Displaying publications 1 - 20 of 42 in total

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  1. Hamyoon H, Yee Chan W, Mohammadi A, Yusuf Kuzan T, Mirza-Aghazadeh-Attari M, Leong WL, et al.
    Eur J Radiol, 2022 Dec;157:110591.
    PMID: 36356463 DOI: 10.1016/j.ejrad.2022.110591
    PURPOSE: To develop and validate a machine learning (ML) model for the classification of breast lesions on ultrasound images.

    METHOD: In the present study, three separate data cohorts containing 1288 breast lesions from three countries (Malaysia, Iran, and Turkey) were utilized for MLmodel development and external validation. The model was trained on ultrasound images of 725 breast lesions, and validation was done separately on the remaining data. An expert radiologist and a radiology resident classified the lesions based on the BI-RADS lexicon. Thirteen morphometric features were selected from a contour of the lesion and underwent a three-step feature selection process. Five features were chosen to be fed into the model separately and combined with the imaging signs mentioned in the BI-RADS reference guide. A support vector classifier was trained and optimized.

    RESULTS: The diagnostic profile of the model with various input data was compared to the expert radiologist and radiology resident. The agreement of each approach with histopathologic specimens was also determined. Based on BI-RADS and morphometric features, the model achieved an area under the receiver operating characteristic (ROC) curve (AUC) of 0.885, which is higher than the expert radiologist and radiology resident performances with AUC of 0.814 and 0.632, respectively in all cohorts. DeLong's test also showed that the AUC of the ML protocol was significantly different from that of the expert radiologist (ΔAUCs = 0.071, 95%CI: (0.056, 0.086), P = 0.005).

    CONCLUSIONS: These results support the possible role of morphometric features in enhancing the already well-excepted classification schemes.

  2. Chan WF, Lim MK, Aun LM
    Med J Malaysia, 1974 Sep;29(1):54-6.
    PMID: 4282631
  3. Aad G, Abbott B, Abeling K, Abicht NJ, Abidi SH, Aboulhorma A, et al.
    Phys Rev Lett, 2024 Jan 12;132(2):021803.
    PMID: 38277607 DOI: 10.1103/PhysRevLett.132.021803
    The first evidence for the Higgs boson decay to a Z boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around 140  fb^{-1} for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is 2.2±0.7 times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.
  4. Lim LL, Lau ESH, Ozaki R, Chung H, Fu AWC, Chan W, et al.
    PLoS Med, 2020 10;17(10):e1003367.
    PMID: 33007052 DOI: 10.1371/journal.pmed.1003367
    BACKGROUND: Diabetes outcomes are influenced by host factors, settings, and care processes. We examined the association of data-driven integrated care assisted by information and communications technology (ICT) with clinical outcomes in type 2 diabetes in public and private healthcare settings.

    METHODS AND FINDINGS: The web-based Joint Asia Diabetes Evaluation (JADE) platform provides a protocol to guide data collection for issuing a personalized JADE report including risk categories (1-4, low-high), 5-year probabilities of cardiovascular-renal events, and trends and targets of 4 risk factors with tailored decision support. The JADE program is a prospective cohort study implemented in a naturalistic environment where patients underwent nurse-led structured evaluation (blood/urine/eye/feet) in public and private outpatient clinics and diabetes centers in Hong Kong. We retrospectively analyzed the data of 16,624 Han Chinese patients with type 2 diabetes who were enrolled in 2007-2015. In the public setting, the non-JADE group (n = 3,587) underwent structured evaluation for risk factors and complications only, while the JADE (n = 9,601) group received a JADE report with group empowerment by nurses. In a community-based, nurse-led, university-affiliated diabetes center (UDC), the JADE-Personalized (JADE-P) group (n = 3,436) received a JADE report, personalized empowerment, and annual telephone reminder for reevaluation and engagement. The primary composite outcome was time to the first occurrence of cardiovascular-renal diseases, all-site cancer, and/or death, based on hospitalization data censored on 30 June 2017. During 94,311 person-years of follow-up in 2007-2017, 7,779 primary events occurred. Compared with the JADE group (136.22 cases per 1,000 patient-years [95% CI 132.35-140.18]), the non-JADE group had higher (145.32 [95% CI 138.68-152.20]; P = 0.020) while the JADE-P group had lower event rates (70.94 [95% CI 67.12-74.91]; P < 0.001). The adjusted hazard ratios (aHRs) for the primary composite outcome were 1.22 (95% CI 1.15-1.30) and 0.70 (95% CI 0.66-0.75), respectively, independent of risk profiles, education levels, drug usage, self-care, and comorbidities at baseline. We reported consistent results in propensity-score-matched analyses and after accounting for loss to follow-up. Potential limitations include its nonrandomized design that precludes causal inference, residual confounding, and participation bias.

    CONCLUSIONS: ICT-assisted integrated care was associated with a reduction in clinical events, including death in type 2 diabetes in public and private healthcare settings.

  5. Pan K, Chan W
    Malays Orthop J, 2013 Nov;7(3):21-3.
    PMID: 25674303 MyJurnal DOI: 10.5704/MOJ.1311.003
    Fractures of the femoral shaft treated with interlocking nails will ultimately result in breakage of the nail if the bone does not unite. Further management requires removal of the broken nail which may be a difficult process for the distal segment. If we can identify the symptoms just before the nail breaks, an exchange nailing becomes much easier. We present a patient with fibromatosis who underwent repeated surgery as well as radiotherapy at the age of 16. Six years later, she had a pathological fracture of the upper third of the femur for which an interlocking nail was inserted. The femur did not unite and the nail subsequently broke. Over a period of 12 years, three nails broke and had to be replaced. Two to 3 months before each breakage, the patient experienced the same set of symptoms for each episode. Knowing that her fracture was not going to heal will now alert us to do an exchange nailing before the nail broke again. It is well known that where there is evidence of non-union, pre-emptive treatment is necessary before implant failure.

    KEY WORDS: Femur nonunion, interlocking nail, symptoms before breakage of nail.

  6. Zulkarnaen M, Pan K, Shanmugam P, Ibrahim Z, Chan W
    Malays Orthop J, 2012 Mar;6(1):49-52.
    PMID: 25279044 MyJurnal DOI: 10.5704/MOJ.1203.003
    ABSTRACT: Synovial sarcoma is primarily a soft tissue malignancy that most often affects adolescents and young adults. It very rarely presents as a primary bone tumour and has only been reported in nine other cases to date. We report a case of primary synovial sarcoma arising from the proximal femur in a 57-year-old man.

    KEY WORDS: Synovial sarcoma, primary bone tumour.

  7. Mak JW, Cheong WH, Yen PK, Lim PK, Chan WC
    Acta Trop, 1982 Sep;39(3):237-45.
    PMID: 6128892
    The dynamics of the transmission of subperiodic Brugia malayi in a typical endemic area in Malaysia was studied over a period of 4 years. Mass chemotherapeutic control with diethylcarbamazine citrate was found to be inefficient, new cases being detected even after the fifth treatment cycle of 6 mg/kg X 6 days per cycle. This is in marked contrast to the situation in periodic b. malayi areas where mass treatment efficiently controlled the infection. The disparity in results in these two areas is attributed to zoonotic transmission of subperiodic B. malayi from non-human primates where a mean infection rate of 76.3% was found.
  8. Ong HC, Chan WF
    Cancer, 1978 Apr;41(4):1538-42.
    PMID: 639009
    A study of 207 benign ovarian tumors seen at the University Hospital, Kuala Lumpur between 1968 and 1975 was made to evaluate the clinical features that might be useful in the preoperative differentiation of mucinous cystadenoma, serous cystadenoma, and cystic teratoma of the ovary. This study indicated that the pertinent information included the mean age of the patient, the marital and menstrual status, and the estimated tumor size. The racial background was an additional factor in serous cystadenoma. Features like parity, the location of the tumor, and ABO blood group pattern were of no value in the preoperative differentiation.
  9. Ong HC, Chan WF
    Singapore Med J, 1977 Jun;18(2):100-4.
    PMID: 929220
    Benign cystic teratoma of the ovary has a varied incidence, varying from 30 to 50 per cent of all benign ovarian tumours. This tumour tends to occur in the reproductive age group (20 to 40 years), and the majority of patients are married with children. About 40 per cent of patients are symptomless. Of those with symptoms, abdominal pain and mass are the commonest. Torsion is the most frequent complication encountered, and the presence of acute pain should make one suspect this complication. The tumour is bilateral in 10 to 20 per cent of patients. This high bilateral occurrence places a responsibility on the gynaecologist to inspect the opposite ovary in all cases of unilateral dermoid cyst of the ovary at the time of laparotomy. Germ·layer derivatives are predominantly ectodermal in origin, although both mesodermal and entodermal derivatives occur frequently.
  10. Liong CC, Ravindran S, Gnana Kumar G, Chin EF, Koh PS, Chan WK
    Med J Malaysia, 2016 04;71(2):88-90.
    PMID: 27326953 MyJurnal
    Chronic diarrhoea in tropical countries may be due to a myriad of causes from infective to non-infective. This case report illustrates the challenges faced in the investigation of a middle-age Chinese gentleman who presented with chronic diarrhoea and weight loss. The diagnosis of type II enteropathy-associated T-cell lymphoma (EATL) was finally made. The diagnosis of EATL was least suspected as the condition is almost unheard of in this part of the world. The epidemiology, presentation, diagnosis, management and prognosis of this rare condition are discussed.
  11. Karuthan SR, Koh PS, Chinna K, Chan WK
    Med J Malaysia, 2021 03;76(2):199-204.
    PMID: 33742628
    INTRODUCTION: We aimed to compare the Barcelona Clinic Liver Cancer (BCLC) and Hong Kong Liver Cancer (HKLC) staging systems.

    MATERIALS AND METHODS: This is a retrospective study on patients with newly diagnosed hepatocellular carcinoma (HCC) at the University Malaya Medical Centre between 2011 and 2014. Survival times were analysed using the Kaplan- Meier procedure and comparison between groups was done using the log rank test.

    RESULTS: The data of 190 patients was analysed. Chronic hepatitis B was the most common aetiology for HCC (43.7%), but a large proportion was cryptogenic or non-alcoholic steatohepatitis-related (41.6%). Only 11.1% were diagnosed early (BCLC Stage 0-A) while majority were diagnosed at an intermediate stage (BCLC Stage B, 53.7%). The median survival rate was significantly different between the different groups when either of the staging systems was used (p<0.05 for all comparisons). However, the two staging systems lacked agreement (weighted kappa 0.519, 95%CI: 0.449, 0.589) with significant difference in median survival rates between BCLC Stage A and HKLC Stage 2, and between BCLC Stage C and HKLC Stage 4.

    CONCLUSION: Both staging systems were able to stratify patients according to survival, but they only had moderate agreement with significant differences observed in two groups of the staging systems.

  12. Chan WK
    PMID: 538514
    Industrial development in Malaysia is discussed in relation to impact on health. Trends in Malaysia are evaluated and the findings of some studies in Malaysia are reviewed.
  13. Ab Mumin N, Azman RR, Chan WY
    Med J Malaysia, 2019 Jun;74(3):240-242.
    PMID: 31256183
    In central venous obstruction, vertebral marrow enhancement (VME) may be seen secondary to collateral venous flow via the vertebral venous plexus.1 There are only sporadic case reports on pseudolesions due to collateral enhancement mimicking sclerotic osseous metastasis. This abnormal vertebral enhancement may lead to erroneous diagnosis of sclerotic metastases or suspicious bone lesion which affect the management and prognosis. We describe a case of brachiocephalic vein obstruction-related vertebral body pseudolesions as identified in contrast-enhanced computed tomography (CECT) scan.
  14. Bohan S, Ramli Hamid MT, Poh KS, Chow TK, Chan WY
    Malays J Pathol, 2020 Dec;42(3):461-467.
    PMID: 33361730
    INTRODUCTION: Primary gastrointestinal melanomas are mucosal malignancies that arise from melanocytes in the oropharynx, rectum, and anus. Anorectal malignant melanoma (ARMM) are exceedingly rare, accounting for less than 1% of all melanomas, 0.1% of all rectal malignancies and 4% of anal malignancies. Diagnosis is frequently delayed as these lesions are often mistaken for haemorrhoids. Histological evaluation with special immunohistochemical stains is often necessary for definitive diagnosis. Due to the aggressive nature, 61% of patients with ARMM would already have lymph node involvement or distant metastases, by the time of diagnosis. Prognosis is usually poor with 5-year survival rate of <20%. We report a case of metastatic ARMM in an elderly lady who presented with symptoms and signs mimicking a haemorrhoid.

    CASE REPORT: A 69-year-old lady presented with one year history of intermittent rectal bleed and an anorectal mass that was initially treated as haemorrhoid. Colonoscopy showed a hyperpigmented mass in the anorectal region which was confirmed as malignant melanoma on histopathological examination. Imaging with CT and MRI demonstrated locally advanced tumour with distant metastases to the liver and lung. Patient was referred for palliative management.

    CONCLUSION: ARMM is a rare malignancy and often presented with non-specific clinical signs. Diagnosis is frequently delayed without high index of suspicion. MRI pelvis is the imaging of choice to assess local extent of disease. Histologic evaluation with special immunohistochemical stains is often necessary for definitive diagnosis. Prognosis is poor despite surgical and chemotherapeutic interventions.

  15. Fann RJ, Vidya RR, Chong HE, Indralingam V, Christopher Chan WS
    Med J Malaysia, 2020 01;75(1):52-56.
    PMID: 32008021
    INTRODUCTION: Malaysia is endemic for leptospirosis with increasing incidence recorded over the years. Perak has recorded one of the highest incidence and mortality of leptospirosis since 2004.

    METHODS: This is a retrospective study of confirmed leptospirosis cases in Larut, Matang and Selama (LMS) district in Perak reported in 2016. The demographic, clinical presentation, laboratory result and clinical outcomes data were analysed and presented.

    RESULTS: Forty-two patients with confirmed diagnosis of leptospirosis were included into the study. Majority of patients were males and Malays. The case fatality rate was 14.3%. Patients with leptospirosis present with variable clinical presentations and are commonly seen with coinfection. Patients 70-year-old and older, have clinical presentations suggestive of organ dysfunction and require intensive care are associated with higher mortality.

    CONCLUSION: Leptospirosis is endemic in LMS district of Perak with high incidence and case fatality rate. The clinical presentation of leptospirosis is variable. Co-infection of leptospirosis with other acute febrile illness is common. Patients presenting with symptoms and signs of organ dysfunctions or require intensive care are associated with an increased odds of death.

  16. Sahdi H, Chan WH, Dollah NB, Entri A
    Malays Orthop J, 2018 Nov;12(3):43-46.
    PMID: 30555646 MyJurnal DOI: 10.5704/MOJ.1811.011
    Acquired radial clubhand deformity can be a consequence of large bone gap left by premature extensive radius osteomyelitis sequestrectomy. Single-bone forearm reconstruction is a salvage procedure when other motion-preserving techniques are not feasible. Here we present a child who developed radial clubhand deformity after an untimely sequestrectomy of radius diaphysis. In view of limited microsurgical expertise in our centre, single-bone forearm procedure was done utilising simple Kirshner wires to achieve radio-ulnar fusion. The procedure resulted in pain-free stable wrist, restoration of hand function and improved cosmesis.
  17. Naicker AS, Roohi SA, Lee CS, Chan WH, Tay LS, Din XJ, et al.
    Med J Malaysia, 2006 Feb;61 Suppl A:10-3.
    PMID: 17042221
    Poor glycaemic control and the duration of diabetes mellitus are known to accelerate development and progression of neuropathy. Diabetic co-morbidities: hypertension and hyperlipidaemia, have been postulated to associate with development of neuropathy. A diabetic foot with low temperature and frequent exposure to low temperature environment has recently been hypothesized to be at higher risk to develop early neuropathy. This cross-sectional study is undertaken to identify risk factors for diabetic neuropathy and the association between foot temperature and development of diabetic neuropathy by using simple clinical examination in the outpatient setting. From April 18, to April 30, 2005, universal sampling method was used to select 134 diabetic patients (type 1 or type 2 for >1 year) with peripheral neuropathy. Excluded are those with chronic alcoholism, drug-induced neuropathy, dietary history of vitamin B deficiency and family history of porphyria and hereditary sensorimotor neuropathy. The patient's duration of diabetes, glycaemic control status and the presence of co-morbids: hypertension and hyperlipidemia, were recorded. The temperature of the foot was measured by using thermo buddy. Of 134 patients representing Malaysian ethnic distribution with an equal number of males and females, 20.1% were in the age group of 61 to 65 years and, 85.1% and 67.9% belonged to lower socioeconomic and educational groups respectively. Associations between diabetic neuropathy and glycaemic control (p = 0.018) and duration of diabetes (p < 0.05) were significant. However, hypertension, hyperlipidaemia and low foot temperature were not significantly associated with development of diabetic neuropathy. Poor glycaemic control is significantly associated with diabetic neuropathy. Foot temperature alteration is merely an effect of autonomic neuropathy with a cold foot is attributed to co-existing peripheral arterial disease.

    Study site: Pusat Perubatan Primer Bandar Tasik Selatan, Kuala Lumpur, Malaysia
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