title: Myocardial perfusion magnetic resonance imaging using sliding-window conjugate-gradient HYPR methods in canine with stenotic coronary arteries.
abstract: OBJECTIVE
  First-pass perfusion magnetic resonance imaging (MRI) is a promising technique for detecting ischemic heart disease. However, the diagnostic value of the method is limited by the low spatial coverage, resolution, signal-to-noise ratio (SNR), and cardiac motion-related image artifacts. A combination of sliding window and conjugate-gradient HighlY constrained back-PRojection reconstruction (SW-CG-HYPR) method has been proposed in healthy volunteer studies to reduce the acquisition window for each slice while maintaining the temporal resolution of 1 frame per heartbeat in myocardial perfusion MRI. This method allows for improved spatial coverage, resolution, and SNR.
  
  
  METHODS
  In this study, we use a controlled animal model to test whether the myocardial territory supplied by a stenotic coronary artery can be detected accurately by SW-CG-HYPR perfusion method under pharmacological stress.
  
  
  RESULTS
  Results from 6 mongrel dogs (15-25 kg) studies demonstrate the feasibility of SW-CG-HYPR to detect regional perfusion defects. Using this method, the acquisition time per cardiac cycle was reduced by a factor of 4, and the spatial coverage was increased from 2 to 3 slices to 6 slices as compared with the conventional techniques including both turbo-Fast Low Angle Short (FLASH) and echoplanar imaging (EPI). The SNR of the healthy myocardium at peak enhancement with SW-CG-HYPR (12.68 ± 2.46) is significantly higher (P < 0.01) than the turbo-FLASH (8.65 ± 1.93) and EPI (5.48 ± 1.24). The spatial resolution of SW-CG-HYPR images is 1.2 × 1.2 × 8.0 mm, which is better than the turbo-FLASH (1.8 × 1.8 × 8.0 mm) and EPI (2.0 × 1.8 × 8.0 mm).
  
  
  CONCLUSIONS
  Sliding-window CG-HYPR is a promising technique for myocardial perfusion MRI. This technique provides higher image quality with respect to significantly improved SNR and spatial resolution of the myocardial perfusion images, which might improve myocardial perfusion imaging in a clinical setting.
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Ge
authors.forename: Aya
authors.initials: A
authors.lastname: Kino
authors.forename: Daniel
authors.initials: D
authors.lastname: Lee
authors.forename: Rohan
authors.initials: R
authors.lastname: Dharmakumar
authors.forename: James C
authors.initials: JC
authors.lastname: Carr
authors.forename: Debiao
authors.initials: D
authors.lastname: Li
mesh_terms: D000818:Animals; D003287:Contrast Media; D023921:Coronary Stenosis / Q000175:diagnosis*; D004195:Disease Models, Animal; D004285:Dogs; D005240:Feasibility Studies; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000379:methods*
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA