Korean J Med Phys.  2007 Jun;18(2):65-72.

Multi-slice Multi-echo Pulsed-gradient Spin-echo (MePGSE) Sequence for Diffusion Tensor Imaging MRI: A Preliminary Result

• Jahng GH
• Pickup S

Abstract

An echo planar imaging (EPI)-based spin-echo sequence is often used to obtain diffusion tensor imaging (DTI) data on most of the clinical MRI systems. However, this sequence is confounded with the susceptibility artifacts, especially on the temporal lobe in the human brain. Therefore, the objective of this study was to design a pulse sequence that relatively immunizes the susceptibility artifacts, but can map diffusion tensor components in a single-shot mode. A multi-slice multi-echo pulsed-gradient spin-echo (MePGSE) sequence with eight echoes wasdeveloped with selective refocusing pulses for all slices to map the full tensor. The first seven echoes in the train were diffusion-weighted allowing for the observation of diffusion in several different directions in a single experiment and the last echo was for crusher of the residual magnetization. All components of diffusion tensor were measured by a single shot experiment. The sequence was applied in diffusive phantoms. The preliminary experimental verification of the sequence was illustrated by measuring the apparent diffusion coefficient (ADC) for tap water and by measuring diffusion tensor components for watermelon. The ADC values in the series of the water phantom were reliable. The MePGSE sequence, therefore, may be useful in human brain studies.

Keyword

MRI; Multi-slice multi-echo PGSE; Diffusion tensor imaging; Slice selective 180 degrees

MeSH Terms

Artifacts
Brain
Citrullus
Diffusion Tensor Imaging*
Diffusion*
Echo-Planar Imaging
Humans
Magnetic Resonance Imaging*
Temporal Lobe
Water
Water