Relaxation along Fictitious Field (RAFF) provide an appropriate alternative method for imaging chronic myocardial infarct without exogenous contrast media

Author(s): Seyed Amir Mirmojarabian, Esa Liukkonen, Victor Casula, Mikko J. Nissi, Lauri Ahvenjarvi, Juhani Junttila, Timo Liimatainen

Background: Relaxation along Fictitious Field with rank 2 (RAFF2) has been shown to provide contrast agent-free alternative for gadolinium based Late Gadolinium Enhancement (LGE) measurement in mouse model. To characterize chronic Myocardial Infarction (MI) by using Relaxation along Fictitious Field in human myocardium without contrast agents.

Methods and findings: Data for this study were collected in 18 patients with chronic infarct at 1.5 T. Scarred and remote area averages of RAFF2 relaxation time and steady state (TRAFF2 and SSRAFF2), native T1 and T2, Extra Cellular Volume (ECV) and LGE were calculated. Subsequently infarct sizes were determined and compared between LGE, ECV and RAFF2 maps. In addition, area of overestimation (AOE) was estimated for RAFF2 maps.

The TRAFF2 and SSRAFF2, native T1 and T2 relaxation times, ECV and LGE values elevated at scar compared to remote area. Areas of increased LGE were highly correlated to the areas with increased SSRAFF2 (R=0.71, p<0.01) and TRAFF2 (R=0.47, p<0.05).

Summary: RAFFn has been used to characterize myocardial infarction in humans and in mice. RAFFn owns potential to be used in the MI diagnosis without contrast agents.