The Role of Improved Motion-Sensitized Driven Equilibrium Blood Suppression and Fat Saturation on T Relaxation Time, Using GraSE Sequence in Cardiac Magnetic Resonance Imaging

Background: T mapping is a valuable technique in cardiac MR imaging that offers insights into the microstructural characteristics of myocardial tissue. However, it was shown that myocardial T relaxation times (T) measured vary significantly depending on sequence, sequence parameters, and field strength.

Purpose: To assess T variability and image quality in cardiac T maps using four variants of the gradient-spin echo (GraSE) sequence, having different methods of blood signal suppression (double inversion recovery (DIR) and improved motion-sensitized driven equilibrium (iMSDE) and with and without the addition of fat saturation (FS).

Study Type: Prospective.

Population: 48 healthy volunteers (46.7 +/- 21.5 years, 24 male) with no cardiac history.

Field Strength/sequence: GraSE sequence with DIR (GraSE), with iMSDE (GraSE) and FS (GraSE-FS) and with both iMSDE and FS (GraSE-FS) at 1.5T.

Assessment: Global T from three short axis myocardial slices. and image quality assessments using a 5-point Lickert scale (1, (non-diagnostic) to 5, (excellent)) were conducted to evaluate the impact of DB and FS techniques on myocardial T measurements and image quality.

Statistical Tests: Paired t-tests or non-parametric equivalents for comparisons between sequences. The Bland-Altmann plots and Pearson rank correlation analyses, as appropriate. A P value <0.05 was considered statistically significant.

Results: The mean global T values for GraSE, GraSE-FS, GraSE, and GraSE-FS, were 52.84 ± 5.72 msec, 54.98 ± 3.59 msec, 53.9 ± 4.05 msec, and 55.14 ± 4.28 msec, respectively, with no significant differences (P = 0.092). High image quality scores (>4 out of 5) were obtained for all sequence variants with no significant differences between them (P = 0.11).

Data Conclusion: All GraSE sequence variants exhibited approximately the same results and variations in the DB technique and addition of FS did not have significant impact on myocardial T values.

Level Of Evidence: 2 TECHNICAL EFFICACY: Stage 1.