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Maternal mortality in University Hospital Kuala Lumpur, Malaysia

Kong H, Sinnathuray TA, Ng KH

Med J Malaysia, 1974 Jun;28(4):226-8.
PMID: 4278955
Fulltext Teaching and learning of postgraduate medical physics using Internet-based e-learning during the COVID-19 pandemic - A case study from Malaysia

Azlan CA, Wong JHD, Tan LK, A D Huri MSN, Ung NM, Pallath V, et al.

Phys Med, 2020 Dec;80:10-16.
PMID: 33070007 DOI: 10.1016/j.ejmp.2020.10.002

PURPOSE: We present the implementation of e-learning in the Master of Medical Physics programme at the University of Malaya during a partial lockdown from March to June 2020 due to the COVID-19 pandemic.
METHODS: Teaching and Learning (T&L) activities were conducted virtually on e-learning platforms. The students' experience and feedback were evaluated after 15 weeks.
RESULTS: We found that while students preferred face-to-face, physical teaching, they were able to adapt to the new norm of e-learning. More than 60% of the students agreed that pre-recorded lectures and viewing videos of practical sessions, plus answering short questions, were beneficial. Certain aspects, such as hands-on practical and clinical experience, could never be replaced. The e-learning and study-from-home environment accorded a lot of flexibility. However, students also found it challenging to focus because of distractions, lack of engagement and mental stress. Technical problems, such as poor Internet connectivity and limited data plans, also compounded the problem.
CONCLUSION: We expect e-learning to prevail in future. Hybrid learning strategies, which includes face-to-face classes and e-learning, will become common, at least in the medical physics programme of the University of Malaya even after the pandemic.
Fulltext Association of Radiation Doses and Cancer Risks from CT Pulmonary Angiography Examinations in Relation to Body Diameter

Harun HH, Abdul Karim MK, Abbas Z, Abdul Rahman MA, Sabarudin A, Ng KH

Diagnostics (Basel), 2020 Sep 09;10(9).
PMID: 32917029 DOI: 10.3390/diagnostics10090681

In this study, we aimed to estimate the probability of cancer risk induced by CT pulmonary angiography (CTPA) examinations concerning effective body diameter. One hundred patients who underwent CTPA examinations were recruited as subjects from a single institution in Kuala Lumpur. Subjects were categorized based on their effective diameter size, where 19-25, 25-28, and >28 cm categorized as Groups 1, 2, and 3, respectively. The mean value of the body diameter of the subjects was 26.82 ± 3.12 cm, with no significant differences found between male and female subjects. The risk of cancer in breast, lung, and liver organs was 0.009%, 0.007%, and 0.005% respectively. The volume-weighted CT dose index (CTDIvol) was underestimated, whereas the size-specific dose estimates (SSDEs) provided a more accurate description of the radiation dose and the risk of cancer. CTPA examinations are considered safe but it is essential to implement a protocol optimized following the As Low as Reasonably Achievable (ALARA) principle.
A comparative study of radiation doses between phantom and patients via CT angiography of the intra-/extra-cranial, pulmonary, and abdominal/pelvic arteries

Karim MKA, Sabarudin A, Muhammad NA, Ng KH

Radiol Phys Technol, 2019 Dec;12(4):374-381.
PMID: 31468370 DOI: 10.1007/s12194-019-00532-8

This study aimed to evaluate effective dose and size-specific dose estimate (SSDE) of computed tomography angiography (CTA) examination using an anthropomorphic phantom. We included three CTA examination protocols to evaluate the intra- and extra-cranial arteries, pulmonary artery (CTPA), and abdominal vessels. Patient SSDEs were measured retrospectively to estimate patient dose, relative to the bodyweight of the patient and volume CT dose index (CTDIvol). Our findings revealed that the highest dose was absorbed by the left lobe of the thyroid gland during intra-/extra-cranial CTA and CTPA, that is, 14.11 ± 0.24 mGy and 16.20 ± 3.95 mGy, respectively. However, the highest absorbed dose in abdominal/pelvic CTA was the gonads (8.98 ± 0.30 mGy), while other radiosensitive organs in intra- and extra-cranial CTA, CTPA, and abdominal/pelvic CTA did not demonstrate significant differences between organs/structures with p value 0.88, 0.11, and 0.54, respectively. The estimated effective dose in intra-/extra-cranial CTA was lower in patients (0.80 ± 0.60 mSv) than in the phantom (0.83 mSv), but it was the opposite for CTPA, with the effective dose being higher in patients (7.54 ± 3.09 mSv) than in the phantom (6.68 mSv). Similar to the effective dose, only CTPA SSDEs were significantly higher in men than in women (19.74 ± 4.79 mGy versus 7.9 mGy). Effective dose and SSDE are clinically relevant parameters that can help estimate a more accurate patient dose based on a patient's size.
Adoption of TiO2-photocatalysis for palm oil mill effluent (POME) treatment: Strengths, weaknesses, opportunities, threats (SWOT) and its practicality against traditional treatment in Malaysia

Ng KH

Chemosphere, 2021 May;270:129378.
PMID: 33422998 DOI: 10.1016/j.chemosphere.2020.129378

The technical feasibility of TiO2-photocatalysis towards palm oil mill effluent (POME) treatment is well-proven in previous studies. As a continuity, current study evaluated the strengths, weaknesses, opportunities and threats (SWOT) in a concise manner, subsequently discussed its practicality in palm oil industry of Malaysia. Indeed, TiO2-photocatalysis displays a promising technical feasibility in treating POME, but its wide application is economically-suppressed. It is positing that biological-based treatments (including the existing open-ponding system) are more likely to be employed as the major treating approach for POME over TiO2-photocatalysis. This is particularly true as biological-based treatments offer better performance index for concentrated POME with comparatively lower treatment cost and technicality needed. Furthermore, it is also prevailed with high biogas generability, therefore being irreplaceably benchmarked for POME treatment in Malaysia. Instead of replacing biological treatment entirely, the adoption of TiO2-photocatalysis as complementing tertiary treatment for biological-treated-POME is more practical, bestowed to its robust organic-mineralizing feature for low concentration POME. Such integrated system is expected to augment the POME degradation efficiency, hence effectively preserve the environment from POME pollution.
Fulltext Diagnostic Efficacy of Synthesized 2D Digital Breast Tomosynthesis in Multi-ethnic Malaysian Population

Mumin NA, Rahmat K, Fadzli F, Ramli MT, Westerhout CJ, Ramli N, et al.

Sci Rep, 2019 02 06;9(1):1459.
PMID: 30728394 DOI: 10.1038/s41598-018-37451-4

Synthesized 2D images can be reconstructed from tomosynthesis images in breast imaging. This study aims to investigate the diagnostic efficacy of synthesized 2D images (C-View) in comparison to full field digital mammography (FFDM) when used with digital breast tomosynthesis (DBT) in multi-ethnic Malaysian population. FFDM and C-View images (n = 380) were independently evaluated by three readers through Breast Imaging Reporting and Data System (BI-RADS) categorisation, breast density and lesion characterisation. Statistical analysis was done comparing sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of C-View + DBT with FFDM + DBT as standard of reference. Very good interreader agreement in BI-RADS category and density assessment between C-View + DBT and FFDM + DBT, with high sensitivity, specificity, PPV and NPV of C-View + DBT when compared with FFDM + DBT. There was comparable PPV between C-View + DBT and FFDM + DBT, with histopathology as gold standard. High level of interreader agreement in BI-RADS category and density assessment for FFDM + DBT and C-View + DBT. There was good agreement between FFDM + DBT and C-View + DBT in mass characterization, and almost perfect agreement in calcification and asymmetric density. 52.2% lower radiation dose incurred when using C-View + DBT. Hence, synthesized 2D images are comparable to FFDM with reduction in radiation dose within the limits of Malaysian multi-ethnic population.
Comparison of Shear Wave Elastography and Conventional Ultrasound in Assessing Kidney Function as Measured Using 51Cr-ethylenediaminetetraacetic Acid and 99Tc-Dimercaptosuccinic Acid

Leong SS, Wong JHD, Md Shah MN, Vijayananthan A, Jalalonmuhali M, Ng KH

Ultrasound Med Biol, 2019 06;45(6):1417-1426.
PMID: 30962016 DOI: 10.1016/j.ultrasmedbio.2019.01.024

The purpose of this study was to assess the potential of shear wave elastography (SWE) as an indicator of abnormal kidney function defined by radiolabeled glomerular filtration rate (GFR). Fifty-seven patients referred for 51Cr-ethylenediaminetetraacetic acid GFR and 99mTc-dimercaptosuccinic acid renal scintigraphy were included. Young's modulus (YM) measured with SWE and kidney length, volume, cortical thickness and parenchymal echogenicity measured with conventional ultrasound were correlated with patients' GFR and renal scintigraphy results. Spearman correlation coefficients between SWE and GFR were negative for the right (r = -0.635, p < 0.0001) and left (r = -0.817, p < 0.0001) kidneys. Positive correlations between left renal cortical thickness (r = 0.381, p = 0.04) and left kidney volume (r = 0.356, p = 0.019) with GFR were reported. SWE correctly predicted the dominant functioning kidney in 94.7% of cases. The area under the receiver operating characteristic curve for SWE (0.800) was superior to that for conventional ultrasound (0.252-0.415). The cutoff value of ≥5.52 kPa suggested a kidney function ≤60 mL/min/1.73 m2 (82.4% sensitivity and 76.2% specificity). SWE has advantages over conventional ultrasound in assessing kidney function and distinguishing the dominant functioning kidney.
Fulltext Robust radiogenomics approach to the identification of EGFR mutations among patients with NSCLC from three different countries using topologically invariant Betti numbers

Ninomiya K, Arimura H, Chan WY, Tanaka K, Mizuno S, Muhammad Gowdh NF, et al.

PLoS One, 2021;16(1):e0244354.
PMID: 33428651 DOI: 10.1371/journal.pone.0244354

OBJECTIVES: To propose a novel robust radiogenomics approach to the identification of epidermal growth factor receptor (EGFR) mutations among patients with non-small cell lung cancer (NSCLC) using Betti numbers (BNs).
MATERIALS AND METHODS: Contrast enhanced computed tomography (CT) images of 194 multi-racial NSCLC patients (79 EGFR mutants and 115 wildtypes) were collected from three different countries using 5 manufacturers' scanners with a variety of scanning parameters. Ninety-nine cases obtained from the University of Malaya Medical Centre (UMMC) in Malaysia were used for training and validation procedures. Forty-one cases collected from the Kyushu University Hospital (KUH) in Japan and fifty-four cases obtained from The Cancer Imaging Archive (TCIA) in America were used for a test procedure. Radiomic features were obtained from BN maps, which represent topologically invariant heterogeneous characteristics of lung cancer on CT images, by applying histogram- and texture-based feature computations. A BN-based signature was determined using support vector machine (SVM) models with the best combination of features that maximized a robustness index (RI) which defined a higher total area under receiver operating characteristics curves (AUCs) and lower difference of AUCs between the training and the validation. The SVM model was built using the signature and optimized in a five-fold cross validation. The BN-based model was compared to conventional original image (OI)- and wavelet-decomposition (WD)-based models with respect to the RI between the validation and the test.
RESULTS: The BN-based model showed a higher RI of 1.51 compared with the models based on the OI (RI: 1.33) and the WD (RI: 1.29).
CONCLUSION: The proposed model showed higher robustness than the conventional models in the identification of EGFR mutations among NSCLC patients. The results suggested the robustness of the BN-based approach against variations in image scanner/scanning parameters.
Epithelial-to-mesenchymal transition in ameloblastoma: focus on morphologically evident mesenchymal phenotypic transition

Siar CH, Ng KH

Pathology, 2019 Aug;51(5):494-501.
PMID: 31262562 DOI: 10.1016/j.pathol.2019.04.004

The ameloblastoma is the most common and clinically significant odontogenic epithelial neoplasm known for its locally-invasive behaviour and high recurrence risk. Epithelial-to-mesenchymal transition (EMT) is a fundamental process whereby epithelial cells lose their epithelial characteristics and gain mesenchymal properties. EMT induction via transcription repression has been investigated in ameloblastoma. However, morphologically evident mesenchymal phenotypic transition remains ill-defined. To determine this, 24 unicystic (UA), 34 solid/multicystic (SA) and 18 recurrent ameloblastoma (RA) were immunohistochemically examined for three EMT-related mesenchymal markers, alpha smooth muscle actin (α-SMA), osteonectin and neuronal cadherin (N-cadherin). All three factors were heterogeneously detected in ameloblastoma samples (α-SMA, n=71/76, 93.4%; osteonectin, n=72/76, 94.7%; N-cadherin, n=24/76, 31.6%). In the tumoural parenchyma, immunoreactive cells were not morphologically distinct from their non-reactive cellular counterparts. Rather, α-SMA and osteonectin predominantly labelled the cytoplasm of central polyhedral > peripheral columnar/cuboidal tumour cells. N-cadherin demonstrated weak-to-moderate circumferential membranous staining in both neoplastic cell types and cytoplasmic expression in spindle-celled epithelium of desmoplastic amelobastoma. For all tumour subsets, α-SMA and osteonectin scored significantly higher in the stroma > parenchyma whilst α-SMA was overexpressed along the tumour invasive front > centre (p<0.05). Stromal N-cadherin scored higher in SA > UA and RA > UA (p<0.05). Other clinicopathological parameters showed no significant associations. Taken together, acquisition of mesenchymal traits without morphologically evident mesenchymal alteration suggests partial EMT in ameloblastoma. Stromal upregulation of these proteins in SA and RA implicates a role in local invasiveness.
Stiffness and Anisotropy Effect on Shear Wave Elastography: A Phantom and in Vivo Renal Study

Leong SS, Wong JHD, Md Shah MN, Vijayananthan A, Jalalonmuhali M, Mohd Sharif NH, et al.

Ultrasound Med Biol, 2020 01;46(1):34-45.
PMID: 31594681 DOI: 10.1016/j.ultrasmedbio.2019.08.011

Tissue elasticity is related to the pathologic state of kidneys and can be measured using shear wave elastography (SWE). However, SWE quantification has not been rigorously validated. The aim of this study was to evaluate the accuracy of SWE-measured stiffness and the effect of tissue anisotropy on SWE measurements. Point SWE (pSWE), 2-D SWE and dynamic mechanical analysis (DMA) were used to measure stiffness and evaluate the effect of tissue anisotropy on the measurements. SWE and DMA were performed on phantoms of different gelatin concentrations. In the tissue anisotropy study, SWE and DMA were performed on the outer cortex of sheep kidneys. In the in vivo study, 15 patients with different levels of interstitial fibrosis were recruited for pSWE measurements. Another 10 healthy volunteers were recruited for tissue anisotropy studies. SWE imaging revealed a non-linear increase with gelatin concentration. There was a significant correlation between pSWE and 2-D SWE, leading to the establishment of a linear regression equation between the two SWE ultrasound measurements. In the anisotropy study, the median difference in stiffness between shear waves oriented at 0° and 90° towards the pyramid axis was significant. In the in vivo study, there was a strong positive linear correlation between pSWE and the percentage of interstitial fibrosis. There was a significant difference in the Young's modulus (YM) between severities of fibrosis. The mean YM values were lower in control patients than in patients with mild, moderate and severe fibrosis. YM values were also significantly higher when shear waves were oriented at 0° toward the pyramid axis. Tissue stiffness and anisotropy affects SWE measurements. These factors should be recognized before applying SWE for the interpretation of measured values.
Fulltext The use of radiochromic EBT2 film for the quality assurance and dosimetric verification of 3D conformal radiotherapy using Microtek ScanMaker 9800XL flatbed scanner

Sim GS, Wong JH, Ng KH

J Appl Clin Med Phys, 2013 Jul 08;14(4):4182.
PMID: 23835383 DOI: 10.1120/jacmp.v14i4.4182

Radiochromic and radiographic films are widely used for radiation dosimetry due to the advantage of high spatial resolution and two-dimensional dose measurement. Different types of scanners, including various models of flatbed scanners, have been used as part of the dosimetry readout procedure. This paper focuses on the characterization of the EBT2 film response in combination with a Microtek ScanMaker 9800XL scanner and the subsequent use in the dosimetric verification of a 3D conformal radiotherapy treatment. The film reproducibility and scanner uniformity of the Microtek ScanMaker 9800XL was studied. A three-field 3D conformal radiotherapy treatment was planned on an anthropomorphic phantom and EBT2 film measurements were carried out to verify the treatment. The interfilm reproducibility was found to be 0.25%. Over a period of three months, the films darkened by 1%. The scanner reproducibility was ± 2% and a nonuniformity was ±1.9% along the direction perpendicular to the scan direction. EBT2 measurements showed an underdose of 6.2% at high-dose region compared to TPS predicted dose. This may be due to the inability of the treatment planning system to predict the correct dose distribution in the presence of tissue inhomogeneities and the uncertainty of the scanner reproducibility and uniformity. The use of EBT2 film in conjunction with the axial CT image of the anthropomorphic phantom allows the evaluation of the anatomical location of dose discrepancies between the EBT2 measured dose distribution and TPS predicted dose distribution.
Marrow Fat Content and Composition in β-Thalassemia: A Study using 1 H-MRS

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
Leadership and mentoring in medical physics: The experience of a medical physics international mentoring program

Santos JC, Goulart LF, Giansante L, Lin YH, Sirico ACA, Ng AH, et al.

Phys Med, 2020 Aug;76:337-344.
PMID: 32759035 DOI: 10.1016/j.ejmp.2020.07.023

Mentoring aims to improve careers and create benefits for the participants' personal and professional lives. Mentoring can be an individual or a shared experience for a group, while the mentor's role remains the same in both models. Mentors should increase confidence, teach, inspire, and set examples, helping the mentees to mould their path, contributing to the pursuit of their personal and professional goals. This study aims to report on the experience of early-career medical physics professionals and postgraduate students participating in a global mentoring program and to assess the impact of this activity on their professional development. The objectives of this mentoring program are to develop leadership roles among young medical physicists and to provide guidance and support. An online questionnaire was administered to the mentee participants. The analysis of their responses is reported in this work and the current status of the programme was examined using a SWOT analysis. In general, the mentoring experience had a positive impact on the mentees. The mentors were found especially helpful in the decision-making situations and in other conflicts that may arise with career development. Additionally, the mentees felt that mentoring contributed to the development of leadership skills required for the job market and assist in personal development. This paper concludes that participation of young medical physicists in a mentoring group program is beneficial to their career and therefore should be encouraged.
Shear wave elastography accurately detects chronic changes in renal histopathology

Leong SS, Wong JHD, Md Shah MN, Vijayananthan A, Jalalonmuhali M, Chow TK, et al.

Nephrology (Carlton), 2021 Jan;26(1):38-45.
PMID: 33058334 DOI: 10.1111/nep.13805

AIM: Renal biopsy is the gold standard for the histological characterization of chronic kidney disease (CKD), of which renal fibrosis is a dominant component, affecting its stiffness. The aim of this study was to investigate the correlation between kidney stiffness obtained by shear wave elastography (SWE) and renal histological fibrosis.
METHODS: Shear wave elastography assessments were performed in 75 CKD patients who underwent renal biopsy. The SWE-derived estimates of the tissue Young's modulus (YM), given as kilopascals (kPa), were measured. YM was correlated to patients' renal histological scores, broadly categorized into glomerular, tubulointerstitial and vascular scores.
RESULTS: Young's modulus correlates significantly with tubulointerstitial score (ρ = 0.442, P
Comparison of two-dimensional synthesized mammograms versus original digital mammograms: a quantitative assessment

Tan M, Al-Shabi M, Chan WY, Thomas L, Rahmat K, Ng KH

Med Biol Eng Comput, 2021 Feb;59(2):355-367.
PMID: 33447988 DOI: 10.1007/s11517-021-02313-1

This study objectively evaluates the similarity between standard full-field digital mammograms and two-dimensional synthesized digital mammograms (2DSM) in a cohort of women undergoing mammography. Under an institutional review board-approved data collection protocol, we retrospectively analyzed 407 women with digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) examinations performed from September 1, 2014, through February 29, 2016. Both FFDM and 2DSM images were used for the analysis, and 3216 available craniocaudal (CC) and mediolateral oblique (MLO) view mammograms altogether were included in the dataset. We analyzed the mammograms using a fully automated algorithm that computes 152 structural similarity, texture, and mammographic density-based features. We trained and developed two different global mammographic image feature analysis-based breast cancer detection schemes for 2DSM and FFDM images, respectively. The highest structural similarity features were obtained on the coarse Weber Local Descriptor differential excitation texture feature component computed on the CC view images (0.8770) and MLO view images (0.8889). Although the coarse structures are similar, the global mammographic image feature-based cancer detection scheme trained on 2DSM images outperformed the corresponding scheme trained on FFDM images, with area under a receiver operating characteristic curve (AUC) = 0.878 ± 0.034 and 0.756 ± 0.052, respectively. Consequently, further investigation is required to examine whether DBT can replace FFDM as a standalone technique, especially for the development of automated objective-based methods.
Fulltext Modelling knowledge, health beliefs, and health-promoting behaviours related to cardiovascular disease prevention among Malaysian university students

Lim BC, Kueh YC, Arifin WN, Ng KH

PLoS One, 2021;16(4):e0250627.
PMID: 33909664 DOI: 10.1371/journal.pone.0250627

BACKGROUND: Healthy lifestyle habits formed during young adulthood may have a sustaining impact on health across later life. The current study aimed to test the theoretical model of factors (selected demographic variables, knowledge of heart disease, health belief related to cardiovascular disease (CVD), self-efficacy, cues to action, and screening intention) influencing health-promoting behaviours among Malaysian university students.
METHODS: In a cross-sectional survey, the undergraduate students in Universiti Sains Malaysia were invited to complete the self-administered questionnaires. Participants were selected using a purposive sampling method. The proposed hypothesised model was analysed using a structural equation modelling with Mplus 7.3 program. A total of 788 (70.7% female) undergraduate students with a mean age of 20.2 (SD = 1.02) participated in the study. The primary outcome of knowledge, health beliefs, and health-promoting behaviours related to CVD were measured by questionnaires namely: Knowledge of Heart Disease, Health Beliefs Related to CVD, and Health Promoting Lifestyle Profiles-II.
RESULTS: The final hypothetical structural model showed a good fit to the data based on several fit indices: with comparative fit index (CFI) at .921, standardised root mean square residual (SRMR) at .037, and root mean square error of approximation (RMSEA) at .044 (90% CI: .032, .054). The final structural model supported 13 significant path estimates. These variables explained 12% of the total variance in health-promoting behaviours. Through perceived benefits, total knowledge had an indirect effect on health-promoting behaviours.
CONCLUSION: The results suggest that perceived barriers, perceived benefits, family history of CVD, and screening intention enable young adults to engage in health-promoting behaviours.
Fulltext Validation of Health Promoting Lifestyle Profile. II: A confirmatory study with a Malaysian undergraduate students sample

Lim BC, Kueh YC, Arifin WN, Ng KH

Education in Medicine Journal, 2016;8(2):65-77.
MyJurnal

Objective: To determine the factor structure of the Health Promoting Behaviours (HPB) component of Health Promoting Lifestyle Profile-II among undergraduate students in Universiti Sains Malaysia (USM) by confirmatory factor analysis (CFA).
Methods: A cross sectional study was conducted among undergraduate students. The data was collected in the USM campus using a proportionate cluster sampling method. The HPB questionnaire was handed to students in the lecture hall and collected immediately when the lecture finished. CFA was conducted using robust maximum likelihood estimation due to violation of multivariate normality assumption. A three-factor model was tested for measurement model validity and construct validity.
Results: A total of 788 students participated in the study. CFA of a 21-item, three-factor model yielded an adequate goodness-of-fit values. The measurement model also showed a good convergent and discriminant validity after model re-specification.
Conclusion: The health promoting behaviours scale was proven to have a valid measurement model and reliable constructs. It was deemed suitable for use to measure the health promoting behaviours components of a healthy lifestyle among Malaysian undergraduate students. It was recommended to further conduct cross-validation studies in other Malaysian public universities to provide additional empirical evidence to support its use.
Fulltext Mammographic compression in Asian women

Lau S, Abdul Aziz YF, Ng KH

PLoS One, 2017;12(4):e0175781.
PMID: 28419125 DOI: 10.1371/journal.pone.0175781

OBJECTIVES: To investigate: (1) the variability of mammographic compression parameters amongst Asian women; and (2) the effects of reducing compression force on image quality and mean glandular dose (MGD) in Asian women based on phantom study.
METHODS: We retrospectively collected 15818 raw digital mammograms from 3772 Asian women aged 35-80 years who underwent screening or diagnostic mammography between Jan 2012 and Dec 2014 at our center. The mammograms were processed using a volumetric breast density (VBD) measurement software (Volpara) to assess compression force, compression pressure, compressed breast thickness (CBT), breast volume, VBD and MGD against breast contact area. The effects of reducing compression force on image quality and MGD were also evaluated based on measurement obtained from 105 Asian women, as well as using the RMI156 Mammographic Accreditation Phantom and polymethyl methacrylate (PMMA) slabs.
RESULTS: Compression force, compression pressure, CBT, breast volume, VBD and MGD correlated significantly with breast contact area (p<0.0001). Compression parameters including compression force, compression pressure, CBT and breast contact area were widely variable between [relative standard deviation (RSD)≥21.0%] and within (p<0.0001) Asian women. The median compression force should be about 8.1 daN compared to the current 12.0 daN. Decreasing compression force from 12.0 daN to 9.0 daN increased CBT by 3.3±1.4 mm, MGD by 6.2-11.0%, and caused no significant effects on image quality (p>0.05).
CONCLUSIONS: Force-standardized protocol led to widely variable compression parameters in Asian women. Based on phantom study, it is feasible to reduce compression force up to 32.5% with minimal effects on image quality and MGD.
Computer aided diagnosis of Coronary Artery Disease, Myocardial Infarction and carotid atherosclerosis using ultrasound images: A review

Faust O, Acharya UR, Sudarshan VK, Tan RS, Yeong CH, Molinari F, et al.

Phys Med, 2017 Jan;33:1-15.
PMID: 28010920 DOI: 10.1016/j.ejmp.2016.12.005

The diagnosis of Coronary Artery Disease (CAD), Myocardial Infarction (MI) and carotid atherosclerosis is of paramount importance, as these cardiovascular diseases may cause medical complications and large number of death. Ultrasound (US) is a widely used imaging modality, as it captures moving images and image features correlate well with results obtained from other imaging methods. Furthermore, US does not use ionizing radiation and it is economical when compared to other imaging modalities. However, reading US images takes time and the relationship between image and tissue composition is complex. Therefore, the diagnostic accuracy depends on both time taken to read the images and experience of the screening practitioner. Computer support tools can reduce the inter-operator variability with lower subject specific expertise, when appropriate processing methods are used. In the current review, we analysed automatic detection methods for the diagnosis of CAD, MI and carotid atherosclerosis based on thoracic and Intravascular Ultrasound (IVUS). We found that IVUS is more often used than thoracic US for CAD. But for MI and carotid atherosclerosis IVUS is still in the experimental stage. Furthermore, thoracic US is more often used than IVUS for computer aided diagnosis systems.
Genomic recombination in primate bocavirus: inconsistency and alternative interpretations

Chong YL, Ng KH

Virus Genes, 2017 Dec;53(6):774-777.
PMID: 28456924 DOI: 10.1007/s11262-017-1459-6

Human bocavirus (HBoV) is a single-stranded DNA virus in Parvoviridae family, causing respiratory diseases in human. The recent identifications of genomic recombination among the four human bocavirus genotypes and related non-human primate bocaviruses have shed lights into the evolutionary processes underpinning the diversity of primate bocavirus. Among these reports, however, we found inconsistency and possible alternative interpretations of the recombination events. In this study, these recombination events were reviewed, and the related genome sequences were re-analysed, aiming to inform the research community of bocavirus with more consistent knowledge and comprehensive interpretations on the recombination history of primate bocavirus.

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