Diagnostic value of non-contrast MRI sequences in the emergency evaluation of acute isolated headache

Because gadolinium-based contrast agents (GBCAs) are almost systematically used in emergency MRI for acute isolated headache, with potential safety and environmental concerns, we aimed to assess their contribution and evaluate the value of non-contrast sequences.

We conducted a retrospective single-center study including 435 outpatients who underwent emergency brain MRI for acute isolated headache between January 2021 and June 2023. Diagnostic yield was calculated, and a subgroup analysis of 50 examinations (including all confirmed cerebral venous thromboses [CVT]) was performed to assess the sensitivity of pre-contrast sequences.

Headache-related findings were identified in 10% (45/435) of patients, with sinusitis being the most frequent. CVT was rare, diagnosed in only 3 patients (0.7%). In this cohort, all confirmed CVT cases showed abnormalities on pre-contrast sequences. No diagnosis appeared to rely exclusively on GBCA for initial detection, although contrast-enhanced imaging may still have contributed to diagnostic confirmation or characterization in selected cases. In the 50-case subgroup, a strategy restricted to examinations with suspicious pre-contrast findings would have markedly reduced GBCA administrations while preserving detection of all confirmed CVT cases.

In emergency MRI for acute isolated headache, headache-related findings were infrequent and CVT was rare. Our findings support further evaluation of a non-contrast-first MRI strategy in this setting.