High Resolution CMR T1 Mapping for Imaging Right Ventricular Myocardial Fibrosis

Gadolinium-enhanced T1 mapping MRI is becoming increasingly important for the diagnosis of left ventricular (LV) myocardial fibrosis. Modified Look-Locker inversion recovery (MOLLI) and shortened MOLLI (ShMOLLI) are the current widely-used T1 mapping techniques for the heart but have limited spatial resolution due to physiological motion during image acquisition. These techniques typically have in-plane spatial resolutions in the range of 2.0–2.4 mm2, and they are well-suited for T1 mapping of thick structures such as LV wall. Because of this, the application of T1 mapping has generally been confined to the LV. However, T1 mapping might also be valuable in thinner structures such as the right ventricle (RV) and left atrial wall to assess fibrosis in disorders such as pulmonary arterial hypertension, arrhythmogenic right ventricular cardiomyopathy, congenital heart disease, and atrial fibrillation. For imaging structures with complex geometry such as the RV wall, both high in-plane resolution and high through-plane resolution are crucial. Furthermore, several applications such as the quantitative assessment of the peri-infarct region require continuous 3D coverage of the myocardial structure. Therefore, the overall goal of this dissertation is to develop and apply noninvasive high-resolution T1 mapping MRI to assess myocardial fibrosis in thin structures such as the RV wall.

For this dissertation, Specific Aim 1 is to develop a novel high spatial resolution 2D cardiac T1 mapping technique to image the thin wall of the RV. Specific Aim 2 is to assess right ventricular fibrosis in patients with pulmonary arterial hypertension using the T1 mapping technique developed in Aim 1. Specific Aim 3 is to extend the T1 mapping method developed in Aim #1 to perform high-resolution, three-dimensional T1 mapping of the heart within a clinically acceptable scan time.