title: Arterial flow characteristics in the presence of vascular disease and implications for fast spin echo-based noncontrast MR angiography.
abstract: OBJECTIVE
  To investigate arterial flow characteristics in the setting of vascular disease, and examine their effect on the performance of fast spin-echo (FSE)-based noncontrast MR angiography (NC-MRA).
  
  
  METHODS
  Seventeen patients were recruited from among those scheduled for routine contrast-enhanced MR angiography (CE-MRA) of the lower extremities at 1.5 Tesla. The research portion of the exam was performed before the clinically-indicated protocol and included phase-contrast imaging at multiple levels in the legs and FSE-based NC-MRA in the calf and thigh, using a three-dimensional ECG-gated technique that exploits differences in arterial flow velocity between diastole and systole.
  
  
  RESULTS
  Vascular occlusions were associated with reduced systolic velocity, a delayed systolic peak, and, in two middle-aged patients, an increase in diastolic velocity. Elevated systolic and diastolic velocities were observed in a subject with a nonhealing ulcer. NC-MRA allowed visualization of arteries with systolic velocities as low as 3 cm/s, and exhibited comparable depiction to CE-MRA for diastolic velocities as high as 6 cm/s. At the highest diastolic velocities observed (15 cm/s) arterial depiction was severely degraded.
  
  
  CONCLUSIONS
  FSE-based NC-MRA as presently implemented performs successfully over a wide range of flow patterns, but does not accommodate extremely low systolic velocities or very high diastolic velocities.
authors.affiliation: Radiology Department, New York University School of Medicine, New York, USA. pippa.storey@nyumc.org
authors.forename: Pippa
authors.initials: P
authors.lastname: Storey
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Lim
authors.forename: Sooah
authors.initials: S
authors.lastname: Kim
authors.forename: David R
authors.initials: DR
authors.lastname: Stoffel
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries / Q000473:pathology / Q000503:physiopathology*; D001783:Blood Flow Velocity; D003971:Diastole; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013599:Systole; D014652:Vascular Diseases / Q000503:physiopathology*