Factors associated with significant MRI findings in medical walk-in patients with acute headache

QUESTION: Acute headache is a main reason for emergency consultations and can be a symptom of dangerous neurological conditions. We hypothesised that in medical walk-in headache patients with low suspicion of intracranial bleeding significant findings in brain magnetic resonance imaging (MRI) are associated with clinical features. METHODS: Retrospective chart review on medical outpatient referrals for brain MRI (2010-2014) with the chief complaint "acute headache" (duration < 4 weeks). MRI findings were classified by relevance (significant yes/no) and whether they potentially caused headache. Stepwise logistic regression analysis was applied to identify clinical features associated with pathological findings. RESULTS: Among 513 MRI examinations, acute headache was the second most common reason for a brain MRI (n = 82, 16%). Of those, forty-one (50%) were completely normal, 16 (19.5%) had an "nonsignificant" finding not causing headache, 10 (12%) had a nonsignificant finding potentially explaining the headache, 8 (9.8%) a "significant" finding probably explaining the headache, and 7 (8.5%) a significant finding probably not causing headache. Syncope (odds ratio [OR] 31.4, 95% confidence interval [CI] 1.7-570), vomiting (OR 7.5, 95% CI 1.2-46.4), ophthalmological symptoms (OR 3.9, 95% CI 1.0-15.6) and female gender (OR 3.1, 95% CI 0.7-13.7) were associated with significant MRI findings. A clinical score based on these variables was associated with a significant MRI finding potentially causing headache with high sensitivity and specificity. CONCLUSION: Among walk-in patients who underwent MRI for acute headache with low suspicion for intracranial bleeding, 20% had a significant MRI finding. A simple clinical score identified all patients with significant findings that explained the headache. If prospectively validated, this might be a useful tool in selecting those walk-in headache patients requiring urgent cranial MRI.