Single-shot diffusion trace-weighted MR spectroscopy: Comparison with unipolar and bipolar diffusion-weighted...

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Diffusion Weighted Imaging
• Spectroscopy

Background:

• Conventional diffusion-weighted (DW)-PRESS sequences have limitations in speed and trace ADC quantification.
• Accurate measurement of trace apparent diffusion coefficient (ADC) is crucial for various neurological applications.

Purpose of the Study:

• To demonstrate the feasibility and performance of a novel point-resolved spectroscopy (PRESS)-based, single-shot diffusion trace-weighted sequence.
• To compare the novel sequence with conventional DW-PRESS variants for trace ADC quantification.
• To assess the accuracy and reliability of the sequence in phantoms and in vivo.

Main Methods:

• Implementation of a single-shot diffusion trace-weighted PRESS sequence on a 3-T MRI/MRS scanner.
• Comparison with bipolar and unipolar DW-PRESS sequences using phantom datasets.
• In vivo scanning of seven volunteers across three brain regions.

Main Results:

• The single-shot sequence yielded statistically significantly higher and more stable trace ADC values compared to conventional sequences.
• Reliable estimation of total n-acetylaspartate, total creatine, and total choline with Cramér-Rao lower bounds ≤20%.
• Excellent agreement of phantom trace ADCs and good agreement of in vivo ADCs with expected gray and white matter differences.

Conclusions:

• The single-shot diffusion trace-weighted sequence is feasible and performs well on a clinical 3-T scanner.
• This novel sequence offers a significantly shorter scan time (nearly a factor of 3 reduction) compared to conventional DW-PRESS.
• The sequence provides accurate trace ADC estimates, potentially improving the efficiency of brain MRI/MRS.