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Amide proton transfer (APT) imaging of brain tumors at 7 T: The role of tissue water T 1 -Relaxation properties.
- Source :
-
Magnetic resonance in medicine [Magn Reson Med] 2017 Apr; Vol. 77 (4), pp. 1525-1532. Date of Electronic Publication: 2016 Apr 08. - Publication Year :
- 2017
-
Abstract
- Purpose: To provide insight into the effect of water T <subscript>1</subscript> relaxation (T <subscript>1wat</subscript> ) on amide proton transfer (APT) contrast in tumors. Three different metrics of APT contrast-magnetization transfer ratio (MTR <subscript>Rex</subscript> ), relaxation-compensated MTR <subscript>Rex</subscript> (AREX), and traditional asymmetry (MTR <subscript>asym</subscript> )-were compared in normal and tumor tissues in a variety of intracranial tumors at 7 Tesla (T).<br />Methods: Six consented intracranial tumor patients were scanned using a low-power, three-dimensional (3D) APT imaging sequence. MTR <subscript>Rex</subscript> and MTR <subscript>asym</subscript> were calculated in the region of 3 to 4 ppm. AREX was calculated by T <subscript>1wat</subscript> correction of MTR <subscript>Rex</subscript> . Tumor tissue masks, which classify different tumor tissues, were drawn by an experienced neuroradiologist. ROI-averaged tumor tissue analysis was done for MTR <subscript>Rex</subscript> , AREX, and MTR <subscript>asym</subscript> .<br />Results: MTR <subscript>Rex</subscript> and MTR <subscript>asym</subscript> were slightly elevated in tumor-associated structures. Both metrics were positively correlated to T <subscript>1wat</subscript> . The correlation coefficient (R) was determined to be 0.88 (P < 0.05) and 0.92 (P << 0.05) for MTR <subscript>Rex</subscript> and MTR <subscript>asym</subscript> , respectively. After T <subscript>1wat</subscript> correction (R = -0.21, P = 0.69), no difference between normal and tumor tissues was found for AREX.<br />Conclusions: The strong correlation of MTR <subscript>Rex</subscript> and MTR <subscript>asym</subscript> with T <subscript>1wat</subscript> and the absence thereof in AREX suggests that much of APT contrast in tumors for the low-power, 3D-acquisition scheme at 7 T originates from the inherent tissue water T <subscript>1</subscript> -relaxation properties. Magn Reson Med 77:1525-1532, 2017. © 2016 International Society for Magnetic Resonance in Medicine.<br /> (© 2016 International Society for Magnetic Resonance in Medicine.)
- Subjects :
- Body Water metabolism
Female
Humans
Image Interpretation, Computer-Assisted methods
Middle Aged
Molecular Imaging methods
Protons
Reproducibility of Results
Sensitivity and Specificity
Amides metabolism
Body Water diagnostic imaging
Brain Neoplasms diagnostic imaging
Brain Neoplasms metabolism
Magnetic Resonance Imaging methods
Subjects
Details
- Language :
- English
- ISSN :
- 1522-2594
- Volume :
- 77
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Magnetic resonance in medicine
- Publication Type :
- Academic Journal
- Accession number :
- 27060863
- Full Text :
- https://doi.org/10.1002/mrm.26232