Combining multiband slice selection with consistent k-t-space EPSI for accelerated spectral imaging.

Area of Science:

• Magnetic Resonance Imaging
• Spectroscopic Imaging
• Medical Physics

Background:

• Echo planar spectroscopic imaging (EPSI) faces challenges with data inconsistencies, often requiring separate reconstruction of positive and negative datasets.
• Existing methods for addressing EPSI inconsistencies can limit spectral width or increase scan time.

Purpose of the Study:

• To develop and implement a novel multislice MRSI method for accelerated spectroscopic imaging.
• To enhance spectral width and reduce scan duration using a modified EPSI technique.

Main Methods:

• A consistent k-t-space EPSI method was developed by interposing EPSI readouts with alternating "blipped" phase-encode gradients.
• Multiband CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration) slice selection was integrated for further acceleration.
• Four pulse scheme variants were evaluated in phantom and in vivo brain imaging at 3 Tesla.

Main Results:

• The consistent k-t-space EPSI method demonstrated feasibility in phantom and in vivo brain imaging.
• This approach allows for optimization of spectral width and scan acceleration, addressing key in vivo limitations.
• Dual-band CAIPIRINHA integration resulted in a 4-fold reduction in scan duration.

Conclusions:

• Consistent k-t-space EPSI offers a method to accelerate MRSI or double its spectral width.
• The addition of dual-band CAIPIRINHA provides a further 2-fold acceleration in acquisition time.
• This advanced MRSI technique holds promise for faster and more comprehensive in vivo spectroscopic analysis.