Emergency Interventional Radiology in Rural Japan: Spatial Transfer Patterns, Temporal Workload Distribution, and the Clinical and Procedural Spectrum With Implications for Regional Interventional Radiology Workforce and Care Systems.

PURPOSE: To characterize emergency interventional radiology (IR) practice at a tertiary care center in a rural Japanese prefecture, focusing on spatial transfer patterns, temporal workload distribution, and the clinical and procedural spectrum.

MATERIALS AND

METHODS

This retrospective single-center study included patients who underwent emergency IR between February 2023 and April 2025. Patient demographics, referral status, medical region, procedure timing, indications, procedural categories, and 7- and 30-day outcomes were analyzed. Interregional transfer patterns were evaluated using both former 8 and current 3 secondary medical service areas, with transfer rates standardized per 100,000 population.

RESULTS

A total of 150 emergency IR procedures were analyzed. Most procedures involved interhospital transfers (64.0%), while 36.0% were in-hospital emergencies. Among transferred patients, the median transfer distance was 40 km, the median time to procedure was 339 minutes, and no significant association was observed between transfer distance and time to procedure. Population-adjusted transfer rates differed from absolute case counts. After-hours procedures accounted for 65.3% of all cases. Nonneoplastic conditions were the most frequent indication. Embolization constituted 89% of procedures. The 7- and 30-day mortality rates were 6% and 10.7%, respectively, consistent with previously reported outcomes.

CONCLUSIONS

Emergency IR in this rural prefecture was characterized by substantial interregional patient transfers, a high after-hours workload, and a predominance of embolization procedures for hemorrhagic conditions. Given the low case volume per region and limited workforce, a centralized hub-based model with structured regional transfer systems may represent a practical and sustainable approach for delivering emergency IR services in rural settings.