title: Three-dimensional coronary MR angiography performed with subject-specific cardiac acquisition windows and motion-adapted respiratory gating.
abstract: OBJECTIVE
  In coronary MR angiography, data are conventionally accepted in only short and fixed periods of the cardiac and respiratory cycles. We hypothesized that a more flexible and subject-specific approach to cardiac and respiratory gating may shorten scanning times while maintaining image quality.
  
  
  METHODS
  We implemented an acquisition technique that uses subject-specific acquisition windows in the cardiac cycle and a motion-adapted gating window for respiratory navigator gating. Cardiac acquisition windows and trigger delays were determined individually from a coronary motion scan. Motion-adapted gating used a 2-mm acceptance window for the central 35% of k-space and a 6-mm window for the outer 65% of k-space. In 10 subjects, three-dimensional coronary MR angiograms of the right and left coronary systems were acquired with this technique (the "adaptive technique") as well as a conventional acquisition method, and the scanning times and image quality were compared. The adaptive technique was then applied prospectively to 40 patients who underwent coronary radiographic angiography.
  
  
  RESULTS
  Scanning times with the adaptive technique were reduced by a factor of 2.3 for the right coronary artery and by a factor of 2.2 for the left coronary artery system compared with the conventional technique, mainly because we were able to use longer subject-specific acquisition windows in patients with low heart rates. Subjective and objective measurements of image quality showed no significant differences between the two techniques. Prospective evaluation of MR angiograms yielded a sensitivity and specificity of 74.3% and 88.2%, respectively, to detect significant coronary artery stenoses.
  
  
  CONCLUSIONS
  Coronary MR angiography with subject-specific acquisition windows and motion-adapted respiratory gating reduces scanning times while maintaining image quality and provides high diagnostic accuracy for the detection of coronary artery stenosis.
authors.affiliation: British Heart Foundation-Cardiac MRI Unit, Rm. 170, D Fl., Jubilee Building, Leeds General Infirmary, Great George Street, Leeds LS1 3EX, United Kingdom.
authors.forename: Sven
authors.initials: S
authors.lastname: Plein
authors.forename: Tim R
authors.initials: TR
authors.lastname: Jones
authors.forename: John P
authors.initials: JP
authors.lastname: Ridgway
authors.forename: Mohan U
authors.initials: MU
authors.lastname: Sivananthan
mesh_terms: D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000473:pathology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity