Feasibility of high-resolution MR imaging for the diagnosis of intracranial vertebrobasilar artery dissection.

OBJECTIVES

To evaluate the feasibility of high-resolution MRI (HR-MRI) for diagnosing intracranial vertebrobasilar artery dissection (VBD) and to identify the most useful imaging findings suggesting dissection.

METHODS

We retrospectively reviewed 50 patients with suspected intracranial VBDs who underwent HR-MRI. Two neuroradiologists independently reviewed the HR-MR images. The diagnosis based on HR-MRI was compared with the final diagnosis by consensus among the neuroradiologists, neurointerventionist, and neurologist. Two neuroradiologists also sought signs of dissection (mural hematoma, dissection flap, outer-diameter enlargement on T2WI of steno-occlusive lesions). Inter- and intraobserver agreements were analysed.

RESULTS

HR-MRI corroborated the final diagnosis in 47 (94%; 31 VBD and 16 non-VBD) patients. A mural haematoma was best detected on T1WI and contrast-enhanced (CE)-T1WI (54.3%). Dissection flaps were observed in almost all cases on CE-T1WI (91.4 %), and then were detected on T2WI (68.6%). Outer-diameter enlargement of the steno-occlusive lesions on angiography was detected in more than half of the cases (62.9%). The two reviewers showed almost perfect agreement for the diagnosis of VBD and detecting dissection signs on every sequence.

CONCLUSIONS

HR-MRI can be a useful and non-invasive diagnostic tool for intracranial VBD, and dissection flaps on CE-T1WI are the signs with the greatest diagnostic value.

KEY POINTS

Direct imaging findings of dissection were well visualised by HR-MRI. Detection of a dissection flap on CE-T1WI is the most reliable diagnostic finding. HR-MRI could be a useful diagnostic tool for intracranial VBDs.