Early MRI-negative posterior circulation stroke presenting as acute dizziness

The aim of this study was to determine the frequency, clinical and radiological features, and efficacy of clinical evaluation and perfusion-weighted imaging (PWI) for the prediction of final stroke in patients with DWI/MRI-negative posterior circulation stroke (PCS) presenting acute dizziness/vertigo. From our comprehensive prospective stroke registry of acute ischemic stroke during a 7-year period, we identified 1846 consecutive patients with PCS, 850 of whom presented with acute dizziness/vertigo. Of these 850 patients, initial DWI-MRI was negative in 35 (4.1%). In these 35 patients, dizziness/vertigo was acute prolonged in 31 and recurrent transient in 4. Focal neurological signs or profound imbalance were present in 16/35 or 18/34, respectively. Spontaneous nystagmus was absent in 21/35; the HINTS protocol (head impulse, nystagmus, and test-of-skew) was not applicable to them. In 12/26 patients, PWI was positive and the same time as DWI was negative. The usual site of lesion was the lateral medulla (n=18). Twenty-nine patients (83%) had small strokes, while 19 (54%) had large vessel strokes. The sensitivity of systematic clinical evaluation adopting neurological examination, HINTS plus, and assessment of equilibrium was 83%, for prediction of final stroke and 100% when combined with PWI. An integrated approach using systematic neurological and neuro-otological examinations combined with PWI accurately diagnoses PCS presenting with acute dizziness/vertigo. Although most patients with acute vertigo and MRI-negative PCS have small brainstem strokes, about a half have large vessel stroke with greater risk of progression requiring prompt treatment.