Reverse double inversion-recovery: Improving motion robustness of cardiac T2 -weighted dark-blood turbo spin-echo sequence

Abstract

Background: Cardiac dark-blood turbo spin-echo (TSE) imaging is sensitive to through-plane motion, resulting in myocardial signal reduction.

Purpose: To propose and validate reverse double inversion-recovery (RDIR)-a dark-blood preparation with improved motion robustness for the cardiac dark-blood TSE sequence.

Study type: Prospective.

Population: Healthy volunteers (n = 10) and patients (n = 20).

Field strength: 1.5T (healthy volunteers) and 3T (patients).

Assessment: Compared to double inversion recovery (DIR), RDIR swaps the two inversion pulses in time and places the slice-selective 180° in late-diastole of the previous cardiac cycle to minimize slice misregistration. RDIR and DIR were performed in the same left-ventricular basal short-axis slice. Healthy subjects were imaged with two preparation slice thicknesses, 110% and 200%, while patients were imaged using a 200% slice thickness only. Images were assessed quantitatively, by measuring the myocardial signal heterogeneity and the extent of dropout, and also qualitatively on a 5-point scale.

Statistical tests: Quantitative and qualitative data were assessed with Student's t-test and Wilcoxon signed-rank test, respectively.

Results: In healthy subjects, RDIR with 110% slice thickness significantly reduced signal heterogeneity in both the left ventricle (LV) and right ventricle (RV) (LV: P = 0.006, RV: P < 0.0001) and the extent of RV dropout (P < 0.0001), while RDIR with 200% slice thickness significantly reduced RV signal heterogeneity (P = 0.001) and the extent of RV dropout (P = 0.0002). In patients, RDIR significantly reduced RV myocardial signal heterogeneity (0.31 vs. 0.43; P = 0.003) and the extent of RV dropout (24% vs. 46%; P = 0.0005). LV signal heterogeneity exhibited a trend towards improvement with RDIR (0.12 vs. 0.16; P = 0.06). Qualitative evaluation showed a significant improvement of LV and RV visualization in RDIR compared to DIR (LV: P = 0.04, RV: P = 0.0007) and a significantly improved overall image quality (P = 0.03).

Data conclusion: RDIR TSE is less sensitive to through-plane motion, potentiating increased clinical utility for black-blood TSE.

Level of evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1498-1508.

Keywords: dark blood imaging; double inversion recovery; edema imaging; motion artifacts; right ventricle; turbo spin-echo (TSE).