Acute Cardioembolic and Thrombotic Middle Cerebral Artery Occlusions Have Different Morphological Susceptibility Signs on T2 (∗) -Weighted Magnetic Resonance Images.

Mei Zheng,Dong-Sheng Fan

doi:10.1155/2015/839820

Abstract

Presence of susceptibility sign on middle cerebral artery (MCA) in T2∗-weighted magnetic resonance (MR) images has been reported to detect acute MCA thromboembolic occlusion. However, the pathophysiologic course of thrombotic MCA occlusion differs from embolic occlusion, which might induce different imaging characters. Our study found that the occurrence rate of the MCA susceptibility sign in cardioembolism (CE) patients was significantly higher than in large artery atherosclerosis (LAA) patients, and the diameter of the MCA susceptibility sign for CE was greater than for LAA. Moreover, the patients with hemorrhagic transformation had MCA susceptibility signs with a significant larger mean diameter than patients without hemorrhagic transformation. Therefore, we hypothesized that the morphology of susceptibility signs could be used to differentiate acute cardioembolic and thrombotic MCA occlusions, which helped to select appropriate treatment strategies for different patients.

Highlights

Previous studies have reported that the middle cerebral artery (MCA) susceptibility sign in T2∗-weighted magnetic resonance (MR) images can be indicative of an acute thromboembolic occlusion [1,2,3,4,5]
The exclusion criteria were as follows: (1) there are recurrent cerebral infarction and past cerebral hemorrhage; (2) MCA occlusion is caused by Moyamoya disease, arterial dissection, vasculitis, tumor, and blood hypercoagulability, among other causes; (3) thrombolytic or anticoagulant therapies were performed prior to the imaging examination; (4) MR angiogram (MRA) confirmed that the internal carotid artery contained moderate stenosis or occlusion; and (5) metal dentures affected T2∗-weighted MR image quality
CE patients were significantly older than large artery atherosclerosis (LAA) patients (70.5±5.9 years versus 62.3 ± 11.2 years, P < 0.01) and had a higher proportion of history of coronary heart disease (50.0% versus 22.7%, P < 0.05)

Summary

Introduction

Previous studies have reported that the middle cerebral artery (MCA) susceptibility sign in T2∗-weighted magnetic resonance (MR) images can be indicative of an acute thromboembolic occlusion [1,2,3,4,5]. Acute thrombi and emboli contain large amounts of deoxygenated hemoglobin, which can severely shorten T2-weighted signals. This magnetic susceptibility effect produces a nonuniform magnetic field and a rapid dephasing of proton spins, which result in signal loss that is best observed on T2∗ susceptibility-weighted images [6]. Recent studies show that the MCA susceptibility sign is more sensitive in predicting acute thromboembolism than HMCAS in CT [7] and can be used to predict the immediate effectiveness of intra-arterial thrombolysis [3]

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