How to avoid false positive hyperdense middle cerebral artery sign detection in ischemic stroke

Abstract

Objectives: The aim of the study was to find how to differentiate hyperdense middle cerebral artery sign (HMCAS) in stroke patients from asymmetric hyperdensity not related to stroke, by comparison of the CT density values typical for HMCAS to the values in normal or atherosclerotic middle cerebral artery (MCA).

Methods: The group analyzed consisted of 100 patients with ischemic stroke, presenting HMCAS on the admission CT. Density measurements in HU were performed in the hyperdense segment of the involved MCA, contralateral MCA, brain cortex adjacent to the hyperdense MCA. The control group consisted of 100 patients with no symptoms of cerebral stroke. Density measurements in HU were performed: in the M1 segment of right and left MCA, brain cortex adjacent to the more dense from right or left MCA.

Results: In the stroke group the median values obtained were: in the hyperdense MCA 59 HU, contralateral MCA 41 HU, brain cortex 36 HU. In the control group the median values obtained were: in the more dense MCA 43 HU, contralateral MCA 40 HU, brain cortex 34 HU. The range of HMCAS/contralateral MCA density ratios in stroke only slightly overlapped the range of more dense MCA/contralateral MCA density ratios in non-stroke patients.

Conclusion: The ratio of hyperdense MCA CT density/contralateral density is a good tool to differentiate HMCAS from asymmetric hyperdensity not related to stroke. The threshold ≥1.16 provided 100% sensitivity and 97% specificity, whereas ≥1.22 provided 94% sensitivity and 100% specificity.

Keywords: Atherosclerosis; Cerebral ischemic stroke; Computed tomography; Hyperdense middle cerebral artery sign.