Added value of high-resolution MR imaging in the diagnosis of vertebral artery dissection

Abstract

Background and purpose: The optimal imaging method for the diagnosis of VAD remains undefined. Our aim was to evaluate the added value of HR-MR imaging for the diagnosis of VAD.

Materials and methods: We retrospectively extracted 35 consecutive patients suspected of having acute VAD who had the following: 1) a focal lumen abnormality of the VA on CE-MRA, 2) HR-MR imaging during the initial hospital stay, and 3) clinical and imaging follow-up within 6 months. Two neurologists classified patients as either VAD (group A) or non-VAD (group B) by reviewing all the available data at hospital discharge, except HR-MR imaging data. On HR-MR imaging, 2 radiologists searched for signs of acute VAD. The 2 classifications were compared. In case of discordance, CE-MRA follow-up and axial fat-suppressed T1WI, used to obtain supportive evidence for or against VAD, were considered as the standard of reference.

Results: In 4/18 patients in group A, HR-MR imaging did not demonstrate any signs of acute VAD and perivertebral signal-intensity changes were attributed to venous plexus, with an unchanged lumen on follow-up. In 4/17 patients in group B, HR-MRI demonstrated a mural hematoma, with lumen normalization on follow-up CE-MRA.

Conclusions: Our results encourage the use of HR-MR imaging as a second-line diagnostic tool in the event of suspicion of acute VAD and doubtful findings on standard imaging.

Fig 1.

Distinction between mural hematoma and perivertebral hypertrophic venous plexus on HR-MR imaging. Axial high-resolution fat-suppressed PDWI (A and E), fat-suppressed T2WI (B and F), T1WI (C and G), and TOF sequences (D and H). In case 1 (top row), crescentic high signal intensity of the vertebral wall, brighter than the signal intensity of the sternocleidomastoid muscle on all sequences (A−D), is associated with a low signal intensity of the intimal layer between the lumen and the crescentic hyperintense mural thickening on TOF (D, arrow), corresponding to a mural hematoma. In case 2 (bottom row), crescentic high signal intensity of the vertebral wall, brighter than muscle signal intensity on TOF, PDWI, and T2WI (E, F, and H), is isointense to the muscle on T1WI (G), without magnetic susceptibility artifacts (H), leading to the diagnosis of inflow enhancement of a hypertrophic venous structure.

Fig 2.

Example of discordance between the standard approach and HR-MR imaging. Suspicion of traumatic right acute VA dissection in a 25-year-old woman with sudden neck pain and dizziness, without stroke. DUS findings were consistent with a right vertebral mural hematoma (not shown). A, On CE-MRA, note irregularity of the right V2 segment (arrow). B, On axial fat-suppressed cervical T1WI, note hyperintense crescentic thickening of the right VA, associated with a slight crescentic hyperintensity of the left VA (arrows). C, On axial high-resolution T1WI, obtained 24 hours later, the crescentic hyperintense mural thickening is no longer present, leading to the diagnosis of inflow enhancement of the hypertrophic venous structure. D, On 6-month follow-up CE-MRA, the lumen of the right VA remains unchanged (arrow).

Fig 3.

Example of discordance between the standard approach and HR-MR imaging. Suspicion of spontaneous acute dissection in a 40-year-old woman with left neck pain and laterobulbar acute stroke. A, On CE-MRA, note occlusion of the right VA and stenosis (arrow) of the left V3 segment. B, On axial fat-suppressed cervical T1WI, note inconclusive crescentic hyperintense mural thickening of the left VA (arrow) and a hyperintense occluded lumen of the right V3 segment (double arrow). DUS did not demonstrate any mural hematoma (not shown). C, On axial high-resolution fat-suppressed T2WI, obtained 24 hours later, note crescentic hyperintense mural thickening (arrow). D, On 5-month follow-up CE-MRA, note clear improvement of the left V3 stenosis. This favors the diagnosis of VAD.

Fig 4.

Example of discordance between the standard approach and HR-MR imaging. Suspicion of spontaneous acute dissection in a 47-year-old woman with postchiropractic right neck pain and transient dizziness, without stroke. Findings of DUS were inconclusive (not shown). B, On standard axial fat-suppressed cervical T1WI, note nonspecific hyperintense crescentic mural thickening of the right V3 segment (arrows). A and D, On CE-MRA, note stenosis (arrow, A) of the right V3 segment, which was partially resolved on 1-year follow-up CE-MRA (D, arrow). C, Coronal high-resolution T1WI, obtained 24 hours after CE-MRA, demonstrates a clear hyperintense crescentic mural thickening of the right V3 segment (arrow). This supports the diagnosis of VAD.