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Magnetization transfer from inhomogeneously broadened lines (ihMT): Improved imaging strategy for spinal cord applications
Author(s) -
Girard Olivier M.,
Callot Virginie,
Prevost Valentin H.,
Robert Benjamin,
Taso Manuel,
Ribeiro Guilherme,
Varma Gopal,
Rangwala Novena,
Alsop David C.,
Duhamel Guillaume
Publication year - 2017
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.26134
Subject(s) - magnetic resonance imaging , magnetization transfer , computer science , synchronization (alternating current) , spinal cord , signal (programming language) , signal averaging , white matter , cardiac cycle , signal to noise ratio (imaging) , nuclear magnetic resonance , biomedical engineering , medicine , pattern recognition (psychology) , algorithm , physics , artificial intelligence , radiology , channel (broadcasting) , cardiology , telecommunications , signal transfer function , transmission (telecommunications) , psychiatry , analog signal , programming language
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 T 1 ‐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