Open-source myocardial T₁ mapping with simultaneous multi-slice acceleration: Combining an auto-calibrated...

Area of Science:

• Magnetic Resonance Imaging
• Cardiovascular Imaging
• Quantitative Imaging

Background:

• Myocardial T1 mapping is crucial for clinical diagnosis but often time-consuming.
• Existing methods face limitations in speed and coverage.
• Fast and accessible T1 mapping is needed to broaden its clinical use.

Purpose of the Study:

• To develop and validate Open-MOLLI-SMS, a novel, accelerated T1 mapping sequence.
• To combine simultaneous multi-slice (SMS) imaging with auto-calibration and VERSE-multiband pulses for faster acquisition.
• To enable rapid, single-shot T1 mapping across multiple slices.

Main Methods:

• Integration of SMS with the open-source Open-MOLLI sequence.
• Implementation of auto-calibration blip patterns for data-coil consistency.
• Utilized a blipped-balanced SSFP (bSSFP) readout and VERSE-multiband pulses to minimize TR and SAR.
• Acquisition of data in phantoms and healthy volunteers using SMS2 and SMS3.

Main Results:

• Accurate T1 estimates in phantoms across a range of 400-2200 ms.
• In vivo T1 values for Open-MOLLI-SMS2 (993 ± 10 ms) and SMS3 (1031 ± 17 ms) were comparable to single-band Open-MOLLI (1005 ± 47 ms).
• Open-MOLLI-SMS2 demonstrated the closest T1 estimates to reference values.

Conclusions:

• Open-MOLLI-SMS successfully accelerates T1 mapping acquisitions and increases slice coverage.
• The combination of auto-calibration, bSSFP readout, and VERSE-multiband pulses is feasible for rapid T1 mapping.
• The open-source nature of Open-MOLLI facilitates rapid prototyping and sharing of advanced MRI techniques.