Vertebral artery dissection: peculiarities of clinical and magnetic resonance imaging manifestations

The aim of this study was to analyze clinical and neuroimaging manifestations of vertebral artery (VA) dissection. Twenty seven patients (19 men, 8 women, mean age 34.1 +/- 6.1) with the VA dissection were enrolled. All the patients underwent MRA, neck MRI (T1 f-s, T2 f-s) and head MRI. Twenty six of 27 patients had follow-up MRA/MRT studies: during the acute period and after 2 months or later. Clinical manifestations of VA dissection included ischemic stroke (IS, 52%), transient ischemic attack (TIA, 4%) and isolated neck pain/headache (44%). Ninety two percent of patients in the group of patients with isolated pain and 53% in the group with brain ischemia were women. Bilateral dissection of VA was found in 10 of 27 patients (37%), concomitant internal carotid artery dissection - in 2 patient (7,4%). In 93% of the patients, IS/TIA was associated with neck pain and/or headache. In 64% patients, the pain occurred after neck movements or mild head trauma. The pain preceded brain ischemia symptoms by a few days/2-3 weeks (80%) or appeared simultaneously with them (13%). Symptoms of brain ischemia developed abruptly (82%) usually in wakeful state (80%) during rotation/ bending of the head. Most patients (93%) had complete or good regress of neurological deficit. MRA/MRI revealed hemodynamically insignificant VA stenosis (92%), VA occlusion (5%), increasing of the external VA diameter (100%), dual lumen (8%) and small dissecting aneurysm (11%). In 4 of 6 stroke patients studied within the first week, the signs of arterial embolism were found. The follow up MRA/MRI showed the regress of all stenosis and recanalization of one of two occlusions. In patients with isolated pain, dissections occurred more often in the V1-V2 segments of VA (83%), while in patients with IS/TIA the dissections were mostly found in the V3-V4 segments (47%) (p<0.05). The patients with IS/TIA had more prominent VA stenosis and smaller external arterial diameters in comparison with patients with isolated pain. This suggests the subintimal localization of intramural hematoma (IMH) in the group of ischemic manifestation and subadventicial localization of IMH in patients with isolated head/neck pain. Clinical manifestations of VA dissection depend on the IMH localization. The main mechanism of brain ischemia appears to be an arterial embolism by clotted IMH fragments from the secondary intimal tear. It is suggested that in patients with isolated pain, the media may be weaker than in patients with brain ischemia that in turn promotes subadventicial IMH propagation.