Integrated Short-TE and Hadamard-edited Multi-Sequence (ISTHMUS) for advanced MRS

Area of Science:

• Neuroimaging
• Magnetic Resonance Spectroscopy (MRS)
• Neuroscience

Background:

• The Healthy Brain and Child Development (HBCD) study utilizes ISTHMUS as its standardized MR spectroscopy sequence.
• ISTHMUS is designed to ensure data quality and reproducibility across multiple sites.

Purpose of the Study:

• To evaluate the data quality and reproducibility of the ISTHMUS MR spectroscopy sequence.
• To assess the performance of ISTHMUS within the multi-site HBCD study.

Main Methods:

• ISTHMUS involves consecutive acquisition of short-TE PRESS and long-TE HERCULES data with dual-TE water reference scans.
• Data were analyzed using Osprey software after voxel placement in specific brain regions (centrum semiovale, ACC, PCC, thalamus).
• T2 correction methods were compared, including dual-TE water integrals, default Osprey values, and literature-derived shorter T2 values.

Main Results:

• No significant linewidth differences were found between PRESS and HERCULES sequences.
• Bilateral thalamus spectra showed significantly higher linewidth (p<0.001).
• Scan-to-scan linewidth differences were minimal (<1 Hz), and T2 correction using shorter T2 values showed better agreement with dual-TE water integral ratios.

Conclusions:

• ISTHMUS streamlines MR spectroscopy data acquisition and post-processing.
• The sequence reduces operator workload, minimizing potential human error.
• ISTHMUS contributes to reliable and reproducible neuroimaging data for large-scale studies like HBCD.