Diagnostic yield of emergency MRI in non-traumatic headache

Abstract

Purpose: Non-traumatic headache is one of the most common neurological complaints in emergency departments. A relatively low diagnostic yield of magnetic resonance imaging (MRI) among outpatients has been previously reported, but studies of emergency patients are lacking. We sought to determine the diagnostic yield of emergency MRI among outpatients presenting to the emergency department with non-traumatic headache.

Methods: In this retrospective cohort study, we analyzed emergency MRI referrals in a tertiary hospital for non-traumatic headache over a five-year period. We recorded patient characteristics, relevant clinical information from the referrals, and imaging outcomes.

Results: In total, 696 emergency patients with non-traumatic headache underwent MRI, most within 24 h of presentation. Significant findings related to headache were found in 136 (20%) patients, and incidental findings in 22% of patients. In a multivariate model, the predisposing factors of the significant findings were age, smoking, nausea, and signs/symptoms of infection. The protective factors were numbness and history of migraine. A predictive clinical score reached only moderate performance.

Conclusion: Although emergency MRI shows headache-related findings in one in five patients, accurate prediction modeling remains a challenge, even with statistically significant predictors and a large sample size.

Keywords: Diagnostic yield; Emergency imaging; Headache; Magnetic resonance imaging.

Fig. 1

Examples of various emergency MRI findings of pathologies considered significantly related to headache. Examples are: internal carotid artery dissection (a), small infarcts (b–d), intracerebral hemorrhage (e), cavernoma (f), meningitis (g), abscess (h), demyelination (i), meningioma (j), glioma (k), central neurocytoma with hydrocephalus (l), dural venous sinus thrombosis (m), idiopathic intracranial hypertension (n), posterior reversible encephalopathy syndrome (o), and sphenoid sinusitis (p). White arrows denote relevant findings

Fig. 2.

Distributions of the clinical score points within groups with (gray dots) and without headache-related findings (open dots) in emergency MRI. The score consisted of age > 40 years (5 points), smoking (5 p.), signs/symptoms of infection (5 p.) and nausea (4 p.), no numbness (3 p.), and no history of migraine (4 p.).