Measurement of Myocardial T1ρ with a Motion Corrected, Parametric Mapping Sequence in Humans.

Abstract

PurposeTo develop a robust T1ρ magnetic resonance imaging (MRI) sequence for assessment of myocardial disease in humans.Materials and methodsWe developed a breath-held T1ρ mapping method using a single-shot, T1ρ-prepared balanced steady-state free-precession (bSSFP) sequence. The magnetization trajectory was simulated to identify sources of T1ρ error. To limit motion artifacts, an optical flow-based image registration method was used to align T1ρ images. The reproducibility and accuracy of these methods was assessed in phantoms and 10 healthy subjects. Results are shown in 1 patient with pre-ventricular contractions (PVCs), 1 patient with chronic myocardial infarction (MI) and 2 patients with hypertrophic cardiomyopathy (HCM).ResultsIn phantoms, the mean bias was 1.0 ± 2.7 msec (100 msec phantom) and 0.9 ± 0.9 msec (60 msec phantom) at 60 bpm and 2.2 ± 3.2 msec (100 msec) and 1.4 ± 0.9 msec (60 msec) at 80 bpm. The coefficient of variation (COV) was 2.2 (100 msec) and 1.3 (60 msec) at 60 bpm and 2.6 (100 msec) and 1.4 (60 msec) at 80 bpm. Motion correction improved the alignment of T1ρ images in subjects, as determined by the increase in Dice Score Coefficient (DSC) from 0.76 to 0.88. T1ρ reproducibility was high (COV ConclusionSingle-shot, motion corrected, spin echo, spin lock MRI permits 2D T1ρ mapping in a breath-hold with good accuracy and precision.