title: Contrast enhancement of manganese-hydroxypropyl-tetraacetic acid, an MR contrast agent with potential for detecting differences in myocardial blood flow.
abstract: OBJECTIVE
  To determine whether the contrast agent MnHPTA has potential for detecting differences in myocardial blood flow.
  
  
  METHODS
  R1 in the myocardium was calculated from MR signal intensity measurements in 18 pigs after intravenous injection of 5, 15, or 25 micromol MnHPTA/kg body weight. Measurements were made in each animal after administration at rest and during dobutamine-induced stress.
  
  
  RESULTS
  A difference of approximately 0.1 sec-1 in the R1 increase between rest and stress still remained 31 minutes after administration of 25 micromol MnHPTA/kg body weight. When two consecutive MnHPTA injections were performed, the second injection induced a lower R1 increase than the corresponding first injection.
  
  
  CONCLUSIONS
  MnHPTA at a dose of 25 micromol/kg body weight (b.w.) has the potential to detect perfusion differences in myocardium. When two consecutive injections of MnHPTA were administered, the R1 change after the second injection was affected by the earlier administration. Therefore, a protocol including more than one administration is not ideal for this contrast agent.
authors.affiliation: MR Unit, Department of Radiology, Uppsala University Hospital, Uppsala, Sweden. rolf.eriksson@radiol.uu.se
authors.forename: Rolf
authors.initials: R
authors.lastname: Eriksson
authors.forename: Lars
authors.initials: L
authors.lastname: Johansson
authors.forename: Tomas
authors.initials: T
authors.lastname: Bjerner
authors.forename: Jan Olof G
authors.initials: JO
authors.lastname: Karlsson
authors.forename: Håkan
authors.initials: H
authors.lastname: Ahlström
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003287:Contrast Media / Q000737:chemistry* / Q000493:pharmacokinetics*; D003326:Coronary Circulation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008345:Manganese / Q000493:pharmacokinetics*; D015394:Molecular Structure; D009206:Myocardium / Q000378:metabolism*; D009942:Organometallic Compounds / Q000737:chemistry / Q000493:pharmacokinetics; D013552:Swine
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C516343:manganese-hydroxypropyl-tetraacetic acid; D008345:Manganese