Cardiac T1 Mapping

Abstract

Cardiac T1 mapping is a method for mapping the myocardial T1 relaxation properties with single-pixel resolution, in its native state (i.e., pre-contrast state), and after administration of a paramagnetic, extracellular contrast agent. Both native T1 and the change of the myocardial T1 relative to its native state (preferably normalized by the change of T1 in blood) have become important biomarkers to detect abnormal water homeostasis and adverse myocardial remodeling, respectively, in a broad range of cardiac diseases. The quest to optimize accuracy, precision, and reproducibility of these biomarkers has driven the development of T1 mapping techniques, both in terms of pulse sequence design and of post-processing to overcome sequence and acquisition imperfections. These technical advances also led to the realization that myocardial T1 relaxation times do not represent an intrinsic tissue property that is independent of the applied pulse sequence technique, but instead encompasses probing a mixture of T1 relaxation mechanisms, that depends on the pulse sequence technique. Untangling different T1 relaxation mechanisms will likely remain a challenge for cardiac T1 mapping, in particular when limited to native T1 measurements, but this will not necessarily impede the detection of disease, assuming that normative values have been established with the same T1 mapping technique as used in patients.