Robust motion correction for myocardial T1 and extracellular volume mapping by principle component analysis-based groupwise image registration

Abstract

Background: Myocardial tissue characterization by MR T₁ and extracellular volume (ECV) mapping has demonstrated clinical value. The modified Look-Locker inversion recovery (MOLLI) sequence is a standard mapping technique, but its quality can be negatively affected by motion.

Purpose: To develop a robust motion correction method for T₁ and ECV mapping.

Study type: Retrospective analysis of clinical data.

Population: Fifty patients who were referred to cardiac MR exam for T₁ mapping.

Field strength/sequence: 3.0T cardiac MRI with precontrast and postcontrast MOLLI acquisition of the left ventricle (LV).

Assessment: A groupwise registration method based on principle component analysis (PCA) was developed to register all MOLLI frames simultaneously. The resulting T₁ and ECV maps were compared to those from the original and motion-corrected MOLLI with pairwise registration, in terms of standard deviation (SD) error.

Statistical test: Paired variables were compared using the Wilcoxon signed-rank test.

Results: The groupwise registration method demonstrated improved registration performance compared to pairwise registration, with the T₁ SD error reduced from 31 ± 20 msec to 26 ± 15 msec (P < 0.05), and ECV SD error reduced from 4.1 ± 3.6% to 2.8 ± 2.0% (P < 0.05). In LV segmental analysis, the performance was particularly improved in lateral segments, which are most affected by motion. The running time of groupwise registration was significantly shorter than that of the pairwise registration, 17.5 ± 3.0 seconds compared to 43.5 ± 2.2 seconds (P < 0.05).

Data conclusion: We developed an automatic, robust motion correction method for myocardial T₁ and ECV mapping based on a new groupwise registration scheme. The method led to lower mapping error compared to the conventional pairwise registration method in reduced execution time.

Level of evidence: 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1397-1405.

Keywords: ECV; PCA; motion correction; myocardial T1 mapping.