title: Nonenhanced methods for lower-extremity MRA: a phantom study examining the effects of stenosis and pathologic flow waveforms at 1.5T.
abstract: OBJECTIVE
  To evaluate the signal properties of 2D time of flight (TOF), quiescent-interval single-shot (QISS), ECG-gated 3D fast spin-echo (FBI), and ungated 3D fast spin-echo ghost (Ghost) magnetic resonance angiography (MRA) over a range of flow velocities in a pulsatile flow phantom with a 50% diameter stenosis at 1.5T.
  
  
  METHODS
  Blood-mimicking fluid was pumped at eight peak flow velocities through a stenotic region in triphasic and monophasic waveforms. Vascular signal proximal, within, and distal to the stenosis was measured from the source images of the four MRA methods. Coronal maximum intensity projection images were used to compare image quality.
  
  
  RESULTS
  TOF and QISS signal trends were similar, but QISS exhibited the most consistent signal across velocities. At high velocities (≥ 42.4 cm/s), TOF showed poststenotic signal loss that was not observed with QISS. FBI and Ghost signals peaked at low velocities (3.9-9.7 cm/s) without flow compensation and at high velocities (≥ 64.6 cm/s) with flow compensation.
  
  
  CONCLUSIONS
  FBI and Ghost demonstrated dependence on blood flow velocity and flow compensation. TOF was sensitive to flow artifacts at high velocities. QISS proved most robust for accurately depicting the normal lumen and stenosis under a wide range of flow conditions. Monophasic and triphasic flow did not appreciably affect the signal performance of any method.
authors.affiliation: Department of Radiology, NorthShore University HealthSystem, Evanston, Illinois 60201, USA. EOfferman@northshore.org
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Offerman
authors.forename: Philip A
authors.initials: PA
authors.lastname: Hodnett
authors.forename: Robert R
authors.initials: RR
authors.lastname: Edelman
authors.forename: Ioannis
authors.initials: I
authors.lastname: Koktzoglou
mesh_terms: D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D001783:Blood Flow Velocity; D003287:Contrast Media; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D035002:Lower Extremity / Q000098:blood supply* / Q000473:pathology* / Q000503:physiopathology; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D058729:Peripheral Arterial Disease / Q000175:diagnosis*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media