Spontaneous acute dissection of the internal carotid artery: high-resolution magnetic resonance imaging at 3.0 tesla with a dedicated surface coil.

PURPOSE: Magnetic Resonance Imaging (MRI) has become the method of choice in the evaluation of patients with suspected cervical artery dissection (CAD). However, reliable identification of acute CAD might be impaired by the limited spatial resolution of standard 1.5 T MRI. In this preliminary study, we implemented a multicontrast high-resolution noninvasive vessel wall imaging approach at 3.0 T in patients with spontaneous CAD. METHODS AND MATERIALS: Ten patients with CAD of the internal carotid artery (ICA) were included in the study. 3.0 T MRI (Gyroscan Intera, Philips) was acquired using a dedicated phased-array coil. MRI-protocol consisted of: (1) bright blood 3D inflow MRA (TR/TE/FA = 25 milliseconds/3.1 millisecond/16 degrees , 120 slices, reconstructed voxel size 0.3 x 0.3 x 0.8 mm); (2) black blood cardiac-gated water-selective T1w 3D spoiled GE (TR/TE/FA = 31 milliseconds/7.7 milliseconds/15 degrees , 36 slices, 0.3 x 0.3 x 1.0 mm); and (3) black blood cardiac triggered fat suppressed T2w TSE (TR/TE/ETL = 3 heart beats/44 milliseconds/7, 18 slices, 0.3 x 0.3 x 2 mm). Three observers in consensus performed image analysis. Special attention was paid to the integrity of the luminal and adventitial vessel boundary and the presence of a communicating intimal tear or flap.
RESULTS: 3.0 T MRI provided excellent delineation of vessel lumen and vessel wall as a result of the nearly complete suppression of arterial blood signal. An intramural hematoma could be identified in all patients, confined between the luminal and adventitial vessel boundary. In no patient a communicating intimal tear could be identified. Clear distinction between intramural hematoma and thrombus was possible.
CONCLUSION: High-resolution vessel wall imaging in patients with acute CAD is feasible. The increased signal-to-noise ratio at 3.0 T can be invested to obtain a higher spatial resolution, permitting depiction of intimal and adventitial vessel wall boundary and the intramural hematoma in the diseased vessel segment. The morphologic information that is gained is helpful in the understanding of the underlying pathomechanismen of CAD.