Abstract 11927: MRI T1 Mapping of the Right Ventricle Using High Resolution ANGIE
Introduction: MRI T1 mapping has become an important method for the quantitative assessment of left ventricular myocardial fibrosis. T1 mapping of the right ventricle (RV) would also be valuable, however current methods lack adequate spatial resolution. We developed and evaluated an Accelerated and Navigator-Gated look-locker Imaging sequence for cardiac T1 Estimation (ANGIE) to overcome limitations induced by breathholding and enable high-resolution T1 mapping of the RV.
Methods: ANGIE incorporated a segmented and k-t undersampled readout as well as navigator gating into a look-locker acquisition to perform high-resolution, non-breathhold cardiac T1 mapping. For image reconstruction, we used compressed sensing (CS) with matrix rank sparsity. Five healthy volunteers (age 28 ± 4 yrs) underwent short-axis MRI using conventional MOLLI (2.0-2.3x2.5-2.9x4 mm3) and high-resolution ANGIE (1.2-1.3x1.2-1.3x4 mm3). The scan time for MOLLI was 17 heartbeats, while for ANGIE it was 184 ± 59s.
Results: As shown in Figure 1, high-resolution ANGIE provides spatial resolution sufficient to quantify T1 of the RV wall, whereas MOLLI suffers from insufficient spatial resolution for the RV. While ANGIE and MOLLI show good agreement in quantifying LV T1 values (T1 = 972 ± 62ms for MOLLI, and T1 = 941 ± 100ms for ANGIE, p=NS), for the RV, ANGIE measured T1 = 970 ± 103ms, and MOLLI measured T1 = 1059 ± 189ms (p=NS). The intrascan variation in the RV T1 estimate was greater for MOLLI than for ANGIE (p<0.05). The higher variation using the lower-resolution MOLLI method was likely due to partial volume effects where blood was included in RV voxels.
Conclusion: ANGIE provides high-resolution T1 mapping which is critical for the assessment of thin structures such as the RV. These novel methods will allow T1 mapping of the RV in the assessment of disorders such as ARVC, pulmonary hypertension, and congenital heart disease.
- © 2013 by American Heart Association, Inc.