title: Real-time dynamics of an extravascular magnetic resonance contrast medium in acutely infarcted myocardium using inversion recovery and gradient-recalled echo-planar imaging.
abstract: OBJECTIVE
  The purposes of this study are to evaluate the first-pass profile of gadolinium-BOPTA/Dimeg (Gd-BOPTA/Dimeg) during its transit through hearts subjected to acute myocardial infarction, and to delineate these infarcted regions by the use of ultrafast magnetic resonance imaging (MRI).
  
  
  METHODS
  Regional ischemia was induced in anesthetized rats by occluding the left coronary artery. Imaging parameters for single shot EPI included TE, 10 mseconds; AT, 33 mseconds; and 64 x 64-pixel matrix. Consecutive images were obtained every 1 to 2 seconds over a 30-second period. After approximately two images, Gd-BOPTA/Dimeg was injected intravenously (0.05 and 0.25 mmol/kg).
  
  
  RESULTS
  Gd-BOPTA/Dimeg (0.05 mmol/kg), with inversion recovery EPI, produced a substantial increase in signal intensity of right and then left ventricular blood. Normally perfused myocardium also was enhanced, but not the acutely infarcted region. Clear delineation of the infarcted region as negatively enhanced "cold spots" persisted for at least 20 seconds. Gd-BOPTA/Dimeg (0.25 mmol/kg) with standard gradient-recalled EPI produced a different profile of signal intensity changes. Signal intensities of ventricular blood and normal myocardium were greatly reduced, leaving the infarcted zone as a positively enhanced "hot spot." Delineation of the infarcted region persisted for 6 to 8 seconds. The infarcted zone detected with MRI corresponded to that observed at autopsy.
  
  
  CONCLUSIONS
  Regions of acute myocardial infarction can be detected as negatively enhanced "cold spots" or positively enhanced "hot spots" by studying the first-pass dynamics of Gd-BOPTA/Dimeg through hearts with regional ischemia by use of single shot EPI.
authors: Department of Radiology, University of California, San Francisco 94143.
authors: K K
authors: KK
authors: Yu
authors: M
authors: M
authors: Saeed
authors: M F
authors: MF
authors: Wendland
authors: N
authors: N
authors: Derugin
authors: F M
authors: FM
authors: Cavagna
authors: C B
authors: CB
authors: Higgins
mesh_terms: D000818:Animals; D017352:Echo-Planar Imaging; D005260:Female; D008536:Meglumine / Q000031:analogs & derivatives*; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D009942:Organometallic Compounds; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine