Displaying publications 21 - 40 of 116 in total

Abstract:
Sort:
  1. Ramli N, Nair SR, Ramli NM, Lim SY
    Clin Radiol, 2015 May;70(5):555-64.
    PMID: 25752581 DOI: 10.1016/j.crad.2015.01.005
    The purpose of this review is to illustrate the differentiating features of multiple-system atrophy from Parkinson's disease at MRI. The various MRI sequences helpful in the differentiation will be discussed, including newer methods, such as diffusion tensor imaging, MR spectroscopy, and nuclear imaging.
    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  2. Fadzli F, Ramli N, Ramli NM
    Clin Radiol, 2013 Oct;68(10):e538-51.
    PMID: 23932674 DOI: 10.1016/j.crad.2013.05.104
    Visual field defects are a conglomerate of patterns of visual impairment derived from diseases affecting the optic nerve as it extends from the globe to the visual cortex. They are complex signs requiring perimetry or visual confrontation for delineation and are associated with diverse aetiologies. This review considers the chiasmatic and post-chiasmatic causes of visual disturbances, with an emphasis on magnetic resonance imaging (MRI) techniques. Newer MRI sequences are considered, such as diffusion-tensor imaging. MRI images are correlated with perimetric findings in order to demonstrate localization of lesions in the visual pathway. This may serve as a valuable reference tool to clinicians and radiologists in the early diagnostic process of differentiating causes of various visual field defects in daily practice.
    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  3. Tan SL, Rahmat K, Rozalli FI, Mohd-Shah MN, Aziz YF, Yip CH, et al.
    Clin Radiol, 2014 Jan;69(1):63-71.
    PMID: 24156797 DOI: 10.1016/j.crad.2013.08.007
    To investigate the capability and diagnostic accuracy of diffusion-weighted imaging (DWI) in differentiating benign from malignant breast lesions using 3 T magnetic resonance imaging (MRI).
    Matched MeSH terms: Diffusion Magnetic Resonance Imaging/methods*
  4. Suppiah S, Rahmat K, Mohd-Shah MN, Azlan CA, Tan LK, Aziz YF, et al.
    Clin Radiol, 2013 Sep;68(9):e502-10.
    PMID: 23706826 DOI: 10.1016/j.crad.2013.04.002
    To investigate the diagnostic accuracy of single-voxel proton magnetic resonance spectroscopy (SV (1)H MRS) by quantifying total choline-containing compounds (tCho) in differentiating malignant from benign lesions, and subsequently, to analyse the relationship of tCho levels in malignant breast lesions with their histopathological subtypes.
    Matched MeSH terms: Magnetic Resonance Imaging/methods
  5. Ramli N, Yap A, Muridan R, Seow P, Rahmat K, Fong CY, et al.
    Clin Radiol, 2020 01;75(1):77.e15-77.e22.
    PMID: 31668796 DOI: 10.1016/j.crad.2019.09.134
    AIM: To evaluate the microstructural abnormalities of the white matter tracts (WMT) using diffusion tensor imaging (DTI) in children with global developmental delay (GDD).

    MATERIALS AND METHODS: Sixteen children with GDD underwent magnetic resonance imaging (MRI) and cross-sectional DTI. Formal developmental assessment of all GDD patients was performed using the Mullen Scales of Early Learning. An automated processing pipeline for the WMT assessment was implemented. The DTI-derived metrics of the children with GDD were compared to healthy children with normal development (ND).

    RESULTS: Only two out of the 17 WMT demonstrated significant differences (p<0.05) in DTI parameters between the GDD and ND group. In the uncinate fasciculus (UF), the GDD group had lower mean values for fractional anisotropy (FA; 0.40 versus 0.44), higher values for mean diffusivity (0.96 versus 0.91×10-3 mm2/s) and radial diffusivity (0.75 versus 0.68×10-3 mm2/s) compared to the ND group. In the superior cerebellar peduncle (SCP), mean FA values were lower for the GDD group (0.38 versus 0.40). Normal myelination pattern of DTI parameters was deviated against age for GDD group for UF and SCP.

    CONCLUSION: The UF and SCP WMT showed microstructural changes suggestive of compromised white matter maturation in children with GDD. The DTI metrics have potential as imaging markers for inadequate white matter maturation in GDD children.

    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  6. Sim KS, Chia FK, Nia ME, Tso CP, Chong AK, Abbas SF, et al.
    Comput Biol Med, 2014 Jun;49:46-59.
    PMID: 24736203 DOI: 10.1016/j.compbiomed.2014.03.003
    A computer-aided detection auto-probing (CADAP) system is presented for detecting breast lesions using dynamic contrast enhanced magnetic resonance imaging, through a spatial-based discrete Fourier transform. The stand-alone CADAP system reduces noise, refines region of interest (ROI) automatically, and detects the breast lesion with minimal false positive detection. The lesions are then classified and colourised according to their characteristics, whether benign, suspicious or malignant. To enhance the visualisation, the entire analysed ROI is constructed into a 3-D image, so that the user can diagnose based on multiple views on the ROI. The proposed method has been applied to 101 sets of digital images, and the results compared with the biopsy results done by radiologists. The proposed scheme is able to identify breast cancer regions accurately and efficiently.
    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  7. Pszczolkowski S, Law ZK, Gallagher RG, Meng D, Swienton DJ, Morgan PS, et al.
    Comput Biol Med, 2019 03;106:126-139.
    PMID: 30711800 DOI: 10.1016/j.compbiomed.2019.01.022
    BACKGROUND: Spontaneous intracerebral haemorrhage (SICH) is a common condition with high morbidity and mortality. Segmentation of haematoma and perihaematoma oedema on medical images provides quantitative outcome measures for clinical trials and may provide important markers of prognosis in people with SICH.

    METHODS: We take advantage of improved contrast seen on magnetic resonance (MR) images of patients with acute and early subacute SICH and introduce an automated algorithm for haematoma and oedema segmentation from these images. To our knowledge, there is no previously proposed segmentation technique for SICH that utilises MR images directly. The method is based on shape and intensity analysis for haematoma segmentation and voxel-wise dynamic thresholding of hyper-intensities for oedema segmentation.

    RESULTS: Using Dice scores to measure segmentation overlaps between labellings yielded by the proposed algorithm and five different expert raters on 18 patients, we observe that our technique achieves overlap scores that are very similar to those obtained by pairwise expert rater comparison. A further comparison between the proposed method and a state-of-the-art Deep Learning segmentation on a separate set of 32 manually annotated subjects confirms the proposed method can achieve comparable results with very mild computational burden and in a completely training-free and unsupervised way.

    CONCLUSION: Our technique can be a computationally light and effective way to automatically delineate haematoma and oedema extent directly from MR images. Thus, with increasing use of MR images clinically after intracerebral haemorrhage this technique has the potential to inform clinical practice in the future.

    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  8. Gandhamal A, Talbar S, Gajre S, Razak R, Hani AFM, Kumar D
    Comput Biol Med, 2017 Sep 01;88:110-125.
    PMID: 28711767 DOI: 10.1016/j.compbiomed.2017.07.008
    Knee osteoarthritis (OA) progression can be monitored by measuring changes in the subchondral bone structure such as area and shape from MR images as an imaging biomarker. However, measurements of these minute changes are highly dependent on the accurate segmentation of bone tissue from MR images and it is challenging task due to the complex tissue structure and inadequate image contrast/brightness. In this paper, a fully automated method for segmenting subchondral bone from knee MR images is proposed. Here, the contrast of knee MR images is enhanced using a gray-level S-curve transformation followed by automatic seed point detection using a three-dimensional multi-edge overlapping technique. Successively, bone regions are initially extracted using distance-regularized level-set evolution followed by identification and correction of leakages along the bone boundary regions using a boundary displacement technique. The performance of the developed technique is evaluated against ground truths by measuring sensitivity, specificity, dice similarity coefficient (DSC), average surface distance (AvgD) and root mean square surface distance (RMSD). An average sensitivity (91.14%), specificity (99.12%) and DSC (90.28%) with 95% confidence interval (CI) in the range 89.74-92.54%, 98.93-99.31% and 88.68-91.88% respectively is achieved for the femur bone segmentation in 8 datasets. For tibia bone, average sensitivity (90.69%), specificity (99.65%) and DSC (91.35%) with 95% CI in the range 88.59-92.79%, 99.50-99.80% and 88.68-91.88% respectively is achieved. AvgD and RMSD values for femur are 1.43 ± 0.23 (mm) and 2.10 ± 0.35 (mm) respectively while for tibia, the values are 0.95 ± 0.28 (mm) and 1.30 ± 0.42 (mm) respectively that demonstrates acceptable error between proposed method and ground truths. In conclusion, results obtained in this work demonstrate substantially significant performance with consistency and robustness that led the proposed method to be applicable for large scale and longitudinal knee OA studies in clinical settings.
    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  9. Subudhi A, Acharya UR, Dash M, Jena S, Sabut S
    Comput Biol Med, 2018 12 01;103:116-129.
    PMID: 30359807 DOI: 10.1016/j.compbiomed.2018.10.016
    It is difficult to develop an accurate algorithm to detect the stroke lesions using magnetic resonance imaging (MRI) images due to variation in different lesion sizes, variation in morphological structure, and similarity in intensity of lesion with normal brain in three types of stroke, namely partial anterior circulation syndrome (PACS), lacunar syndrome (LACS) and total anterior circulation stroke (TACS). In this paper, we have integrated the advantages of Delaunay triangulation (DT) and fractional order Darwinian particle swarm optimization (FODPSO), called DT-FODPSO technique for automatic segmentation of the structure of the stroke lesion. The approach was validated on 192 MRI images obtained from different stroke subjects. Statistical and morphological features were extracted and classified according to the Oxfordshire community stroke project (OCSP) using support vector machine (SVM) and random forest (RF) classifiers. The method effectively detected the stroke lesions and achieved promising results with an average sensitivity of 0.93, accuracy of 0.95, JI of 0.89 and Dice similarity index of 0.93 using RF classifier. These promising results indicates the DT based optimized approach is efficient in detecting ischemic stroke and it can aid the neuro-radiologists to validate their routine screening.
    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  10. Liu F, Wang H, Liang SN, Jin Z, Wei S, Li X, et al.
    Comput Biol Med, 2023 May;157:106790.
    PMID: 36958239 DOI: 10.1016/j.compbiomed.2023.106790
    Structural magnetic resonance imaging (sMRI) is a popular technique that is widely applied in Alzheimer's disease (AD) diagnosis. However, only a few structural atrophy areas in sMRI scans are highly associated with AD. The degree of atrophy in patients' brain tissues and the distribution of lesion areas differ among patients. Therefore, a key challenge in sMRI-based AD diagnosis is identifying discriminating atrophy features. Hence, we propose a multiplane and multiscale feature-level fusion attention (MPS-FFA) model. The model has three components, (1) A feature encoder uses a multiscale feature extractor with hybrid attention layers to simultaneously capture and fuse multiple pathological features in the sagittal, coronal, and axial planes. (2) A global attention classifier combines clinical scores and two global attention layers to evaluate the feature impact scores and balance the relative contributions of different feature blocks. (3) A feature similarity discriminator minimizes the feature similarities among heterogeneous labels to enhance the ability of the network to discriminate atrophy features. The MPS-FFA model provides improved interpretability for identifying discriminating features using feature visualization. The experimental results on the baseline sMRI scans from two databases confirm the effectiveness (e.g., accuracy and generalizability) of our method in locating pathological locations. The source code is available at https://github.com/LiuFei-AHU/MPSFFA.
    Matched MeSH terms: Magnetic Resonance Imaging/methods
  11. Cheng J, Wang H, Wei S, Mei J, Liu F, Zhang G
    Comput Biol Med, 2024 Mar;170:108000.
    PMID: 38232453 DOI: 10.1016/j.compbiomed.2024.108000
    Alzheimer's disease (AD) is a neurodegenerative disease characterized by various pathological changes. Utilizing multimodal data from Fluorodeoxyglucose positron emission tomography(FDG-PET) and Magnetic Resonance Imaging(MRI) of the brain can offer comprehensive information about the lesions from different perspectives and improve the accuracy of prediction. However, there are significant differences in the feature space of multimodal data. Commonly, the simple concatenation of multimodal features can cause the model to struggle in distinguishing and utilizing the complementary information between different modalities, thus affecting the accuracy of predictions. Therefore, we propose an AD prediction model based on de-correlation constraint and multi-modal feature interaction. This model consists of the following three parts: (1) The feature extractor employs residual connections and attention mechanisms to capture distinctive lesion features from FDG-PET and MRI data within their respective modalities. (2) The de-correlation constraint function enhances the model's capacity to extract complementary information from different modalities by reducing the feature similarity between them. (3) The mutual attention feature fusion module interacts with the features within and between modalities to enhance the modal-specific features and adaptively adjust the weights of these features based on information from other modalities. The experimental results on ADNI database demonstrate that the proposed model achieves a prediction accuracy of 86.79% for AD, MCI and NC, which is higher than the existing multi-modal AD prediction models.
    Matched MeSH terms: Magnetic Resonance Imaging/methods
  12. Vairavan R, Abdullah O, Retnasamy PB, Sauli Z, Shahimin MM, Retnasamy V
    Curr Med Imaging Rev, 2019;15(2):85-121.
    PMID: 31975658 DOI: 10.2174/1573405613666170912115617
    BACKGROUND: Breast carcinoma is a life threatening disease that accounts for 25.1% of all carcinoma among women worldwide. Early detection of the disease enhances the chance for survival.

    DISCUSSION: This paper presents comprehensive report on breast carcinoma disease and its modalities available for detection and diagnosis, as it delves into the screening and detection modalities with special focus placed on the non-invasive techniques and its recent advancement work done, as well as a proposal on a novel method for the application of early breast carcinoma detection.

    CONCLUSION: This paper aims to serve as a foundation guidance for the reader to attain bird's eye understanding on breast carcinoma disease and its current non-invasive modalities.

    Matched MeSH terms: Magnetic Resonance Imaging/methods; Diffusion Magnetic Resonance Imaging/methods
  13. Khan SU, Ullah N, Ahmed I, Ahmad I, Mahsud MI
    Curr Med Imaging Rev, 2019;15(3):243-254.
    PMID: 31989876 DOI: 10.2174/1573405614666180726124952
    BACKGROUND: Medical imaging is to assume greater and greater significance in an efficient and precise diagnosis process.

    DISCUSSION: It is a set of various methodologies which are used to capture internal or external images of the human body and organs for clinical and diagnosis needs to examine human form for various kind of ailments. Computationally intelligent machine learning techniques and their application in medical imaging can play a significant role in expediting the diagnosis process and making it more precise.

    CONCLUSION: This review presents an up-to-date coverage about research topics which include recent literature in the areas of MRI imaging, comparison with other modalities, noise in MRI and machine learning techniques to remove the noise.

    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  14. Jatoi MA, Kamel N, Musavi SHA, López JD
    Curr Med Imaging Rev, 2019;15(2):184-193.
    PMID: 31975664 DOI: 10.2174/1573405613666170629112918
    BACKGROUND: Electrical signals are generated inside human brain due to any mental or physical task. This causes activation of several sources inside brain which are localized using various optimization algorithms.

    METHODS: Such activity is recorded through various neuroimaging techniques like fMRI, EEG, MEG etc. EEG signals based localization is termed as EEG source localization. The source localization problem is defined by two complementary problems; the forward problem and the inverse problem. The forward problem involves the modeling how the electromagnetic sources cause measurement in sensor space, while the inverse problem refers to the estimation of the sources (causes) from observed data (consequences). Usually, this inverse problem is ill-posed. In other words, there are many solutions to the inverse problem that explains the same data. This ill-posed problem can be finessed by using prior information within a Bayesian framework. This research work discusses source reconstruction for EEG data using a Bayesian framework. In particular, MSP, LORETA and MNE are compared.

    RESULTS: The results are compared in terms of variational free energy approximation to model evidence and in terms of variance accounted for in the sensor space. The results are taken for real time EEG data and synthetically generated EEG data at an SNR level of 10dB.

    CONCLUSION: In brief, it was seen that MSP has the highest evidence and lowest localization error when compared to classical models. Furthermore, the plausibility and consistency of the source reconstruction speaks to the ability of MSP technique to localize active brain sources.

    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  15. Keserci B, Duc NM, Nadarajan C, Huy HQ, Saizan A, Wan Ahmed WA, et al.
    Diagn Interv Radiol, 2020 May;26(3):207-215.
    PMID: 32209511 DOI: 10.5152/dir.2019.19157
    PURPOSE: We sought to present our preliminary experience on the effectiveness and safety of magnetic resonance imaging (MRI)-guided, high-intensity focused ultrasound (HIFU) therapy using a volumetric ablation technique in the treatment of Association of Asian Nations (ASEAN) patients with symptomatic uterine leiomyomas.

    METHODS: This study included 33 women who underwent HIFU treatment. Tissue characteristics of leiomyomas were assessed based on T2- and T1-weighted MRI. The immediate nonperfused volume (NPV) ratio and the treatment effectiveness of MRI-guided HIFU on the basis of the degrees of volume reduction and improvement in transformed symptom severity score (SSS) were assessed.

    RESULTS: The median immediate NPV ratio was 89.8%. Additionally, the median acoustic sonication power and HIFU treatment durations were 150 W and 125 min, respectively. At six-month follow-up, the median leiomyoma volume had decreased from 139 mL at baseline to 84 mL and the median transformed SSS had decreased from 56.2 at baseline to 18.8. No major adverse events were observed.

    CONCLUSION: The preliminary results demonstrated that volumetric MRI-guided HIFU therapy for the treatment of symptomatic leiomyomas in ASEAN patients appears to be clinically acceptable with regard to treatment effectiveness and safety.

    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  16. Yazdani S, Yusof R, Riazi A, Karimian A
    Diagn Pathol, 2014;9:207.
    PMID: 25540017 DOI: 10.1186/s13000-014-0207-7
    Brain segmentation in magnetic resonance images (MRI) is an important stage in clinical studies for different issues such as diagnosis, analysis, 3-D visualizations for treatment and surgical planning. MR Image segmentation remains a challenging problem in spite of different existing artifacts such as noise, bias field, partial volume effects and complexity of the images. Some of the automatic brain segmentation techniques are complex and some of them are not sufficiently accurate for certain applications. The goal of this paper is proposing an algorithm that is more accurate and less complex).
    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  17. Annuar BR, Liew CK, Chin SP, Ong TK, Seyfarth MT, Chan WL, et al.
    Eur J Radiol, 2008 Jan;65(1):112-9.
    PMID: 17466480
    To compare the assessment of global and regional left ventricular (LV) function using 64-slice multislice computed tomography (MSCT), 2D echocardiography (2DE) and cardiac magnetic resonance (CMR).
    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  18. Loh KB, Ramli N, Tan LK, Roziah M, Rahmat K, Ariffin H
    Eur Radiol, 2012 Jul;22(7):1413-26.
    PMID: 22434420 DOI: 10.1007/s00330-012-2396-3
    OBJECTIVES: The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas.

    METHODS: Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction.

    RESULTS: DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued.

    CONCLUSION: DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data.

    KEY POINTS: Diffusion tensor imaging outperforms conventional MRI in depicting white matter maturation. • DTI will become an important clinical tool for diagnosing paediatric neurological diseases. • DTI appears especially helpful for developmental abnormalities, tumours and white matter disease. • An automated processing pipeline assists quantitative analysis of high throughput DTI data.

    Matched MeSH terms: Diffusion Magnetic Resonance Imaging/methods*
  19. Nair SR, Tan LK, Mohd Ramli N, Lim SY, Rahmat K, Mohd Nor H
    Eur Radiol, 2013 Jun;23(6):1459-66.
    PMID: 23300042 DOI: 10.1007/s00330-012-2759-9
    OBJECTIVE: To develop a decision tree based on standard magnetic resonance imaging (MRI) and diffusion tensor imaging to differentiate multiple system atrophy (MSA) from Parkinson's disease (PD).

    METHODS: 3-T brain MRI and DTI (diffusion tensor imaging) were performed on 26 PD and 13 MSA patients. Regions of interest (ROIs) were the putamen, substantia nigra, pons, middle cerebellar peduncles (MCP) and cerebellum. Linear, volumetry and DTI (fractional anisotropy and mean diffusivity) were measured. A three-node decision tree was formulated, with design goals being 100 % specificity at node 1, 100 % sensitivity at node 2 and highest combined sensitivity and specificity at node 3.

    RESULTS: Nine parameters (mean width, fractional anisotropy (FA) and mean diffusivity (MD) of MCP; anteroposterior diameter of pons; cerebellar FA and volume; pons and mean putamen volume; mean FA substantia nigra compacta-rostral) showed statistically significant (P < 0.05) differences between MSA and PD with mean MCP width, anteroposterior diameter of pons and mean FA MCP chosen for the decision tree. Threshold values were 14.6 mm, 21.8 mm and 0.55, respectively. Overall performance of the decision tree was 92 % sensitivity, 96 % specificity, 92 % PPV and 96 % NPV. Twelve out of 13 MSA patients were accurately classified.

    CONCLUSION: Formation of the decision tree using these parameters was both descriptive and predictive in differentiating between MSA and PD.

    KEY POINTS: • Parkinson's disease and multiple system atrophy can be distinguished on MR imaging. • Combined conventional MRI and diffusion tensor imaging improves the accuracy of diagnosis. • A decision tree is descriptive and predictive in differentiating between clinical entities. • A decision tree can reliably differentiate Parkinson's disease from multiple system atrophy.

    Matched MeSH terms: Magnetic Resonance Imaging/methods*
  20. Ramli N, Khairy AM, Seow P, Tan LK, Wong JH, Ganesan D, et al.
    Eur Radiol, 2016 Jul;26(7):2019-29.
    PMID: 26560718 DOI: 10.1007/s00330-015-4045-0
    OBJECTIVES: We evaluated the feasibility of using chemical shift gradient-echo (GE) in- and opposed-phase (IOP) imaging to grade glioma.

    METHODS: A phantom study was performed to investigate the correlation of (1)H MRS-visible lipids with the signal loss ratio (SLR) obtained using IOP imaging. A cross-sectional study approved by the institutional review board was carried out in 22 patients with different glioma grades. The patients underwent scanning using IOP imaging and single-voxel spectroscopy (SVS) using 3T MRI. The brain spectra acquisitions from solid and cystic components were obtained and correlated with the SLR for different grades.

    RESULTS: The phantom study showed a positive linear correlation between lipid quantification at 0.9 parts per million (ppm) and 1.3 ppm with SLR (r = 0.79-0.99, p 

    Matched MeSH terms: Magnetic Resonance Imaging/methods*
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links