title: Carotid magnetic resonance angiography: improved image quality with dual 3-inch surface coils.
abstract: Magnetic resonance angiography (MRA) hs inherent artifacts due to variation in velocity and direction of flowing blood in the carotid bulb and regions of stenosis. We examined the efficiency of dual 3-inch surface coils to delineate carotid artery flow better. Carotid MRA was performed on ten healthy volunteers and six patients, on a 1.5 T system. A special adapter was constructed to use with 3-inch (receive-only) coils, which were placed over the carotid bifurcations. Routine anterior neck coils were also used. Contiguous axial two-dimensional (45/8.7, 1.5 mm, flip angle 60 degrees) time-of-flight sequences were used. Image matrix was 256 x 256 with two signals averaged and acquisition time 6-10 min. These images were postprocessed and reformatted into angiographic views using a maximum intensity projection algorithm. Computer simulation of carotid artery blood flow throughout the cardiac cycle based on vessel contours derived from digital subtraction angiography was carried out by finite element analysis. Improved definition of vessel margin, particularly at the carotid bifurcation, and substantially increased signal-to-background ratio of flowing blood were obtained with 3-in-chcoils. Apparent loss of signal in the carotid bulb was diminished. In one patient, contiguous flow throughout a high-grade stenosis was well defined, with the surface coil method, while drop-off of signal was observed with routine neck coil imaging.
authors.affiliation: Department of Radiologic Sciences, Medical College of Pennsylvania, Philadelphia 19129, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Faro
authors.forename: S
authors.initials: S
authors.lastname: Vinitski
authors.forename: H V
authors.initials: HV
authors.lastname: Ortega
authors.forename: F B
authors.initials: FB
authors.lastname: Mohamed
authors.forename: C Y
authors.initials: CY
authors.lastname: Chen
authors.forename: A E
authors.initials: AE
authors.lastname: Flanders
authors.forename: C F
authors.initials: CF
authors.lastname: Gonzales
authors.forename: R A
authors.initials: RA
authors.lastname: Zimmerman
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D001161:Arteriosclerosis / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D001783:Blood Flow Velocity; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D002340:Carotid Artery Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D008875:Middle Aged