Dataset Information

Cerebral metabolic rate of oxygen (CMRO2 ) mapping by combining quantitative susceptibility mapping (QSM) and quantitative blood oxygenation level-dependent imaging (qBOLD).

ABSTRACT: PURPOSE:To map the cerebral metabolic rate of oxygen (CMRO2 ) by estimating the oxygen extraction fraction (OEF) from gradient echo imaging (GRE) using phase and magnitude of the GRE data. THEORY AND METHODS:3D multi-echo gradient echo imaging and perfusion imaging with arterial spin labeling were performed in 11 healthy subjects. CMRO2 and OEF maps were reconstructed by joint quantitative susceptibility mapping (QSM) to process GRE phases and quantitative blood oxygen level-dependent (qBOLD) modeling to process GRE magnitudes. Comparisons with QSM and qBOLD alone were performed using ROI analysis, paired t-tests, and Bland-Altman plot. RESULTS:The average CMRO2 value in cortical gray matter across subjects were 140.4?±?14.9, 134.1?±?12.5, and 184.6?±?17.9??mol/100?g/min, with corresponding OEFs of 30.9?±?3.4%, 30.0?±?1.8%, and 40.9?±?2.4% for methods based on QSM, qBOLD, and QSM+qBOLD, respectively. QSM+qBOLD provided the highest CMRO2 contrast between gray and white matter, more uniform OEF than QSM, and less noisy OEF than qBOLD. CONCLUSION:Quantitative CMRO2 mapping that fits the entire complex GRE data is feasible by combining QSM analysis of phase and qBOLD analysis of magnitude.

SUBMITTER: Cho J

PROVIDER: S-EPMC6097883 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Cerebral metabolic rate of oxygen (CMRO<sub>2</sub> ) mapping by combining quantitative susceptibility mapping (QSM) and quantitative blood oxygenation level-dependent imaging (qBOLD).

Cho Junghun J Kee Youngwook Y Spincemaille Pascal P Nguyen Thanh D TD Zhang Jingwei J Gupta Ajay A Zhang Shun S Wang Yi Y

Magnetic resonance in medicine 20180307 4

<h4>Purpose</h4>To map the cerebral metabolic rate of oxygen (CMRO<sub>2</sub> ) by estimating the oxygen extraction fraction (OEF) from gradient echo imaging (GRE) using phase and magnitude of the GRE data.<h4>Theory and methods</h4>3D multi-echo gradient echo imaging and perfusion imaging with arterial spin labeling were performed in 11 healthy subjects. CMRO<sub>2</sub> and OEF maps were reconstructed by joint quantitative susceptibility mapping (QSM) to process GRE phases and quantitative bl ...[more]

PMID: 29516537

Similar Datasets

Project description:BACKGROUND:Quantitative susceptibility mapping (QSM) offers a consistent hemorrhage volume measurement independent of imaging parameters. PURPOSE:To investigate the magnetic susceptibility of intracerebral hemorrhage (ICH) as a quantitative measurement for monitoring treatment in hematoma patients. STUDY TYPE:Prospective. POPULATION:Twenty-six patients with acute ICH were recruited and enrolled in treatment including surgery or medication (mannitol) for 1 week. FIELD STRENGTH/SEQUENCE:A 3D gradient echo sequence at 3.0T. ASSESSMENT:The hematoma volumes on computed tomography (CT) and QSM were calculated and used for correlation analysis. Magnetic susceptibility changes from pre- to posttreatment were calculated and compared to the National Institutes of Health stroke scale (NIHSS) measure of neurological deficit for each patient. STATISTICAL TESTS:Mean susceptibility values were calculated over each region of interest (ROI). A one-sample t-test was used to assess the changes of total volumes and mean magnetic susceptibility of ICH identified between pre- and posttreatment images (P < 0.05 was considered significant) and the Bland-Altman analysis with 95% limits of agreement (average difference, ±1.96 SD of the difference). Regression of volume measurements on QSM vs. CT and fitted linear regression of mean susceptibility vs. CT signal intensity for hematoma regions were conducted in all patients. RESULTS:Good correlation was found between hemorrhage volumes calculated from CT and QSM (CT volume = 0.94*QSM volume, r = 0.98). Comparison of QSM pre- and posttreatment showed that the mean ICH volume was reduced by a statistically insignificant amount from 5.74 cm3 to 5.45 cm3 (P = 0.21), while mean magnetic susceptibility was reduced significantly from 0.48 ppm to 0.38 ppm (P = 0.004). A significant positive association was found between changes in magnetic susceptibility values and NIHSS following hematoma treatment (P < 0.01). DATA CONCLUSIONS:QSM in hematoma assessment, as compared with CT, offers a comparably accurate volume measurement; however, susceptibility measurements may enable improved monitoring of ICH treatment compared to volume measurements alone. LEVEL OF EVIDENCE:2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:907-915.

Project description:Silent cerebral infarction (SCI) is the most commonly reported radiological abnormality in patients with sickle cell anemia (SCA) and is associated with future clinical stroke risk. To date, there have been few histological and quantitative MRI studies of SCI and multiple radiological definitions exist. As a result, the tissue characteristics and composition of SCI remain elusive. The objective of this work was therefore to investigate the composition of segmented SCI lesions using quantitative MRI for R 2* and quantitative magnetic susceptibility mapping (QSM). 211 SCI lesions were segmented from 32 participants with SCA and 6 controls. SCI were segmented according to two definitions (FLAIR+/-T1w-based threshold) using a semi-automated pipeline. Magnetic susceptibility (χ) and R 2* maps were calculated from a multi-echo gradient echo sequence and mean SCI values were compared to an equivalent region of interest in normal appearing white matter (NAWM). SCI χ and R 2* were investigated as a function of SCI definition, patient demographics, anatomical location, and cognition. Compared to NAWM, SCI were significantly less diamagnetic (χ = -0.0067 ppm vs. -0.0153 ppm, p < 0.001) and had significantly lower R 2* (16.7 s-1 vs. 19.2 s-1, p < 0.001). SCI definition had a significant effect on the mean SCI χ and R 2* , with lesions becoming significantly less diamagnetic and having significantly lower R 2* after the application of a more stringent T1w-based threshold. SCI-NAWM R 2* decrease was significantly greater in patients with SCA compared with controls (-2.84 s-1 vs. -0.64 s-1, p < 0.0001). No significant association was observed between mean SCI-NAWM χ or R2* differences and subject age, lesion anatomical location, or cognition. The increased χ and decreased R 2* in SCI relative to NAWM observed in both patients and controls is indicative of lower myelin or increased water content within the segmented lesions. The significant SCI-NAWM R 2* differences observed between SCI in patients with SCA and controls suggests there may be differences in tissue composition relative to NAWM in SCI in the two populations. Quantitative MRI techniques such as QSM and R 2* mapping can be used to enhance our understanding of the pathophysiology and composition of SCI in patients with SCA as well as controls.

Dataset Information

Cerebral metabolic rate of oxygen (CMRO2 ) mapping by combining quantitative susceptibility mapping (QSM) and quantitative blood oxygenation level-dependent imaging (qBOLD).

Publications

Cerebral metabolic rate of oxygen (CMRO<sub>2</sub> ) mapping by combining quantitative susceptibility mapping (QSM) and quantitative blood oxygenation level-dependent imaging (qBOLD).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets