Magnetization Transfer Ratio Histogram Analysis of Normal-Appearing Gray Matter and Normal-Appearing White Matter in Multiple Sclerosis

Ge, Yulin; Grossman, Robert I.; Udupa, Jayaram K.; Babb, James S.; Mannon, Lois J.; McGowan, Joseph C.

doi:10.1097/00004728-200201000-00009

Cited by 96 publications

(68 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…T 2 /FLAIR hyperintensities are readily apparent in the scans from both patients, as are enhancing lesions in the right posterior subcortical WM. Similar to data acquired at 1.5T (4,7,34), the MTR at 3T is abnormally low within MS lesions, and in some cases falls to approx- N ϭ 9) for 10 ROIs drawn in each subject. ROIs were chosen to minimize visual partial volume effects, and reflect a survey of different substructures visible in MTR images.…”

Section: Figsupporting

confidence: 52%

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

Smith

Farrell

Jones

et al. 2006

Magnetic Resonance in Med

View full text Add to dashboard Cite

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 T 1 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 Magnetization transfer ratio (MTR) imaging (1-5) has been used as a noninvasive method to quantitatively assay white matter (WM) degeneration in multiple sclerosis (MS) (4,6 -14) and more recently in neuropsychiatric diseases such as Alzheimer's disease and bipolar disorder (15)(16)(17). Since MT imaging is exquisitely sensitive to the solid-like macromolecular content of central nervous system (CNS) tissue, it can detect subtle pathological changes and sometimes even conventionally unobserved pathology (18,19). Pulsed MT imaging (1,20) employs a series of short (ϳ10 -30 ms), high-amplitude pulses, and relies on the build-up of a saturation steady state over multiple TR periods (1) as opposed to the large saturation induced by continuous wave (CW) experiments within a single TR. The increased speed provided by pulsed MT has allowed investigators to survey the frequency dependence of the MT effect and to determine MT-based parameters, such as fractional pool sizes and exchange rates, within a reasonable clinical scan time (4,10 -12,21-23). However, this comes at the price of a reduced contrast-to-noise ratio (CNR) and increased power deposition, which comes close to maximum specific absorption rate (SAR) levels, even when the transmit/receive head coil is used at a field strength of 1.5T. To harness the power of parallel imaging (24) and further reduce the scan time, it is necessary to use a larger coil (i.e., a body coil in standard sensitivity encoding (SENSE) imaging) for transmission, which unfortunately exacerbates the power-deposition problem. This SAR restriction also appears to be a prohibitive barrier for translating pulsed MT to higher field strengths (e.g., 3T), where a higher signal-to-noise ratio (SNR) would allow faster scan times or an improved contrast-to-noise ratio. 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...

show abstract

Section: Figsupporting

confidence: 52%

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

Smith

Farrell

Jones

et al. 2006

Magnetic Resonance in Med

View full text Add to dashboard Cite

show abstract

“…10,[26][27][28][29][30] Our findings indicate that MTI measures in HD correlate with disease burden, specific motor tasks, and cognitive measures in this study population. The finding of correlations of MTI with specific clinical parameters indicates that MTI is a good reflection of the disease status, as shown by motor and cognitive measures.…”

Section: Figsupporting

confidence: 54%

Magnetization Transfer Imaging in Premanifest and Manifest Huntington Disease

Bogaard

Dumas

Milles

et al. 2012

AJNR Am J Neuroradiol

View full text Add to dashboard Cite

show abstract

“…88,95 Furthermore, MTI has been helpful in improving the ability to detect damage in GM, including the cerebral cortex and subcortical nuclei. 93,96,97 These changes may appear very early in the course of the disease, 93,96 -99 and they are more severe in progressive patients. 100 Conversely, the distribution of GM MTR changes reported across various studies is not consistent.…”

Section: Fig 5 Axial Magnetization Transfer (Mt) Images and Maps Ofmentioning

confidence: 99%

MRI in Multiple Sclerosis: What’s Inside the Toolbox?

et al. 2007

View full text Add to dashboard Cite

Summary: Magnetic resonance imaging (MRI) has played a central role in the diagnosis and management of multiple sclerosis (MS). In addition, MRI metrics have become key supportive outcome measures to explore drug efficacy in clinical trials. Conventional MRI measures have contributed to the understanding of MS pathophysiology at the macroscopic level yet have failed to provide a complete picture of underlying MS pathology. They also show relatively weak relationships to clinical status such as predictive strength for clinical progression. Advanced quantitative MRI measures such as magnetization transfer, spectroscopy, diffusion imaging, and relaxometry techniques are somewhat more specific and sensitive for underlying pathology. These measures are particularly useful in revealing diffuse damage in cerebral white and gray matter and therefore may help resolve the dissociation between clinical and conventional MRI findings. In this article, we provide an overview of the array of tools available with brain and spinal cord MRI technology as it is applied to MS. We review the most recent data regarding the role of conventional and advanced MRI techniques in the assessment of MS. We focus on the most relevant pathologic and clinical correlation studies relevant to these measures.

show abstract

Magnetization Transfer Ratio Histogram Analysis of Normal-Appearing Gray Matter and Normal-Appearing White Matter in Multiple Sclerosis

Cited by 96 publications

References 51 publications

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

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

Magnetization Transfer Imaging in Premanifest and Manifest Huntington Disease

MRI in Multiple Sclerosis: What’s Inside the Toolbox?

Contact Info

Product

Resources

About