Displaying all 16 publications

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  1. You YX, Shahar S, Mohamad M, Yahya HM, Haron H, Abdul Hamid H
    J Magn Reson Imaging, 2020 04;51(4):1142-1153.
    PMID: 31386268 DOI: 10.1002/jmri.26891
    BACKGROUND: Working memory and cognitive flexibility are supported by the dorsolateral prefrontal cortex (DLPFC). Aging adults from low-income households are individuals with a high risk of cognitive decline who incorporate ulam in their daily diet.

    PURPOSE: To examine relationship between ulam consumption and the working memory and cognitive flexibility among aging adults from low-income households who are more susceptible to cognitive decline.

    STUDY TYPE: Cross-sectional.

    POPULATION/SUBJECTS: Thirty-two aging adults (45-75 years old).

    FIELD STRENGTH/SEQUENCE: Task-based fMRI, 3.0T, T1 -weighted anatomical images, T2 *-weighted imaging data.

    ASSESSMENT: The dietary and ulam consumption were assessed using the respective validated Dietary History and semiquantitative Food Frequency questionnaires. Working memory and cognitive flexibility were evaluated by using neuropsychological batteries (ie, mini-mental state examination [MMSE], Digit Span, and Rey auditory verbal learning test [RAVLT]) and task-based fMRI (N-back and Stroop Color Word Test [SCWT]). Brodmann's areas 9 and 46 were the regions of interest (ROIs) of DLPFC activation.

    STATISTICAL TESTS: Multiple linear regression used to understand the relationship between ulam consumption and the working memory and cognitive flexibility, while analysis of covariance (ANCOVA) was used to compare the difference of working memory and cognitive flexibility among four percentiles of ulam consumption, after age, gender, and education years adjustments. Significance was decided by two-sided, P 

  2. Othman EA, Yusoff AN, Mohamad M, Abdul Manan H, Abd Hamid AI, Giampietro V
    J Magn Reson Imaging, 2020 06;51(6):1821-1828.
    PMID: 31794119 DOI: 10.1002/jmri.27016
    BACKGROUND: The auditory and prefrontal cortex supports auditory working memory processing. Many neuroimaging studies have shown hemispheric lateralization of auditory working memory brain regions in the presence of background noise, but few studies have focused on the lateralization of these regions during stochastic resonance.

    PURPOSE: To investigate the effects of stochastic resonance on lateralization of auditory working memory regions, and also to examine the brain-behavior relationship during stochastic resonance.

    STUDY TYPE: Cross-sectional.

    POPULATION/SUBJECTS: Forty healthy young adults (18-24 years old).

    FIELD STRENGTH/SEQUENCE: 3.0T, T1 , and T2 *-weighted imaging.

    ASSESSMENT: The auditory working memory performance was assessed using a backward recall task. Functional magnetic resonance imaging (fMRI) was used to measure brain activity during task performance. Functional MRI data were analyzed using SPM12 and WFU PickAtlas.

    STATISTICAL TESTS: One-way independent analyses of variance (ANOVA) were conducted on the behavioral and functional data to examine the main effect of noise level on performance (P 

  3. Cheah PL, Krisnan T, Wong JHD, Rozalli FI, Fadzli F, Rahmat K, et al.
    J Magn Reson Imaging, 2021 02;53(2):437-444.
    PMID: 32918328 DOI: 10.1002/jmri.27354
    BACKGROUND: Charcot-Marie-Tooth (CMT) disease is diagnosed through clinical findings and genetic testing. While there are neurophysiological tools and clinical functional scales in CMT, objective disease biomarkers that can facilitate in monitoring disease progression are limited.

    PURPOSE: To investigate the utility of diffusion tensor imaging (DTI) in determining the microstructural integrity of sciatic and peroneal nerves and its correlation with the MRI grading of muscle atrophy severity and clinical function in CMT as determined by the CMT neuropathy score (CMTNS).

    STUDY TYPE: Prospective case-control.

    SUBJECTS: Nine CMT patients and nine age-matched controls.

    FIELD STRENGTH/SEQUENCE: 3 T T1 -weighted in-/out-of phase spoiled gradient recalled echo (SPGR) and DTI sequences.

    ASSESSMENT: Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) values for sciatic and peroneal nerves were obtained from DTI. Muscle atrophy was graded according to the Goutallier classification using in-/out-of phase SPGRs. DTI parameters and muscle atrophy grades were compared between CMT and controls, and the relationship between DTI parameters, muscle atrophy grades, and CMTNS were assessed.

    STATISTICAL TESTS: The Wilcoxon Signed Ranks test was used to compare DTI parameters between CMT and controls. The relationship between DTI parameters, muscle atrophy grades, and CMTNS were analyzed using the Spearman correlation. Receiver operating characteristic (ROC) analyses of DTI parameters that can differentiate CMT from healthy controls were done.

    RESULTS: There was a significant reduction in FA and increase in RD of both nerves (P 

  4. Ismail UN, Azlan CA, Khairullah S, Azman RR, Omar NF, Md Shah MN, et al.
    J Magn Reson Imaging, 2021 01;53(1):190-198.
    PMID: 33237616 DOI: 10.1002/jmri.27294
    BACKGROUND: β-thalassemia is a genetic disease that causes abnormal production of red blood cells (ineffective erythropoiesis, IE). IE is a condition known to change bone marrow composition.

    PURPOSE: To evaluate the effect of IE on the marrow fat content and fat unsaturation levels in the proximal femur using 1 H-MRS.

    STUDY TYPE: Prospective.

    SUBJECTS: Twenty-three subjects were included in this study, seven control and 16 β-thalassemia subjects.

    FIELD STRENGTH/SEQUENCE: 3.0T; stimulated echo acquisition Mode (STEAM); magnetic resonance spectroscopy (MRS) sequence.

    ASSESSMENT: Multiecho MRS scans were performed in four regions of the proximal left femur of each subject, that is, diaphysis, femoral neck, femoral head, and greater trochanter. The examined regions were grouped into red (diaphysis and femoral neck) and yellow marrow regions (femoral head and greater trochanter).

    STATISTICAL TESTS: The Jonckheere-Terpstra test was used to evaluate the impact of increasing disease severity on bone marrow fat fraction (BMFF), marrow conversion index, and fat unsaturation index (UI). Pairwise comparison analysis was performed when a significant trend (P 

  5. Leong CO, Liew YM, Bilgen M, Abdul Aziz YF, Chee KH, Chiam YK, et al.
    J Magn Reson Imaging, 2016 Jul 15.
    PMID: 27418150 DOI: 10.1002/jmri.25390
    To propose a cardiac motion tracking model that evaluates wall motion abnormality in postmyocardial infarction patients. Correlation between the motion parameter of the model and left ventricle (LV) function was also determined.
  6. Khalid A, Lim E, Chan BT, Abdul Aziz YF, Chee KH, Yap HJ, et al.
    J Magn Reson Imaging, 2019 04;49(4):1006-1019.
    PMID: 30211445 DOI: 10.1002/jmri.26302
    BACKGROUND: Existing clinical diagnostic and assessment methods could be improved to facilitate early detection and treatment of cardiac dysfunction associated with acute myocardial infarction (AMI) to reduce morbidity and mortality.

    PURPOSE: To develop 3D personalized left ventricular (LV) models and thickening assessment framework for assessing regional wall thickening dysfunction and dyssynchrony in AMI patients.

    STUDY TYPE: Retrospective study, diagnostic accuracy.

    SUBJECTS: Forty-four subjects consisting of 15 healthy subjects and 29 AMI patients.

    FIELD STRENGTH/SEQUENCE: 1.5T/steady-state free precession cine MRI scans; LGE MRI scans.

    ASSESSMENT: Quantitative thickening measurements across all cardiac phases were correlated and validated against clinical evaluation of infarct transmurality by an experienced cardiac radiologist based on the American Heart Association (AHA) 17-segment model.

    STATISTICAL TEST: Nonparametric 2-k related sample-based Kruskal-Wallis test; Mann-Whitney U-test; Pearson's correlation coefficient.

    RESULTS: Healthy LV wall segments undergo significant wall thickening (P 50% transmurality) underwent remarkable wall thinning during contraction (thickening index [TI] = 1.46 ± 0.26 mm) as opposed to healthy myocardium (TI = 4.01 ± 1.04 mm). For AMI patients, LV that showed signs of thinning were found to be associated with a significantly higher percentage of dyssynchrony as compared with healthy subjects (dyssynchrony index [DI] = 15.0 ± 5.0% vs. 7.5 ± 2.0%, P 

  7. You YX, Shahar S, Mohamad M, Rajab NF, Haron H, Che Din N, et al.
    J Magn Reson Imaging, 2021 12;54(6):1804-1818.
    PMID: 34080265 DOI: 10.1002/jmri.27762
    BACKGROUND: Cosmos caudatus (CC) is traditional Asian vegetable, commonly consumed among the Southeast Asian population. It has been reported to be high in flavonoids and might potentially improve brain activity among older adults with mild cognitive impairment (MCI). The effect of CC in brain activation improvement using neuroimaging is yet to be discovered.

    PURPOSE: To investigate the effects of CC supplement on brain activity using functional magnetic resonance imaging (fMRI) among older adults with MCI.

    STUDY TYPE: Prospective, randomized, double-blind, placebo-controlled trial.

    POPULATION/SUBJECTS: Twenty older adults with mild cognitive impairment (60-75 years old), 14 of them (70%) were female subjects.

    FIELD STRENGTH/SEQUENCE: A 3.0-T, T1-weighted anatomical images, T2*-weighted imaging data, A single shot, gradient echo-echo planar imaging (EPI) sequence.

    ASSESSMENT: All subjects were asked to consume two 500 mg capsules of either CC supplement or placebo (maltodextrin) daily for 12 weeks. Cognitive function was measured using validated neuropsychological tests (i.e. Mini-mental State Examination and Digit Span) and task-based fMRI (N-back and Stroop Color Word Test) at baseline and 12th week. Brodmann's area 9, 46 and anterior cingulate cortex were selected as the regions of interest to define dorsolateral prefrontal cortex (DLPFC) in fMRI analysis.

    STATISTICAL TESTS: Normality test was performed with the Shapiro-Wilk test. Two-way repeated ANOVA determined the intervention effects of the CC supplementation on brain activity after adjustments for covariates. Significance level at P 

  8. Tan LK, McLaughlin RA, Lim E, Abdul Aziz YF, Liew YM
    J Magn Reson Imaging, 2018 07;48(1):140-152.
    PMID: 29316024 DOI: 10.1002/jmri.25932
    BACKGROUND: Left ventricle (LV) structure and functions are the primary assessment performed in most clinical cardiac MRI protocols. Fully automated LV segmentation might improve the efficiency and reproducibility of clinical assessment.

    PURPOSE: To develop and validate a fully automated neural network regression-based algorithm for segmentation of the LV in cardiac MRI, with full coverage from apex to base across all cardiac phases, utilizing both short axis (SA) and long axis (LA) scans.

    STUDY TYPE: Cross-sectional survey; diagnostic accuracy.

    SUBJECTS: In all, 200 subjects with coronary artery diseases and regional wall motion abnormalities from the public 2011 Left Ventricle Segmentation Challenge (LVSC) database; 1140 subjects with a mix of normal and abnormal cardiac functions from the public Kaggle Second Annual Data Science Bowl database.

    FIELD STRENGTH/SEQUENCE: 1.5T, steady-state free precession.

    ASSESSMENT: Reference standard data generated by experienced cardiac radiologists. Quantitative measurement and comparison via Jaccard and Dice index, modified Hausdorff distance (MHD), and blood volume.

    STATISTICAL TESTS: Paired t-tests compared to previous work.

    RESULTS: Tested against the LVSC database, we obtained 0.77 ± 0.11 (Jaccard index) and 1.33 ± 0.71 mm (MHD), both metrics demonstrating statistically significant improvement (P < 0.001) compared to previous work. Tested against the Kaggle database, the signed difference in evaluated blood volume was +7.2 ± 13.0 mL and -19.8 ± 18.8 mL for the end-systolic (ES) and end-diastolic (ED) phases, respectively, with a statistically significant improvement (P < 0.001) for the ED phase.

    DATA CONCLUSION: A fully automated LV segmentation algorithm was developed and validated against a diverse set of cardiac cine MRI data sourced from multiple imaging centers and scanner types. The strong performance overall is suggestive of practical clinical utility.

    LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

  9. Chuah SH, Tan LK, Md Sari NA, Chan BT, Hasikin K, Lim E, et al.
    J Magn Reson Imaging, 2023 Jul 15.
    PMID: 37452574 DOI: 10.1002/jmri.28915
    BACKGROUND: Increased afterload in aortic stenosis (AS) induces left ventricle (LV) remodeling to preserve a normal ejection fraction. This compensatory response can become maladaptive and manifest with motion abnormality. It is a clinical challenge to identify contractile and relaxation dysfunction during early subclinical stage to prevent irreversible deterioration.

    PURPOSE: To evaluate the changes of regional wall dynamics in 3D + time domain as remodeling progresses in AS.

    STUDY TYPE: Retrospective.

    POPULATION: A total of 31 AS patients with reduced and preserved ejection fraction (14 AS_rEF: 7 male, 66.5 [7.8] years old; 17 AS_pEF: 12 male, 67.0 [6.0] years old) and 15 healthy (6 male, 61.0 [7.0] years old).

    FIELD STRENGTH/SEQUENCE: 1.5 T Magnetic resonance imaging/steady state free precession and late-gadolinium enhancement sequences.

    ASSESSMENT: Individual LV models were reconstructed in 3D + time domain and motion metrics including wall thickening (TI), dyssynchrony index (DI), contraction rate (CR), and relaxation rate (RR) were automatically extracted and associated with the presence of scarring and remodeling.

    STATISTICAL TESTS: Shapiro-Wilk: data normality; Kruskal-Wallis: significant difference (P 

  10. Liew A, Lee CC, Subramaniam V, Lan BL, Tan M
    J Magn Reson Imaging, 2023 Jun;57(6):1728-1740.
    PMID: 36208095 DOI: 10.1002/jmri.28456
    BACKGROUND: Research suggests that treatment of multiple brain metastases (BMs) with stereotactic radiosurgery shows improvement when metastases are detected early, providing a case for BM detection capabilities on small lesions.

    PURPOSE: To demonstrate automatic detection of BM on three MRI datasets using a deep learning-based approach. To improve the performance of the network is iteratively co-trained with datasets from different domains. A systematic approach is proposed to prevent catastrophic forgetting during co-training.

    STUDY TYPE: Retrospective.

    POPULATION: A total of 156 patients (105 ground truth and 51 pseudo labels) with 1502 BM (BrainMetShare); 121 patients with 722 BM (local); 400 patients with 447 primary gliomas (BrATS). Training/pseudo labels/validation data were distributed 84/51/21 (BrainMetShare). Training/validation data were split: 121/23 (local) and 375/25 (BrATS).

    FIELD STRENGTH/SEQUENCE: A 5 T and 3 T/T1 spin-echo postcontrast (T1-gradient echo) (BrainMetShare), 3 T/T1 magnetization prepared rapid acquisition gradient echo postcontrast (T1-MPRAGE) (local), 0.5 T, 1 T, and 1.16 T/T1-weighted-fluid-attenuated inversion recovery (T1-FLAIR) (BrATS).

    ASSESSMENT: The ground truth was manually segmented by two (BrainMetShare) and four (BrATS) radiologists and manually annotated by one (local) radiologist. Confidence and volume based domain adaptation (CAVEAT) method of co-training the three datasets on a 3D nonlocal convolutional neural network (CNN) architecture was implemented to detect BM.

    STATISTICAL TESTS: The performance was evaluated using sensitivity and false positive rates per patient (FP/patient) and free receiver operating characteristic (FROC) analysis at seven predefined (1/8, 1/4, 1/2, 1, 2, 4, and 8) FPs per scan.

    RESULTS: The sensitivity and FP/patient from a held-out set registered 0.811 at 2.952 FP/patient (BrainMetShare), 0.74 at 3.130 (local), and 0.723 at 2.240 (BrATS) using the CAVEAT approach with lesions as small as 1 mm being detected.

    DATA CONCLUSION: Improved sensitivities at lower FP can be achieved by co-training datasets via the CAVEAT paradigm to address the problem of data sparsity.

    LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

  11. Ismail UN, Azlan CA, Khairullah S, Azman RR, Omar NF, Md Shah MN, et al.
    J Magn Reson Imaging, 2024 Mar 31.
    PMID: 38556790 DOI: 10.1002/jmri.29366
    BACKGROUND: Growing evidence suggests that marrow adipocytes play an active role in the regulation of bone metabolism and hematopoiesis. However, research on the relationship between bone and fat in the context of hematological diseases, particularly β-thalassemia, remains limited.

    PURPOSE: To investigate the relationship between marrow fat and cortical bone thickness in β-thalassemia and to identify key determinants influencing these variables.

    STUDY TYPE: Prospective.

    SUBJECTS: Thirty-five subjects in four subject groups of increasing disease severity: 6 healthy control (25.0 ± 5.3 years, 2 male), 4 β-thalassemia minor, 13 intermedia, and 12 major (29.1 ± 6.4 years, 15 male).

    FIELD STRENGTH/SEQUENCE: 3.0 T, 3D fast low angle shot sequence and T1-weighted turbo spin echo.

    ASSESSMENT: Analyses on proton density fat fraction (PDFF) and R2* values in femur subregions (femoral head, greater trochanter, intertrochanteric, diaphysis, distal) and cortical thickness (CBI) of the subjects' left femur. Clinical data such as age, sex, body mass index (BMI), and disease severity were also included.

    STATISTICAL TESTS: One-way analysis of variance (ANOVA), mixed ANOVA, Pearson correlation and multiple regression. P-values <0.05 were considered significant.

    RESULTS: Bone marrow PDFF significantly varied between the femur subregions, F(2.89,89.63) = 44.185 and disease severity, F(1,3) = 12.357. A significant interaction between subject groups and femur subregions on bone marrow PDFF was observed, F(8.67,89.63) = 3.723. Notably, a moderate positive correlation was observed between PDFF and CBI (r = 0.33-0.45). Multiple regression models for both PDFF (R2 = 0.476, F(13,151) = 10.547) and CBI (R2 = 0.477, F(13,151) = 10.580) were significant. Significant predictors for PDFF were disease severity (βTMi = 0.36, βTMa = 0.17), CBI (β = 0.24), R2* (β = -0.32), and height (β = -0.29) while for CBI, the significant determinants were sex (β = -0.27), BMI (β = 0.55), disease severity (βTMi = 2.15), and PDFF (β = 0.25).

    DATA CONCLUSION: This study revealed a positive correlation between bone marrow fat fraction and cortical bone thickness in β-thalassemia with varying disease severity, potentially indicating a complex interplay between bone health and marrow composition.

    EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 3.

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