T1 Mapping MOLLI 5(3)3 Acquisition Scheme Yields High Accuracy in 1.5 T Cardiac Magnetic Resonance

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Quantitative Myocardial Perfusion
• T1 Mapping Techniques

Background:

• Modified Look-Locker inversion recovery (MOLLI) T1 mapping is crucial for assessing myocardial tissue characteristics.
• Optimizing MOLLI sequences is essential for accurate native and post-contrast T1 measurements and extracellular volume (ECV) quantification.
• Different MOLLI schemes are designed for specific T1 ranges, necessitating comparison for clinical application.

Purpose of the Study:

• To systematically compare the 5(3)3 and 4(1)3(1)2 MOLLI T1 mapping sequences.
• To evaluate their impact on native myocardial T1 values, post-contrast T1 values, and extracellular volume (ECV).
• To determine the optimal MOLLI sequence for different phases of cardiovascular magnetic resonance (CMR) imaging.

Main Methods:

• Prospective inclusion of 200 patients undergoing 1.5 T CMR for cardiomyopathy work-up.
• Acquisition of both 5(3)3 and 4(1)3(1)2 MOLLI sequences in native and post-contrast states in mid-ventricular short-axis slices.
• Analysis of datasets from 163 patients to compare T1 values and ECV across sequences.

Main Results:

• The 5(3)3 sequence yielded significantly higher native myocardial T1 values (1017 ± 42 ms) compared to 4(1)3(1)2 (956 ± 40 ms).
• Post-contrast myocardial T1 values were similar between 5(3)3 (494 ± 48 ms) and 4(1)3(1)2 (490 ± 45 ms) sequences.
• Myocardial ECV measurements were comparable, with a mean difference of -0.6 percentage points between the 5(3)3 and 4(1)3(1)2 sequences.

Conclusions:

• The 5(3)3 MOLLI sequence reliably estimates native and post-contrast myocardial T1 values and ECV across clinically relevant ranges.
• The 4(1)3(1)2 MOLLI sequence is primarily suitable for post-contrast T1 mapping due to its design for shorter T1 values.
• Sequence selection impacts native T1 measurements, highlighting the importance of using appropriate MOLLI schemes for accurate cardiovascular magnetic resonance assessments.