Displaying publications 21 - 40 of 120 in total

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  1. Diagnostic ability of computed tomography using DentaScan software in endodontics: case reports
    Siotia J, Gupta SK, Acharya SR, Saraswathi V
    Int J Comput Dent, 2011;14(4):321-34.
    PMID: 22324223
    Radiographic examination is essential in diagnosis and treatment planning in endodontics. Conventional radiographs depict structures in two dimensions only. The ability to assess the area of interest in three dimensions is advantageous. Computed tomography is an imaging technique which produces three-dimensional images of an object by taking a series of two-dimensional sectional X-ray images. DentaScan is a computed tomography software program that allows the mandible and maxilla to be imaged in three planes: axial, panoramic, and cross-sectional. As computed tomography is used in endodontics, DentaScan can play a wider role in endodontic diagnosis. It provides valuable information in the assessment of the morphology of the root canal, diagnosis of root fractures, internal and external resorptions, pre-operative assessment of anatomic structures etc. The aim of this article is to explore the clinical usefulness of computed tomography and DentaScan in endodontic diagnosis, through a series of four cases of different endodontic problems.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  2. Computed tomography scan for cardiac interventions
    Sim KH, Ong TK, Chin SP, Wong M
    Indian Heart J, 2007 Mar-Apr;59(2 Suppl B):B25-32.
    PMID: 19153433
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  3. Fulltext A Double Whammy of Mycotic Aneurysms and Acquired Dysfibrinogenemia in a Patient with Septicemia
    Sim CY, Khoo CS, Mustafar R, Chai JN
    Balkan Med J, 2021 01;38(1):55-56.
    PMID: 32720494 DOI: 10.4274/balkanmedj.galenos.2020.2020.5.208
    Matched MeSH terms: Tomography, X-Ray Computed/methods
  4. Fulltext Automatic COVID-19 Lung Infection Segmentation through Modified Unet Model
    Shamim S, Awan MJ, Mohd Zain A, Naseem U, Mohammed MA, Garcia-Zapirain B
    J Healthc Eng, 2022;2022:6566982.
    PMID: 35422980 DOI: 10.1155/2022/6566982
    The coronavirus (COVID-19) pandemic has had a terrible impact on human lives globally, with far-reaching consequences for the health and well-being of many people around the world. Statistically, 305.9 million people worldwide tested positive for COVID-19, and 5.48 million people died due to COVID-19 up to 10 January 2022. CT scans can be used as an alternative to time-consuming RT-PCR testing for COVID-19. This research work proposes a segmentation approach to identifying ground glass opacity or ROI in CT images developed by coronavirus, with a modified structure of the Unet model having been used to classify the region of interest at the pixel level. The problem with segmentation is that the GGO often appears indistinguishable from a healthy lung in the initial stages of COVID-19, and so, to cope with this, the increased set of weights in contracting and expanding the Unet path and an improved convolutional module is added in order to establish the connection between the encoder and decoder pipeline. This has a major capacity to segment the GGO in the case of COVID-19, with the proposed model being referred to as "convUnet." The experiment was performed on the Medseg1 dataset, and the addition of a set of weights at each layer of the model and modification in the connected module in Unet led to an improvement in overall segmentation results. The quantitative results obtained using accuracy, recall, precision, dice-coefficient, F1score, and IOU were 93.29%, 93.01%, 93.67%, 92.46%, 93.34%, 86.96%, respectively, which is better than that obtained using Unet and other state-of-the-art models. Therefore, this segmentation approach proved to be more accurate, fast, and reliable in helping doctors to diagnose COVID-19 quickly and efficiently.
    Matched MeSH terms: Tomography, X-Ray Computed/methods
  5. Dislocation of cervico-thoracic spine with no neurological deficit--a case report
    Saw A, Sengupta S
    Injury, 2001 Jun;32(5):430-2.
    PMID: 11382432
    Matched MeSH terms: Tomography, X-Ray Computed/methods
  6. A rare case of unilateral postaxial duplicated foot in a developmentally normal child
    Sahdi H, Hoong CW, Rasit AH, Arianto F, Siong LK, Abdullah NA
    J Orthop Surg (Hong Kong), 2017 01;25(1):2309499016684989.
    PMID: 28166702 DOI: 10.1177/2309499016684989
    Diplopodia, being a rare congenital disorder, is infrequently discussed in published texts. Most reported cases have accounted the involvement of duplicated preaxial digits with other associated organ system and physical deformities. Here, we present an unusual case of isolated diplopodia involving postaxial toes in a child with no other organ and physical abnormalities. Radiological studies revealed a set of 10-digit-duplicated foot over the lateral aspect of the native foot, complete with phalanges and its corresponding metatarsals as well as tarsals, supplied by an anomalous posterior branch of the popliteal artery. Definitive surgery was performed just before the child was learning to walk.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  7. Fulltext GraphCovidNet: A graph neural network based model for detecting COVID-19 from CT scans and X-rays of chest
    Saha P, Mukherjee D, Singh PK, Ahmadian A, Ferrara M, Sarkar R
    Sci Rep, 2021 04 15;11(1):8304.
    PMID: 33859222 DOI: 10.1038/s41598-021-87523-1
    COVID-19, a viral infection originated from Wuhan, China has spread across the world and it has currently affected over 115 million people. Although vaccination process has already started, reaching sufficient availability will take time. Considering the impact of this widespread disease, many research attempts have been made by the computer scientists to screen the COVID-19 from Chest X-Rays (CXRs) or Computed Tomography (CT) scans. To this end, we have proposed GraphCovidNet, a Graph Isomorphic Network (GIN) based model which is used to detect COVID-19 from CT-scans and CXRs of the affected patients. Our proposed model only accepts input data in the form of graph as we follow a GIN based architecture. Initially, pre-processing is performed to convert an image data into an undirected graph to consider only the edges instead of the whole image. Our proposed GraphCovidNet model is evaluated on four standard datasets: SARS-COV-2 Ct-Scan dataset, COVID-CT dataset, combination of covid-chestxray-dataset, Chest X-Ray Images (Pneumonia) dataset and CMSC-678-ML-Project dataset. The model shows an impressive accuracy of 99% for all the datasets and its prediction capability becomes 100% accurate for the binary classification problem of detecting COVID-19 scans. Source code of this work can be found at GitHub-link .
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  8. Wavelet-based compression of medical images: filter-bank selection and evaluation
    Saffor A, bin Ramli AR, Ng KH
    Australas Phys Eng Sci Med, 2003 Jun;26(2):39-44.
    PMID: 12956184
    Wavelet-based image coding algorithms (lossy and lossless) use a fixed perfect reconstruction filter-bank built into the algorithm for coding and decoding of images. However, no systematic study has been performed to evaluate the coding performance of wavelet filters on medical images. We evaluated the best types of filters suitable for medical images in providing low bit rate and low computational complexity. In this study a variety of wavelet filters are used to compress and decompress computed tomography (CT) brain and abdomen images. We applied two-dimensional wavelet decomposition, quantization and reconstruction using several families of filter banks to a set of CT images. Discreet Wavelet Transform (DWT), which provides efficient framework of multi-resolution frequency was used. Compression was accomplished by applying threshold values to the wavelet coefficients. The statistical indices such as mean square error (MSE), maximum absolute error (MAE) and peak signal-to-noise ratio (PSNR) were used to quantify the effect of wavelet compression of selected images. The code was written using the wavelet and image processing toolbox of the MATLAB (version 6.1). This results show that no specific wavelet filter performs uniformly better than others except for the case of Daubechies and bi-orthogonal filters which are the best among all. MAE values achieved by these filters were 5 x 10(-14) to 12 x 10(-14) for both CT brain and abdomen images at different decomposition levels. This indicated that using these filters a very small error (approximately 7 x 10(-14)) can be achieved between original and the filtered image. The PSNR values obtained were higher for the brain than the abdomen images. For both the lossy and lossless compression, the 'most appropriate' wavelet filter should be chosen adaptively depending on the statistical properties of the image being coded to achieve higher compression ratio.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  9. The potential role of artificial intelligence-assisted chest X-ray imaging in detecting early-stage lung cancer in the community-a proposed algorithm for lung cancer screening in Malaysia
    Sachithanandan A, Lockman H, Azman RR, Tho LM, Ban EZ, Ramon V
    Med J Malaysia, 2024 Jan;79(1):9-14.
    PMID: 38287751
    INTRODUCTION: The poor prognosis of lung cancer has been largely attributed to the fact that most patients present with advanced stage disease. Although low dose computed tomography (LDCT) is presently considered the optimal imaging modality for lung cancer screening, its use has been hampered by cost and accessibility. One possible approach to facilitate lung cancer screening is to implement a risk-stratification step with chest radiography, given its ease of access and affordability. Furthermore, implementation of artificial-intelligence (AI) in chest radiography is expected to improve the detection of indeterminate pulmonary nodules, which may represent early lung cancer.

    MATERIALS AND METHODS: This consensus statement was formulated by a panel of five experts of primary care and specialist doctors. A lung cancer screening algorithm was proposed for implementation locally.

    RESULTS: In an earlier pilot project collaboration, AI-assisted chest radiography had been incorporated into lung cancer screening in the community. Preliminary experience in the pilot project suggests that the system is easy to use, affordable and scalable. Drawing from experience with the pilot project, a standardised lung cancer screening algorithm using AI in Malaysia was proposed. Requirements for such a screening programme, expected outcomes and limitations of AI-assisted chest radiography were also discussed.

    CONCLUSION: The combined strategy of AI-assisted chest radiography and complementary LDCT imaging has great potential in detecting early-stage lung cancer in a timely manner, and irrespective of risk status. The proposed screening algorithm provides a guide for clinicians in Malaysia to participate in screening efforts.

    Matched MeSH terms: Tomography, X-Ray Computed/methods
  10. Index of suspicion with appropriate timing of CT scan helps prevent missed diagnosis in urologic trauma
    Sabrina B, Tan KL, Johann FK, Andre D
    Med J Malaysia, 2018 08;73(4):255-256.
    PMID: 30121691 MyJurnal
    Ureteric and bladder injuries are uncommon, difficult to diagnose and rarely occur in isolation. Diagnosis is often delayed or missed at presentation. Therefore, high clinical suspicion and appropriate timing of computed tomography (CT) are of paramount importance. We report two cases (ureteropelvic junction avulsion and ruptured dome of bladder) whereby the presentations were subtle and would have been missed if not for high clinical suspicion. This article discusses the problems associated with these urologic injuries, as well as how to develop a high index of suspicion based on the pattern of anatomical disruption, mechanism of injury, physiological abnormality and comorbidity.
    Matched MeSH terms: Tomography, X-Ray Computed/methods
  11. Radiation dose associated with cerebral CT angiography and CT perfusion: an experimental phantom study
    Sabarudin A, Yusof MZ, Mohamad M, Sun Z
    Radiat Prot Dosimetry, 2014 Dec;162(3):316-21.
    PMID: 24255172 DOI: 10.1093/rpd/nct280
    A study on the radiation dose associated with cerebral CT angiography (CTA) and CT perfusion (CTP) was conducted on an anthropomorphic phantom with the aim of estimating the effective dose (E) and entrance skin dose (ESD) in the eyes and thyroid gland during different CTA and CTP protocols. The E was calculated to be 0.61 and 0.28 mSv in CTA with 100 and 80 kV(p), respectively. In contrast, CTP resulted in an estimated E of 2.74 and 2.07 mSv corresponding to 40 and 30 s protocols, respectively. The eyes received a higher ESD than the thyroid gland in all of these protocols. The results of this study indicate that combining both CTA and CTP procedures are not recommended in the stroke evaluation due to high radiation dose. Application of modified techniques in CTA (80 kV(p)) and CTP (30 s) is highly recommended in clinical practice for further radiation dose reduction.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  12. Dual-source CT coronary angiography: effectiveness of radiation dose reduction with lower tube voltage
    Sabarudin A, Md Yusof AK, Tay MF, Ng KH, Sun Z
    Radiat Prot Dosimetry, 2013;153(4):441-7.
    PMID: 22807493 DOI: 10.1093/rpd/ncs127
    This study was conducted to investigate the effectiveness of dose-saving protocols in dual-source computed tomography (CT) coronary angiography compared with invasive coronary angiography (ICA). On 50 patients who underwent coronary CT angiography was performed dual-source CT (DSCT) and compared with ICA procedures. Entrance skin dose (ESD), which was measured at the thyroid gland, and effective dose (E) were assessed for both imaging modalities. The mean ESD measured at the thyroid gland was the highest at 120 kVp, followed by the 100 kVp DSCT and the ICA protocols with 4.0±1.8, 2.7±1.0 and 1.1±1.2 mGy, respectively. The mean E was estimated to be 10.3±2.1, 6.2±2.3 and 5.3±3.4 mSv corresponding to the 120-kVp, 100-kVp DSCT and ICA protocols, respectively. The application of 100 kVp in DSCT coronary angiography is feasible only in patients with a low body mass index of <25 kg m(-2), which leads to a significant dose reduction with the radiation dose being equivalent to that of ICA.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  13. Inter-observer Variability Analysis of Automatic Lung Delineation in Normal and Disease Patients
    Saba L, Than JC, Noor NM, Rijal OM, Kassim RM, Yunus A, et al.
    J Med Syst, 2016 Jun;40(6):142.
    PMID: 27114353 DOI: 10.1007/s10916-016-0504-7
    Human interaction has become almost mandatory for an automated medical system wishing to be accepted by clinical regulatory agencies such as Food and Drug Administration. Since this interaction causes variability in the gathered data, the inter-observer and intra-observer variability must be analyzed in order to validate the accuracy of the system. This study focuses on the variability from different observers that interact with an automated lung delineation system that relies on human interaction in the form of delineation of the lung borders. The database consists of High Resolution Computed Tomography (HRCT): 15 normal and 81 diseased patients' images taken retrospectively at five levels per patient. Three observers manually delineated the lungs borders independently and using software called ImgTracer™ (AtheroPoint™, Roseville, CA, USA) to delineate the lung boundaries in all five levels of 3-D lung volume. The three observers consisted of Observer-1: lesser experienced novice tracer who is a resident in radiology under the guidance of radiologist, whereas Observer-2 and Observer-3 are lung image scientists trained by lung radiologist and biomedical imaging scientist and experts. The inter-observer variability can be shown by comparing each observer's tracings to the automated delineation and also by comparing each manual tracing of the observers with one another. The normality of the tracings was tested using D'Agostino-Pearson test and all observers tracings showed a normal P-value higher than 0.05. The analysis of variance (ANOVA) test between three observers and automated showed a P-value higher than 0.89 and 0.81 for the right lung (RL) and left lung (LL), respectively. The performance of the automated system was evaluated using Dice Similarity Coefficient (DSC), Jaccard Index (JI) and Hausdorff (HD) Distance measures. Although, Observer-1 has lesser experience compared to Obsever-2 and Obsever-3, the Observer Deterioration Factor (ODF) shows that Observer-1 has less than 10% difference compared to the other two, which is under acceptable range as per our analysis. To compare between observers, this study used regression plots, Bland-Altman plots, two tailed T-test, Mann-Whiney, Chi-Squared tests which showed the following P-values for RL and LL: (i) Observer-1 and Observer-3 were: 0.55, 0.48, 0.29 for RL and 0.55, 0.59, 0.29 for LL; (ii) Observer-1 and Observer-2 were: 0.57, 0.50, 0.29 for RL and 0.54, 0.59, 0.29 for LL; (iii) Observer-2 and Observer-3 were: 0.98, 0.99, 0.29 for RL and 0.99, 0.99, 0.29 for LL. Further, CC and R-squared coefficients were computed between observers which came out to be 0.9 for RL and LL. All three observers however manage to show the feature that diseased lungs are smaller than normal lungs in terms of area.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  14. Fulltext Computed tomography of blunt renal trauma
    Razali MR, Azian AA, Amran AR, Azlin S
    Singapore Med J, 2010 Jun;51(6):468-73; quiz 474.
    PMID: 20658105
    Renal injury is observed in 10 percent of cases of abdominal trauma, and the majority (80 percent to 90 percent) of these are attributable to blunt trauma. Intravenous urography and ultrasonography of the abdomen were previously the modalities of choice in the imaging of renal injuries. However, computed tomography (CT) is currently the imaging modality of choice in the evaluation of blunt renal injury, since it provides the exact staging of renal injuries. The purpose of this article is to describe the CT staging of renal injuries observed in blunt abdominal trauma based on the Federle Classification and the American Association for the Surgery of Trauma renal injury severity scale.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  15. Follicular bronchiolitis in an HIV-infected individual on combination antiretroviral therapy with low CD4+ cell count but sustained viral suppression
    Rasmussen LD, Pedersen C, Madsen HD, Laursen CB
    BMJ Case Rep, 2017 Nov 29;2017.
    PMID: 29191821 DOI: 10.1136/bcr-2017-221025
    A 36-year-old Danish man, living in Asia, was diagnosed with Pneumocystis pneumonia (PCP) and HIV in 2013 (CD4+ count: 6 cells/µL; viral load: 518 000 copies/mL). He initiated combination antiretroviral therapy. Later that year, he was also diagnosed with granulomatosis with polyangiitis and was treated with prednisolone. Despite complete viral suppression and increasing CD4+ count (162 cells/µL), he was readmitted with PCP in April 2015. Subsequently, he returned to Denmark (CD4+ count: 80 cells/µL, viral suppression). Over the following months, he developed progressive dyspnoea. Lung function tests demonstrated severely reduced lung capacity with an obstructive pattern and a moderately reduced diffusion capacity. High resolution computer tomography revealed minor areas with tree-in-bud pattern and no signs of air trapping on expiratory views. Lung biopsy showed lymphocytic infiltration surrounding the bronchioles with sparing of the alveolar septa. He was diagnosed with follicular bronchiolitis. The patient spontaneously recovered along with an improvement of the immune system.
    Matched MeSH terms: Tomography, X-Ray Computed/methods
  16. MRI and CT findings of cryptococcal vaginitis
    Ranganathan S, Moosa F, Kamarulzaman A, Looi LM
    Br J Radiol, 2005 Apr;78(928):353-4.
    PMID: 15774599
    Cryptococcus neoformans is a yeast like fungus, which is commonly found in bird droppings, especially pigeons. Most cases of cryptococcal infections occur in immunocompromised patients or in those who are on long term immunosuppressant therapies. Cryptococcal infection usually presents as a meningoencephalitis or a pulmonary infection. Skin, bone and genital infections are very rare. We report the second case of vaginal cryptococcossis to be reported in English literature and the first to be imaged with CT and MRI.
    Matched MeSH terms: Tomography, X-Ray Computed/methods
  17. Proptosis--Correlation and Agreement between Hertel Exophthalmometry and Computed Tomography
    Ramli N, Kala S, Samsudin A, Rahmat K, Abidin ZZ
    Orbit, 2015;34(5):257-62.
    PMID: 26186249 DOI: 10.3109/01676830.2015.1057291
    To determine the correlation and agreement between Hertel exophthalmometry and computed tomography (CT) of the orbits in measuring proptosis.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  18. Fulltext Bilateral internal carotid artery hypotrophy in malignant osteopetrosis
    Ramli N, Rahmat K, Tan GP
    Singapore Med J, 2008 Jul;49(7):e175-7.
    PMID: 18695851
    Malignant osteopetrosis is associated with petrous carotid canal and internal carotid artery stenosis in the skull base. We present a four-year-old boy with malignant osteopetrosis who developed right frontal lobe infarction as a result of bilateral internal carotid artery hypotrophy.
    Matched MeSH terms: Tomography, X-Ray Computed/methods
  19. Computed tomography analysis of the anterior ethmoid genu of the frontal recess in non-diseased sinuses
    Raman K, Govindaraju R, James K, Abu Bakar MZ, Patil N, Shah MN
    J Laryngol Otol, 2023 Feb;137(2):169-173.
    PMID: 34924062 DOI: 10.1017/S0022215121004175
    OBJECTIVE: Knowledge of anatomical variations of the frontal recess and frontal sinus and recognition of endoscopic landmarks are vital for safe and effective endoscopic sinus surgery. This study revisited an anatomical landmark in the frontal recess that could serve as a guide to the frontal sinus.

    METHOD: Prevalence of the anterior ethmoid genu, its morphology and its relationship with the frontal sinus drainage pathway was assessed. Computed tomography scans with multiplanar reconstruction were used to study non-diseased sinonasal complexes.

    RESULTS: The anterior ethmoidal genu was present in all 102 anatomical sides studied, independent of age, gender and race. Its position was within the frontal sinus drainage pathway, and the drainage pathway was medial to it in 98 of 102 cases. The anterior ethmoidal genu sometimes extended laterally and formed a recess bounded by the lamina papyracea laterally, by the uncinate process anteriorly and by the bulla ethmoidalis posteriorly. Distance of the anterior ethmoidal genu to frontal ostia can be determined by the height of the posterior wall of the agger nasi cell rather than its volume or other dimensions.

    CONCLUSION: This study confirmed that the anterior ethmoidal genu is a constant anatomical structure positioned within frontal sinus drainage pathway. The description of anterior ethmoidal genu found in this study explained the anatomical connection between the agger nasi cell, uncinate process and bulla ethmoidalis and its structural organisation.

    Matched MeSH terms: Tomography, X-Ray Computed/methods
  20. The nasopharynx in infants with cleft lip and palate
    Rajion ZA, Al-Khatib AR, Netherway DJ, Townsend GC, Anderson PJ, McLean NR, et al.
    Int J Pediatr Otorhinolaryngol, 2012 Feb;76(2):227-34.
    PMID: 22136741 DOI: 10.1016/j.ijporl.2011.11.008
    The purpose of this study was to use three-dimensional computed tomography data and computer imaging technology to assess the skeletal components of the naso-pharyngeal area in patients with cleft lip and palate and to quantify anatomical variations.
    Matched MeSH terms: Tomography, X-Ray Computed/methods
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