Displaying publications 121 - 140 of 1500 in total

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  1. Abdullah KA, McEntee MF, Reed WM, Kench PL
    J Appl Clin Med Phys, 2020 Sep;21(9):209-214.
    PMID: 32657493 DOI: 10.1002/acm2.12977
    PURPOSE: The purpose of this study was to investigate the effect of increasing iterative reconstruction (IR) algorithm strength at different tube voltages in coronary computed tomography angiography (CCTA) protocols using a three-dimensional (3D)-printed and Catphan® 500 phantoms.

    METHODS: A 3D-printed cardiac insert and Catphan 500 phantoms were scanned using CCTA protocols at 120 and 100 kVp tube voltages. All CT acquisitions were reconstructed using filtered back projection (FBP) and Adaptive Statistical Iterative Reconstruction (ASIR) algorithm at 40% and 60% strengths. Image quality characteristics such as image noise, signal-noise ratio (SNR), contrast-noise ratio (CNR), high spatial resolution, and low contrast resolution were analyzed.

    RESULTS: There was no significant difference (P > 0.05) between 120 and 100 kVp measures for image noise for FBP vs ASIR 60% (16.6 ± 3.8 vs 16.7 ± 4.8), SNR of ASIR 40% vs ASIR 60% (27.3 ± 5.4 vs 26.4 ± 4.8), and CNR of FBP vs ASIR 40% (31.3 ± 3.9 vs 30.1 ± 4.3), respectively. Based on the Modulation Transfer Function (MTF) analysis, there was a minimal change of image quality for each tube voltage but increases when higher strengths of ASIR were used. The best measure of low contrast detectability was observed at ASIR 60% at 120 kVp.

    CONCLUSIONS: Changing the IR strength has yielded different image quality noise characteristics. In this study, the use of 100 kVp and ASIR 60% yielded comparable image quality noise characteristics to the standard CCTA protocols using 120 kVp of ASIR 40%. A combination of 3D-printed and Catphan® 500 phantoms could be used to perform CT dose optimization protocols.

    Matched MeSH terms: Tomography, X-Ray Computed*; Computed Tomography Angiography*
  2. Eng, K.J., Safinaz, M.K., Malisa, A.
    Medicine & Health, 2020;15(2):306-312.
    MyJurnal
    Sindrom distensi beg kapsul ialah salah satu komplikasi yang jarang berlaku selepas fakoemulsifikasi dengan implan kanta intraokular dimasukkan ke dalam bag kanta dalam mata. Kami menerangkan satu kes sindrom distensi beg kapsul yang berlaku pada seorang lelaki berusia pertengahan yang menjalani fakoemulsifikasi dengan ‘plat haptic’ implan kanta intraokular (Zeiss CT ASPHINA 509MP) ke dalam mata kanan. Penglihatan mata kanan semasa pemeriksaan susulan 1 minggu and susulan 5 minggu selepas pembedahan tidak menunjukan penambahbaikan dengan refraksi kuasa mata bertukar menjadi minus 2.5 diopter. Tekanan intraokular hanya meningkat pada 2 jam selepas pembedahan dan normal semasa pemeriksaan susulan berikutnya. Beg kapsul distensi telah disahkan dengan menggunakan IOL Master 700. IOL Master 700 menunjukkan pengasingan abnormal beg kapsul dari implan kanta intraokular. Diagnosis sindrom distensi beg kapsul yang disebabkan oleh pengekalan viskoelastik dibuat. Pengeluaran viskoelastik yang tertinggal di dalam mata kanan telah dilakukan dan sindrom distensi beg kapsul berjaya diselesaikan dengan penglihatan mata kanan kembali ke 6/6. Oleh itu, pengeluaran viskoelastik dengan sepenuhnya semasa fakoemulsifikasi dengan ‘plat haptic’ implan kanta intrakular adalah penting untuk mengelakkan sindrom distensi beg kapsul.
    Matched MeSH terms: Tomography, X-Ray Computed
  3. Ibrahim N, Parsa A, Hassan B, van der Stelt P, Rahmat RA, Ismail SM, et al.
    BMC Oral Health, 2021 05 08;21(1):249.
    PMID: 33964918 DOI: 10.1186/s12903-021-01595-z
    BACKGROUND: The aim of this study was to compare the trabecular bone microstructures of anterior and posterior edentulous regions of human mandible using cone-beam computed tomography (CBCT) and micro computed tomography (µCT).

    METHODS: Twenty volumes of interests consisting of six anterior and fourteen posterior edentulous regions were obtained from human mandibular cadavers. A CBCT system with a resolution of 80 µm (3D Accuitomo 170, J. Morita, Kyoto, Japan) and a µCT system with a resolution of 35 µm (SkyScan 1173, Kontich, Belgium) were used to scan the mandibles. Three structural parameters namely, trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp) were analysed using CTAn software (v 1.11, SkyScan, Kontich, Belgium). For each system, the measurements obtained from anterior and posterior regions were tested using independent sample t-test. Subsequently, all measurements between systems were tested using paired t-test.

    RESULTS: In CBCT, all parameters of the anterior and posterior mandible showed no significant differences (p > 0.05). However, µCT showed a significant different of Tb.Th (p = 0.023) between anterior and posterior region. Regardless of regions, the measurements obtained using both imaging systems were significantly different (p ≤ 0.021) for Tb.Th and Tb.N.

    CONCLUSIONS: The current study demonstrated that only the variation of Tb.Th between anterior and posterior edentulous region of mandible can be detected using µCT. In addition, CBCT is less feasible than µCT in assessing trabecular bone microstructures at both regions.

    Matched MeSH terms: Cone-Beam Computed Tomography
  4. Alsaih K, Yusoff MZ, Tang TB, Faye I, Mériaudeau F
    Comput Methods Programs Biomed, 2020 Oct;195:105566.
    PMID: 32504911 DOI: 10.1016/j.cmpb.2020.105566
    BACKGROUND AND OBJECTIVES: Aged people usually are more to be diagnosed with retinal diseases in developed countries. Retinal capillaries leakage into the retina swells and causes an acute vision loss, which is called age-related macular degeneration (AMD). The disease can not be adequately diagnosed solely using fundus images as depth information is not available. The variations in retina volume assist in monitoring ophthalmological abnormalities. Therefore, high-fidelity AMD segmentation in optical coherence tomography (OCT) imaging modality has raised the attention of researchers as well as those of the medical doctors. Many methods across the years encompassing machine learning approaches and convolutional neural networks (CNN) strategies have been proposed for object detection and image segmentation.

    METHODS: In this paper, we analyze four wide-spread deep learning models designed for the segmentation of three retinal fluids outputting dense predictions in the RETOUCH challenge data. We aim to demonstrate how a patch-based approach could push the performance for each method. Besides, we also evaluate the methods using the OPTIMA challenge dataset for generalizing network performance. The analysis is driven into two sections: the comparison between the four approaches and the significance of patching the images.

    RESULTS: The performance of networks trained on the RETOUCH dataset is higher than human performance. The analysis further generalized the performance of the best network obtained by fine-tuning it and achieved a mean Dice similarity coefficient (DSC) of 0.85. Out of the three types of fluids, intraretinal fluid (IRF) is more recognized, and the highest DSC value of 0.922 is achieved using Spectralis dataset. Additionally, the highest average DSC score is 0.84, which is achieved by PaDeeplabv3+ model using Cirrus dataset.

    CONCLUSIONS: The proposed method segments the three fluids in the retina with high DSC value. Fine-tuning the networks trained on the RETOUCH dataset makes the network perform better and faster than training from scratch. Enriching the networks with inputting a variety of shapes by extracting patches helped to segment the fluids better than using a full image.

    Matched MeSH terms: Tomography, Optical Coherence
  5. Hariri F, Zainudin NAA, Anuar AMS, Ibrahim N, Abdullah NA, Aziz IA, et al.
    J Craniofac Surg, 2020 11 7;32(1):355-359.
    PMID: 33156163 DOI: 10.1097/SCS.0000000000006981
    BACKGROUND: In syndromic craniosynostosis (SC), unlike persistent corneal irritation due to severe exophthalmos and increased intracranial pressure, optic canal (OC) stenosis has been scarcely reported to cause visual impairment. This study aimed to validate the OC volumetric and surface area measurement among SC patients.

    METHODS: Sixteen computed tomography scan of SC patients (8 months-6 years old) were imported to Materialise Interactive Medical Image Control System (MIMICS) and Materialise 3-matics software. Three-dimensional (3D) OC models were fabricated, and linear measurements were obtained. Mathematical formulas were used for calculation of OC volume and surface area from the 3D model. The same measurements were obtained from the software and used as ground truth. Data normality was investigated before statistical analyses were performed. Wilcoxon test was used to validate differences of OC volume and surface area between 3D model and software.

    RESULTS: The mean values for OC surface area for 3D model and MIMICS software were 103.19 mm2 and 31.27 mm2, respectively, whereas the mean for OC volume for 3D model and MIMICS software were 184.37 mm2 and 147.07 mm2, respectively. Significant difference was found between OC volume (P = 0.0681) and surface area (P = 0.0002) between 3D model and software.

    CONCLUSION: Optic canal in SC is not a perfect conical frustum thus making 3D model measurement and mathematical formula for surface area and volume estimation not ideal. Computer software remains the best modality to gauge dimensional parameter and is useful to elucidates the relationship of OC and eye function as well as aiding intervention in SC patients.

    Matched MeSH terms: Tomography, X-Ray Computed
  6. Chen EJ, Tan TH, Chew MT, Chye PC
    Clin Nucl Med, 2020 Jul;45(7):e317-e319.
    PMID: 32404702 DOI: 10.1097/RLU.0000000000003053
    Recent case reports and series have demonstrated the usefulness of Ga/F-PSMA PET/CT in restaging recurrent renal cancer after nephrectomy. We presented a case of a patient with renal mass who had undergone both F-FDG and Ga-PSMA PET/CT for diagnosis and staging. Concordant tracer uptake in the primary tumor and metastatic lesions was demonstrated by both radiotracers. Final histopathological reports revealed clear cell renal cell carcinoma. Furthermore, unusual left metacarpal bone metastasis was also detected.
    Matched MeSH terms: Positron Emission Tomography Computed Tomography*
  7. Ch'ng TW, Gillmann K, Hoskens K, Rao HL, Mermoud A, Mansouri K
    Eye (Lond), 2020 03;34(3):562-571.
    PMID: 31409906 DOI: 10.1038/s41433-019-0560-6
    OBJECTIVES: To determine the effect of surgical intraocular pressure (IOP) lowering on peripapillary retinal nerve fibre layer thickness (RNFL), fovea avascular zone (FAZ), peripapillary and macular vessel density (VD) in glaucoma using with optical coherence tomography angiography (OCT-A).

    METHODS: This was a prospective observational study performed at the Glaucoma Research Centre, Montchoisi Clinic, Lausanne. In total 40 eyes with open-angle glaucoma were included. OCT-A scans were performed before glaucoma surgery, and at 1-month, 3-month, 6-month, and 12-month post-operatively. AngioVue AngioAnalytic (Optovue Inc, Fremont, CA) software was used to analyse the RNFL, FAZ, peripapillary and macular VD. Changes were analysed using analysis of variance (ANOVA) models.

    RESULTS: Mean IOP dropped from 19.4 (±7.0) mmHg pre-surgery and stabilized at 13.0 (±3.1) mmHg at 12 months (p 

    Matched MeSH terms: Tomography, Optical Coherence
  8. Nizam, A., Gopal, R.N., Naing, L., Hakim, A.B., Samsudin, A.R.
    MyJurnal
    The purpose of this study was to determine the dimensional accuracy of the skull models produced by Rapid prototyping technology using stereolithography apparatus. Computed tomography images were captured from four dry normal adult human skulls. The resultant 2-D images were stored in Digital Imaging and Communications in Medicine (DICOM) format. The segmentation of the images was prepared in MIMICS software. The slice files were then exported to a stereolithography apparatus (SLA) to produce the replica of each skull. Eight linear measurements were repeatedly made between identified landmarks on each of the original skull and its replica model using an electronic digital calliper. Each of the linear measurements was repeated 5 times and the average was taken to determine the absolute difference and percent difference between the original skull and its replica model. The overall absolute difference between the four human adult skulls and its replica models was 0.23 mm with a standard deviation of 1.37 mm. The percent difference was 0.08% with a standard deviation of 1.25%. The degree of error established by this system seems affordable in clinical applications when these models are used in the field of dental surgery for surgical treatment planning.
    Matched MeSH terms: Tomography, X-Ray Computed
  9. Abu Hassan H, Suppiah S
    Ann Acad Med Singap, 2016 Dec;45(12):567-568.
    PMID: 28062887
    Matched MeSH terms: Tomography, X-Ray Computed
  10. Juanna Bahadun, Abou-Hamden, Amal, Anderson, Peter J.
    MyJurnal
    Paediatric facial traumas are often accompanied by other intracranial and non-head injuries. Use of
    Computed Tomography (CT) has increased diagnostic accuracy when compared to plain radiographs alone. Coexisting anomalies can sometimes be a chance finding from the imagings and this highlights the need of a formalreporting by a radiologist. We report a case of a traumatic unilateral condylar fracture with a coexisting life-threatening abnormality detected from careful assessment of the imagings.
    Matched MeSH terms: Tomography, X-Ray Computed
  11. Haszelini Hassan, Hikmah Mohd Nor, Nur Athiah Shaberi, Nur Aqila Syaqina Zuber, Nur Hasnaa Hishamudin
    MyJurnal
    Adequate space is required in the interforaminal region for anterior mandibular
    surgery, where the anterior loop is located within this region. The aim of this study is to evaluate
    the prevalence of the anterior loop (AL) of the inferior alveolar nerve, and to measure its length
    and position in patients attending Kulliyyah of Dentistry using cone beam computed tomography
    (CBCT). (Copied from article).
    Matched MeSH terms: Cone-Beam Computed Tomography
  12. Tan TH, Lai CNB
    Clin Nucl Med, 2017 Aug;42(8):622-623.
    PMID: 28632691 DOI: 10.1097/RLU.0000000000001730
    A 47-year-old man with newly diagnosed nasopharyngeal carcinoma underwent staging F-FDG PET/CT. Apart from showing increased FDG uptake in the primary site and locoregional nodal and liver metastases, an unusual site of intense FDG focus was demonstrated in the left adrenal gland. He underwent CT-guided biopsy, and the histopathologic diagnosis was benign fibrous histiocytoma.
    Matched MeSH terms: Positron Emission Tomography Computed Tomography*
  13. Subapriya Suppiah, Andi Anggeriana Andi Asri, Fathinul Fikri Ahmad Saad, Hasyma Abu Hassan, Norhafizah Mohtarrudin, Chang, Wing Liong, et al.
    MyJurnal
    Introduction: Suspicious adnexal masses need to be investigated thoroughly as it may represent ovarian cancer, which is the fourth most common gynaecological cancer in Malaysia. Conventional cross sectional imaging may reveal non-specific findings, thus lead to unnecessary biopsies. 18F-Fluorodeoxyglucose positron emission tomography/ computed tomography (18F-FDG PET/CT) has emerged as a useful tool, for characterization of indeterminate adnexal masses. Most studies have been conducted in Western population, and little information is available in Asian population in general and Malaysian population in particular. Methods: Prospective study of women with suspicious adnexal masses, referred to the Centre for Nuclear Diagnostic Imaging, Universiti Putra Malaysia to undergo pre-operative whole-body contrast-enhanced 18F-FDG PET/CT scans from January 2014 to January 2016. Subjects underwent Contrast-Enhanced Computed Tomography (CECT) scans followed by positron emission tomography (PET) scans using a hybrid scanner. Two radiologists analyzed the CECT and PET/CT images by consensus; blinded to the HPE results. Then the PET/CT findings were correlated with HPE results as the gold standard. Results: 11 whole-body PET/CT scans and 18 adnexal masses (12 HPE-proven malignant lesions and 6 benign lesions) were analyzed. The sensitivity, specificity, PPV, and NPV of CECT alone compared to PET/CT was 91.7%, 50.0%, 78.6%, and 75.0% vs. 91.7%, 100%, 100% and 85.7% respectively. Conclusions: Improved diagnostic accuracy for characterizing benign and malignant adnexal masses can be achieved using contrast-enhanced 18F-FDG PET/CT, making it a potential investigation of choice which can help in treatment planning.
    Matched MeSH terms: Tomography, X-Ray Computed; Positron-Emission Tomography; Positron Emission Tomography Computed Tomography
  14. Gao X, Guo L, Li J, Thu HE, Hussain Z
    J Control Release, 2018 12 28;292:29-57.
    PMID: 30359665 DOI: 10.1016/j.jconrel.2018.10.024
    Lung cancer (LC) is the second most prevalent type of cancer and primary cause of mortality among both men and women, worldwide. The most commonly employed diagnostic modalities for LC include chest X-ray (CXR), magnetic-resonance-imaging (MRI), computed tomography (CT-scan), and fused-positron-emitting-tomography-CT (PET-CT). Owing to several limitations associated with the use of conventional diagnostic tools such as radiation burden to the patient, misleading diagnosis ("missed lung cancer"), false staging and low sensitivity and resolution, contemporary diagnostic regimen needed to be employed for screening of LC. In recent decades, nanotechnology-guided interventions have been transpired as emerging nanoimaging probes for detection of LC at advanced stages, while producing signal amplification, better resolution for surface and deep tissue imaging, and enhanced translocation and biodistribution of imaging probes within the cancerous tissues. Besides enormous potential of nanoimaging probes, nanotechnology-based advancements have also been evidenced for superior efficacy for treatment of LC and abolishing pulmonary metastasis (PM). The success of nanotherapeutics is due to their ability to maximise translocation and biodistribution of anti-neoplastic agents into the tumor tissues, improve pharmacokinetic profiles of anti-metastatic agents, optimise target-specific drug delivery, and control release kinetics of encapsulated moieties in target tissues. This review aims to overview and critically discuss the superiority of nanoimaging probes and nanotherapeutics over conventional regimen for early detection of LC and abolishing PM. Current challenges to clinical transition of nanoimaging probes and therapeutic viability of nanotherapeutics for treatment for LC and PM have also been pondered.
    Matched MeSH terms: Tomography, X-Ray Computed; Positron-Emission Tomography; Positron Emission Tomography Computed Tomography
  15. Ting FF, Sim KS, Lim CP
    Comput Med Imaging Graph, 2018 11;69:82-95.
    PMID: 30219737 DOI: 10.1016/j.compmedimag.2018.08.011
    Computed Tomography (CT) images are widely used for the identification of abnormal brain tissues following infarct and hemorrhage of a stroke. The treatment of this medical condition mainly depends on doctors' experience. While manual lesion delineation by medical doctors is currently considered as the standard approach, it is time-consuming and dependent on each doctor's expertise and experience. In this study, a case-control comparison brain lesion segmentation (CCBLS) method is proposed to segment the region pertaining to brain injury by comparing the voxel intensity of CT images between control subjects and stroke patients. The method is able to segment the brain lesion from the stacked CT images automatically without prior knowledge of the location or the presence of the lesion. The aim is to reduce medical doctors' burden and assist them in making an accurate diagnosis. A case study with 300 sets of CT images from control subjects and stroke patients is conducted. Comparing with other existing methods, the outcome ascertains the effectiveness of the proposed method in detecting brain infarct of stroke patients.
    Matched MeSH terms: Tomography, X-Ray Computed
  16. Nurwahidah, M., Wan, E.Z.W.A.R., Shaharuddin, C.S.
    MyJurnal
    This paper presents the application of active contours region-based method of image segmentation to Computed Tomography (CT) images. Previous researchers applied this region based method on Magnetic Resonance Image (MRI), in vivo images and synthetic images which contain intensity inhomogeneities. In this paper, a different modality known as Computed Tomography (CT) scan was applied. CT scan also produces images containing intensity inhomogeneity, and it is predicted that this method provide good segmentation results. The main objective of applying this method is to check its applicability on CT images. The segmentation process begins by finding the area of interest (black region). Results from this experiment are then used in estimating time of death. Experimental results show that this method has successfully segmented the black region when some parameters changed, provided that the regions are closed to each other. If the black regions are located far from each other, then this method will only segment certain areas.
    Matched MeSH terms: Tomography, X-Ray Computed
  17. Md Noh MSF, Abdul Rashid AM, Ar A, B N, Mohammed Y, A R E
    BJR Case Rep, 2017;3(3):20170006.
    PMID: 30363220 DOI: 10.1259/bjrcr.20170006
    Emphysematous aortitis is a rare condition that manifests through the presence of air within or surrounding the inflamed aorta. Aortic inflammation may result from either an infective or a non-infective cause. Recognition of this rare condition is important as the resultant clinical deterioration may be rapid and lead to inevitable death. Cross-sectional imaging, with its relatively wide availability, proves an important tool in the diagnosis and subsequent management of this condition. We report two such cases encountered in our centre, with particular focus on the imaging findings on CT.
    Matched MeSH terms: Tomography, X-Ray Computed
  18. Majid Y, Warade M, Sinha J, Kalyanpur A, Gupta T
    Biomed Imaging Interv J, 2011 01 01;7(1):e2.
    PMID: 21655111 DOI: 10.2349/biij.7.1.e2
    Noninvasive imaging of coronary artery disease is rapidly replacing angiography as the first line of investigation. Multislice CT is the non-invasive modality of choice for imaging coronary artery disease and provides high speed with good spatial resolution. CT coronary angiography in addition to detecting and characterising atherosclerotic coronary artery disease is also a good imaging tool for evaluating anomalies of coronary arteries. Superdominant right coronary artery with absent left circumflex artery is one such rare coronary artery anomaly which is well evaluated with multislice CT angiography. The authors report one such case of superdominant right coronary artery with absent left circumflex artery imaged with 64-slice MDCT.
    Matched MeSH terms: Computed Tomography Angiography
  19. Ong TK, Harun N, Lim TW
    Eur Endod J, 2019;4(2):90-95.
    PMID: 32161894 DOI: 10.14744/eej.2019.13007
    In this case report, three teeth with complete or incomplete cemental tear in two patients were presented. Even though periapical radiograph could detect cemental tear in these three teeth, the cone-beam computed tomography scanning clearly revealed the pattern of the cemental tear, which was later confirmed by histopathological examination. Therefore, this case report shows the benefits of incorporating both cone-beam computed tomography and histopathological examination to diagnose cemental tear.
    Matched MeSH terms: Cone-Beam Computed Tomography
  20. Isa INC, Rahmat SMS, Dom SM, Kayun Z, Karim MKA
    J Xray Sci Technol, 2019;27(4):631-639.
    PMID: 31205011 DOI: 10.3233/XST-190491
    There are several factors that may contribute to the increase in radiation dose of CT including the use of unoptimized protocols and improper scanning technique. In this study, we aim to determine significant impact on radiation dose as a result of mis-centering during CT head examination. The scanning was performed by using Toshiba Aquilion 64 slices multi-detector CT (MDCT) scanner and dose were measured by using calibrated ionization chamber. Two scanning protocols of routine CT head; 120 kVp/ 180 mAs and 100 kVp/ 142 mAs were used represent standard and low dose, respectively. As reference measurement, the dose was first measured on standard cylindrical polymethyl methacrylate (PMMA) phantom that positioned at 104 cm from the floor (reference isocenter). The positions then were varied to simulate mis-centering by 5 cm from isocenter, superiorly and inferiorly at 109 cm, 114 cm, 119 cm, 124 cm and 99 cm, 94 cm, 89 cm, 84 cm, respectively. Scanning parameter and dose information from the console were recorded for the radiation effective dose (E) measurement. The highest mean CTDIvol value for MCS and MCI were 105.06 mGy (at +10 cm) and 105.51 mGy (at - 10 cm), respectively which differed significantly (p 
    Matched MeSH terms: Tomography, X-Ray Computed/standards*; Tomography Scanners, X-Ray Computed/standards*
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