title: Rapid High-resolution, Self-registered, Dual Lumen-contrast MRI Method for Vessel-wall Assessment in Peripheral Artery Disease:: A Preliminary Investigation.
abstract: OBJECTIVE
  Contrast-enhanced angiographic evaluation by magnetic resonance imaging (MRI) and computed tomography (CT) is the reference standard for assessing peripheral artery disease (PAD). However, because PAD and diabetes often coexist, the prevalence of renal insufficiency is a major challenge to contrast-based angiography. The objective of this work is to describe and demonstrate a new application of three-dimensional double-echo steady-state (3D DESS) as a noncontrast vascular MRI method for evaluating peripheral atherosclerosis at 3 Tesla (3T).
  
  
  METHODS
  A water-selective 3D DESS pulse sequence was designed to simultaneously collect two steady-state free-precession signals (free induction decay and Echo) yielding "black blood" (BB) and "gray blood" (GB) images. For completeness Bloch equation, simulations were performed to characterize DESS signals of various tissues including blood at different velocities and to assess two healthy subjects for the purpose of pulse sequence optimization. Exploratory studies were performed as an add-on protocol to an existing study involving patients with PAD. To evaluate the method's specificity for detecting calcification, images from select patients were compared against CT angiography.
  
  
  RESULTS
  Simulations agreed qualitatively with in vivo images supporting DESS' potential for generating distinct lumen contrast (GB vs BB). Lesions representing calcium were easily identifiable on the basis of signal void occurring on both image types and were confirmed by CT angiography. Further, BB allowed visualization of stent restenosis, and data suggest its ability to visualize acute thrombus by virtue of T2 weighting.
  
  
  CONCLUSIONS
  Preliminary investigation and results suggest noncontrast 3D DESS to have the potential to improve diagnosis of PAD patients by providing detailed structural assessment of vessel-wall architecture.
authors.affiliation: Departments of Radiology, University of Pennsylvania School of Medicine, 3400 Spruce St. 19104, Philadelphia, PA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Langham
authors.affiliation: Departments of Radiology, University of Pennsylvania School of Medicine, 3400 Spruce St. 19104, Philadelphia, PA.
authors.forename: Benoit
authors.initials: B
authors.lastname: Desjardins
authors.affiliation: Departments of Radiology, University of Pennsylvania School of Medicine, 3400 Spruce St. 19104, Philadelphia, PA.
authors.forename: Erin K
authors.initials: EK
authors.lastname: Englund
authors.affiliation: Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Emile R
authors.initials: ER
authors.lastname: Mohler
authors.affiliation: Departments of Anesthesiology, Stony Brook University Medical Center, Stony Brook, New York.
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Floyd
authors.affiliation: Departments of Radiology, University of Pennsylvania School of Medicine, 3400 Spruce St. 19104, Philadelphia, PA. Electronic address: wehrli@mail.med.upenn.edu.
authors.forename: Felix W
authors.initials: FW
authors.lastname: Wehrli
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000473:pathology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Black-blood imaging; SSFP-Echo; SSFP-FID; angiography; calcification; double-echo steady-state; gray-blood imaging; peripheral artery disease; vessel-wall imaging