Prevalence of Stroke and Diagnostic Performance of Emergency MRI in Acute Isolated Dizziness.

Objective: Stroke is frequently misdiagnosed in patients presenting with acute isolated dizziness; the optimal imaging modality for this population remains debated. This study aimed to determine the prevalence of stroke among patients with isolated dizziness and to assess the diagnostic accuracy of magnetic resonance imaging (MRI) and computed tomography (CT) for stroke detection.

Methods: Consecutive patients presenting to the neuroemergency department with acute dizziness between April and December 2024 were enrolled. Isolated dizziness, defined as dizziness or vertigo without accompanying neurological deficits, was identified. Clinical characteristics were compared between patients with and without stroke. The diagnostic performance of MRI and CT for detecting stroke in patients with isolated dizziness was evaluated.

Results: Among 251 patients with acute dizziness, 129 (51.4%) exhibited isolated dizziness. Of these, 121 (93.7%) underwent emergency MRI. Acute ischemic stroke was diagnosed in 33 out of 129 patients (25.6%) and hemorrhagic stroke in 3 patients (2.3%) with isolated dizziness. Clinical characteristics were similar between patients with and without stroke. The sensitivity and specificity of MRI for detecting acute stroke were 0.939 (95% CI, 0.798-0.993) and 1.000 (95% CI, 0.959-1.000), respectively, whereas CT demonstrated a sensitivity of 0.519 (95% CI, 0.319-0.713) and specificity of 0.795 (95% CI, 0.647-0.902).

Interpretation: Stroke is a frequent but underrecognized cause of isolated dizziness. Clinical features and emergency CT provide limited diagnostic value, whereas MRI offers high accuracy for detecting stroke in this population. Employing MRI as the first-line imaging modality for patients presenting with dizziness may substantially reduce the risk of misdiagnosis.