Hounsfield Unit Comparison of Opposite Hemispheres in Computed Tomography for Early Diagnosis of Ischemic Stroke.

Abstract

Sometimes, non-contrast computed tomography (NCCT) is the only neuroimaging technique available due to the disadvantages of magnetic resonance imaging (MRI) (e.g., MRI is not suitable for patients with a cardiac pacemaker, hemodynamically unstable patients etc.). This study aims to examine the use of Hounsfield Unit (HU) measurement comparison of symmetrical anatomical regions in opposite hemispheres of the brain for the early diagnosis of acute ischemic stroke patients. Eighty-one ischemic stroke patients were included in this retrospective study. Infarct areas were defined in diffusion-weighted magnetic resonance imaging (DWMRI) as hyperintense areas. The same anatomical regions were then identified in previously performed computed tomography, and the density of these areas in HUs was measured. Symmetrical anatomical regions were found in the opposite hemisphere, and HU measurements of these areas were obtained. The means of infarct area HU measurements and normal area HU measurements were compared between groups. The infarct area HU measurements (IAHUm) were significantly lower than the symmetrical normal area HU measurements (NAHUm) (p < 0.001) in all patient groups. The ratio of infarct to normal area HU measurements (rHU) showed remarkable consistency across groups (0.75, 0.77, 0.68). Our findings suggest that comparing HU measurements is an effective means of early diagnosis for ischemic stroke. We propose that this technique may be useful for patients when DWMRI is not available or not suitable. We further suggest that this technique can be used more accurately if the calculations are done automatically by computer software.