[Ischemic myocardial viability assessment with interleaved T1-T2* magnetic resonance imaging].
OBJECTIVE
To investigate the value of ischemic myocardial viability assessment using interleaved T1-T2* magnetic resonance imaging.


METHODS
The left anterior descending coronary arteries (LAD) were occluded for 2 hours, followed by 1-hour reperfusion in 7 pigs. The hearts were then removed and perfused with a mixture of pig blood and crystalloid solution in 1:1 ratio. T1 relaxation times of the myocardium were measured with a TurboFLASH inversion-recovery sequence. The contrast agent, Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) was then injected as a bolus into the aortic perfusion line (0.05 mmol/kg body wt). The first pass of the contrast agent through the heart was followed using the interleaved T1-T2* imaging sequence. Once the concentration of Gd-DTPA was in an equilibrium state, T1 relaxation times were measured again.


RESULTS
The percentage recovery of T2* intensity (PRT2*) at the maximum T1 intensity measured during the first pass of the contrast agent with the interleaved T1-T2* imaging was statistically different in normal myocardium (37 +/- 11)%, infarct rim (90 +/- 15)% and infarct core (100 +/- 5)%, F = 66.585, P = 0.000. Moreover, the infarcted regions shown on PR(T2)* maps matched well with the infarcted myocardium measured by TTC staining. The median of T(1) relaxation time in normal region, infarct rim and infarct core was 531 ms, 541 ms and 1298 ms, respectively (H = 6.284, P = 0.043). However, normal region could not be differentiated from infarct rim with T1 relaxation times (q = 0.082, P = 0.775).


CONCLUSIONS
Infarcted myocardium and ischemic myocardial viability can be correctly identified and evaluated by the interleaved T1-T2* magnetic resonance imaging in this model.
Li
Gang
G
Department of Cardiac Surgery, The Second Affiliated Hospital, Harbin Medical University, Harbin 150086, China. gangli73@163.com.
Tian
Wei-Chen
WC
Ji
Ya-Nan
YN
Li
Song-Mei
SM
Yu
Bo
B
Tian
Gang-Hong
GH
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000175:diagnosis*; D017202:Myocardial Ischemia / Q000175:diagnosis; D009206:Myocardium / Q000473:pathology; D013552:Swine