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Lung Nodule Classification using Deep Local-Global Networks [article]

Mundher Al-Shabi, Boon Leong Lan, Wai Yee Chan, Kwan-Hoong Ng, Maxine Tan
2019 arXiv   pre-print
Purpose: Lung nodules have very diverse shapes and sizes, which makes classifying them as benign/malignant a challenging problem. In this paper, we propose a novel method to predict the malignancy of nodules that have the capability to analyze the shape and size of a nodule using a global feature extractor, as well as the density and structure of the nodule using a local feature extractor. Methods: We propose to use Residual Blocks with a 3x3 kernel size for local feature extraction, and
more » ... al Blocks to extract the global features. The Non-Local Block has the ability to extract global features without using a huge number of parameters. The key idea behind the Non-Local Block is to apply matrix multiplications between features on the same feature maps. Results: We trained and validated the proposed method on the LIDC-IDRI dataset which contains 1,018 computed tomography (CT) scans. We followed a rigorous procedure for experimental setup namely, 10-fold cross-validation and ignored the nodules that had been annotated by less than 3 radiologists. The proposed method achieved state-of-the-art results with AUC=95.62%, while significantly outperforming other baseline methods. Conclusions: Our proposed Deep Local-Global network has the capability to accurately extract both local and global features. Our new method outperforms state-of-the-art architecture including Densenet and Resnet with transfer learning.
arXiv:1904.10126v1 fatcat:7vcoczjj2vahja76l6x2wgdltq

Mammographic compression in Asian women

Susie Lau, Yang Faridah Abdul Aziz, Kwan Hoong Ng, Pei-Yi Chu
2017 PLoS ONE  
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
more » ... ensity (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).
doi:10.1371/journal.pone.0175781 pmid:28419125 pmcid:PMC5395189 fatcat:mxho2yojwbgrhezg4acnxvej6m

Diagnostic Radiology in the Tropics: Technical Considerations

Kwan-Hoong Ng, Ian Mclean
2011 Seminars in Musculoskeletal Radiology  
information for each piece of equipment should include the name, manufacturer, and serial number; dates of acquisition and installation; instruction manual; acceptance DIAGNOSTIC RADIOLOGY IN THE TROPICS/NG  ... 
doi:10.1055/s-0031-1293490 pmid:22081279 fatcat:u6bcexnwafhddgcglrffbwelbe

Hearing loss after noise exposure

Revadi Govindaraju, Rahmat Omar, Raman Rajagopalan, Ramli Norlisah, Ng Kwan-Hoong
2011 Auris, nasus, larynx  
The higher field strength magnetic resonance imaging (MRI) such as 3 Tesla (T) and above generates noise that has potential detrimental effects on the hearing. Temporary threshold shifts following MRI examination have been reported for MRI with lower field strength. Such effect, however, have not been reported so far for a 3 T MRI. We report a case that exemplifies the possible detrimental effects of a 3 T MRI generated noise on the auditory system. Our patient underwent investigation of his
more » ... onic backache in a 3 T MRI unit and developed hearing loss and tinnitus post-MRI examination. Hearing assessment was done using pure tone audiogram, distortion product otoacoustic emission (DPOAE) and brainstem electrical response audiometry (BERA) which revealed a unilateral sensorineural hearing loss which recovered within 3 days. However the tinnitus persisted. This is possibly a case of temporary threshold shift following noise exposure. However a sudden sensorineural hearing loss remains the other possibility. #
doi:10.1016/j.anl.2010.12.006 pmid:21236610 fatcat:oqa33b4qw5gljifgzi5l75jjie

Prejudice in science – Lessons from the coronavirus story

Kwan Hoong Ng, Eva Bezak
2020 Physica medica (Testo stampato)  
In the current pandemic times, medical physicists may not be aware that there is an interesting story on two significant discoveries related to the coronavirus. One is the invention of the polymerase chain reaction (PCR) and the other is the first electron microscopic observation and identification of the coronavirus. Both of them were disregarded by the reviewers and major journals declined to publish these discoveries. These days, PCR, for example, is a widespread method for analyzing DNA,
more » ... ing a profound effect on healthcare, especially now during the Covid-19 pandemic. Prejudice or perhaps ignorance prevail in every aspect of our society, and there is no exception in scientific research. We need to, however, learn from these two stories and be open-minded about novel discoveries and findings - as they may be just disruptive in the "right" way to lead to an unexpected breakthrough.
doi:10.1016/j.ejmp.2020.06.011 pmid:32559649 pmcid:PMC7284236 fatcat:nmlgg3notzguhdfmjwt3mgbeuy

International Collaboration in Journal Publishing

Wah-Yun Low, Kwan-Hoong Ng
2011 Asia-Pacific journal of public health  
We were invited to present a paper at the First Asia Pacific Association for Medical Journal Editors (APAME: conference held last month in Seoul, Korea, and we were amazed as to the status of scientific publications in this region. There is fierce competition between higher learning institutions and universities and both alike are aggressively targeting themselves for a place in reputable and high-impact scientific journals, namely for the incentives and status that come
more » ... ong with it and the push for a higher ranking for their institutions in the global arena. International collaboration in research and journal publishing is something that we need to seriously think about, particularly in our region, where resources are scarce and we do need to compensate these from elsewhere. We summarize the key points of our presentation here. Because of globalization and the rapid development of information technology and scientific communication, international cooperation in public health activities has been intensified to further promote public health. Where scientific research is becoming more global in nature, journal visibility is a must in this age of information, communication, and technological (ICT) advancement and in view of globalization. There is greater emphasis on elevating journals to a higher level and thus a dire need for good research and high-quality publication. However, many journals in this region are of varying quality, resulting in competition for high-quality articles. Some of the problems that journals are facing include finance, peer review system, journal management, and operation guidelines; these have to be addressed in order for us to compete with more established journals from advanced countries. The other problems include the rather low representation of regional journals, including biomedical journals, in international indexing databases. Language issue and the lack of research culture have also compounded the problems of high-quality research and publication. Because of financial constraint, there is a need to collaborate and share experiences and resources at the regional level and thus to compensate for these, resources from overseas need to be sought. Collaboration is also needed with regard to training for editors, reviewers, researchers, and educators, and such international collaboration helps researchers improve the quality of their publication in reputable international scientific journals. Taking advantage of the Internet technology and Web-based social networks is crucial for international collaboration in research and publication. Social networking among scientists and researchers should be seen as an outreach tool particularly in the cyber infrastructure and e-science. 1 As for citation, it has been shown that publications stemming from international collaborative
doi:10.1177/1010539511424481 pmid:21984491 fatcat:stapo6sy4rd2pkjxon6ax3xu4y

Understanding and reducing the fear of COVID-19

Kwan Hoong Ng, Ray Kemp
2020 Journal of Zhejiang University SCIENCE B  
Compliance with ethics guidelines Kwan Hoong NG and Ray KEMP declare that they have no conflict of interest.  ...  Contributors Both Kwan Hoong NG and Ray KEMP have taken part equally in the conception, drafting, editing, and approval of the final article. Fig. 1 1 Vicious circle of fear and panic  ... 
doi:10.1631/jzus.b2000228 pmid:32893533 pmcid:PMC7301038 fatcat:nuxhxvjwifhrvit4xe3hyxsgvq

Medical Physics Contributes to The Advancement in Medicine

Kwan Hoong Ng, Jeannie Hsiu Ding Wong, Chai Hong Yeong, Hafiz Mohd Zin, Noriah Jamal
2021 ASM Science Journal  
et al., 2009; Ng, 2008) .  ...  diagnostic imaging physics, nuclear medicine physics, radiation oncology physics, medical health physics (radiation protection), non-ionising radiation physics and physiological measurement (IOMP, 2012; Ng  ... 
doi:10.32802/asmscj.2020.505 fatcat:de5x4dvl5vfl7juocn4kyy4yxu

Radiation Safety in Emergency Medicine: Balancing the Benefits and Risks

Raja Rizal Azman, Mohammad Nazri Md Shah, Kwan Hoong Ng
2019 Korean Journal of Radiology  
The use of computed tomography (CT) in emergency departments has increased over several decades, as physicians increasingly depend on imaging for diagnoses. Patients and medical personnel are put at risk due to frequent exposure to and higher levels of radiation, with very little evidence of improvements in outcomes. Here, we explore why CT imaging has a tendency to be overused in emergency departments and the obstacles that medical personnel face in ensuring patient safety. The solution
more » ... s cooperation from all emergency care stakeholders as well as the continuous education of doctors on how CT scans help in particular cases.
doi:10.3348/kjr.2018.0416 pmid:30799570 pmcid:PMC6389812 fatcat:27u6mcueazf2baln22utt3usmu

Therapeutic radionuclides in nuclear medicine: current and future prospects

Chai-Hong Yeong, Mu-hua Cheng, Kwan-Hoong Ng
2014 Journal of Zhejiang University SCIENCE B  
Compliance with ethics guidelines Chai-Hong YEONG, Mu-hua CHENG, and Kwan-Hoong NG declare that they have no conflict of interest.  ...  Kwan-Hoong NG, the author of this invited review, is an editorial board member of Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology) . Dr.  ...  Ng is a professor at the Department of Biomedical Imaging, University of Malaya, Malaysia. He is certified by the American Board of Medical Physicist.  ... 
doi:10.1631/jzus.b1400131 pmid:25294374 pmcid:PMC4201313 fatcat:x5xvx67mszbapaaik2ytvkmu7a

Volumetric breast density measurement: sensitivity analysis of a relative physics approach

Susie Lau, Kwan Hoong Ng, Yang Faridah Abdul Aziz
2016 British Journal of Radiology  
Volumetric breast density measurement: sensitivity analysis of a relative physics approach. Br J Radiol 2016; 89: 20160258. Gaussian noise was generated and introduced into the original images. Results: Errors in filter thickness, mAs, detector gain and offset had limited effects on FGV, BV and VBD. Significant effects in VBD were observed when CBT, kVp, detector offset and image noise were varied (p , 0.0001). Maximum shifts in the mean (1.2%) and median (1.1%) VBD of the study population
more » ... red when CBT was varied. Conclusion: Volpara was robust to expected clinical variations, with errors in most investigated parameters giving limited changes in results, although extreme variations in CBT and kVp could lead to greater errors. Advances in knowledge: Despite Volpara's robustness, rigorous quality control is essential to keep the parameter errors within reasonable bounds. Volpara appears robust within those bounds, albeit for more advanced applications such as tracking density change over time, it remains to be seen how accurate the measures need to be. CBT, compressed breast thickness; CI, confidence interval; kVp, tube voltage; mAs, tube current-exposure time product; N, total number of subject. Full paper: VBD measurement: sensitivity analysis of a relative physics approach BJR
doi:10.1259/bjr.20160258 pmid:27452264 pmcid:PMC5124801 fatcat:5tglxk7ppncjnd2u3q7pmqrxiu

A review on the accuracy of bladder cancer detection methods

Chao-Zhe Zhu, Hua-Nong Ting, Kwan-Hoong Ng, Teng-Aik Ong
2019 Journal of Cancer  
Hua-Nong Ting, Kwan-Hoong Ng and Teng-Aik Ong revised the manuscript. Competing Interests The authors have declared that no competing interest exists.  ... 
doi:10.7150/jca.28989 pmid:31417648 pmcid:PMC6692607 fatcat:pl5wwdw4pfan5nk27qdnc6vyx4

Evaluation of conventional and computerised monitoring of cardiac function in the coronary care unit

Ng Kwan Hoong
1983 The Medical journal of Malaysia  
Fig. 2 2 Block diagram of a computerised patient monitoring system with facilities for automatic and manual data entry. 4 ) . ) Ng Kwan Hoong, BSc (Hons), MSc, MIPM School of Arts and Science Tunku Abdul  ... 
pmid:6599984 fatcat:csrzmahk5nhpxgacvy2rccrbdy

A Model for Online Interactive Remote Education for Medical Physics Using the Internet

Milton K Woo, Kwan-Hoong Ng
2003 Journal of Medical Internet Research  
doi:10.2196/jmir.5.1.e3 pmid:12746208 pmcid:PMC1550549 fatcat:tsyf45yusza2jiglkq62rgo3qm

Automated diagnosis of epileptic EEG using entropies

U. Rajendra Acharya, Filippo Molinari, S. Vinitha Sree, Subhagata Chattopadhyay, Kwan-Hoong Ng, Jasjit S. Suri
2012 Biomedical Signal Processing and Control  
Epilepsy is a neurological disorder characterized by the presence of recurring seizures. Like many other neurological disorders, epilepsy can be assessed by the electroencephalogram (EEG). The EEG signal is highly non-linear and non-stationary, and hence, it is difficult to characterize and interpret it. However, it is a well-established clinical technique with low associated costs. In this work, we propose a methodology for the automatic detection of normal, pre-ictal, and ictal conditions
more » ... recorded EEG signals. Four entropy features namely Approximate Entropy (ApEn), Sample Entropy (SampEn), Phase Entropy 1 (S1), and Phase Entropy 2 (S2) were extracted from the collected EEG signals. These features were fed to seven different classifiers: Fuzzy Sugeno Classifier (FSC), Support Vector Machine (SVM), K-Nearest Neighbour (KNN), Probabilistic Neural Network (PNN), Decision Tree (DT), Gaussian Mixture Model (GMM), and Naive Bayes Classifier (NBC). Our results show that the Fuzzy classifier was able to differentiate the three classes with a high accuracy of 98.1%. Overall, compared to previous techniques, our proposed strategy is more suitable for diagnosis of epilepsy with higher accuracy.
doi:10.1016/j.bspc.2011.07.007 fatcat:dbo5rgphwfczjm2k55fkh3nrlu
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