Lale Umutlu MD, Presenter: Consultant, Bayer AG

Nina Theysohn MD, Abstract Co-Author: Nothing to Disclose

Soren Johst, Abstract Co-Author: Nothing to Disclose

Michael Forsting MD, Abstract Co-Author: Nothing to Disclose

Marc U. Schlamann, Abstract Co-Author: Nothing to Disclose

Karsten Wrede, Abstract Co-Author: Nothing to Disclose

The purpose of this study was to intraindividually compare the delineation of intracranial arterial vasculature utilizing ultra-high-resolution TOF MRA versus non-enhanced MPRAGE at 7 Tesla.

40 subjects were examined on a 7 T whole-body MR system (Siemens Healthcare) utilizing a 32-channel transmit / receive head coil (Nova Medical). TOF MRA was performed with a voxel size (vs) of 0.2 x 0.2 x 0.2 mm3, non-enhanced MPRAGE with a vs of 0.7x0.7 x0.7mm3. For qualitative analysis, two readers assessed the delineation of the following arteries and segments: (1) internal carotid artery [cervical segment, petrous segment, cavernous segment], (2) anterior cerebral artery [A1, A2], (3), anterior communicating artery, (4) middle cerebral artery [M1, M2, M3], (5) posterior communicating artery, (6) posterior cerebral artery [P1, P2], (7) basilar artery. Additionally, (1) overall image quality, (2) vessel sharpness, (3) vessel to background contrast and (4) image impairment due to artifacts was assessed. For qualitative analysis a five-point-scale was utilized for rating (5 = excellent image quality to 1 = non-diagnostic). For quantitative analysis contrast-ratios of the middle cerebral artery in correlation to surrounding grey matter were measured in both sequences. For statistical analysis a Wilcoxon signed rank test was applied.

Both sequences enabled high quality delineation of all assessed vessel segments with superior depiction of the vessels of the anterior circulation (meananterior circulation MPRAGE=4.6 TOF MRA=4.4) compared to the vessels of the posterior (circulation meanposterior circulation MPRAGE=4.1 TOF MRA=3.8). While TOF MRA yielded superior vessel sharpness over MPRAGE (meanvessel sharpness MPRAGE 4.3 TOF MRA 4.6), MPAGE MRI yielded superior vessel to background contrast (meanvessel contrast MPRAGE=4.6 TOF MRA=4.2), also reflected in higher CR values for MPRAGE MRI.

Our results demonstrate the high diagnostic value of both non-enhanced MRA techniques, with overall superiority of MPRAGE MRI, offering a robust and artifact-free high-resolution delineation of the intracranial vasculature.

7T MPRAGE MRI may serve as a high quality diagnostic tool for high-resolution assessment of the intracranial vasculature, particularly for recurrent radiation-free follow-up imaging.

Umutlu, L, Theysohn, N, Johst, S, Forsting, M, Schlamann, M, Wrede, K, Ultra-high-Resolution Imaging of the Intracranial Arteries at 7T: TOF MRA versus Non-enhanced MPRAGE.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018861.html