Detectability of acute ischemic stroke with thin (3 mm) axial versus thin (3 mm) coronal diffusion-weighted imaging in patients presenting to the emergency department with acute dizziness.

Abstract

Background and purpose: Ischemic strokes can cause vertigo, particularly when involving the posterior circulation of the brain. Prior research has suggested that thin-section (3 mm) axial or coronal DWI may improve the detection of ischemic stroke compared to thick (5 mm) DWI. However, relative sensitivity of differing thin DWI sequences is unknown. In this retrospective cohort study, we compare the sensitivity of thin coronal DWI and thin axial DWI in detection of brain ischemia.

Materials and methods: Retrospective study at a single institution (2/18/2020-8/31/2023) of patients who presented to the emergency department with vertigo/dizziness and underwent an abbreviated MRI protocol (3 mm axial DWI, 3 mm coronal DWI, axial FLAIR, and axial SWI). For each case with an ischemic lesion, the visibility of infarct on thin axial and coronal DWIs was rated; location and size were also recorded. Visibility on either sequence was considered the reference standard. Sensitivity was compared with McNemar's test.

Results: 615 abbreviated MRI examinations were performed; 24/615 (3.9%) had an ischemic lesion (15 cerebral, 7 brainstem, 13 cerebellar). 24 of these MRI examinations with ischemic lesions were performed using 3 mm axial MRI and on 3T MRI. All lesions (24/24) were visible on thin axial DWI (100% sensitivity, 95% CI: 0.95-1.00). Fewer lesions (20/24) were seen on thin coronal DWI (83% sensitivity, 95% CI: 0.72-0.91). The difference in sensitivity was statistically significant (p = 0.0374). Lesions not visible on coronal DWI were 2-8 mm in size, the largest in the middle cerebellar peduncle.

Conclusions: Thin coronal DWI may not improve additional diagnostic utility beyond thin axial DWI for the detection of ischemia in patients with dizziness. When designing protocols tailored for stroke detection (particularly in the posterior circulation), replacing conventional (5 mm) DWI with thin (3 mm) axial DWI may be preferable to adding a thin coronal sequence.