title: Combined respiratory and cardiac triggering improves blood pool contrast-enhanced pediatric cardiovascular MRI.
abstract: BACKGROUND
  Contrast-enhanced cardiac MRA suffers from cardiac motion artifacts and often requires a breath-hold.
  
  
  OBJECTIVE
  This work develops and evaluates a blood pool contrast-enhanced combined respiratory- and ECG-triggered MRA method.
  
  
  METHODS
  An SPGR sequence was modified to enable combined cardiac and respiratory triggering on a 1.5-T scanner. Twenty-three consecutive children referred for pediatric heart disease receiving gadofosveset were recruited in HIPAA-compliant fashion with IRB approval and informed consent. Children underwent standard non-triggered contrast-enhanced MRA with or without suspended respiration. Additionally, a free-breathing-triggered MRA was acquired. Triggered and non-triggered studies were presented in blinded random order independently to two radiologists twice. Anatomical structure delineation was graded for each triggered and non-triggered acquisition and the visual quality on triggered MRA was compared directly to that on non-triggered MRA.
  
  
  RESULTS
  Triggered images received higher scores from each radiologist for all anatomical structures on each of the two reading sessions (Wilcoxon rank sum test, P < 0.05). In direct comparison, triggered images were preferred over non-triggered images for delineating cardiac structures, with most comparisons reaching statistical significance (binomial test, P < 0.05).
  
  
  CONCLUSIONS
  Combined cardiac and respiratory triggering, enabled by a blood pool contrast agent, improves delineation of most anatomical structures in pediatric cardiovascular MRA.
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Lucile Packard Children's Hospital, 725 Welch Road, Room 1679, Stanford, CA 94305-5913, USA. vasanawala@stanford.edu
authors.forename: Shreyas S
authors.initials: SS
authors.lastname: Vasanawala
authors.forename: Frandics P
authors.initials: FP
authors.lastname: Chan
authors.forename: Beverley
authors.initials: B
authors.lastname: Newman
authors.forename: Marcus T
authors.initials: MT
authors.lastname: Alley
mesh_terms: D000293:Adolescent; D016477:Artifacts; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006331:Heart Diseases / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007223:Infant; D016247:Information Storage and Retrieval / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D009942:Organometallic Compounds; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D005682:Gadolinium; C109932:gadofosveset trisodium