Association between magnetic resonance imaging-based prostatic tissue morphology and changes in International Prostate Symptom Score and maximum urinary flow rate after prostatic artery embolization.

PURPOSE: To evaluate whether baseline multiparametric magnetic resonance imaging (mpMRI)-defined prostate morphological phenotypes are associated with changes in the International Prostate Symptom Score (ΔIPSS) and maximum urinary flow rate (ΔQmax) following prostatic artery embolization (PAE) in patients with benign prostatic hyperplasia (BPH).

METHODS: This retrospective single-center study included patients who underwent technically successful PAE with preprocedural mpMRI performed within 8 weeks of intervention. Prostate morphology was classified as glandular-dominant, stromal-dominant, or mixed phenotype based on the predominant nodule signal characteristics on T2-weighted imaging (T2WI), with supplemental assessment using diffusion-weighted and contrast-enhanced sequences when available. Symptomatic and functional outcomes-ΔIPSS and ΔQmax-were assessed at 3, 6, 12, and 24 months post-procedure. Associations between morphology and outcomes were evaluated using multivariable regression and subgroup analysis.

RESULTS: A total of 152 patients (mean age, 70.0 ± 9.9 years) who underwent technically successful PAE were included in the study, all of whom had preprocedural MRI performed within 8 weeks prior to the intervention. All MRI-defined morphological phenotypes demonstrated improvements in the Qmax and IPSS after PAE. The glandular-dominant phenotype exhibited the most pronounced and earliest response, with peak improvements at 6 months (ΔQmax: 10.45 mL/s; ΔIPSS: 14.11 points) and sustained benefits through 24 months (ΔQmax: 8.78 mL/s; ΔIPSS: 13.04 points). Stromal-dominant and mixed phenotypes showed smaller, delayed improvements, typically peaking at 12 months. Morphology-related phenotype differences remained statistically significant at 24 months in unadjusted comparisons, particularly between glandular and stromal phenotypes, although ΔIPSS differences were attenuated in multivariable models (24-month β: 0.104, P = 0.547). Glandular morphology was consistently associated with a greater ΔQmax across all timepoints (e.g., 24-month β: 0.450, P < 0.001) and significantly interacted with baseline symptom severity (IPSS ≥ 20) to predict enhanced 24-month ΔIPSS (interaction β: 0.349, P = 0.045). Subgroup analyses stratified by prostate volume (< 80 vs. ≥ 80 mL) corroborated these findings, with glandular morphology consistently outperforming that of stromal and mixed phenotypes.

CONCLUSION: Baseline MRI-defined prostate morphology, assessed primarily on T2WIs, was significantly associated with clinical outcomes after PAE; glandular-dominant morphology was linked to larger and more sustained improvements in both the Qmax and IPSS. Therefore, MRI-based phenotypes offer a practical imaging biomarker for patient stratification, warranting prospective validation.