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Magn Reson Med. 2017 Feb;77(2):581-591. doi: 10.1002/mrm.26134. Epub 2016 Mar 9.

Magnetization transfer from inhomogeneously broadened lines (ihMT): Improved imaging strategy for spinal cord applications.

Author information

1
Aix-Marseille Université, CRMBM, UMR 7339 CNRS - AMU, Marseille, France.
2
Pôle d'Imagerie Médicale, CEMEREM, AP-HM, Marseille, France.
3
Siemens Healthcare, Saint-Denis, France.
4
Aix-Marseille Université, IFSTTAR, LBA UMR T24, Marseille, France.
5
Department of Radiology, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, Massachusetts, USA.

Abstract

PURPOSE:

Inhomogeneous magnetization transfer (ihMT) shows great promise for specific imaging of myelinated tissues. Whereas the ihMT technique has been previously applied in brain applications, the current report presents a strategy for cervical spinal cord (SC) imaging free of cerebrospinal fluid (CSF) pulsatility artifacts.

METHODS:

A pulsed ihMT preparation was combined with a single-shot HASTE readout. Electrocardiogram (ECG) synchronization was used to acquire all images during the quiescent phase of SC motion. However ihMT signal quantification errors may occur when a variable recovery delay is introduced in the sequence as a consequence of variable cardiac cycle. A semiautomatic retrospective correction algorithm, based on repetition time (TR) -matching, is proposed to correct for signal variations of long T1 -components (e.g., CSF).

RESULTS:

The proposed strategy combining ECG synchronization and retrospective data pairing led to clean SC images free of CSF artifacts. Lower variability of the ihMT metrics were obtained with the correction algorithm, and allowed for shorter TR to be used, hence improving signal-to-noise ratio efficiency.

CONCLUSION:

The proposed methodology enabled faster acquisitions, while offering robust ihMT quantification and exquisite SC image quality. This opens great perspectives for widening the in vivo characterization of SC physiopathology using MRI, such as studying white matter tracts microstructure or impairment in degenerative pathologies. Magn Reson Med 77:581-591, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

KEYWORDS:

CSF pulsatility; ECG synchronization; inhomogeneous magnetization transfer; motion correction; myelin; spinal cord; white matter

PMID:
26959278
DOI:
10.1002/mrm.26134
[Indexed for MEDLINE]

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