MT: Magnetization Transfer

Tofts, Paul S.; Steens, Stefan C. A.; Buchem, Mark A. van

doi:10.1002/0470869526.ch8

Cited by 30 publications

(31 citation statements)

References 129 publications

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“…Although the acquisition and processing of qMT data is more complex than magnetisation transfer ratios (MTR), it may be more sensitive to pathology. MTR is approximately proportional to both f B and T 1 (19); thus, the changes seen in these parameters will tend to counteract each other, effectively reducing the sensitivity of the technique. For example, ref.…”

Section: Discussionmentioning

confidence: 99%

Quantitative magnetisation transfer imaging in glioma: preliminary results

Tozer¹,

Rees²,

Benton³

et al. 2010

NMR in Biomedicine

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Quantitative magnetisation transfer imaging (qMTI) is an extension of conventional MT techniques and allows the measurement of parameters that reflect tissue ultrastructure through the properties of macromolecule-bound protons; these include the bound proton fraction and the relaxation times of free and bound proton pools. It has been used in multiple sclerosis and Alzheimer's disease, and has shown changes in some of the parameters, particularly the bound proton fraction. The purpose of this pilot study was to assess whether qMTI could distinguish between gliomas and normal brain tissue, and provide proof of principle for its use in tumour characterisation. Eight subjects [three men, five women; mean age, 44 years; range, 27-66 years; seven World Health Organization (WHO) Grade II, one Grade III] with biopsy-proven glioma were imaged with a structural MRI protocol that included three-dimensional qMTI. qMTI parameters were extracted from regions of interest selected from different tumour components visible on conventional MR sequences, normal-appearing peritumoral tissue and distant normal-appearing white matter. All patients gave informed consent and the study was approved by the Local Research Ethics Committee. Almost all of the qMTI parameters detected abnormalities in both glioma and the peritumoral region relative to the distant white matter. In particular, the bound proton fraction was reduced significantly from 6.0 percentage units (pu) [standard deviation (SD), 0.5 pu] in normal-appearing white matter to 1.7 pu (SD = 0.5 pu) in solid tumour and 2.2 pu (SD = 0.5 pu) in peritumoral areas. This work shows that qMTI reveals abnormalities, not only in glioma, but also in the apparently normal tissue surrounding the conventionally defined tumour. Thus, qMTI shows promise for tumour characterisation and for studying tumour boundaries. These preliminary data justify larger studies in a range of different tumour types and grades.

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Section: Discussionmentioning

confidence: 99%

Quantitative magnetisation transfer imaging in glioma: preliminary results

Tozer¹,

Rees²,

Benton³

et al. 2010

NMR in Biomedicine

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“…Although MTR imaging is used in some centres in the clinical setting, it is difficult to be reproduced across different studies, as it highly depends on pulse sequence details and relaxation properties (Cercignani et al, 2005;Ou and Gochberg, 2008;Ramani et al, 2002;Tofts et al, 2003). Therefore, in characterizing the MT phenomenon by simply assessing MTR, potentially essential diagnostic information might be missed.…”

Section: Introductionmentioning

confidence: 99%

Characterization of normal appearing brain structures using high-resolution quantitative magnetization transfer steady-state free precession imaging

et al. 2010

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“…Although MTR imaging has been applied for the characterization of different pathologies, including brain infarction, tumors, and white matter (WM) lesions [3,5,[8][9][10][11][12][13][14], this technique is still not a widely established method in the daily clinical routine, especially due to its long acquisition times. In addition, MTR suffers from its difficulty to be reproduced across different studies as it is very sensitive to pulse sequence details and relaxation properties [1,7,12,15,16]. Furthermore, clinical limitations on power absorption, i.e., specific absorption rate (SAR), preclude a complete saturation of the restricted pool protons, hereby making data interpretation and standardization difficult [15,17].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, MTR suffers from its difficulty to be reproduced across different studies as it is very sensitive to pulse sequence details and relaxation properties [1,7,12,15,16]. Furthermore, clinical limitations on power absorption, i.e., specific absorption rate (SAR), preclude a complete saturation of the restricted pool protons, hereby making data interpretation and standardization difficult [15,17]. In addition, the comparability of MTR values is complicated by several technical issues, such as field strength, MT saturation and sequence properties, B1-inhomogeneity, and subject positioning [18].…”

Section: Introductionmentioning

confidence: 99%

MTR variations in normal adult brain structures using balanced steady-state free precession

et al. 2010

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Introduction Magnetization transfer (MT) is sensitive to the macromolecular environment of water protons and thereby provides information not obtainable from conventional magnetic resonance imaging (MRI). Compared to standard methods, MT-sensitized balanced steady-state free precession (bSSFP) offers high-resolution images with significantly reduced acquisition times. In this study, high-resolution magnetization transfer ratio (MTR) images from normal appearing brain structures were acquired with bSSFP. Methods Twelve subjects were studied on a 1.5 T scanner. MTR values were calculated from MT images acquired in 3D with 1.3 mm isotropic resolution. The complete MT data set was acquired within less than 3.5 min. Forty-one brain structures of the white matter (WM) and gray matter (GM) were identified for each subject.Results MTR values were higher for WM than GM. In general, MTR values of the WM and GM structures were in good accordance with the literature. However, MTR values showed more homogenous values within WM and GM structures than previous studies. Conclusions MT-sensitized bSSFP provides isotropic high-resolution MTR images and hereby allows assessment of reliable MTR data in also very small brain structures in clinically feasible acquisition times and is thus a promising sequence for being widely used in the clinical routine. The present normative data can serve as a reference for the future characterization of brain pathologies.

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MT: Magnetization Transfer

Cited by 30 publications

References 129 publications

Quantitative magnetisation transfer imaging in glioma: preliminary results

Quantitative magnetisation transfer imaging in glioma: preliminary results

Characterization of normal appearing brain structures using high-resolution quantitative magnetization transfer steady-state free precession imaging

MTR variations in normal adult brain structures using balanced steady-state free precession

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