ORCID Profile
0000-0002-5849-5857
Current Organisation
Curtin University
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Publisher: Wiley
Date: 10-2009
Publisher: MDPI AG
Date: 17-11-2022
DOI: 10.3390/APP122211681
Abstract: Various commercial auto-contouring solutions have emerged over past few years to address labor-intensiveness, and inter- and intra-operator variabilities issues of traditional manual anatomy contouring for head and neck (H& N) radiation therapy (RT). The purpose of this study is to compare the clinical performances between RaySearch Laboratories deep learning (DL) and atlas-based auto-contouring tools for organs at risk (OARs) segmentation in the H& N RT with the manual contouring as reference. Forty-five H& N computed tomography datasets were used for the DL and atlas-based auto-contouring tools to contour 16 OARs and time required for the segmentation was measured. Dice similarity coefficient (DSC), Hausdorff distance (HD) and HD 95th-percentile (HD95) were used to evaluate geometric accuracy of OARs contoured by the DL and atlas-based auto-contouring tools. Paired s le t-test was employed to compare the mean DSC, HD, HD95, and contouring time values of the two groups. The DL auto-contouring approach achieved more consistent performance in OARs segmentation than its atlas-based approach, resulting in statistically significant time reduction of the whole segmentation process by 40% (p 0.001). The DL auto-contouring had statistically significantly higher mean DSC and lower HD and HD95 values (p 0.001–0.009) for 10 out of 16 OARs. This study proves that the RaySearch Laboratories DL auto-contouring tool has significantly better clinical performances than its atlas-based approach.
Publisher: Elsevier BV
Date: 09-2011
DOI: 10.1016/J.CMPB.2010.07.008
Abstract: The diagnostic reference levels (DRLs) concept is a methodology proposed by the International Commission on Radiological Protection (ICRP) for identifying any unusual high patient doses involved in radiological examinations. However, some challenges are anticipated in the DRLs concept including resource demand for running the audit cycle by in idual imaging departments and availability of DRLs. The objective of this study was to develop an online automatic DRLs management system for digital radiography (DR) with the aim of addressing the challenges of the DRLs obligation. An online automatic DRLs management system for DR composed of freeware was developed. The system was tested with 75 DR images. This pilot experience shows that the system successfully addresses the challenges in the DRLs management, i.e. resource demand for running the audit cycle by in idual imaging departments and availability of DRLs. It can provide at a low cost an efficient and effective solution to the implementation of regular audits of patient doses using DR in busy clinical departments. It can also contribute to the development of DRLs at local and national levels. In this way, any unacceptable radiological practice (examination used unjustified high radiation dose) can be identified.
Publisher: The Korean Society of Radiology
Date: 2010
Publisher: MDPI AG
Date: 14-07-2022
Abstract: Radiation dose optimization is particularly important in pediatric radiology, as children are more susceptible to potential harmful effects of ionizing radiation. However, only one narrative review about artificial intelligence (AI) for dose optimization in pediatric computed tomography (CT) has been published yet. The purpose of this systematic review is to answer the question “What are the AI techniques and architectures introduced in pediatric radiology for dose optimization, their specific application areas, and performances?” Literature search with use of electronic databases was conducted on 3 June 2022. Sixteen articles that met selection criteria were included. The included studies showed deep convolutional neural network (CNN) was the most common AI technique and architecture used for dose optimization in pediatric radiology. All but three included studies evaluated AI performance in dose optimization of abdomen, chest, head, neck, and pelvis CT CT angiography and dual-energy CT through deep learning image reconstruction. Most studies demonstrated that AI could reduce radiation dose by 36–70% without losing diagnostic information. Despite the dominance of commercially available AI models based on deep CNN with promising outcomes, homegrown models could provide comparable performances. Future exploration of AI value for dose optimization in pediatric radiology is necessary due to small s le sizes and narrow scopes (only three modalities, CT, positron emission tomography/magnetic resonance imaging and mobile radiography, and not all examination types covered) of existing studies.
Publisher: AME Publishing Company
Date: 2019
Publisher: American Scientific Publishers
Date: 04-2014
Publisher: Wiley
Date: 10-2013
Publisher: Hindawi Limited
Date: 13-06-2013
DOI: 10.1111/IJCP.12186
Abstract: In assessing patients with headaches, general practitioners (GPs) play an important role in determining which patients require computed tomography (CT) scans. The purpose of this study was to identify factors that influence GPs' decisions to refer CT scans for patients with headaches. A self-administered survey was presented to GPs in Western Australia. One hundred and twenty-eight vignettes describing patients who may have required CT referral for headache were constructed encompassing six clinical variables. Nine vignettes, selected at random, were presented to each respondent. Respondents were asked if they would refer the patient for diagnostic imaging tests, if so, which imaging modalities would they request, how urgently and the perceived benefits of the requested imaging modality. Multinomial logistic regression was used for the multivariate analysis. We received 105 completed questionnaires (21%). GPs were more likely to refer patients with headaches for diagnostic imaging and CT scans in the following clinical scenarios: patients with a history of colorectal cancer and epilepsy and patients feeling unwell for the past 6 weeks and headache being exacerbated with valsalva manoeuvrers. Private health insurance and other respondent demographics such as GPs experience and site of care increased imaging referral. GP's referral decisions of diagnostic imaging and CT examinations for patients with headaches are dependent on clinical scenarios and the likelihood of a significant pathology. Further research is required to identify the significant clinical findings with regard to the CT referrals and ensure that CT scans are not requested in patients who are unlikely to benefit.
Publisher: Elsevier BV
Date: 08-2005
Publisher: Hindawi Limited
Date: 2009
DOI: 10.1093/ECAM/NEM100
Abstract: Using an adjuvant-induced arthritis rat model, we investigated the effects of a lipid extract of Perna canaliculus (Lyprinol®) on pain. Radiological examinations, as well as levels of pro- and anti-inflammatory (AI) cytokines, were measured aiming to provide independent objective data to the pain controlling investigation. We confirmed the ability of Lyprinol® to control pain at the initial phase of its administration with similar efficacy to that observed with Naproxen. The pain scores slowly increased again in the group of rats treated with Lyprinol® after day 9–14. The Naproxen-treated rats remained pain-free while treated. Both Naproxen and Lyprinol® decreased the levels of the pro-inflammatory cytokines TNF-α and IFN-γ, and increased that of IL-10. Extra-virgin olive oil was ineffective on cytokine secretion. Rats treated with Lyprinol® were apparently cured after 1 year. This study confirms the AI efficacy of this lipid extract of P. canaliculus , its initial analgesic effect, its perfect tolerance and its long-term healing properties.
Publisher: American Scientific Publishers
Date: 08-2021
Abstract: Introduction : Three-dimensional (3D) printing provides an opportunity to develop anthropomorphic computed tomography (CT) phantoms with anatomical and radiological features mimicking a range of patients’ conditions, thus allowing development of in idualised, low dose scanning protocols. However, previous studies of 3D printing in CT phantom development could only create anatomical structures using potassium iodide with attenuation values up to 1200 HU which is insufficient to mimic the radiological features of some high attenuation structures such as cortical bone. This study aimed at investigating the feasibility of using 3D printing in modelling cortical bone with a non-iodinated material. Methods : This study had 2 stages. Stage 1 involved a vat photopolymerisation 3D printer to directly print cube phantoms with different percentage compositions of calcium phosphate (CP) and resin (approach 1), and approach 2 using a material extrusion 3D printer to develop a cube mould for infilling of the CP with hardener as the phantom. The approach able to create the cube phantom with the CT attenuation value close to that of a tibial mid-diaphysis cortex of a real patient, 1475±205 HU was employed to develop a tibial mid-diaphysis phantom. The mean CT numbers of the cube and tibia phantoms were measured and compared with that of the original CT dataset through unpaired t-test. Results : All phantoms were scanned by CT using a lower extremity scanning protocol. The moulding approach was selected to develop the tibia middiaphysis phantom with CT attenuation value, 1434±184 HU which was not statistically significantly different from the one of the original dataset ( p = 0.721). Conclusion : This study demonstrates the feasibility to use the material extrusion 3D printer to create a tibial mid-diaphysis mould for infilling of the CP as an anthropomorphic CT phantom and the attenuation value of its cortex matches the real patient’s one.
Publisher: American Scientific Publishers
Date: 08-2017
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.RADI.2019.06.003
Abstract: Immobilisation may be necessary to ensure patient safety and examination success in paediatric medical imaging. Little guidance exists regarding the selection of different immobilisation methods. The purpose of this study was to explore radiographers' selection of immobilisation methods in paediatric medical imaging and the influences on their choices. Ethical approval was obtained. A mixed methods approach consisting of online questionnaire distribution followed by in idual interviews was used to explore Australasian radiographers' self-reported patterns of immobilisation use and the underlying reasons and beliefs. Quantitative data were described using frequency data, with a Fisher's Exact test used to determine any association between demographic variables and immobilisation methods. Qualitative data were evaluated using content analysis. Sixty-five radiographers returned completed questionnaires, with seven participating in interviews. Psychological immobilisation methods were preferred to minimise patient pain and distress, but physical methods were considered more effective, with parental holding the most likely method to be used (63/65, 96.9%). Participants assumed certain methods to be more appropriate based on patient age and examination type, but adapted their choices based on many other factors, seeking to provide personalised care. Further training was strongly desired (48/64, 75.0%). Participants disagreed on whether introducing written guidance would be beneficial (33/62, 53.2%). Choosing an immobilisation method appears to be a case-by-case activity requiring critical assessment of multiple factors in order to balance patient care with examination success. Improvements in quality and quantity of education are recommended to enhance radiographers' ability to make choices based on all relevant factors.
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1016/J.ACRA.2010.03.004
Abstract: The aim of the study was to investigate the optimal protocols of dual-source computed tomography (CT) angiography in aortic stent grafting in terms of image noise and radiation dose, based on an in vitro phantom study. A series of helical CT cans were performed on a human aorta phantom using a dual-source CT scanner with kVp of 100, 120, and 140, corresponding mAs of 180, 150, and 100 slice thickness of 1.0, 1.5, and 2.0 mm and pitch value of 0.5, 1.0, and 1.5, respectively. Image quality was determined by measuring the standard deviation (SD) on three-dimensional virtual intravascular endoscopy (VIE) images. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured on two-dimensional (2D) axial images at superior mesenteric artery (SMA), renal arteries, and aneurysm. Effective dose was determined based on dose-length product. SD measured on VIE images was independent of kVp and pitch values but was determined by the slice thickness (P < .05) at the SMA and renal arteries. SNR and CNR measured on 2D images showed significant differences between variable kVp values and slice thicknesses (P < .05), but were independent of pitch values. The mean estimated effective dose for 120 kVp and 140 kVp protocols were 2.66 +/- 0.21 mSv and 2.68 +/- 0.18 mSv, respectively. The mean estimated effective dose for 100 kVp protocol was significantly lower (1.97 +/- 0.07 mSv, P < .0001). This indicates a reduction of 26.5% radiation dose when the kVp was lowered from 140 to 100. A scanning protocol of 1.5-mm slice thickness, pitch 1.5 with 100 kVp, and 180 mAs is recommended for a dual-source CT angiography in aortic stent grafting as it leads to significant reduction of radiation dose while achieving diagnostic images.
Publisher: Elsevier BV
Date: 2010
DOI: 10.1016/J.CMPB.2009.07.001
Abstract: Recent studies have reported the computed radiography (CR) dose creep problem and therefore the need to have monitoring processes in place in clinical departments. The objective of this study is to provide a better technological solution to implement a regular CR dose monitoring process. An online automatic CR dose data mining program which can be applied to different systems was developed based on freeware and existing softwares in the Picture Archiving and Communication System (PACS) server. The program was tested with 69 CR images. This preliminary study shows that the program addresses the major weaknesses of some existing studies including involvement of manual procedures in the monitoring process and being only applicable to a single manufacturer's CR images. The proposed method provides an efficient and effective solution to implement a CR dose monitoring program regularly in busy clinical departments to regulate the dose creep problem so as to reinforce the 'As Low As Reasonably Achievable' (ALARA) principle.
Publisher: Wiley
Date: 25-08-2014
Publisher: MDPI AG
Date: 10-08-2023
Abstract: Generative artificial intelligence, especially with regard to the generative adversarial network (GAN), is an important research area in radiology as evidenced by a number of literature reviews on the role of GAN in radiology published in the last few years. However, no review article about GAN in pediatric radiology has been published yet. The purpose of this paper is to systematically review applications of GAN in pediatric radiology, their performances, and methods for their performance evaluation. Electronic databases were used for a literature search on 6 April 2023. Thirty-seven papers met the selection criteria and were included. This review reveals that the GAN can be applied to magnetic resonance imaging, X-ray, computed tomography, ultrasound and positron emission tomography for image translation, segmentation, reconstruction, quality assessment, synthesis and data augmentation, and disease diagnosis. About 80% of the included studies compared their GAN model performances with those of other approaches and indicated that their GAN models outperformed the others by 0.1–158.6%. However, these study findings should be used with caution because of a number of methodological weaknesses. For future GAN studies, more robust methods will be essential for addressing these issues. Otherwise, this would affect the clinical adoption of the GAN-based applications in pediatric radiology and the potential advantages of GAN could not be realized widely.
Publisher: Elsevier BV
Date: 12-2021
Publisher: Springer Science and Business Media LLC
Date: 02-2019
Publisher: Elsevier BV
Date: 08-2008
Publisher: Copernicus GmbH
Date: 03-03-2016
DOI: 10.5194/BG-2016-69
Abstract: Abstract. The western Indian Ocean has been warming rapidly over the past decades and this has adversely impacted the Asian Monsoon circulation. It is therefore of paramount importance to improve our understanding of links between Indian Ocean Sea Surface Temperature (SST) variability, climate change, and sustainability of reef ecosystems. Here we present two monthly-resolved coral Sr/Ca records (Totor, Cabri) from Rodrigues Island (63° E, 19° S) in the south-central Indian Ocean trade wind belt, and reconstruct SST based on the linear relationship with the Sr/Ca proxy. The records extend to 1781 and 1945, respectively. We assess the reproducibility of the Sr/Ca records, and potential biases in our reconstruction associated with the orientation of corallites. We quantify long-term SST trends and identify interannual relationships with the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). We conclude that careful screening for diagenesis and orientation of corallites is of paramount importance to assess the quality of Sr/Ca-based SST reconstructions. Our proxy records provide a reliable SST reconstruction between 1945 and 2006. We identify strong teleconnections with the ENSO/PDO over the past 60 years, eg. warming of SST during El Niño or positive PDO. We suggest that additional records from Rodrigues Island can provide excellent records of SST variations in the southern Indian Ocean trade wind belt and teleconnections with the ENSO/PDO on longer time scales.
Publisher: CRC Press
Date: 02-2015
DOI: 10.1201/B20752
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 02-2022
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2015
Publisher: Elsevier BV
Date: 04-2010
DOI: 10.1016/J.EJRAD.2009.01.027
Abstract: The purpose of the study was to investigate the optimal scanning protocol of 64-slice CT angiography for assessment of coronary artery stents based on a phantom study. Coronary stents with a diameter of 2.5mm was implanted in thin plastic tubes with an inner diameter of 3.0mm to simulate a coronary artery. The tubes were filled with iodinated contrast medium diluted to 178HU, closed at both ends and positioned in a plastic container filled with vegetable oil (-70 to -100HU). A series of scans were performed with a 64-slice CT scanner with the following protocols: section thickness: 0.67mm, 1.0mm, 1.5mm, 2.0mm, pitch value: 0.2, 0.3, 0.5 and reconstruction interval of 50% overlap of the section thickness. 2D axial and multiplanar reformatted images were generated to assess the visibility of stent lumen, while virtual intravascular endoscopy (VIE) was reconstructed to evaluate the artery wall and stent surface. Our results showed that a scanning protocol of 1.0mm slice thickness with a pitch of 0.3 produced acceptable images with best demonstration of the intrastent lumen and stent surface with minimal image noise or artifacts. In contrast, submillimeter scans with 0.67mm resulted in moderate artifacts which affected visualization of the coronary lumen, in addition to the increased noise. When the section thickness increased to 1.5mm and 2.0mm, visualization of the artery wall and stent surface was compromised, although the intrastent lumen was still visible. Our in vitro study suggested that a scanning protocol of 1.0mm section thickness with pitch of 0.3 is the optimal protocol for evaluation of coronary artery stents as it allows generation of acceptable images with better visualization of stent lumen, stent surface and coronary artery wall.
Publisher: IEEE
Date: 06-2009
Publisher: Copernicus GmbH
Date: 25-10-2016
Abstract: Abstract. The western Indian Ocean has been warming rapidly over recent decades, causing a greater number of extreme climatic events. It is therefore of paramount importance to improve our understanding of links between Indian Ocean sea surface temperature (SST) variability, climate change and sustainability of tropical coral reef ecosystems. Here we present monthly resolved coral Sr ∕ Ca records from two different locations from Rodrigues Island (63° E, 19° S) in the south-central Indian Ocean trade wind belt. We reconstruct SST based on a linear relationship with the Sr ∕ Ca proxy with records starting from 1781 and 1945, respectively. We assess relationships between the observed long-term SST and climate fluctuations related to the El Niño–Southern Oscillation (ENSO), the Subtropical Indian Ocean Dipole Mode (SIOD) and the Pacific Decadal Oscillation (PDO) between 1945 and 2006, respectively. The reproducibility of the Sr ∕ Ca records is assessed as are the potential impacts of diagenesis and corallite orientation on Sr ∕ Ca–SST reconstructions. We calibrate in idual robust Sr ∕ Ca records with in situ SST and various gridded SST products. The results show that the SST record from Cabri provides the first Indian Ocean coral proxy time series that records the SST signature of the PDO in the south-central Indian Ocean since 1945. We suggest that additional records from Rodrigues Island can provide excellent records of SST variations in the southern Indian Ocean trade wind belt to unravel teleconnections with the SIOD/ENSO/PDO on longer timescales.
Publisher: MDPI AG
Date: 04-07-2023
DOI: 10.20944/PREPRINTS202307.0214.V1
Abstract: Synchrotron radiation computed tomography (SRCT) allows more accurate calcified plaque and coronary stenosis assessment as a result of its superior spatial resolution, however, typical micro-computed tomography (micro-CT) systems have even higher resolution. The purpose of this study was to compare performance of high-resolution micro-CT with SRCT in the assessment of calcified plaques and a previously published dataset of coronary stenosis assessment. This experimental study involved micro-CT scanning of three-dimensional printed coronary artery models with calcification in situ used in our previously published SRCT study on coronary stenosis assessment. Measurements of coronary stenosis utilizing both modalities were compared using a paired s le t-test. The degrees of stenosis measured on all but one micro-CT dataset were statistically significantly lower than the corresponding SRCT measurements reported in our previous paper (p& .0005-0.05). This indicates that the superior spatial resolution of micro-CT was able to further reduce over-estimation of stenosis caused by extensive calcification of coronary arteries and hence false positive results. This study shows that high-resolution micro-CT outperforms SRCT in both calcified plaque and coronary stenosis assessment. This finding will become clinically important for cardiovascular event prediction and enable reclassification of in iduals with low and intermediate risk into appropriate risk categories when the technical challenges of micro-CT in clinical practice such as the small field of view and demanding on image processing power are addressed.
Publisher: Wiley
Date: 06-2012
Publisher: Wiley
Date: 12-2007
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.JMIR.2015.03.003
Abstract: Computed tomography (CT) dose optimization is an important issue in radiography because CT is the largest contributor to medical radiation dose and its use is increasing. However, CT dose optimization for pediatric patients could be more challenging than their adult counterparts. The purpose of this literature review was to identify and discuss the current pediatric CT dose saving techniques. Optimized pediatric protocols were also proposed. A comprehensive literature search was conducted using the Medline, ProQuest Health and Medical Complete, PubMed, ScienceDirect, Scopus, Springer Link, and Web of Science databases and the keywords CT, pediatric, optimization, protocol, and radiation dose to identify articles focusing on pediatric CT dose optimization strategies published between 2004 and 2014. Seventy-seven articles were identified in the literature search. Strategies for optimizing a range of scan parameters and technical considerations including tube voltage and current, iterative reconstruction, diagnostic reference levels, bowtie filters, scout view, pitch, scan collimation and time, overscanning, and overbeaming for pediatric patients with different ages and body sizes and compositions were discussed. An ex le of optimized pediatric protocols specific to age and body size for the 64-slice CT scanners was devised. It is expected that this ex le could provide medical radiation technologists, radiologists, and medical physicists with ideas to optimize their pediatric protocols.
Publisher: Wiley
Date: 10-2009
Publisher: MDPI AG
Date: 03-09-2021
DOI: 10.3390/BIOM11091307
Abstract: The diagnostic value of coronary computed tomography angiography (CCTA) is significantly affected by high calcification in the coronary arteries owing to blooming artifacts limiting its accuracy in assessing the calcified plaques. This study aimed to simulate highly calcified plaques in 3D-printed coronary models. A combination of silicone + 32.8% calcium carbonate was found to produce 800 HU, representing extensive calcification. Six patient-specific coronary artery models were printed using the photosensitive polyurethane resin and a total of 22 calcified plaques with diameters ranging from 1 to 4 mm were inserted into different segments of these 3D-printed coronary models. The coronary models were scanned on a 192-slice CT scanner with 70 kV, pitch of 1.4, and slice thickness of 1 mm. Plaque attenuation was measured between 1100 and 1400 HU. Both maximum-intensity projection (MIP) and volume rendering (VR) images (wide and narrow window widths) were generated for measuring the diameters of these calcified plaques. An overestimation of plaque diameters was noticed on both MIP and VR images, with measurements on the MIP images close to those of the actual plaque sizes ( % deviation), and a large measurement discrepancy observed on the VR images (up to 50% overestimation). This study proves the feasibility of simulating extensive calcification in coronary arteries using a 3D printing technique to develop calcified plaques and generate 3D-printed coronary models.
Publisher: Wiley
Date: 03-2019
DOI: 10.1002/JMRS.1_324
Publisher: MDPI AG
Date: 23-08-2022
DOI: 10.3390/JPM12091354
Abstract: The purpose of this study was to finetune a deep learning model, real-enhanced super-resolution generative adversarial network (Real-ESRGAN), and investigate its diagnostic value in calcified coronary plaques with the aim of suppressing blooming artifacts for the further improvement of coronary lumen assessment. We finetuned the Real-ESRGAN model and applied it to 50 patients with 184 calcified plaques detected at three main coronary arteries (left anterior descending [LAD], left circumflex [LCx] and right coronary artery [RCA]). Measurements of coronary stenosis were collected from original coronary computed tomography angiography (CCTA) and Real-ESRGAN-processed images, including Real-ESRGAN-high-resolution, Real-ESRGAN-average and Real-ESRGAN-median (Real-ESRGAN-HR, Real-ESRGAN-A and Real-ESRGAN-M) with invasive coronary angiography as the reference. Our results showed specificity and positive predictive value (PPV) of the Real-ESRGAN-processed images were improved at all of the three coronary arteries, leading to significant reduction in the false positive rates when compared to those of the original CCTA images. The specificity and PPV of the Real-ESRGAN-M images were the highest at the RCA level, with values being 80% (95% CI: 64.4%, 90.9%) and 61.9% (95% CI: 45.6%, 75.9%), although the sensitivity was reduced to 81.3% (95% CI: 54.5%, 95.9%) due to false negative results. The corresponding specificity and PPV of the Real-ESRGAN-M images were 51.9 (95% CI: 40.3%, 63.5%) and 31.5% (95% CI: 25.8%, 37.8%) at LAD, 62.5% (95% CI: 40.6%, 81.2%) and 43.8% (95% CI: 30.3%, 58.1%) at LCx, respectively. The area under the receiver operating characteristic curve was also the highest at the RCA with value of 0.76 (95% CI: 0.64, 0.89), 0.84 (95% CI: 0.73, 0.94), 0.85 (95% CI: 0.75, 0.95) and 0.73 (95% CI: 0.58, 0.89), corresponding to original CCTA, Real-ESRGAN-HR, Real-ESRGAN-A and Real-ESRGAN-M images, respectively. This study proves that the finetuned Real-ESRGAN model significantly improves the diagnostic performance of CCTA in assessing calcified plaques.
Publisher: AME Publishing Company
Date: 07-2018
Publisher: Wiley
Date: 05-2016
DOI: 10.1002/AJUM.12008
Publisher: SAGE Publications
Date: 19-09-2017
Abstract: To compare in vivo the use of synchrotron radiation to computed tomography angiography (CTA) for the measurement of cross-sectional area (CSA) reduction of the aortic branch ostia caused by suprarenal stent-graft wires. This study was performed with a Zenith stent-graft placed in a phantom of the human aorta to simulate treatment of abdominal aortic aneurysm. Synchrotron radiation scans were performed using beam energies between 40 and 100 keV and spatial resolution of 19.88 μm per pixel. CSA reduction of the aortic branch ostia by suprarenal stent wires was calculated based on these exposure factors and compared with measurements from CTA images acquired on a 64-row scanner with slice thicknesses of 1.0, 1.5, and 2.0 mm. Images acquired with synchrotron radiation showed <10% of the CSA occupied by stent wires when a single wire crossed a renal artery ostium and <20% for 2 wires crossing a renovisceral branch ostium. The corresponding areas ranged from 24% to 25% for a single wire and from 40% to 48% for double wires crossing the branch ostia when measured on CT images. The stent wire was accurately assessed on synchrotron radiation with a diameter between 0.38±0.01 and 0.53±0.03 mm, which is close to the actual size of 0.47±0.01 mm. The wire diameter measured on CT images was greatly overestimated (1.15±0.01 to 1.57±0.02 mm). CTA has inferior spatial resolution that hinders accurate assessment of CSA reduction. This experiment demonstrated the superiority of synchrotron radiation over CTA for more accurate assessment of aortic stent wires and CSA reduction of the aortic branch ostia.
Publisher: Elsevier BV
Date: 11-2020
Publisher: MDPI AG
Date: 09-2023
DOI: 10.3390/JVD2030026
Publisher: Springer Science and Business Media LLC
Date: 07-05-2010
Publisher: Nofer Institute of Occupational Medicine
Date: 2013
DOI: 10.2478/S13382-013-0159-2
Abstract: It is recommended that magnetic resonance (MR) technologists should not work alone due to potential occupational health risks although lone working is legally acceptable. The objective of this study was to investigate the current situation of lone working MR technologists in Western Australia (WA) and any issue against the regulations. A questionnaire regarding the issues of occupational health of lone working MR technologists was developed based on relevant literature and distributed to WA MR technologists. Descriptive (percentage of frequency, mean and standard deviation) and inferential statistics (Fisher's exact, Chi(2) and t tests, and analysis of variance) were used to analyze the responses of the yes/no, multiple choice and 5 pt scale questions from the returned questionnaires. The questionnaire response rate was 65.6% (59/90). It was found that about half of the MR technologists (45.8%, 27/59) experienced lone working. The private magnetic resonance imaging (MRI) centers were more likely to arrange technologists to work alone (p < 0.05). The respondents expressed positive views on issues of adequacy of training and arrangement, confidence and comfort towards lone working except immediate assistance for emergency (mean: 3). Factors of existence of MRI safety officer (p < 0.05) and nature of lone working (p < 0.001-0.05) affected MR technologists' concerns. Lone working of MR technologists is common in WA especially in private centers. The training and arrangement provided seem to be adequate for meeting the legal requirements. However, several areas should be improved by the workplaces including enhancement on immediate emergency assistance and concern relief.
Publisher: MDPI AG
Date: 08-03-2023
Abstract: Artificial intelligence (AI)-based computer-aided detection and diagnosis (CAD) is an important research area in radiology. However, only two narrative reviews about general uses of AI in pediatric radiology and AI-based CAD in pediatric chest imaging have been published yet. The purpose of this systematic review is to investigate the AI-based CAD applications in pediatric radiology, their diagnostic performances and methods for their performance evaluation. A literature search with the use of electronic databases was conducted on 11 January 2023. Twenty-three articles that met the selection criteria were included. This review shows that the AI-based CAD could be applied in pediatric brain, respiratory, musculoskeletal, urologic and cardiac imaging, and especially for pneumonia detection. Most of the studies (93.3%, 14/15 77.8%, 14/18 73.3%, 11/15 80.0%, 8/10 66.6%, 2/3 84.2%, 16/19 80.0%, 8/10) reported model performances of at least 0.83 (area under receiver operating characteristic curve), 0.84 (sensitivity), 0.80 (specificity), 0.89 (positive predictive value), 0.63 (negative predictive value), 0.87 (accuracy), and 0.82 (F1 score), respectively. However, a range of methodological weaknesses (especially a lack of model external validation) are found in the included studies. In the future, more AI-based CAD studies in pediatric radiology with robust methodology should be conducted for convincing clinical centers to adopt CAD and realizing its benefits in a wider context.
Publisher: Elsevier BV
Date: 04-2009
DOI: 10.1016/J.CMPB.2008.10.004
Abstract: Increasingly, the use of web database portfolio systems is noted in medical and health education, and for continuing professional development (CPD). However, the functions of existing systems are not always aligned with the corresponding pedagogy and hence reflection is often lost. This paper presents the development of a tailored web database portfolio system with Picture Archiving and Communication System (PACS) connectivity, which is based on the portfolio pedagogy. Following a pre-determined portfolio framework, a system model with the components of web, database and mail servers, server side scripts, and a Query/Retrieve (Q/R) broker for conversion between Hypertext Transfer Protocol (HTTP) requests and Q/R service class of Digital Imaging and Communication in Medicine (DICOM) standard, is proposed. The system was piloted with seventy-seven volunteers. A tailored web database portfolio system (radep.hti.polyu.edu.hk) was developed. Technological arrangements for reinforcing portfolio pedagogy include popup windows (reminders) with guidelines and probing questions of 'collect', 'select' and 'reflect' on evidence of development/experience, limitation in the number of files (evidence) to be uploaded, the 'Evidence Insertion' functionality to link the in idual uploaded artifacts with reflective writing, capability to accommodate ersity of contents and convenient interfaces for reviewing portfolios and communication. Evidence to date suggests the system supports users to build their portfolios with sound hypertext reflection under a facilitator's guidance, and with reviewers to monitor students' progress providing feedback and comments online in a programme-wide situation.
Publisher: MDPI AG
Date: 14-04-2022
DOI: 10.3390/DIAGNOSTICS12040991
Abstract: Background: The presence of heavy calcification in the coronary artery always presents a challenge for coronary computed tomography angiography (CCTA) in assessing the degree of coronary stenosis due to blooming artifacts associated with calcified plaques. Our study purpose was to use an advanced artificial intelligence (enhanced super-resolution generative adversarial network [ESRGAN]) model to suppress the blooming artifact in CCTA and determine its effect on improving the diagnostic performance of CCTA in calcified plaques. Methods: A total of 184 calcified plaques from 50 patients who underwent both CCTA and invasive coronary angiography (ICA) were analysed with measurements of coronary lumen on the original CCTA, and three sets of ESRGAN-processed images including ESRGAN-high-resolution (ESRGAN-HR), ESRGAN-average and ESRGAN-median with ICA as the reference method for determining sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Results: ESRGAN-processed images improved the specificity and PPV at all three coronary arteries (LAD-left anterior descending, LCx-left circumflex and RCA-right coronary artery) compared to original CCTA with ESRGAN-median resulting in the highest values being 41.0% (95% confidence interval [CI]: 30%, 52.7%) and 26.9% (95% CI: 22.9%, 31.4%) at LAD 41.7% (95% CI: 22.1%, 63.4%) and 36.4% (95% CI: 28.9%, 44.5%) at LCx 55% (95% CI: 38.5%, 70.7%) and 47.1% (95% CI: 38.7%, 55.6%) at RCA while corresponding values for original CCTA were 21.8% (95% CI: 13.2%, 32.6%) and 22.8% (95% CI: 20.8%, 24.9%) 12.5% (95% CI: 2.6%, 32.4%) and 27.6% (95% CI: 24.7%, 30.7%) 17.5% (95% CI: 7.3%, 32.8%) and 32.7% (95% CI: 29.6%, 35.9%) at LAD, LCx and RCA, respectively. There was no significant effect on sensitivity and NPV between the original CCTA and ESRGAN-processed images at all three coronary arteries. The area under the receiver operating characteristic curve was the highest with ESRGAN-median images at the RCA level with values being 0.76 (95% CI: 0.64, 0.89), 0.81 (95% CI: 0.69, 0.93), 0.82 (95% CI: 0.71, 0.94) and 0.86 (95% CI: 0.76, 0.96) corresponding to original CCTA and ESRGAN-HR, average and median images, respectively. Conclusions: This feasibility study shows the potential value of ESRGAN-processed images in improving the diagnostic value of CCTA for patients with calcified plaques.
Publisher: Wiley
Date: 04-2016
DOI: 10.1002/JMRS.3_166
Publisher: Springer Science and Business Media LLC
Date: 06-01-2015
Publisher: American Scientific Publishers
Date: 02-2015
Start Date: 2011
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Funder: Australian Synchrotron
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Funder: Curtin University of Technology
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Funder: Curtin University of Technology
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Funder: Curtin University of Technology
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Funder: Australian Synchrotron
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Funder: Australian Synchrotron
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Funder: Royal Perth Hospital Medical Research Foundation
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Funder: Australian Synchrotron
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Funder: Curtin University of Technology
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Funder: Australian Synchrotron
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