Spontaneous and Unruptured Chronic Intracranial Artery Dissection : High-resolution Magnetic Resonance Imaging Findings

Abstract

Purpose: The aim of this article is to present high-resolution magnetic resonance imaging (HR-MRI) findings of chronic stage spontaneous and unruptured intracranial artery dissection (ICAD).

Material and methods: From March 2012 to April 2016 a total of 29 patients (15 male and14 female, age range 37-68 years) with chronic stage spontaneous and unruptured ICAD (vertebral artery 27, posterior inferior cerebellar artery 1 and middle cerebral artery 1) were retrospectively enrolled. Patients underwent HR-MRI more than 2 months (median interval 564 days, range 69-391 days) after symptom onset and were diagnosed at symptom onset or at the first imaging acquisition, which included luminal angiography and/or HR-MRI with clinical information. The HR-MRI findings were evaluated against those of luminal angiography on the basis of the lumen wall morphology, including thickening, contrast enhancement and residual dissection.

Results: The HR-MRI findings were classified into complete normalization (normal lumen and wall with or without mild enhancement, n = 6), complete normalization with minimal wall changes (focal wall thickening with enhancement but normal luminal angiography, n = 8), incomplete normalization (focal wall thickening with enhancement with dilatation and stenosis on luminal angiography, n = 4), dissecting aneurysm (fusiform aneurysm with residual dissection findings, n = 8) and occlusion (small outer arterial diameter with diffuse contrast enhancement, n = 3).

Conclusion: The use of HR-MRI can demonstrate the distinguishing morphological features of chronic stage of spontaneous and unruptured ICAD as complete normalization, complete normalization with minimal wall changes, incomplete normalization, dissecting aneurysm and occlusion.

Keywords: Chronic dissection; Dissecting aneurysm; High-resolution magnetic resonance imaging; Intracranial artery dissection.