title: MR angiography at 3 T for assessment of the external carotid artery system.
abstract: OBJECTIVE
  A number of clinical situations exist in which high-resolution depiction of the external carotid artery system is required, a task not previously addressed by MR angiography. The purpose of this study was to evaluate the extent to which high-spatial-resolution MR angiography at 3 T can be used to map the normal external carotid artery system.
  
  
  METHODS
  Twenty-three consenting adult patients were prospectively evaluated. Images acquired were evaluated by two independent observers, and each branch vessel was scored with regard to image quality, presence and grade of stenoses, and artifacts. Interobserver agreement regarding image quality and the presence and degree of stenosis was tested using the kappa coefficient. Differences in quality ratings between the two observers were assessed using the paired Student's t test.
  
  
  RESULTS
  Of 828 vessels analyzed, 92.63% were designated of diagnostic quality with no significant difference between the observers' image quality scores (p = 0.63). Good agreement was determined regarding image quality achieved (kappa = 0.716). All examinations were free of artifact sufficient to interfere with confident interpretation. Excellent correlation was seen with regard to stenosis detection and grading (kappa = 0.857). Of the external carotid artery systems assessed, 82.6% showed conventional anatomic vascular branching.
  
  
  CONCLUSIONS
  High-spatial-resolution, 3D contrast-enhanced MR angiography at 3 T using sagittal source data acquisition and an advanced acceleration factor of 6 allows high-quality (92.63% of arterial segments) visualization of the external carotid artery system, with complete head and neck vascular coverage.
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Peter V. Ueberroth Bldg., Ste. 3371, 10945 Le Conte Ave., Los Angeles, CA 90095-7206, USA. derek.lohan@gmail.com
authors.forename: Derek G
authors.initials: DG
authors.lastname: Lohan
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Barkhordarian
authors.forename: Roya
authors.initials: R
authors.lastname: Saleh
authors.forename: Mayil
authors.initials: M
authors.lastname: Krishnam
authors.forename: Noriko
authors.initials: N
authors.lastname: Salamon
authors.forename: Stefan G
authors.initials: SG
authors.lastname: Ruehm
authors.forename: J Paul
authors.initials: JP
authors.lastname: Finn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000473:pathology*; D016893:Carotid Stenosis / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity