Blood oxygenation dependence of T1 and T2 in the isolated, perfused rabbit heart at 4.7T.
An MR line scan protocol has been used to measure relaxation parameters (T1 and T2) in isolated, blood perfused rabbit hearts at various blood oxygenations. Hearts were retrogradely perfused at 37 degrees C with a cardioplegic solution (modified St. Thomas' solution) containing sheep red blood cells and adenosine (1 mM) to maximally vasodilate the coronary vascular bed. Arresting the hearts eliminated motion complications and minimized arteriovenous oxygenation differences. The authors have found that under conditions of stable flow, there is a strong correlation between T2 in myocardial septa and hemoglobin (Hb) saturation, while tissue T1 is virtually independent of blood oxygenation. These effects are believed to be due to the paramagnetic agent deoxyhemoglobin.
Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
M K
MK
Atalay
S B
SB
Reeder
E A
EA
Zerhouni
J R
JR
Forder
D000241:Adenosine / Q000627:therapeutic use; D000818:Animals; D001639:Bicarbonates / Q000627:therapeutic use; D002122:Calcium Chloride / Q000627:therapeutic use; D002314:Cardioplegic Solutions / Q000627:therapeutic use; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000033:anatomy & histology; D004912:Erythrocytes; D006321:Heart / Q000033:anatomy & histology*; D006324:Heart Arrest, Induced; D006346:Heart Septum / Q000033:anatomy & histology; D006352:Heart Ventricles / Q000033:anatomy & histology; D006454:Hemoglobins / Q000378:metabolism; D008274:Magnesium / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009206:Myocardium / Q000378:metabolism; D010100:Oxygen / Q000097:blood*; D011189:Potassium Chloride / Q000627:therapeutic use; D011817:Rabbits; D012756:Sheep; D012965:Sodium Chloride / Q000627:therapeutic use; D014018:Tissue Distribution; D014664:Vasodilation
D001639:Bicarbonates; D002314:Cardioplegic Solutions; D006454:Hemoglobins; C041711:St. Thomas' Hospital cardioplegic solution; D012965:Sodium Chloride; D011189:Potassium Chloride; C100003:deoxyhemoglobin; D008274:Magnesium; D000241:Adenosine; D002122:Calcium Chloride; D010100:Oxygen