invasion, evaluation of critical periprostatic structures, and identification of calcifications that may interfere with ultrasound transmission. Immediately after treatment, contrast-enhanced MRI is used to assess the non-perfused ablation zone, whereas serial imaging demonstrates progressive volume reduction and tissue remodeling. Interpretation may be challenging because inflammation, vascular changes, coagulative necrosis, and anatomical distortion can mimic or obscure residual disease. This pictorial essay provides a practical review of patient selection, treatment planning, post-treatment assessment, and imaging pitfalls after TULSA, based on institutional experience with more than 100 cases.