Displaying publications 841 - 860 of 1501 in total

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  1. CT based 3-dimensional treatment planning of intracavitary brachytherapy for cancer of the cervix: comparison between dose-volume histograms and ICRU point doses to the rectum and bladder
    Hashim N, Jamalludin Z, Ung NM, Ho GF, Malik RA, Phua VC
    Asian Pac J Cancer Prev, 2014;15(13):5259-64.
    PMID: 25040985
    BACKGROUND: CT based brachytherapy allows 3-dimensional (3D) assessment of organs at risk (OAR) doses with dose volume histograms (DVHs). The purpose of this study was to compare computed tomography (CT) based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the cervix treated with high-dose-rate (HDR) intracavitary brachytherapy (ICBT).

    MATERIALS AND METHODS: Between March 2011 and May 2012, 20 patients were treated with 55 fractions of brachytherapy using tandem and ovoids and underwent post-implant CT scans. The external beam radiotherapy (EBRT) dose was 48.6 Gy in 27 fractions. HDR brachytherapy was delivered to a dose of 21 Gy in three fractions. The ICRU bladder and rectum point doses along with 4 additional rectal points were recorded. The maximum dose (DMax) to rectum was the highest recorded dose at one of these five points. Using the HDR plus 2.6 brachytherapy treatment planning system, the bladder and rectum were retrospectively contoured on the 55 CT datasets. The DVHs for rectum and bladder were calculated and the minimum doses to the highest irradiated 2cc area of rectum and bladder were recorded (D2cc) for all individual fractions. The mean D2cc of rectum was compared to the means of ICRU rectal point and rectal DMax using the Student's t-test. The mean D2cc of bladder was compared with the mean ICRU bladder point using the same statistical test .The total dose, combining EBRT and HDR brachytherapy, were biologically normalized to the conventional 2 Gy/fraction using the linear-quadratic model. (α/β value of 10 Gy for target, 3 Gy for organs at risk).

    RESULTS: The total prescribed dose was 77.5 Gy α/β10. The mean dose to the rectum was 4.58 ± 1.22 Gy for D 2cc, 3.76 ± 0.65 Gy at D ICRU and 4.75 ± 1.01 Gy at DMax. The mean rectal D 2cc dose differed significantly from the mean dose calculated at the ICRU reference point (p<0.005); the mean difference was 0.82 Gy (0.48 -1.19 Gy). The mean EQD2 was 68.52 ± 7.24 Gy α/β3 for D 2cc, 61.71 ± 2.77 Gy α/β3 at D ICRU and 69.24 ± 6.02 Gy α/β3 at DMax. The mean ratio of D 2cc rectum to D ICRU rectum was 1.25 and the mean ratio of D 2cc rectum to DMax rectum was 0.98 for all individual fractions. The mean dose to the bladder was 6.00 ± 1.90 Gy for D 2cc and 5.10 ± 2.03 Gy at D ICRU. However, the mean D 2cc dose did not differ significantly from the mean dose calculated at the ICRU reference point (p=0.307); the mean difference was 0.90 Gy (0.49-1.25 Gy). The mean EQD2 was 81.85 ± 13.03 Gy α/β3 for D 2cc and 74.11 ± 19.39 Gy α/β3 at D ICRU. The mean ratio of D 2cc bladder to D ICRU bladder was 1.24. In the majority of applications, the maximum dose point was not the ICRU point. On average, the rectum received 77% and bladder received 92% of the prescribed dose.

    CONCLUSIONS: OARs doses assessed by DVH criteria were higher than ICRU point doses. Our data suggest that the estimated dose to the ICRU bladder point may be a reasonable surrogate for the D 2cc and rectal DMax for D 2cc. However, the dose to the ICRU rectal point does not appear to be a reasonable surrogate for the D 2cc.

    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  2. Fulltext 3D mapping of safe and danger zones in the maxilla and mandible for the placement of intermaxillary fixation screws
    Purmal K, Alam MK, Pohchi A, Abdul Razak NH
    PLoS One, 2013;8(12):e84202.
    PMID: 24367643 DOI: 10.1371/journal.pone.0084202
    Intermaxillary (IMF) screws feature several advantages over other devices used for intermaxillary fixation, but using cone beam computed tomography (CBCT) scans to determine the safe and danger zones to place these devices for all patients can be expensive. This study aimed to determine the optimal interradicular and buccopalatal/buccolingual spaces for IMF screw placement in the maxilla and mandible. The CBCT volumetric data of 193 patients was used to generate transaxial slices between the second molar on the right to the second molar on the left in both arches. The mean interradicular and buccopalatal/buccolingual distances and standard deviation values were obtained at heights of 2, 5, 8 and 11 mm from the alveolar bone crest. An IMF screw with a diameter of 1.0 mm and length of 7 mm can be placed distal to the canines (2 - 11 mm from the alveolar crest) and less than 8 mm between the molars in the maxilla. In the mandible, the safest position is distal to the first premolar (more than 5 mm) and distal to the second premolar (more than 2 mm). There was a significant difference (p<0.05) between the right and left quadrants. The colour coding 3D template showed the safe and danger zones based on the mesiodistal, buccopalatal and buccolingual distances in the maxilla and mandible.The safest sites for IMF screw insertion in the maxilla were between the canines and first premolars and between the first and second molars. In the mandible, the safest sites were between the first and second premolars and between the second premolar and first molar. However, the IMF screw should not exceed 1.0 mm in diameter and 7 mm in length.
    Matched MeSH terms: Cone-Beam Computed Tomography*
  3. Fulltext Spectral-domain optical coherence tomography evaluation of postoperative cystoid macular oedema following phacoemulsification with intraoperative complication
    Khaw KW, Lam HH, Khang TF, Wan Ab Kadir AJ, Subrayan V
    BMC Ophthalmol, 2014;14:16.
    PMID: 24533465 DOI: 10.1186/1471-2415-14-16
    To report the rate of cystoid macular oedema (CMO) as detected by spectral-domain optical coherence tomography (SD-OCT) after intraoperative complication during phacoemulsification. The secondary objectives include comparing mean macular thickness and best-corrected visual acuity (BCVA) between those who developed postoperative CMO against those who did not.
    Matched MeSH terms: Tomography, Optical Coherence/methods*
  4. Retinal nerve fiber layer structure abnormalities in schizophrenia and its relationship to disease state: evidence from optical coherence tomography
    Lee WW, Tajunisah I, Sharmilla K, Peyman M, Subrayan V
    Invest Ophthalmol Vis Sci, 2013 Nov;54(12):7785-92.
    PMID: 24135757 DOI: 10.1167/iovs.13-12534
    We determined structural retinal nerve fiber layer (RNFL) changes in schizophrenia patients and established if the structural changes were related to the duration of the illness using spectral-domain optical coherence tomography (SD-OCT).
    Matched MeSH terms: Tomography, Optical Coherence/methods*
  5. Fulltext Sandstorm appearance of pulmonary alveolar microlithiasis incidentally detected in a young, asymptomatic male
    Ch'ng LS, Bux SI, Liam CK, Rahman NA, Ho CY
    Korean J Radiol, 2013 Sep-Oct;14(5):859-62.
    PMID: 24043987 DOI: 10.3348/kjr.2013.14.5.859
    Pulmonary alveolar microlithiasis (PAM) is a rare chronic disease with paucity of symptoms in contrast to the imaging findings. We present a case of a 24-year-old Malay man having an incidental abnormal pre-employment chest radiograph of dense micronodular opacities giving the classical "sandstorm" appearance. High-resolution computed tomography of the lungs showed microcalcifications with subpleural cystic changes. Open lung biopsy showed calcospherites within the alveolar spaces. The radiological and histopathological findings were characteristic of PAM.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  6. Fulltext The role of repeat head computed tomography in the management of mild traumatic brain injury patients with a positive initial head CT
    Sharifuddin A, Adnan J, Ghani AR, Abdullah JM
    Med J Malaysia, 2012 Jun;67(3):305-8.
    PMID: 23082423 MyJurnal
    This was a prospective observational study done to evaluate the role of a repeat head CT in patients with mild traumatic brain injury. The aim was to evaluate wether the repeat head CT were useful in providing information that leads to any neurosurgical intervention. 279 adult patients with a mild head injury (GCS 13-15) were enrolled, and these comprised of patients with an initial traumatic intracranial haemorrhage not warranting any surgical intervention. All patients were subjected to a repeat head CT within 48 hours of admission and these showed no change or improvements of the brain lesion in 217 patients (79.2%) and worsening in 62 patients (20.8%). In thirty-one patients, surgical intervention was done following the repeat head CT. All of these patients had a clinical deterioration prior to the repeat head CT. Even if a repeat head CT had not been ordered on these patients, they would have had a repeat head CT due to deteriorating neurological status. When the 62 patients with a worsening repeat head CT were compared with the 217 patients with an improved or unchanged repeat head CT, they were found to have older age, lower GCS on admission, presenting symptoms of headache, higher incidence of multiple traumatic intracranial pathology and lower haemoglobin level on admission. On stepwise multiple logistic regression analysis, three factors were found to independently predict a worse repeat head CT (Table IV). This includes age of 65 years or older, GCS score of less than 15 and multiple traumatic intracranial lesion on initial head CT. As a conclusion, we recommend that, in patients with a MTBI and a normal neurological examination, a repeat cranial CT is not indicated, as it resulted in no change in management or neurosurgical intervention. Close monitoring is warranted in a subset of patients with risk factors for a worsening repeat head CT.
    Keywords: Computed tomography, brain injury, Hospital Sultanah Aminah, Johor Bahru, Johor, Malaysia
    Matched MeSH terms: Tomography, X-Ray Computed*
  7. Fulltext Cardiac imaging in valvular heart disease
    Choo WS, Steeds RP
    Br J Radiol, 2011 Dec;84 Spec No 3:S245-57.
    PMID: 22723532 DOI: 10.1259/bjr/54030257
    The aim of this article is to provide a perspective on the relative importance and contribution of different imaging modalities in patients with valvular heart disease. Valvular heart disease is increasing in prevalence across Europe, at a time when the clinical ability of physicians to diagnose and assess severity is declining. Increasing reliance is placed on echocardiography, which is the mainstay of cardiac imaging in valvular heart disease. This article outlines the techniques used in this context and their limitations, identifying areas in which dynamic imaging with cardiovascular magnetic resonance and multislice CT are expanding.
    Matched MeSH terms: Multidetector Computed Tomography/methods
  8. Lethal hemorrhage from a ureteric-arterial-enteric fistula diagnosed by postmortem CT angiography
    Rashid SN, Bouwer H, O'Donnell C
    Forensic Sci Med Pathol, 2012 Dec;8(4):430-5.
    PMID: 22477359 DOI: 10.1007/s12024-012-9332-3
    Fistula formation following pelvic surgery and radiotherapy, including ureteric-arterial fistulas (UAF), is well documented, however, ureteric-arterial-enteric fistula is extremely rare. Conventional autopsy is usually required for the definitive diagnosis of pelvic vascular fistulas although an accurate diagnosis can still be complicated and challenging. The role of post-mortem computed tomography (PMCT) as an adjunct to conventional autopsy is well documented in the literature. One of the limitations of PMCT is the diagnosis of vascular conditions. Post-mortem computed tomography angiography (PMCTA) is a recently introduced technique that can assist in detecting such pathology. We present a case of post-radiotherapy ureteric-arterial-enteric fistula presenting as massive rectal and vaginal bleeding diagnosed prior to autopsy on PMCTA. The role of PMCTA in the diagnosis of such a UAF has not previously been reported in the literature.
    Matched MeSH terms: Tomography, X-Ray Computed*
  9. Coronary CT angiography with single-source and dual-source CT: comparison of image quality and radiation dose between prospective ECG-triggered and retrospective ECG-gated protocols
    Sabarudin A, Sun Z, Yusof AK
    Int J Cardiol, 2013 Sep 30;168(2):746-53.
    PMID: 23098849 DOI: 10.1016/j.ijcard.2012.09.217
    This study is conducted to investigate and compare image quality and radiation dose between prospective ECG-triggered and retrospective ECG-gated coronary CT angiography (CCTA) with the use of single-source CT (SSCT) and dual-source CT (DSCT).
    Matched MeSH terms: Tomography, X-Ray Computed/standards*
  10. 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
  11. Fulltext Imaging findings of a primary bladder maltoma
    Maninderpal KG, Amir FH, Azad HA, Mun KS
    Br J Radiol, 2011 Sep;84(1005):e186-90.
    PMID: 21849361 DOI: 10.1259/bjr/66130737
    Secondary involvement of the urinary bladder in non-Hodgkin's lymphoma is relatively common; however, primary malignant lymphoma of this organ is extremely rare. The most common type of primary bladder lymphoma is a low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphoma. We report here on the imaging findings of a primary bladder lymphoma with bone marrow infiltration.
    Matched MeSH terms: Tomography, X-Ray Computed*
  12. Profiling the features of pre-segmented healthy liver CT scans: towards fast detection of liver lesions in emergency scenario
    Pasha MF, Hong KS, Rajeswari M
    Annu Int Conf IEEE Eng Med Biol Soc, 2011;2011:5169-73.
    PMID: 22255503 DOI: 10.1109/IEMBS.2011.6091280
    Automating the detection of lesions in liver CT scans requires a high performance and robust solution. With CT-scan start to become the norm in emergency department, the need for a fast and efficient liver lesions detection method is arising. In this paper, we propose a fast and evolvable method to profile the features of pre-segmented healthy liver and use it to detect the presence of liver lesions in emergency scenario. Our preliminary experiment with the MICCAI 2007 grand challenge datasets shows promising results of a fast training time, ability to evolve the produced healthy liver profiles, and accurate detection of the liver lesions. Lastly, the future work directions are also presented.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  13. Computed tomographic measurement of cervical pedicles for transpedicular fixation in a Malay population
    Yusof MI, Ming LK, Abdullah MS
    J Orthop Surg (Hong Kong), 2007 Aug;15(2):187-90.
    PMID: 17709859
    To measure the cervical pedicles and assess the feasibility of transpedicular fixation in a Malay population.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  14. Computed tomographic evaluation of the odontoid process for two-screw fixation in type-II fracture: a Malaysian perspective
    Yusof MI, Yusof AH, Abdullah MS, Hussin TM
    J Orthop Surg (Hong Kong), 2007 Apr;15(1):67-72.
    PMID: 17429121
    To measure the diameter of the odontoid process in a Malaysian population using computed tomographic (CT) scan and determine the feasibility of treating type-II odontoid fractures using 2 cortical screws.
    Matched MeSH terms: Tomography, X-Ray Computed*
  15. Clinical evaluation of watermarked medical images
    Zain JM, Fauzi AM, Aziz AA
    Conf Proc IEEE Eng Med Biol Soc, 2007 10 20;2006:5459-62.
    PMID: 17946306
    Digital watermarking medical images provides security to the images. The purpose of this study was to see whether digitally watermarked images changed clinical diagnoses when assessed by radiologists. We embedded 256 bits watermark to various medical images in the region of non-interest (RONI) and 480K bits in both region of interest (ROI) and RONI. Our results showed that watermarking medical images did not alter clinical diagnoses. In addition, there was no difference in image quality when visually assessed by the medical radiologists. We therefore concluded that digital watermarking medical images were safe in terms of preserving image quality for clinical purposes.
    Matched MeSH terms: Tomography, X-Ray Computed/methods*
  16. Fulltext The prognostic value of early follow-up computerized tomography of the brain in adult traumatic brain injury
    Kiflie A, Alias NA, Abdul-Kareem MM, Mar W, Abdullah J, Naing NN
    Med J Malaysia, 2006 Oct;61(4):466-73.
    PMID: 17243525 MyJurnal
    A total of 31 adult patients with moderate and severe head injury were assessed clinically on admission for Glasgow Coma Scale (GCS) and short test of mental status (STMS) on follow-up and compared to their initial and follow up CT scan. Good predictors were admission GCS, midline shift, volume of subdural haemorrhage in the initial CT scan of the brain as well as the presence of post-traumatic hydrocephalus, gliosis and site of gliosis in the follow-up CT scan. There was no direct correlation between the significant predictors on the first CT scan and the follow-up CT scan of the brain.
    Matched MeSH terms: Tomography, Emission-Computed*
  17. Design and fabrication of scaffolds for anatomic bone reconstruction
    Hollister SJ, Lin CY, Lin CY, Schek RD, Taboas JM, Flanagan CL, et al.
    Med J Malaysia, 2004 May;59 Suppl B:131-2.
    PMID: 15468853
    Matched MeSH terms: Tomography, X-Ray Computed*
  18. Kostmann's syndrome
    Joazlina ZY, Wastie ML, Kamarulzaman A
    Clin Imaging, 2005 Sep-Oct;29(5):364-6.
    PMID: 16153548
    Kostmann's syndrome is a rare congenital disorder of neutrophil production due to impairment of myeloid differentiation in the bone marrow, with the neutrophil count being characteristically less than 500 x 10(3) cells/l (normal: 2-7 x 10(9)/l). Severe persistent neutropenia results in an increased susceptibility to frequent bacterial infections. The condition can be treated with recombinant human granulocyte colony-stimulating factor (G-CSF). Although several articles have addressed the clinicopathological and haematological aspects of this disorder, little or no information has been available concerning the radiological findings in this disorder. This report summarizes the clinical features, radiological findings and management of a patient with Kostmann's syndrome.
    Matched MeSH terms: Tomography, X-Ray Computed*
  19. 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*
  20. Contrast media induced transient cortical blindness
    Balasingam S, Azman RR, Nazri M
    QJM, 2016 Feb;109(2):121-2.
    PMID: 26101228 DOI: 10.1093/qjmed/hcv121
    Matched MeSH terms: Tomography, X-Ray Computed/methods
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