Background:
Cardiac MRI permits diagnosis with acute myocardial infarction (AMI) by detection of infarct-related myocardial edema (IRME) on black-blood T2-weighted images (T2WIs), and myocardial scar on delayed-enhanced images (DEs). Diffusion-weighted image (DWI) is an established method for detection of cerebral infarction edema, but few reports are available on detection of IRME.
Objective:
To detect IRME using DWIs, and compare the contrast-to-noise ratio (CNR) with T2WIs.
Methods:
Cardiac MRI was performed on a 1.5T scanner (SIEMENS Avanto, Erlangen, Germany) in 12 AMI patients within 14 days after successful reperfusion. T2WIs were acquired using a double inversion-recovery fast-spin echo sequence. DWIs were acquired using combined cardiac and respiratory gated single-shot echo-planar sequence with a b-value of 50 s/mm
2
. DEs were acquired using an inversion-recovery segmented gradient-echo sequence, fifteen minutes after administering 0.15 mmol/kg gadolinium-DTPA. CNR was calculated in the T2WIs and DWIs using the following formula: CNR = (signal intensity[ME]-signal intensity[M]) / SD(B), where ME = myocardial edema, M = myocardium, and SD(B) =standard deviation of background signal intensity.
Results:
IRME was detected on T2WIs, and myocardial scar on DEs in all patients. DWIs revealed an area of significantly increased signal intensity in the same region identified as IRME on T2WIs in all patients. The CNR of DWIs (78.9 ± 44.5) was significantly higher than those of T2WIs (31.5 ± 23.3) (p = 0.0001).
Conclusion:
Our findings indicate that low b-value DWI provides better contrast in infarct-related myocardial edema than T2WIs.
P440Nonlinear dynamics of cardiac repolarization add unique prognostic value to cardiac MRI of myocardial scar for prediction of appropriate shock and cardiac death in primary prevention ICD recipients
