Relaxation along fictitious field with rank n (RAFFn): A promising magnetic resonance imaging method to determine myocardial infarction

Author(s): Elias Yla-Herttuala, Amir Mirmojarabian, Timo Liimatainen

Purpose of this review: Cardiovascular Diseases (CVD) are the leading cause of deaths worldwide. Myocardial Infarction (MI) is one of the deadliest CVDs. MI is causing many complex cellular biological changes in the myocardium after myocardial infarction (MI). Modern magnetic resonance imaging (MRI) techniques, such as rotating frame relaxation time T1ρ, can be used to visualize and quantify the damages in the myocardium after the MI and for the detection of myocardial alternations without the use of contrast agents. However, T1ρ method suffers from high specific absorption rate i.e. tissue heating. Modern MRI technique called Relaxation Along a Fictitious Field (RAFF) in the Rotating Frame of Rank n (RAFFn) has overcome the specific absorption rate problems of T1ρ method. Additionally, RAFFn has been shown to visualize and quantify the MI in both preclinical and clinical studies.

Recent findings: The RAFFn method has been used to characterize the MI in preclinical mouse MI models with promising results. The RAFFn method was implemented in standard clinical 1.5 T magnet for characterizing MI in human patients. The RAFFn has been used to determine also the fibrosis in preclinical hypertrophic cardiomyopathy mouse model and the results revealed the sensitiveness of RAFFn method to hypertrophic cardiomyopathy-related tissue changes in the myocardium.

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.