High-resolution magnetic resonance imaging (MRI) at 3.0 Tesla in the short-term follow-up of patients with proven cervical artery dissection

Abstract

Purpose: For the imaging evaluation of patients with suspected cervical artery dissection (CAD) in the last decade, magnetic resonance imaging (MRI) has become the first line imaging modality. However, CAD is a highly dynamic process with rapid changes over time. Aim of this study was to assess the short-term morphologic changes in patients with proven CAD by MRI within 2 weeks after the initial diagnosis using a multicontrast high-resolution noninvasive vessel wall imaging approach at 3.0 T.

Materials and methods: Eighty-two patients with clinically suspected CAD were examined using a 3.0 T system (Gyroscan Intera, Philips). Imaging protocol consisted of 3-dimensional inflow MRA (repetition time [TR]/echo time [TE]/flip angle [FA] = 25 milliseconds/3.1 milliseconds/16 degrees, reconstructed voxel size 0.3 x 0.3 x 0.8 mm), black blood T1w 3-dimensional spoiled gradient echo (TR/TE/FA = 31 milliseconds/7.7 milliseconds/15 degrees, 0.3 x 0.3 x 1.0 mm), and fat suppressed T2w turbo spin echo (TSE) (TR/TE/echo train length = 3 heart beats/44 milliseconds/7, 0.3 x 0.3 x 2 mm). Three observers in consensus performed image analysis. Images were assessed with regard to presence and size of intramural hematoma, degree of stenosis, presence of intraluminal thrombus, development of pseudoaneurysm, and incidence of additional dissections. In 29 patients (35%) a dissection had initially been proven by direct visualization of an intramural hematoma. Twenty-one patients (72%; 7 male, 14 female; mean age 41.5 years) were available for follow-up studies leading to a total of 24 diseased cervical arteries being reevaluated 2 weeks later for prospective follow-up.

Results: Mean interval between initial study and follow-up was 14.2 days (range 7-30 days). Eighteen patients had presented with an acute CAD in 1 artery, 3 patients with an acute CAD in 2 arteries. At follow-up, degree of stenosis had increased in 2 arteries, remained unchanged in 13, and decreased in 5 arteries. Four initially occluded arteries were recanalized at follow-up. In 3 arteries a pseudoaneurysm had been visible in the initial study and remained unchanged at follow-up; in 1 artery a new pseudoaneurysm was observed. In 3 arteries, new dissections were identified during follow-up.

Conclusion: High-resolution MRI of acute CAD at 3.0 T permits a refined cross-sectional and longitudinal analysis of the morphologic features of CAD. The increased signal-to-noise ratio at 3.0 T allows for a high spatial resolution permitting detailed analysis of the diseased vessel segment. An unequivocal distinction between intramural hematoma and thrombus was possible. Information could be gained with regard to recanalization, degree of stenosis, formation of pseudoaneurysm, and appearance of new dissections making short-term follow-up in pts with acute CAD recommendable. Further studies are needed to assess the relationship between short-term results and definite outcome.