Cardiac T2-mapping using a fast gradient echo spin echo sequence - first in vitro and in vivo experience

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Quantitative MRI Techniques
• Myocardial Tissue Characterization

Background:

• Cardiac T2-mapping is crucial for assessing myocardial tissue properties.
• Existing T2-mapping techniques face limitations in acquisition time or robustness.
• The Gradient Spin Echo (GraSE) technique is evaluated for its potential in cardiac T2-mapping.

Purpose of the Study:

• To evaluate the fast Gradient Spin Echo (GraSE) technique for cardiac T2-mapping.
• To compare GraSE against Multi Echo Spin Echo (MESE) and T2-prepared balanced Steady State Free Precession (T2prep) sequences.
• To assess T2 relaxation time estimation and pixel-by-pixel homogeneity.

Main Methods:

• Phantom and in vivo studies were conducted at 1.5T.
• Three T2-mapping techniques (MESE, T2prep, GraSE) were compared.
• 12 healthy volunteers underwent cardiac MRI, with analysis of short-axis slices.

Main Results:

• GraSE and T2prep overestimated T2 times compared to MESE in phantom studies.
• In vivo, T2prep yielded the lowest T2 estimates (52.4 ± 2.8 ms) and GraSE the highest (59.3 ± 4.0 ms).
• GraSE-derived T2 maps showed the least pixel-by-pixel inhomogeneity.

Conclusions:

• The GraSE sequence is fast, robust, and combines advantages of MESE and T2prep.
• GraSE shows promise for improved clinical applicability of cardiac T2-mapping.
• Future studies should systematically compare sequences and establish reference values.