Short-term follow up in patients with proven cervical artery dissection by high resolution MRI at 3 Tesla

Purpose: Cervical artery dissection is a highly dynamic process with rapid changes over time. To assess these morphological changes patients with proven cervical artery dissection (CAD) underwent follow up MRI within two weeks after the initial diagnosis.

Methods: A total of 66 patients with suspected CAD were examined at a 3.0T system (Gyroscan Intera, Philips) using a purpose build phased array coil with four circular elements. High resolution imaging protocol consisted of bright blood 3D inflow MRA (TR/TE/FA=25ms/3.1ms/16°, reconstructed voxel size 0.3×0.3×0.8mm); black blood T1w 3D spoiled GE (TR/TE/FA=31ms/7.7ms/15°, 0.3×0.3×1.0mm) and fat suppressed T2w TSE (TR/TE/ETL=three heart beats/44ms/7, 0.3×0.3×2mm). In 22 pts a dissection was proven by direct visualization of an intramural hematoma, 19 pts (5 male, 14 female, mean age 40.9 y) were available for follow up studies. Images were assessed with regards to degree of stenosis, size of intramural hematoma, presence of an intraluminal thrombus, development of pseudoaneurysms and incidence of new dissections.

Results: All 19 patients were under effective anticoagulation. Mean interval between initial study and follow up examination was 14,7d. Initially CAD was proven in 21 vessels (14 x internal carotid artery (ICA), 7 x vertebral artery (VA)). 18 vessels showed a stenosis, 3 were occluded. In the follow up study degree of stenosis increased in 3 vessels, remained unchanged in 11 vessels and decreased in 4. All 3 occluded vessels were recanalized on follow up study. Excellent image quality permitted precise delineation of intramural hematoma and clear distinction between intramural hematoma and intraluminal thrombus. In 3 vessels a pseudoaneurysm was visible on the initial study and remained unchanged on follow up; in 1 vessel a new pseudoaneurysm was observed. In 3 vessels new dissections were identified on follow up studies. In one pt with an initial dissection of the left ICA, intramural hematoma of the left VA and the right ICA were visible on follow up, the other pt with a dissection of the left and right ICA showed a new acute dissection of the left VA.

Conclusion: High resolution MRI permitted excellent analysis of morphological features of CAD. Clinical important information can be gained with regard to recanalization, degree of stenosis and the appearance of new dissections. Thus, short-term follow up in pts with acute CAD is recommended. Further studies are needed to assess the relationship between short-term results and definite outcome.