Dataset Information

Rapid measurement of brain macromolecular proton fraction with transient saturation transfer MRI.

ABSTRACT: PURPOSE:To develop an efficient MRI approach to estimate the nonwater proton fraction (f) in human brain. METHODS:We implement a brief, efficient magnetization transfer (MT) pulse that selectively saturates the magnetization of the (semi-) solid protons, and monitor the transfer of this saturation to the water protons as a function of delay after saturation. RESULTS:Analysis of the transient MT effect with two-pool model allowed robust extraction of f at both 3 and 7 T. This required estimating the longitudinal relaxation rate constant (R1,MP and R1,WP ) for both proton pools, which was achieved with the assumption of uniform R1,MP and R1,WP across brain tissues. Resulting values of f were approximately 50% higher than reported previously, which is partly attributed to MT-pulse efficiency and R1,MP being higher than assumed previously. CONCLUSION:Experiments performed on human brain in vivo at 3 and 7?T demonstrate the ability of the method to robustly determine f in a scan time of approximately 5?min. Magn Reson Med 77:2174-2185, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

SUBMITTER: van Gelderen P

PROVIDER: S-EPMC5183566 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Rapid measurement of brain macromolecular proton fraction with transient saturation transfer MRI.

van Gelderen Peter P Jiang Xu X Duyn Jeff H JH

Magnetic resonance in medicine 20160625 6

<h4>Purpose</h4>To develop an efficient MRI approach to estimate the nonwater proton fraction (f) in human brain.<h4>Methods</h4>We implement a brief, efficient magnetization transfer (MT) pulse that selectively saturates the magnetization of the (semi-) solid protons, and monitor the transfer of this saturation to the water protons as a function of delay after saturation.<h4>Results</h4>Analysis of the transient MT effect with two-pool model allowed robust extraction of f at both 3 and 7 T. Thi ...[more]

PMID: 27342121

Similar Datasets

Project description:BackgroundProton exchange rate (k ex) magnetic resonance imaging (MRI) has recently been developed, with preliminary results demonstrating its potential for evaluating reactive oxygen species. This prospective cohort study investigated the k ex in different stroke stages and its correlation with stroke severity and prognosis.MethodsIn all, 96 ischemic stroke patients were included in the study. Patients were divided into 3 groups based on stroke phase (acute, subacute, and chronic). A spin echo-echo planar imaging sequence with presaturation powers of 1.5, 2.5, and 3.5 µT was implemented to obtain Z-spectra, and k ex maps were constructed from direct saturation-removed omega plots. Relative k ex (rk ex) and the relative apparent diffusion coefficient (rADC) were calculated as the ratio of k ex or ADC in the infarcts to values in contralateral tissue, respectively. Correlations between both k ex and rk ex and National Institute of Health Stroke Scale (NIHSS) scores were evaluated. Receiver operating characteristic (ROC) analysis was used to evaluate the performance of k ex, rk ex, rADC, and lesion volume for predicting acute stroke outcome.ResultsThe k ex was significantly higher in ischemic lesions than in contralateral tissue at all stages. In addition, the k ex of acute lesions was higher than that of subacute and chronic lesions [mean (± SD) 935.1±81.5 vs. 881.4±55.7 and 866.9±76.7 s-1, respectively; P<0.05 and P<0.01, respectively]. The difference in k ex between subacute and chronic lesions was not significant. In acute stroke, there was a limited correlation between a lesion's k ex and NIHSS score (R2=0.16; P=0.01) and between rk ex and NIHSS score (R2=0.28; P=0.001). Acute stroke patients with poor prognosis had significantly higher lesion k ex and rk ex than did those with good prognosis (k ex: 991.1±78.2 vs. 893.1±55.1 s-1, P<0.001; rk ex: 1.28±0.09 vs. 1.15±0.06, P<0.001). In ROC analyses, k ex and rk ex showed favorable predictive performance for acute stroke outcome, with areas under the curve (AUC) of 0.837 and 0.880, respectively, which were slightly but not significantly higher than the AUCs for lesion volume (0.730) and rADC (0.673).ConclusionsThis study indicates that k ex MRI is promising for the diagnosis and management of ischemic stroke because it can reflect the oxidative stress of lesions and predict prognosis.

Dataset Information

Rapid measurement of brain macromolecular proton fraction with transient saturation transfer MRI.

Publications

Rapid measurement of brain macromolecular proton fraction with transient saturation transfer MRI.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets