Horizontal gaze deviation on computed tomography: the visual criterion and lesion characteristics in ischemic stroke.

Horizontal gaze deviation (HGD) on computed tomography (CT) is considered a useful finding for detecting ischemic stroke. To enhance its availability, we studied the criterion suitable for visual determination and lesion characteristics. The clinical records of 327 ischemic stroke patients and 193 non-stroke controls were reviewed with measurements of eye deviation angles on CT. Initially, the HGD criterion defined by the minimum angle in unidirectionally deviated eyes was determined from control data. Subsequently, patients were classified by infarcted arterial territory and stroke subtype, and compared with controls in HGD frequency using Fisher's exact test. In patients with middle cerebral artery (MCA) stroke, ipsilesional HGD during a week from symptom onset was modeled in a mixed-effects logistic regression analysis. Among the controls, 4.9% were categorized as pathological with a cutoff of 14°. HGD frequency was significantly increased in most stroke subgroups and prominent in MCA cardioaortic embolism (odds ratio and 95% confidence interval, 24.2 [9.6, 66.3]) and posterior inferior cerebellar artery (PICA) stroke (15.6 [3.2, 76.2]). In MCA stroke, ipsilesional HGD probability decreased daily (0.62 [0.48, 0.78]) and increased with cardioaortic embolism (4.12 [1.05, 16.16]) and lenticular nucleus lesions (3.36 [1.18, 9.58]). HGD is judged pathological if both eyes are unidirectionally deviated by ≥ 14°. This CT sign is frequent in MCA cardioaortic embolism and PICA stroke but does not necessarily indicate specific lesions. In MCA stroke, HGD is influenced by time, stroke subtype, and lesion location. The criterion and basic information on lesion characteristics may enhance the availability of HGD.