Pulsed magnetization transfer imaging with body coil transmission at 3 Tesla: Feasibility and application

Pulsed magnetization transfer (MT) imaging has been applied to quantitatively assess brain pathology in several diseases, especially multiple sclerosis (MS). To date, however, because of the high power deposition associated with the use of short, rapidly repeating MT prepulses, clinical application...

Full description

Saved in:
Bibliographic Details
Published in:Magnetic resonance in medicine 2006-10, Vol.56 (4), p.866-875
Main Authors: Smith, Seth A., Farrell, Jonathan A.D., Jones, Craig K., Reich, Daniel S., Calabresi, Peter A., van Zijl, Peter C.M.
Format: Article
Language:English
Subjects:
Adult
Algorithms
Analysis of Variance
Brain Mapping - methods
Feasibility Studies
high field
Humans
Magnetic Resonance Imaging - methods
magnetization transfer
magnetization transfer ratio
MRI
multiple sclerosis
Multiple Sclerosis, Relapsing-Remitting - pathology
Reproducibility of Results
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Pulsed magnetization transfer (MT) imaging has been applied to quantitatively assess brain pathology in several diseases, especially multiple sclerosis (MS). To date, however, because of the high power deposition associated with the use of short, rapidly repeating MT prepulses, clinical application has been limited to lower field strengths. The contrast‐to‐noise ratio (CNR) of MT is limited, and this method would greatly benefit from the use of higher magnetic fields and phased‐array coil reception. However, power deposition is proportional to the square of the magnetic field and scales with coil size, and MT experiments are already close to the SAR limit at 1.5T even when smaller transmit coils are used instead of the body coil. Here we show that these seemingly great obstacles can be ameliorated by the increased T1 of tissue water at higher field, which allows for longer maintenance of sufficiently high saturation levels while using a reduced duty cycle. This enables a fast (5–6 min) high‐resolution (1.5 mm isotropic) whole‐brain MT acquisition with excellent anatomical visualization of gray matter (GM) and white matter (WM) structures, and even substructures. The method is demonstrated in nine normal volunteers and five patients with relapsing remitting MS (RRMS), and the results show a clear delineation of heterogeneous lesions. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
ISSN:0740-3194
1522-2594
DOI:10.1002/mrm.21035