Time-of-flight magnetic resonance angiography of the canine brain at 3.0 Tesla and 7.0 Tesla.

OBJECTIVE To evaluate the ability of 2-D time-of-flight (ToF) magnetic resonance angiography (MRA) to depict intracranial vasculature and compare results obtained with 3.0- and 7.0-T scanners in dogs. ANIMALS 5 healthy Beagles. PROCEDURES 2-D ToF-MRA of the intracranial vasculature was obtained for each dog by use of a 3.0-T and a 7.0-T scanner. Quantitative assessment of the images was obtained by documentation of the visibility of major arteries comprising the cerebral arterial circle and their branches and recording the number of vessels visualized in the dorsal third of the brain. Qualitative assessment was established by evaluation of overall image quality and image artifacts. RESULTS Use of 3.0- and 7.0-T scanners allowed visualization of the larger vessels of the cerebral arterial circle. Use of a 7.0-T scanner was superior to use of a 3.0-T scanner in depiction of the first- and second-order arterial branches. Maximum-intensity projection images had a larger number of vessels when obtained by use of a 7.0-T scanner than with a 3.0-T scanner. Overall, image quality and artifacts were similar with both scanners. CONCLUSIONS AND CLINICAL RELEVANCE Visualization of the major intracranial arteries was comparable with 3.0- and 7.0-T scanners; the 7.0-T scanner was superior for visualizing smaller vessels. Results indicated that ToF-MRA is an easily performed imaging technique that can be included as part of a standard magnetic resonance imaging examination and should be included in the imaging protocol of dogs suspected of having cerebrovascular disease.