Monitoring Intramural Hematoma on Vessel Wall Imaging to Evaluate the Healing of Intracranial Vertebral Artery Dissection

Abstract

Objective: Unruptured intracranial vertebral artery dissection (VAD) generally heals spontaneously. A chronological evaluation of intramural hematoma (IMH) using T1-weighted vessel wall imaging (VWI) may provide a more detailed understanding of the pathophysiology of VAD. We herein investigated the relationship between chronological signal changes in IMH on VWI and the spontaneous healing of VAD.

Materials and methods: We retrospectively investigated 26 patients with 27 unruptured VADs who underwent magnetic resonance (MR) imaging more than three times during the follow-up period. Morphological changes were evaluated using MR angiography (MRA). The relative signal intensity (RSI) of IMH against the posterior cervical muscle on T1-weighted VWI was calculated. The ratio of chronological RSI changes was defined as follows: maximum RSI/minimum RSI (RSI _max/min). Based on the median value of RSI _max/min, 27 VADs were divided into VADs with and without chronological RSI changes. Statistical analyses were performed to compare clinical and radiological findings between the two groups.

Results: Spontaneous healing occurred in 17 out of 27 VADs (63%). The median value of RSI _max/min was 1.48. The RSI of VADs with chronological RSI changes (RSI _max/min ≥ 1.48) increased until three weeks after their onset and decreased over time, while that of VADs without chronological RSI changes (RSI _max/min < 1.48) showed no change. The frequency of healing was significantly higher in VADs with than without chronological RSI changes (100% vs 23%, p < 0.0001).

Conclusions: Chronological signal changes in IMH on T1-weighted VWI have potential as a diagnostic imaging marker of the spontaneous healing of VAD.

Keywords: Intracranial vertebral artery dissection; Intramural hematoma; Signal intensity change; Spontaneous healing; Vessel wall imaging.