Shorter Difference Between Myocardium and Blood Optimal Inversion Time Suggests Diffuse Fibrosis in Dilated Cardiomyopathy

Purpose: To find evidence of diffuse fibrosis in dilated cardiomyopathy (DCM) patients by comparing measurements on clinical late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) studies between DCM and healthy subjects. Materials and Methods: LGE CMR and the Look-Locker images from 20 DCM patients and 17 healthy controls were analyzed. Blood signal to noise ratio (SNR), myocardium SNR and blood to myocardium contrast-to-noise ratio (CNR) were measured on the LGE-CMR images. The optimal inversion time (T1) to null blood and myocardium was determined on the Look Locker images. The postcontrast T-1 was estimated using a phantom study that correlated optimal T1 and heart rate to T-1. Results: The blood SNR was lower myocardium SNR was higher, and the blood to myocardium CNR was lower (6.6 +/- 0.7 vs. 10.3 +/- 0.9, P = 0.004) on DMC LGE-CMR images as compared to controls. The blood myocardium optimal T1 difference (Delta TI) was lower (38 +/- 2 msec vs. 55 +/- 3 msec, P < 0.0001) in DCM, and the estimated blood myocardium T-1 difference (Delta T-1) (116 +/- 6 msec vs. 152 +/- 8 msec. P = 0.001) was also lower. Conclusion: DCM patients have reduced blood-myocardium Delta TI and Delta T-1 and lower CNR as compared to controls, suggesting the presence of diffuse fibrosis. This may impact the interpretation of LGE data.