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Introduction Chest radiographs (CXR) are widely used for the screening and management of the coronavirus disease 2019 (COVID-19). This paper determinates the radiographic features of COVID-19 based on an initial national cohort of patients. Methods This is a retrospective review of swab-positive COVID-19 patients admitted to four different hospitals in Singapore between 22 January and 9 March 2020. Initial and follow-up CXR were reviewed by three experienced radiologists to identify the predominant pattern and distribution of lung parenchymal abnormalities. Results In total, 347 CXR of 96 patients were reviewed. Initial CXR were abnormal in 41 out of 96 patients (42.7%). The mean time from onset of symptoms to CXR abnormality was 5.3 (range 1-21) days. The predominant pattern of lung abnormality was ground-glass opacity on initial CXR (51.2%) and consolidation on follow-up CXR (51.0%). Multifocal bilateral abnormalities in mixed central and peripheral distribution were seen in 63.4% and 59.2% of abnormal initial and follow-up CXR, respectively. The lower zones were involved in 90.2% of the initial CXR and 93.9% of the follow-up CXR. Conclusion In a cohort of swab-positive patients, including those identified from contact tracing, we found the incidence of CXR abnormality to be lower than previously reported. The most common pattern was ground-glass opacity or consolidation, but mixed central and peripheral involvement was more common than peripheral involvement alone.

Patient: Male, 77-year-old Final Diagnosis: COVID-19 pneumonia Symptoms: Cough • shortness of breath Medication:— Clinical Procedure: — Specialty: Radiology Objective: Challenging differential diagnosis Background: Coronavirus disease 2019 (COVID-19) is caused by a novel coronavirus, SARS-CoV-2, and is associated with severe respiratory disease. There are extensive publications on the chest computed tomography (CT) findings of COVID-19 pneumonia, with ground-glass opacities (GGO) and mixed GGO and consolidation being the most common findings. Those with interstitial thickening manifesting as reticular opacities typically show superimposed ground-glass opacities, giving a crazy-paving pattern. Case Report: We report the case of a 77-year-old man with a background of asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) who presented with progressive cough and shortness of breath for 2 days. He was in close contact with a confirmed COVID-19 case. Reverse-transcription polymerase chain reaction analysis of a nasopharyngeal swab was positive for SARS-CoV-2. The initial chest radiograph was negative for lung consolidation and ground-glass opacities. During admission, he had worsening shortness of breath with desaturation, prompting a chest CT examination, which was performed on day 14 of illness. The chest CT revealed an atypical finding of predominant focal subpleural interstitial thickening in the right lower lobe. He was provided supportive treatment along with steroid and antibiotics. He recovered well and subsequently tested negative for 2 consecutive swabs. He was discharged after 34 days. Conclusions: Interstitial thickening or reticular pattern on CT has been described in COVID-19 pneumonia, but largely in association with ground-glass opacity or consolidation. This case demonstrates an atypical predominance of interstitial thickening on chest CT in COVID-19 pneumonia on day 14 of illness, which is the expected time of greatest severity of the disease.

BACKGROUND: Chest radiography (CXR) is performed more widely and readily than CT for the management of coronavirus disease (COVID-19), but there remains little data on its clinical utility. This study aims to assess the diagnostic performance of CXR, with emphasis on its predictive value, for severe COVID-19 disease. METHODS: A retrospective cohort study was conducted, 358 chest radiographs were performed on 109 COVID-19 patients (median age 44.4 years, 58 males and 30 with comorbidities) admitted between 22 January 2020 and 15 March 2020. Each CXR was reviewed and scored by three radiologists in consensus using a 72-point COVID-19 Radiographic Score (CRS). Disease severity was determined by the need for supplemental oxygen and mechanical ventilation. RESULTS: Patients who needed supplemental oxygen (n=19, 17.4%) were significantly older (P

Background To determine the utility of chest radiography (CXR) for assessing and prognosticating COVID-19 disease with an objective radiographic scoring system.Methods A multicenter, prospective study was conducted, forty patients were included. Seventy-eight CXR’s were performed on the first derivation cohort of twenty patients with COVID-19 (median age 47.5 years, 10 females and four with comorbidities) admitted between 22 January 2020 and 1 February 2020. Each CXR was scored by three radiologists in consensus and graded on a 72-point COVID-19 Radiographic Score (CRS). This was correlated with supplemental oxygen requirement, C-reactive protein (CRP), lactate dehydrogenase (LDH) and lymphocyte count. To validate our findings, the parameters of another validation cohort of twenty patients with 65 CXRs were analysed.Results In the derivation cohort, seven patients needed supplemental oxygen and one was intubated for mechanical ventilation with no death. The maximum CRS was significantly different between patients on and not on supplemental oxygen (p=Conclusion Using an objective scoring system (CRS), the degree of abnormalities on CXR correlates closely with known markers of disease severity. CRS may further be applied to predict patients who require oxygen supplementation during the course of their disease.

The coronavirus disease 2019 (COVID-19) is typically diagnosed by specific assays that detect viral nucleic acid from the upper respiratory tract; however, this may miss infections involving only the lower airways. Computed tomography (CT) has been described as a diagnostic modality in the COVID-19 diagnosis and treatment plan. We present a case series with virologically confirmed COVID-19 pneumonia. Variable CT features were observed: consolidation with ground-glass opacities, ground-glass opacities with subpleural reticular bands, and an anterior-posterior gradient of lung abnormalities resembling that of acute respiratory distress syndrome. Evolution of CT findings was observed in one patient, where there was interval resolution of bilateral lung consolidation with development of bronchiolectasis and subpleural fibrotic bands. While sensitive for detecting lung parenchymal abnormalities in COVID-19 pneumonia, the use of CT for initial diagnosis is discouraged and should be reserved for specific clinical indications. Interpretation of chest CT findings should be correlated with duration of symptoms to better determine the disease stage and aid in patient management. Published version

Lung cancer is the leading cause of cancer-related death around the world, being the top cause of cancer-related deaths among men and the second most common cause of cancer-related deaths among women in Singapore. Currently, no screening programme for lung cancer exists in Singapore. Since there is mounting evidence indicating a different epidemiology of lung cancer in Asian countries, including Singapore, compared to the rest of the world, a unique and adaptive approach must be taken for a screening programme to be successful at reducing mortality while maintaining cost-effectiveness and a favourable risk-benefit ratio. This review article promotes the use of low-dose computed tomography of the chest and explores the radiological challenges and future directions.

The Ministry of Health (MOH) has developed the clinical practice guidelines on Prevention, Diagnosis and Management of Tuberculosis to provide doctors and patients in Singapore with evidence-based treatment for tuberculosis. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Prevention, Diagnosis and Management of Tuberculosis, for the information of SMJ readers. The chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov.sg/content/moh_web/healthprofessionalsportal/doctors/guidelines/cpg_medical.html. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

We assessed the accuracy of 64-slice multidetector computed tomography (MDCT) compared with that of invasive coronary angiography (ICA) in the evaluation of symptomatic postcoronary artery bypass graft (post-CABG) patients.MDCT and ICA were performed in 44 consecutive post-CABG patients with chest pain (mean age 66 +/- 10 years, mean duration post-CABG 9 +/- 5 years). MDCT findings were compared with the corresponding ICA, which was read by an interventional cardiologist blinded to the MDCT findings. Significant stenosis was defined as at least 50% luminal stenosis.One hundred and thirty-seven grafts (31 arterial and 106 venous), all evaluable by MDCT, were assessed. In a 'per graft' analysis, MDCT could detect significant disease in bypass grafts (graft occlusion or stenosis) with a sensitivity of 98% and specificity of 98%. In a 'per segment' analysis, MDCT could detect significant disease in all native coronary arteries with a sensitivity of 91% and specificity of 79% and in clinically relevant native coronary arteries with a sensitivity of 92% and specificity of 84%. In a 'per vessel' analysis, MDCT could differentiate native arterial occlusion from nonocclusive stenosis with a sensitivity of 68% and specificity of 70%. In a 'per patient' analysis, MDCT could detect significant disease in bypass grafts or clinically relevant native coronary arteries with a sensitivity of 100%, specificity of 40% and accuracy of 93%.Sixty-four-slice MDCT allows evaluation of bypass grafts and native coronary arteries in post-CABG patients. Although accurate for detecting bypass graft disease, 64-slice MDCT has significant limitations when evaluating native arteries in post-CABG patients.

Breast cancer is the most frequently occurring malignancy in women. It is characterized by a high mortality rate. For the purpose of detecting this life threatening disease, research efforts are being made worldwide to exploit new technologies, to improve the detection accuracy of current devices and to develop new detection devices, comprehensive diagnostic procedures, and protocols. One such technology that is gaining popular attention over the recent years is the usage of electrical characteristics of the breast tissue to differentiate normal and cancerous tissues. Most of the devices using this technology are currently being used as adjunct diagnostic tools to improve the detection accuracy of established techniques like mammography and ultrasound. Also, early detection of breast cancer can help save many thousands of lives every year and can also reduce unnecessary healthcare expenditure caused by advanced stage treatment options. Hence, more research is also being done to adapt these devices into screening tools for early detection of breast cancer. The main objective of this review is to highlight the features of the currently available commercial devices that use this technology for breast cancer detection. The electrical behavior of normal and cancerous breast tissues is first presented. The various commercial devices that utilize electrical impedance or electropotentials for breast cancer detection are then described. Finally, conclusions and potential areas of research are highlighted.

Study objectives To characterize the long-term pulmonary function and health status in a prospectively identified cohort of patients who survived the severe acute respiratory syndrome (SARS). Design Prospective follow-up cohort study. Setting University-affiliated hospital. Patients Ninety-four patients who recovered from SARS were assessed at a uniform time point of 1 year after hospital discharge. Measurements The study included the measurement of static and dynamic lung volumes, the determination of the diffusing capacity of the lung for carbon monoxide (Dlco), and a health status evaluation using the St. George Respiratory Questionnaire (SGRQ). Results Eleven patients (12%) had mild impairment of FVC, 20 (21%) had mild impairment of FEV1, 5 (5%) had mild impairment of the FEV1/FVC ratio, and 17 (18%) had mild impairment of the Dlco. There was one patient (1%) who had moderate impairment of FVC, one patient (1%) who had moderate impairment of the FEV1/FVC ratio, and three patients (3%) who had moderate impairment of the Dlco. No pulmonary function abnormalities were detected in 59 patients (63%). Mean scores were significantly higher (ie, worse) than the population norms in the activity (p < 0.001), impacts (p < 0.001), and total (p < 0.001) domains of the SGRQ. Conclusions One year after recovery from SARS, persistent pulmonary function impairment was found in about one third of patients. The health status of SARS survivors was also significantly worse compared with the healthy population. The main determinants of morbidity in recovered SARS patients need to be further defined.

Summary Objective Following the severe acute respiratory syndrome (SARS) outbreak, many survivors were observed to suffer from psychosomatic symptoms reminiscent of various endocrine disorders. Hence, we sought to determine the existence of any chronic endocrine sequelae in SARS survivors. Design, patients, measurements Sixty-one survivors of SARS prospectively recruited were analysed for hormonal derangements 3 months following recovery. Patients with pre-existing endocrine disorders were excluded. Any endocrine abnormalities diagnosed were investigated and treated where indicated up to a year. Serial evaluation facilitated characterization of trends and prognostication of any endocrinological aberrations. Results Twenty-four (39·3%) patients had evidence of hypocortisolism. The hypothalamic–pituitary–adrenal (HPA) axis dysfunction of the majority resolved within a year. Two (3·3%) of the hypocortisolic cohort had transient subclinical thyrotoxicosis. Four (6·7%) were biochemically hypothyroid, being comprised of three with central hypothyroidism and one with primary hypothyroidism. Two of the three with central hypothyroidism had concomitant central hypocortisolism. Eight had subnormal DHEAS levels. Conclusions These preliminary findings highlight a possible aetiologic role of SARS-associated coronavirus in causing a reversible hypophysitis or direct hypothalamic effect, with the HPA axis affected more frequently than the HPT axis.

Severe Acute Respiratory Syndrome (SARS) is a highly infectious disease caused by a coronavirus. Screening to detect potential SARS infected subject with elevated body temperature plays an important role in preventing the spread of SARS. The use of infrared (IR) thermal imaging cameras has thus been proposed as a non-invasive, speedy, cost-effective and fairly accurate means for mass blind screening of potential SARS infected persons. Infrared thermography provides a digital image showing temperature patterns. This has been previously utilized in the detection of inflammation and nerve dysfunctions. It is believed that IR cameras may potentially be used to detect subjects with fever, the cardinal symptom of SARS and avian influenza. The accuracy of the infrared system can, however, be affected by human, environmental, and equipment variables. It is also limited by the fact that the thermal imager measures the skin temperature and not the body core temperature. Thus, the use of IR thermal systems at various checkpoints for mass screening of febrile persons is scientifically unjustified such as what is the false negative rate and most importantly not to create false sense of security. This paper aims to study the effectiveness of infrared systems for its application in mass blind screening to detect subjects with elevated body temperature. For this application, it is critical for thermal imagers to be able to identify febrile from normal subjects accurately. Minimizing the number of false positive and false negative cases improves the efficiency of the screening stations. False negative results should be avoided at all costs, as letting a SARS infected person through the screening process may result in potentially catastrophic results. Hitherto, there is lack of empirical data in correlating facial skin with body temperature. The current work evaluates the correlations (and classification) between the facial skin temperatures to the aural temperature using the artificial neural network approach to confirm the suitability of the thermal imagers for human temperature screening. We show that the Train Back Propagation and Kohonen self-organizing map (SOM) can form an opinion about the type of network that is better to complement thermogram technology in fever diagnosis to drive a better parameters for reducing the size of the neural network classifier while maintaining good classification accuracy.

Background Severe acute respiratory syndrome (SARS) is a recently recognized condition of viral origin associated with substantial morbidity and mortality rates in adults. Little information is available on its radiologic manifestations in children. Objective The goal of this study was to characterize the radiographic presentation of children with SARS. Materials and methods We abstracted data (n=62) on the radiologic appearance and course of SARS in pediatric patients with suspect (n=25) or probable (n=37) SARS, diagnosed in five hospital sites located in three cities: Toronto, Singapore, and Hong Kong. Available chest radiographs and thoracic CTs were reviewed for the presence of the following radiographic findings: airspace disease, air bronchograms, airways inflammation and peribronchial thickening, interstitial disease, pleural effusion, and hilar adenopathy. Results A total of 62 patients (suspect=25, probable=37) were evaluated for SARS. Patient ages ranged from 5.5 months to 17 years and 11.5 months (average, 6 years and 10 months) with a female-to-male ratio of 32:30. Forty-one patients (66.1%) were in close contact with other probable, suspect, or quarantined cases; 10 patients (16.1%) had recently traveled to WHO-designated affected areas within 10 days; and 7 patients (11.2%) were transferred from other hospitals that had SARS patients. Three patients, who did not have close/hospital contact or travel history to affected areas, were classified as SARS cases based on their clinical signs and symptoms and on the fact that they were living in an endemic area. The most prominent clinical presentations were fever, with a temperature over 38 °C (100%), cough (62.9%), rhinorrhea (22.6%), myalgia (17.7%), chills (14.5%), and headache (11.3%). Other findings included sore throat (9.7%), gastrointestinal symptoms (9.7%), rigor (8.1%), and lethargy (6.5%). In general, fever and cough were the most common clinical presentations amongst younger pediatric SARS cases (age

Severe acute respiratory syndrome, or SARS, is a new infectious disease pandemic with important public health concerns. The high infectivity rate by means of droplet transmission places health care workers at substantial risk of contracting the disease. Radiology departments are particularly affected, since imaging plays a vital role in both diagnosis and follow-up of this disease. The authors outline their experience in infection control and isolation procedures during this outbreak. Barrier precautions, reconfiguration of the department, separation of imaging equipment, cleaning procedures, personal protective equipment, and staff safety are discussed.

Background Severe acute respiratory syndrome (SARS) is a major infectious disease pandemic that occurred in early 2003, and one of the diagnostic criteria is the presence of chest radiographic findings. Objective To describe the radiographic features of SARS in a cluster of affected children. Materials and methods The chest radiographs of four related children ranging in age from 18 months to 9 years diagnosed as having SARS were reviewed for the presence of air-space shadowing, air bronchograms, peribronchial thickening, interstitial disease, pleural effusion, pneumothorax, hilar lymphadenopathy and mediastinal widening. Results Ill-defined air-space shadowing was the common finding in all the children. The distribution was unifocal or multifocal. No other findings were seen on the radiographs. None of the children developed radiographic findings consistent with acute respiratory distress syndrome. All four children showed significant resolution of the radiographic findings 4–6 days after the initial radiograph. Conclusions Early recognition of these features is important in implementing isolation and containment measures to prevent the spread of infection. SARS in children appears to manifest as a milder form of the disease as compared to adults.

The division of breast cancer cells results in regions of electrical depolarisation within the breast. These regions extend to the skin surface from where diagnostic information can be obtained through measurements of the skin surface electropotentials using sensors. This technique is used by the Biofield Diagnostic System (BDS) to detect the presence of malignancy. This paper evaluates the efficiency of BDS in breast cancer detection and also evaluates the use of classifiers for improving the accuracy of BDS. 182 women scheduled for either mammography or ultrasound or both tests participated in the BDS clinical study conducted at Tan Tock Seng hospital, Singapore. Using the BDS index obtained from the BDS examination and the level of suspicion score obtained from mammography/ultrasound results, the final BDS result was deciphered. BDS demonstrated high values for sensitivity (96.23%), specificity (93.80%), and accuracy (94.51%). Also, we have studied the performance of five supervised learning based classifiers (back propagation network, probabilistic neural network, linear discriminant analysis, support vector machines, and a fuzzy classifier), by feeding selected features from the collected dataset. The clinical study results show that BDS can help physicians to differentiate benign and malignant breast lesions, and thereby, aid in making better biopsy recommendations.

The purpose of this study is to evaluate the efficiency of the Biofield Diagnostic System (BDS) as an adjunct to established diagnostic techniques such as mammography and ultrasound in differentiating benign and malignant breast lesions. The clinical trial was conducted at the Tan Tock Seng hospital, Singapore. 103 women scheduled for mammography and/or ultrasound tests participated in the study. The BDS test recorded a sensitivity of 100%, specificity of 97.6%, and an accuracy of 98.1%. The area under the ROC curve was 0.988 which was slightly lower than that of ultrasound (0.994) and slightly higher than that of mammography (0.951). The BDS test has demonstrated high sensitivity and specificity values in the studied population. The accuracy is also comparable to that of diagnostic techniques like mammography and ultrasound. Thus, it is evident that BDS can be a fast and reliable adjunct tool for getting a secondary opinion on lesions with indeterminate mammographic and sonographic results.

The Biofield Diagnostic System (BDS) is an adjunct breast cancer detection modality that uses recorded skin surface electropotentials for differentiating benign and malignant lesions. The main objective of this paper is to apply data mining techniques to two BDS clinical trial datasets to improve the disease detection accuracy. Both the datasets are pre-processed to remove outliers and are then used for feature selection. Wrapper and filter feature selection techniques are employed and the selected features are used for classification using supervised techniques like Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA), Support Vector Machines (SVM) and Back Propagation Neural Network (BPNN). It was observed that the LDA classifier using the feature subset selected via wrapper technique significantly improved the sensitivity and accuracy of one of the datasets. Also, the key observation is that this feature subset reduced the mild subjective interpretation associated with the current prediction methodology of the BDS device, thereby opening up new development avenues for the BDS device.

The purpose of our study was to determine the prevalence of non-cardiac findings in a large series of patients undergoing contrast-enhanced cardiac multi-detector computed tomography (MDCT) scans. Non-cardiac findings were classified according to the organ of involvement and level of significance. We retrospectively reviewed scans and reports of 1,061 patients performed between 1 April 2004 and 31 April 2006. Non-cardiac findings were considered significant if they warranted further radiological or clinical follow-up. A total of 103 non-cardiac findings were reported in 85 (8.0%) of the 1,061 patients. Of these lesions, 48 (46.7%) were significant and 55 (53.3%) were not. The significant lesions were found in 33 of the 1,061 patients (3.1%). Among the significant abnormalities, the three most common were pulmonary nodules (16.7%), emphysema (16.7%) and possible hepatic carcinomas (12.6%). Patients with non-cardiac findings were significantly older than those without (mean age 60 +/- 6 years vs. 55 +/- 8 years; P0.0001). The prevalence of active smoking was significantly higher in patients with non-cardiac findings (28.2 vs. 17.8%; P = 0.03). The prevalence of non-cardiac abnormalities detected by cardiac MDCT was 8% and about half of these findings were deemed significant. These lesions commonly occurred in the lungs and the liver. Age and active smoking were predictive of the presence of non-cardiac abnormalities.

The aim of this study was to investigate pulmonary function and exercise capacity in a group of survivors of the severe acute respiratory syndrome (SARS). At 3 months after hospital discharge, 46 survivors of SARS underwent the following evaluation: spirometry, static lung volumes and carbon monoxide transfer factor (TL,CO). In total, 44 of these patients underwent cardiopulmonary exercise testing. No abnormalities were detected in the pulmonary function tests in 23 (50%) of the patients. Abnormalities of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC and TL,CO were detected in seven (15%), 12 (26%), one (2%) and 18 (39%) patients, respectively. All of these abnormalities were mild except in one case. In 18 patients (41%), the maximum aerobic capacity was below the lower limit of the normal range. Breathing reserve was low in four patients and significant oxygen desaturation was detected in a further four patients. Comparison of the measured exercise capacity with resting pulmonary function tests showed many cases of discordance in impairment. In conclusion, pulmonary function defects were detected in half of the recovered severe acute respiratory syndrome patients 3 months after hospital discharge, but the impairment was mild in almost all cases. Many patients had reduced exercise capacity that cannot be accounted for by impairment of pulmonary function.

Background Little is known about the long-term consequence of severe acute respiratory syndrome (SARS). We carried out an assessment on SARS patients after their recovery from their acute illness. Method Postal survey comprising Health-Related Quality of Life (HRQoL) questionnaires and anxiety and depression measures was sent to them at 3 months' postdischarge. Results There was a significant impairment in both the HRQoL and mental functioning. Forty-one percent had scores indicative of a posttraumatic stress disorder (PTSD); about 30% had likely anxiety and depression. Conclusion SARS has significant impact on HRQoL and psychological status at 3 months.

This paper evaluates the effectiveness of thermal scanner when it is being used for mass blind screening of potential fever subjects. Both regression and ROC curve are used to analyze the data collected from the SARS hospital in Singapore and conclusive results are drawn from them. These results will be vital in determining two very important information: the best and yet practical region on the face to take readings and optimal pre-set threshold temperature for the thermal imager.