Displaying publications 1 - 20 of 1021 in total

  1. Hayati F, Wong MJJ, Jailani RF, Ng CY
    ANZ J Surg, 2021 10;91(10):2226.
    PMID: 34665495 DOI: 10.1111/ans.17088
    Matched MeSH terms: Tomography, X-Ray Computed
  2. Ariffin AC, Ngadiron H
    World J Surg, 2018 04;42(4):1212.
    PMID: 28879497 DOI: 10.1007/s00268-017-4222-1
    Matched MeSH terms: Tomography, X-Ray Computed*
  3. Pszczolkowski S, Manzano-Patrón JP, Law ZK, Krishnan K, Ali A, Bath PM, et al.
    Eur Radiol, 2021 Oct;31(10):7945-7959.
    PMID: 33860831 DOI: 10.1007/s00330-021-07826-9
    OBJECTIVES: To test radiomics-based features extracted from noncontrast CT of patients with spontaneous intracerebral haemorrhage for prediction of haematoma expansion and poor functional outcome and compare them with radiological signs and clinical factors.

    MATERIALS AND METHODS: Seven hundred fifty-four radiomics-based features were extracted from 1732 scans derived from the TICH-2 multicentre clinical trial. Features were harmonised and a correlation-based feature selection was applied. Different elastic-net parameterisations were tested to assess the predictive performance of the selected radiomics-based features using grid optimisation. For comparison, the same procedure was run using radiological signs and clinical factors separately. Models trained with radiomics-based features combined with radiological signs or clinical factors were tested. Predictive performance was evaluated using the area under the receiver operating characteristic curve (AUC) score.

    RESULTS: The optimal radiomics-based model showed an AUC of 0.693 for haematoma expansion and an AUC of 0.783 for poor functional outcome. Models with radiological signs alone yielded substantial reductions in sensitivity. Combining radiomics-based features and radiological signs did not provide any improvement over radiomics-based features alone. Models with clinical factors had similar performance compared to using radiomics-based features, albeit with low sensitivity for haematoma expansion. Performance of radiomics-based features was boosted by incorporating clinical factors, with time from onset to scan and age being the most important contributors for haematoma expansion and poor functional outcome prediction, respectively.

    CONCLUSION: Radiomics-based features perform better than radiological signs and similarly to clinical factors on the prediction of haematoma expansion and poor functional outcome. Moreover, combining radiomics-based features with clinical factors improves their performance.

    KEY POINTS: • Linear models based on CT radiomics-based features perform better than radiological signs on the prediction of haematoma expansion and poor functional outcome in the context of intracerebral haemorrhage. • Linear models based on CT radiomics-based features perform similarly to clinical factors known to be good predictors. However, combining these clinical factors with radiomics-based features increases their predictive performance.

    Matched MeSH terms: Tomography, X-Ray Computed*
  4. Chan R, Kumar G, Abdullah B, Ng Kh, Vijayananthan A, Mohd Nor H, et al.
    Biomed Imaging Interv J, 2011 Apr;7(2):e12.
    PMID: 22287986 MyJurnal DOI: 10.2349/biij.7.2.e12
    To optimize the delay time before the initiation of arterial phase scan in the detection of focal liver lesions in contrast enhanced 5 phase liver CT using the bolus tracking technique.
    Matched MeSH terms: Tomography, X-Ray Computed
  5. Joshi SC, Pant I, Hamzah F, Kumar G, Shukla AN
    Indian J Cancer, 2008 12 30;45(4):137-41.
    PMID: 19112200
    Positron emission tomography (PET) has emerged as an important diagnostic tool in the management of lung cancers. Although PET is sensitive in detection of lung cancer, but FDG (2-deoxy-2- 18 fluro-D-glucose) is not tumor specific and may accumulate in a variety of nonmalignant conditions occasionally giving false positive result. Addition of CT to PET improves specificity foremost, but also sensitivity in tumor imaging. Thus, PET/CT fusion images are a more accurate test than either of its individual components and are probably also better than side-by-side viewing of images from both modalities. PET/CT fusion images are useful in differentiating between malignant and benign disease, fibrosis and recurrence, staging and in changing patient management to more appropriate therapy. With analysis and discussion it appears that PET/ CT fusion images have the potential to dramatically improve our ability to manage the patients with lung cancer and is contributing to our understanding of cancer cell biology and in development of new therapies.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*; Tomography, X-Ray Computed/trends
  6. Radhiana H, Azian AA, Razali MR, Kamariah CM
    Med J Malaysia, 2010 Dec;65(4):319-25.
    PMID: 21901958
    Computed tomography (CT) is widely used in assessing clinically stable patients with blunt abdominal trauma. In these patients, liver is one of the commonest organs being injured and CT can accurately identify and assess the extent of the injury. The CT features of blunt liver trauma include laceration, subcapsular or parenchymal haematomas, active haemorrhage and vascular injuries. Widespread use of CT has notably influenced the management of blunt liver injury from routine surgical to nonsurgical management. We present pictorial illustrations of various liver injuries depicted on CT in patients with blunt trauma.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  7. Majid AA, Rathakrishnan V, Alhady SF
    J R Soc Med, 1991 Nov;84(11):686-7.
    PMID: 1744882
    Matched MeSH terms: Tomography, X-Ray Computed*
  8. Rais NNM, Bradley DA, Hashim A, Osman ND, Noor NM
    Appl Radiat Isot, 2019 Nov;153:108810.
    PMID: 31351374 DOI: 10.1016/j.apradiso.2019.108810
    For a range of doses familiarly incurred in computed tomography (CT), study is made of the performance of Germanium (Ge)-doped fibre dosimeters formed into cylindrical and flat shapes. Indigenously fabricated 2.3 mol% and 6 mol% Ge-dopant concentration preforms have been used to produce flat- and cylindrical-fibres (FF and CF) of various size and diameters; an additional 4 mol% Ge-doped commercial fibre with a core diameter of 50 μm has also been used. The key characteristics examined include the linearity index f(d), dose sensitivity and minimum detectable dose (MDD), the performance of the fibres being compared against that of lithium-fluoride based TLD-100 thermoluminescence (TL) dosimeters. For doses in the range 2-40 milligray (mGy), delivered at constant potential of 120 kilovoltage (kV), both the fabricated and commercial fibres demonstrate supralinear behaviours at doses  4 mGy. In terms of dose sensitivity, all of the fibres show superior TL sensitivity when compared against TLD-100, the 2.3 mol% and 6 mol% Ge-doped FF demonstrating the greatest TL sensitivity at 84 and 87 times that of TLD-100. The TL yields for the novel Ge-doped silica glass render them appealing for use within the present medical imaging dose range, offering linearity at high sensitivity down to less than 2 mGy.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  9. Ooi EH, Lee KW, Yap S, Khattab MA, Liao IY, Ooi ET, et al.
    Comput Biol Med, 2019 03;106:12-23.
    PMID: 30665137 DOI: 10.1016/j.compbiomed.2019.01.003
    Effects of different boundary conditions prescribed across the boundaries of radiofrequency ablation (RFA) models of liver cancer are investigated for the case where the tumour is at the liver boundary. Ground and Robin-type conditions (electrical field) and body temperature and thermal insulation (thermal field) conditions are examined. 3D models of the human liver based on publicly-available CT images of the liver are developed. An artificial tumour is placed inside the liver at the boundary. Simulations are carried out using the finite element method. The numerical results indicated that different electrical and thermal boundary conditions led to different predictions of the electrical potential, temperature and thermal coagulation distributions. Ground and body temperature conditions presented an unnatural physical conditions around the ablation site, which results in more intense Joule heating and excessive heat loss from the tissue. This led to thermal damage volumes that are smaller than the cases when the Robin type or the thermal insulation conditions are prescribed. The present study suggests that RFA simulations in the future must take into consideration the choice of the type of electrical and thermal boundary conditions to be prescribed in the case where the tumour is located near to the liver boundary.
    Matched MeSH terms: Tomography, X-Ray Computed*
  10. Tan D, Mohamad NA, Wong YH, Yeong CH, Cheah PL, Sulaiman N, et al.
    Int J Hyperthermia, 2019;36(1):554-561.
    PMID: 31132888 DOI: 10.1080/02656736.2019.1610800
    Purpose: This study aimed to evaluate the effects of various computed tomography (CT) acquisition parameters and metal artifacts on CT number measurement for CT thermometry during CT-guided thermal ablation. Methods: The effects of tube voltage (100-140 kVp), tube current (20-250 mAs), pitch (0.6-1.5) and gantry rotation time (0.5, 1.0 s) as well as metal artifacts from a radiofrequency ablation (RFA) needle on CT number were evaluated using liver tissue equivalent polyacrylamide (PAA) phantom. The correlation between CT number and temperature from 37 to 80 °C was studied on PAA phantom using optimum CT acquisition parameters. Results: No statistical significant difference (p > 0.05) was found on CT numbers under the variation of different acquisition parameters for the same temperature setting. On the other hand, the RFA needle has induced metal artifacts on the CT images of up to 8 mm. The CT numbers decreased linearly when the phantom temperature increased from 37 to 80 °C. A linear regression analysis on the CT numbers and temperature suggested that the CT thermal sensitivity was -0.521 ± 0.061 HU/°C (R2 = 0.998). Conclusion: CT thermometry is feasible for temperature assessment during RFA with the current CT technology, which produced a high CT number reproducibility and stable measurement at different CT acquisition parameters. Despite being affected by metal artifacts, the CT-based thermometry could be further developed as a tissue temperature monitoring tool during CT-guided thermal ablation.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  11. Razali MASM, Ahmad MZ, Shuaib IL, Osman ND
    Radiat Prot Dosimetry, 2020 Jun 13;188(2):213-221.
    PMID: 31885043 DOI: 10.1093/rpd/ncz278
    The aim of this study was to propose local diagnostic reference levels (LDRLs) for the most common computed tomography (CT) examinations (including contrast and non-contrast scan phase) performed at Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia (USM), Malaysia. A retrospective CT dose survey of 1488 subjects from January 2015 until December 2018 was performed at AMDI USM, Malaysia. The proposed DRLs were established at 50th and 75th percentile of dose distribution for all dose metrics (CT dose index [CTDI]; CTDIvol, CTDIw and dose-length product). The proposed LDRLs were compared with national DRLs and other established DRLs. The 10 most common CT examinations at AMDI were thorax-abdomen-pelvis (TAP) CT (46%), followed by pelvis CT (17%), abdomen-pelvis CT (10%), brain/head CT (9%) and other CT protocols. The local DRLs were established using the third quartile values of dose distribution and were categorized based on CT region protocols. Most of the proposed DRLs were exceeded the national DRLs (63%) and other international DRLs (67%). From the dose auditing, almost half of the recent dose data (for year 2018) exceeded the proposed local DRLs and the unusual dose were observed in TAP, brain/head and pelvis CT examinations. The unusual higher dose could be due to higher mAs settings, higher number of scan phase for contrast study and higher pitch factor. The local DRLs should be established for dose optimization and reduction of the occurrence of excessive radiation exposure to the patients. The establishment of the Ads and LDRLs should also consider all the factors that affect the variation in DRLs such as CT technology, scanning protocols and population characteristics. The local dose distribution should always be revised for improvement of the current local practice.
    Matched MeSH terms: Tomography, X-Ray Computed*
  12. Lee SA, Chiu CK, Chan CYW, Yaakup NA, Wong JHD, Kadir KAA, et al.
    Spine J, 2020 07;20(7):1114-1124.
    PMID: 32272253 DOI: 10.1016/j.spinee.2020.03.015
    BACKGROUND CONTEXT: Biopsy is important to obtain microbiological and histopathological diagnosis in spine infections and tumors. To date, there have been no prospective randomized trials comparing fluoroscopic guided and computed tomography (CT) transpedicular biopsy techniques. The goal of this study was to evaluate the accuracy, safety, and diagnostic outcome of these two diagnostic techniques.

    PURPOSE: To evaluate the accuracy, safety, and diagnostic outcome of fluoroscopic guided and CT transpedicular biopsy techniques.

    STUDY DESIGN: Prospective randomized trial.

    PATIENT SAMPLE: Sixty consecutive patients with clinical symptoms and radiological features suggestive of spinal infection or malignancy were recruited and randomized into fluoroscopic or CT guided spinal biopsy groups. Both groups were similar in terms of patient demographics, distribution of spinal infections and malignancy cases, and the level of biopsies.

    OUTCOME MEASURES: The primary outcome measure was diagnostic accuracy of both methods, determined based on true positive, true negative, false positive, and false negative biopsy findings. Secondary outcome measures included radiation exposure to patients and doctors, complications, and postbiopsy pain score.

    METHODS: A transpedicular approach was performed with an 8G core biopsy needle. Specimens were sent for histopathological and microbiological examinations. Diagnosis was made based on biopsy results, clinical criteria and monitoring of disease progression during a 6-month follow up duration. Clinical criteria included presence of risk factors, level of inflammatory markers and magnetic resonance imaging findings. Radiation exposure to patients and doctors was measured with dosimeters.

    RESULTS: There was no significant difference between the diagnostic accuracy of fluoroscopic and CT guided spinal biopsy (p=0.67) or between the diagnostic accuracy of spinal infection and spinal tumor in both groups (p=0.402 for fluoroscopy group and p=0.223 for CT group). Radiation exposure to patients was approximately 26 times higher in the CT group. Radiation exposure to doctors in the CT group was approximately 2 times higher compared to the fluoroscopic group if a lead shield was not used. Lead shields significantly reduced radiation exposure to doctors anywhere from 2 to 8 times. No complications were observed for either group and the differences in postbiopsy pain scores were not significant.

    CONCLUSIONS: The accuracy, procedure time, complication rate and pain score for both groups were similar. However, radiation exposure to patients and doctors were significantly higher in the CT group without lead protection. With lead protection, radiation to doctors reduced significantly.

    Matched MeSH terms: Tomography, X-Ray Computed*
  13. Teh V, Sim KS, Wong EK
    Scanning, 2016 Nov;38(6):842-856.
    PMID: 27302216 DOI: 10.1002/sca.21334
    According to the statistic from World Health Organization (WHO), stroke is one of the major causes of death globally. Computed tomography (CT) scan is one of the main medical diagnosis system used for diagnosis of ischemic stroke. CT scan provides brain images in Digital Imaging and Communication in Medicine (DICOM) format. The presentation of CT brain images is mainly relied on the window setting (window center and window width), which converts an image from DICOM format into normal grayscale format. Nevertheless, the ordinary window parameter could not deliver a proper contrast on CT brain images for ischemic stroke detection. In this paper, a new proposed method namely gamma correction extreme-level eliminating with weighting distribution (GCELEWD) is implemented to improve the contrast on CT brain images. GCELEWD is capable of highlighting the hypodense region for diagnosis of ischemic stroke. The performance of this new proposed technique, GCELEWD, is compared with four of the existing contrast enhancement technique such as brightness preserving bi-histogram equalization (BBHE), dualistic sub-image histogram equalization (DSIHE), extreme-level eliminating histogram equalization (ELEHE), and adaptive gamma correction with weighting distribution (AGCWD). GCELEWD shows better visualization for ischemic stroke detection and higher values with image quality assessment (IQA) module. SCANNING 38:842-856, 2016. © 2016 Wiley Periodicals, Inc.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  14. Kua Ch, Abdul Aziz Y
    Biomed Imaging Interv J, 2008 Oct;4(4):e24.
    PMID: 21611013 DOI: 10.2349/biij.4.4.e24
    Presence of air in the kidney can be problematic as the location of the air in different parts of the kidney greatly affects the subsequent management and outcome of the patient. We present here a case of a patient who had emphysematous pyelitis, in which CT scan was able to display presence of air only in the collecting system, thus differentiating this condition from the more fulminant emphysematous pyelonephritis. This leads to a more favourable prognosis and outcome to the patient.
    Matched MeSH terms: Tomography, X-Ray Computed
  15. Rahim RA, Chen LL, San CK, Rahiman MH, Fea PJ
    Sensors (Basel), 2009;9(11):8562-78.
    PMID: 22291523 DOI: 10.3390/s91108562
    This paper explains in detail the solution to the forward and inverse problem faced in this research. In the forward problem section, the projection geometry and the sensor modelling are discussed. The dimensions, distributions and arrangements of the optical fibre sensors are determined based on the real hardware constructed and these are explained in the projection geometry section. The general idea in sensor modelling is to simulate an artificial environment, but with similar system properties, to predict the actual sensor values for various flow models in the hardware system. The sensitivity maps produced from the solution of the forward problems are important in reconstructing the tomographic image.
    Matched MeSH terms: Tomography, X-Ray Computed
  16. Amalourde A, Vinayaga P, Naveed N, Jamal A, Looi LM, Sengupta S
    Med J Malaysia, 2004 Dec;59 Suppl F:60-2.
    PMID: 15941166 MyJurnal
    Although all types of tumour and tumour-like conditions have been described to occur in the clavicle, they only contribute to less then 0.5% of all skeletal tumours. The incidence of primary chondrosarcoma of the clavicle is extremely rare. To our knowledge it has not been reported in Malaysia. We would like to highlight the possibility of chondrosarcoma as a differential diagnosis for a clavicular lesion.
    Matched MeSH terms: Tomography, X-Ray Computed
  17. Sreetharan SS, Prepageran N, Singh S
    Asian J Surg, 2005 Apr;28(2):136-8.
    PMID: 15851369
    Oesophageal penetration and migration of foreign bodies are fairly rare occurrences. Most reported cases in the literature involve fish bones, which are eventually found in the lateral neck soft tissue or thyroid lobule. We present a case of a migrating fish bone in an elderly female which was found embedded in her right sternocleidomastoid muscle. The fish bone was successfully removed via neck exploration. Appropriate literature is reviewed.
    Matched MeSH terms: Tomography, X-Ray Computed
  18. Majid AA
    Aust N Z J Surg, 1992 Jan;62(1):74-6.
    PMID: 1731742
    Although the diagnosis of thymolipoma has improved with the introduction of computerized tomography (CT), variations in CT appearance are still being described; this paper describes a case which resembled a lipoma. The CT features of thymolipoma are discussed with special reference to the differential diagnosis. Surgical excision should be considered for patients who are found to exhibit a fatty intrathoracic mass on CT.
    Matched MeSH terms: Tomography, X-Ray Computed
  19. Pit S, Chea FK, Jamal F
    Postgrad Med J, 1988 Feb;64(748):140-2.
    PMID: 3174527
    Central nervous system involvement in melioidosis is rare. We describe a 48 year old woman who developed septicaemia and a brain abscess due to Pseudomonas pseudomallei. Since there is a continuing practical problem in bacteriological confirmation of the aetiological agent, diagnosis of melioidosis has to be made on clinical suspicion.
    Matched MeSH terms: Tomography, X-Ray Computed
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