Hyperdense middle cerebral artery sign is not associated with functional outcome following mechanical thrombectomy

Arterial hyperdensity on non-contrast CT is a well-recognized indicator of acute thromboembolism within the intracranial arteries. However, its association with functional outcome following mechanical thrombectomy remains inconclusive. This study aimed to evaluate the association between the hyperdense middle cerebral artery sign (HMCAS) and functional outcome in a homogeneous cohort of patients treated with mechanical thrombectomy for occlusion of the M1 segment of the middle cerebral artery (MCA).  METHODS: We conducted a retrospective analysis of a tertiary stroke center prospectively maintained database to identify patients who underwent mechanical thrombectomy for M1 segment occlusion between January 1, 2021, and December 31, 2023. Demographic data, comorbidities, imaging scores, procedural parameters, and clinical parameters were collected.  RESULTS: A total of 220 patients were included in the study. The prevalence of HMCAS did not differ significantly between patients with favorable and unfavorable functional outcomes. Patients with favorable outcomes were significantly younger, had a lower prevalence of arterial hypertension, lower NIHSS scores, better collateral status, and a shorter median symptom onset-to-recanalization time. In multivariable binary logistic regression analysis, HMCAS was not associated with functional outcome (OR 1.41, 95% CI 0.66-3.05, p = 0.377). Lower NIHSS scores and well-developed leptomeningeal collaterals were the strongest predictors of a favorable functional outcome.  CONCLUSION: HMCAS is not associated with functional outcome in patients undergoing mechanical thrombectomy for acute ischemic stroke caused by M1 segment occlusion. Other clinical and collateral factors are the principal determinants of functional outcome.