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Introduction To offer citizens with frailty or dementia living in nursing homes or other institutions a less stressful and anxious X-ray examination, a Danish hospital offers to perform the examination in the citizen's residence. This has changed the working procedure for the radiographers performing the examination. The aim of this study was to explore if the radiographers self-perceived competencies have changed whilst working in the mobile X-ray unit and if so, how these competencies are utilised within the department-based medical imaging team. Method This study had a qualitative design following a hermeneutic approach. Individual semi structured interviews included nine radiographers, four radiographers working in the mobile X-ray unit and five radiographers working exclusively in the medical imaging team. Results Radiographers who worked in the mobile X-ray unit did acquire new competencies such as better communication and creative positioning skills. All nine participants recognised the advantage of sharing experiences and competencies with colleagues, and recommended a formal forum to do so. They sought opportunities for the use of the mobile X-ray unit to be more widespread within their own region, and within the profession. Conclusion This study indicates that radiographers working with mobile X-ray unit gained new competencies in communication and positioning, but without spread of new knowledge to colleagues in the medical imaging team. Implication for practice The use of home-based mobile X-ray is a new way to provide health care services and gain new competencies for the radiographers to focus on patient centred care.

Introduction This study aimed to evaluate the effects of a newly developed Advanced Edge Enhancement software (AEE) (Canon Europe, Amsterdam, NL) on image quality (IQ) of Digital Radiography (DR) hand images focusing on rheumatoid arthritis (RA). Methods and materials Fifty posterior-anterior hand images with or suspected for RA were collected. For each of the 50 images, six copies were made with each their AEE algorithm settings. A total of 330 images (30 images iterated) were evaluated using relative Visual Grading Analysis (VGA) by three observers and combined into a VGA Score (VGAS). Second, 50 images of a technical Contrast Detail Radiography Phantom (CDRAD) was produced with three different AEE software settings, each at level 1,5 and without the AEE software yielding 350 CDRAD images. All images was analysed by the CDRAD Analyser and included for an objective analysis of the AEE software. Results The VGA study showed a significant difference in image quality between a standard image and images with AEE software applied. The average VGA score of the AEE software was better than the standard images (interval between 0.2 and 0.9). The AEE algorithms at level 5 scored significantly lower for noise but significantly higher for spatial resolution, sharpness and contrast in the VGA. The CDRAD images showed that all AEE algorithms had a statistically significant improvement for level 1 and deterioration for level 5 compared to the standard image. Conclusion Overall the AEE algorithm: small structure level 1 showed an improvement of all IQ criteria in the VGA and a better technical IQ. Implications for practice The AEE software ought to be considered as a useful addition to the current software, possibly enabling visualisation of structures currently visible.

Introduction To investigate student clinical placement concerns and opinions, during the initial COVID-19 pandemic outbreak and to inform educational institution support planning. Methods Between mid-June to mid-July 2020, educational institutions from 12 countries were invited to participate in an online survey designed to gain student radiographer opinion from a wide geographical spread and countries with varying levels of COVID-19 cases. Results 1277 respondents participated, of these 592 had completed clinical placements during January to June 2020. Accommodation and cohabiting risks were identified as challenging, as was isolation from family, travel to clinical placements, and to a lesser extent childcare. Students stated they had been affected by the feeling of isolation and concerns about the virus whilst on placement. Overall 35.4% of all respondents were ‘Not at all worried’ about being a radiographer, however, 64.6% expressed varying levels of concern and individual domestic or health situations significantly impacted responses (p ≤ 0.05). Year 4 students and recent graduates were significantly more likely to be ‘Not worried at all’ compared to Year 2 and 3 students (p ≤ 0.05). The need for improved communication regarding clinical placements scheduling was identified as almost 50% of students on clinical placements between January to June 2020 identified the completion of assessments as challenging. Furthermore, only 66% of respondents with COVID-19 imaging experience stated being confident with personal protective equipment (PPE) use. Conclusion Student radiographers identified key challenges which require consideration to ensure appropriate measures are in place to support their ongoing needs. Importantly PPE training is required before placement regardless of prior COVID-19 imaging experience. Implications for practice As the next academic year commences, the study findings identify important matters to be considered by education institutions with responsibility for Radiography training and as students commence clinical placements during the on-going global COVID-19 pandemic.

To investigate the impact of combining the high-resolution (Hi-res) scan mode with deep learning image reconstruction (DLIR) algorithm in CT. Two phantoms (Catphan600® and Lungman, small, medium, large size) were CT scanned using combinations of Hi-res/standard mode and high-definition (HD)/standard kernels. Images were reconstructed with ASiR-V and three levels of DLIR. Spatial resolution, noise and contrast-to-noise ratio (CNR) were assessed. The radiation dose was recorded. The spatial resolution increased using Hi-res & HD. Image noise in the Catphan600® (69%) and the Lungman (10–70%) significantly increased when Hi-res & HD was applied. DLIR reduced the mean noise (54%). The CNR was reduced (64%) for Hi-res & HD. The radiation dose increased for both small (+70%) and medium (+43%) Lungman phantoms but decreased slightly for the large ones (−3%) when Hi-res was applied. In conclusion, the Hi-res scan mode improved the spatial resolution. The HD kernel significantly increased the image noise. DLIR improved the image noise and CNR and did not affect the spatial resolution.

Introduction A hospital environment can be a significant burden and a health risk especially for dementia patients. Mobile x-ray equipment (ME) is used to enable imaging of these patients at home. The aim was to compare image quality (IQ) of chest, hip and pelvis images from ME to the stationary equipment (SE) used in a hospital department. Methods We analysed examinations of the chest (n = 20), hip (n = 64) and pelvis (n = 32). Images were equally obtained from each setting of ME and SE. All images were graded using Visual Grading Analysis (VGA) by three radiographers (hip and pelvis) and three radiologists (chest). Technical IQ assessment was done by 80 additional images of a Contrast-Detail Radiography phantom (CDRAD). Results All chest images were approved for diagnostic use, as well as the hip AP and pelvis images from SE. ‘Approved proportion of ME images was for HIP antero-posterior (AP) and pelvis, 78% [95% CI: 52–94%] and 81% [95% CI: 54–96%] respectively. Hip axial had an overall low, but not significant different approval rate. Ordered logistic regression indicated higher IQ of HIP AP and pelvic images from SE. This contrasts that the CDRAD substudy indicated better IQ, expressed as IQFinv, from ME. Conclusion The VGA showed higher IQ for the SE system, while the CDRAD showed higher IQ for the ME system. Implications for practice Dementia patients can be examined at their home if the acquisition is optimised according to image quality in conjunct to radiation dose. Performing imaging out of the hospital and coordinating the patients’ further treatment are new work areas for radiographers and requires excellent communication skills.

To investigate how ASiR-V and kVp changes in Computed tomography (CT) affect radiation dose and image quality, when using automatic tube current modulation (ATCM) for different sized phantoms.A liver-phantom with two different liver inserts (QRM, Moehrendorf, Germany), with extension rings, representing fat, were additionally applied to the phantom to simulate patients of different sizes (small: 30cm diameter, medium: 35cm and large: 40cm). Abdominal scans were performed on a 256 slice CT scanner (GE Healthcare, Milwaukee, WI, USA), with consistent pitch (0.992), rotation time (0.5s), slice thickness (0.625mm) and collimation (80mm), while other parameters were varied (kVp: 80/100/120/140; Noise Index: 13/22; mA interval 80-720, ASiR-V: 30/60/100%). CTDI and DLP was recorded for each scan and image quality was assessed using objective metrics in predefined anatomic areas (HU and noise). Radiation dose and image quality metrics were compared between protocols.CTDI decreased by 80% from ASIR-V 30% to ASiR-V 100% for prescribed NI 13, and by 79% for the prescribed NI of 22. For 100% ASiR-V and a prescribed NI of 22 the CTDI remained the same regardless of phantom size for the different kVp settings. Pairwise comparison revealed significant differences in CTDI (p 0.0001) for all combinations of prescribed NI and ASIR-V levels, except the difference between ASIR-V levels of 30 and 60%, with a prescribed NI of 13 (p = 0.124). When data from the three phantom sizes were combined, increasing ASIR-V from 30-100%, resulted in noise decreases of 22% for NI of 13 and by 8% for NI of 22. Notably, image quality in the low contrast area of the liver insert was impaired when the large phantom was scanned with 100% ASiR-V and either 80/100kVp (NI 22), because of the large reduction in tube current applied (down to 80 mA).Substantial radiation dose reductions (up to 80%) resulted from increasing ASiR-V levels. However, image quality deteriorates when 100% ASiR-V is applied due to low applied tube current by the ATCM.

Background When rectal tumors are examined using magnetic resonance imaging (MRI) the perpendicular angulation of the axial T2-weighted image to the tumor axis is essential for a correct measure of the shortest distance between tumor and mesorectal facia. Purpose The purpose of this study was to determine the interobserver variability in rectal tumor angulation between a radiologist and a radiographer. Material and Methods Two observers performed the angulation independently. All MRI examinations were performed using an MRI 1.5 Tesla unit. A Bland–Altman plot was used to assess the interobserver variance and Intraclass correlation coefficient (ICC) statistic was used to assess the interobserver reliability. Results MRI was performed in 55 patients with rectal cancer during a one-year period (25 (45.5%) women and 30 (54.5%) men). The median age was 71 years (range 46–87 years). The rectal tumor mean length was 3.9 cm. The interobserver reliability was good (ICC = 0.83, 95% confidence interval 0.72–0.90). Conclusion Radiographers receiving training will be able to perform MRI rectal tumor angulation.

BackgroundHigh-risk coronary artery plaque (HRP) is associated with increased risk of acute coronary syndrome.We aimed to investigate the prevalence of HRP in asymptomatic patients with type 2 diabetes (T2D), and its relation to patient characteristics including cardiovascular risk factors, diabetes profile, and coronary artery calcium score (CACS).MethodsAsymptomatic patients with T2D and no previous coronary artery disease (CAD) were studied using coronary computed tomography angiography (CCTA) in this descriptive study. Plaques with two or more high-risk features (HRP) defined by low attenuation, positive remodeling, spotty calcification, and napkin-ring sign were considered HRP. In addition, total atheroma volume (TAV), proportions of dense calcium, fibrous, fibrous-fatty and necrotic core volumes were assessed. The CACS was obtained from non-enhanced images by the Agatston method. Cardiovascular and diabetic profiles were assessed in all patients.ResultsIn 230 patients CCTA was diagnostic and 161 HRP were detected in 86 patients (37%). Male gender (OR 4.19, 95% CI 1.99–8.87; p ConclusionA high prevalence of HRP was detected in this population of asymptomatic T2D. The presence of HRP was associated with a particular patient profile, but was not ruled out by the absence of coronary artery calcium. CCTA provides important information on plaque morphology, which may be used to risk stratify this high-risk population.Trial registrationThis trial was retrospectively registered at clinical trials.gov January 11, 2017 trial identifier NCT03016910.

Introduction To design a custom phantom of the coronary arteries to optimize CT coronary angiography (CCTA) protocols. Methods Characteristics of the left and right coronary arteries (mean Hounsfield Unit (HU) values and diameters) were collected from consecutive CCTA examinations (n = 43). Four different materials (two mixtures of glycerine, gelatine and water, pig hearts, Ecoflex™ silicone) were scanned inside a Lungman phantom using the CCTA protocol to find the closest model to in vivo data. A 3D printed model of the coronary artery tree was created using CCTA data by exporting a CT volume rendering into Autodesk Meshmixer™ software. The model was placed in an acid bath for 5 h, then covered in Ecoflex™, which was removed after drying. Both the Ecoflex™ and pig heart were later filled with a mixture of contrast (Visipaque 320 mg I/ml), NaCl and gelatin and scanned with different levels of tube current and iterative reconstruction (ASiR-V). Objective (HU, noise and size (vessel diameter) and subjective analysis were performed on all scans. Results The gelatine mixtures had HU values of 130 and 129, Ecoflex™ 65 and the pig heart 56. At the different mA/ASiR-V levels the contrast filled Ecoflex™ had a mean HU 318 ± 4, noise 47±7HU and diameter of 4.4 mm. The pig heart had a mean HU of 209 ± 5, noise 38±4HU and a diameter of 4.4 mm. With increasing iterative reconstruction level the visualisation of the pig heart arteries decreased so no measurements could be performed. Conclusion The use of a 3D printed model of the arteries and casting with the Ecoflex™ silicone is the most suitable solution for a custom-designed phantom. Implications for practice Custom designed phantoms using 3D printing technology enable cost effective optimisation of CT protocols.

Introduction For patients with dementia, behaviour and reactions to stimuli can change and an X-ray examination in the hospital can have be a frightening experience. The aim of this study was to identify the experiences and perspectives of patients with dementia and their caregivers on receiving a mobile x-ray examination in nursing homes. Methods This study was designed as a qualitative study using patient observation and semi structured interviews, with a phenomenology-hermeneutic approach. In total, 23 patients were observed during X-ray examinations in nursing homes, and six semi structured interviews were conducted with the caregivers who participated in the examination. Results The observations and interviews indicated that a known environment, a recognizable framework and calmness were central for a patient with dementia. The patients appeared calm and relaxed during the examination in their usual environment (nursing homes) where there are less stimuli and impressions based of the observations. Conclusion Mobile X-ray examinations for patients with dementia living in nursing homes had a positive impact on patients' reactions towards the X-ray examination. The examinations were performed in the patients' usual and safe environments, where impressions and stimuli were less disturbing for patients with dementia. Implications for practice The mobile x-ray unit can be of benefit for patients suffering from dementia and result in less impact. The patients living in nursing homes have the opportunity to be examined in their familiar environment, because of the mobile x-ray unit.

Purpose This study examined the impact of pronation and supination on the reliability of the radiographically measured values of dorsal tilt, radial inclination (RI), and ulnar variance (UV) in cadaveric forearms with artificially created distal radius fractures. Methods We prepared 21 human cadaveric forearms (11 right and 10 left) for radiostereometric analysis (RSA) by insertion of tantalum markers. Distal radius fractures were created midway between the marker segments. Radiographs and RSA images were taken at different degrees of supination and pronation. The precise degree of forearm rotation was calculated using RSA software. Two observers (H.B.T. and T.T.) independently measured tilt, RI, and UV on all radiographs in a blinded and randomized fashion. Univariate linear regression analyses were used to determine the relationship between forearm rotation and the measured radiographic values. Results The radiographically measured value of tilt was significantly impacted by forearm rotation. Supinating or pronating the forearm by 10° decreased and increased, respectively, the radiographic value of dorsal tilt by approximately 3°. Conclusions This study showed that the positioning of the fractured forearm during the radiographic procedure significantly impacted subsequent radiographic measurements of tilt. Dorsal tilt measurements increased (ie, fracture displacement measured more dorsal) with pronation and decreased (ie, fracture displacement measured more toward neutral, with less dorsal tilt) with supination of the forearm. However, measurements of RI (p = 0.12 and p = 0.55 for observer 1 and 2) and UV (p = 0.34 and p = 0.17, observer 1 and 2) were not significantly impacted by rotation. Clinical relevance Treatment of a distal radius fracture is, at least to some extent, based on radiographic quantification of fracture deformity. Therefore, unreliable measurements may adversely influence clinical decision making.

Background Although dorsal/palmar tilt, radial inclination (RI), and ulnar variance (UV) are measurements commonly performed in wrist radiographs, the impact of forearm rotation on those measurements during the radiographic procedure is uncertain. Our aim was to determine the impact of supination and pronation on the reliability of measurements of tilt, RI, and UV. Methods Tantalum markers were inserted into the distal radius of 21 unfractured cadaver forearms. The forearms were radiographed in different degrees of supination and pronation. The exact degree of rotation was calculated with radiostereometric analyses. Tilt, RI, and UV were measured by two independent readers in a random and anonymised fashion. Association between forearm rotation and radiographic measurements was examined using linear regression. Results Forearm rotation significantly impacted the radiographically measured tilt. One degree of supination and pronation respectively increased and decreased palmar tilt with 0.68° and 0.44°, observers 1 and 2, respectively. As opposed to observer 1, observer 2 found that RI was significantly impacted by rotation with a slope of 0.08. Ulnar variance was not significantly impacted by rotation with linear regression slopes of 0.01° (95% confidence interval [CI] − 0.02–0.05, p = 0.490) and 0.02° (95% CI − 0.02–0.07; p = 0.288), observer 1 and observer 2, respectively. Conclusion In unfractured forearms, the radiographically measured tilt was significantly affected by rotation. Palmar tilt increased with supination and decreased with pronation. Rotation significantly affected radial inclination, although of a magnitude that is probably not clinically relevant. No significant impact on UV was found.

The purpose of this study was to investigate the challenges in comparing digital radiography (DR) systems from different vendors for various combinations of exposure factors in posterior–anterior hand radiographs. Image quality was evaluated for a range of tube voltages and tube current-time products using a technical contrast-detail (CDRAD) phantom and an anthropomorphic hand phantom. 900 technical CDRAD images were analysed providing quality figures of merit (IQFinv) and two experienced reporting radiographers using visual grading analysis (VGA) scored 108 anthropomorphic images. This study demonstrates the differences between the DR systems included. When compensating for variations in dose, Canon showed superior results for technical image quality and Fuji for visual image quality for a standard dose point at DR hand examination (ln(DAP) 1.1, 50 kV and 2.5 mAs).

Introduction The anode heel effect can be used to optimize image quality and/or patient dose in digital radiography (DR). In film-screen radiography, the effect can equalize optical density in regions of varying attenuation. Clinical experience suggests that the implementation of DR has led to less awareness of anode orientation. Post-processing is assumed to compensate, but may also alter image impression and potentially obscure image details. Published evidence was examined for the influence of the anode heel effect on image quality in DR. Method A systematic literature search was carried out using PubMed, Embase, and Web of Science databases. Title and abstracts were screened blinded by three authors, according to in-/exclusion criteria, followed by full-text analysis for final inclusion. Studies where technical and/or visual image quality were reported, was included. All studies were analyzed and assigned quality scores, according to relevant questions. The authors devised a scoring system based on reported information pertaining to reproducibility, interpretation, and generalizability of the methods and conclusions. Results Five studies were included of heterogeneous design, each with methodological shortcomings. Only a few anatomical areas were covered. Very few patients were examined, and in no studies were images evaluated by radiologists or reporting radiographers. Relevant information such as post-processing, image quality criteria and analysis was insufficient in most studies, making reproduction difficult. Results were contradictory, especially concerning technical vs visual image quality. Conclusion Limited published evidence was found quantifying the influence of the anode heel effect on image quality using DR technology. More methodologically, robust studies are needed. The published evidence neither proves nor disproves the impact of the heel effect on image quality in DR. Implications for practice Based on a systematic review, no firm recommendations for anode orientation relating to image quality in DR can be provided.

Improvement of non-invasive identification of high-risk plaque may increase the preventive options of acute coronary syndrome. To describe the characteristics of thin-cap fibroatheroma (TCFA) in a post mortem model in comparison to characteristics of culprit lesions in patients with non-ST-elevation-myocardial-infarction (NSTEMI) using the dual energy computed tomography (DECT). Three post mortem hearts were prepared with iodine-contrast, inserted in a Kyoto phantom and scanned by DECT. Six TCFA were identified using histopathological analysis (cap thickness < 65 μm and necrotic core > 10% of the plaque area). In the NSTEMI group, 29 patients were scheduled to DECT prior to coronary angiography and invasive treatment. Culprit lesions were identified blinded for the patient history by two independent invasive cardiologists using the coronary angiography. The DECT analysis of TCFA and culprit lesions was performed retrospectively with determination of effective atomic number (Effective-Z), Hounsfield Unit (HU), plaque type (non-calcified, predominantly non-calcified, predominantly calcified or calcified), spotty calcification, plaque length, plaque volume and plaque burden and the remodeling index. The Effective-Z, HU and plaqueburden were significantly different between TCFA and culprit lesions (P < 0.05).The TCFA plaques were more calcified in comparison to culprit lesions (P < 0.05). No significant difference in the other plaque characteristics was observed. The use of DECT demonstrated different Effective-Z values and different characteristics of post mortem TCFA in comparison to in vivo culprit lesions. This finding may highlight, that not all TCFA should be considered as vulnerable.

INTRODUCTION: Organ-based tube current modulation (OBTCM) is designed for anterior dose reduction in Computed Tomography (CT). The purpose was to assess dose reduction capability in chest CT using three organ dose modulation systems at different kVp settings. Furthermore, noise, diagnostic image quality and tumour detection was assessed.METHODS: A Lungman phantom was scanned with and without OBTCM at 80-135/140 kVp using three CT scanners; Canon Aquillion Prime, GE Revolution CT and Siemens Somatom Flash. Thermo-luminescent dosimeters were attached to the phantom surface and all scans were repeated five times. Image noise was measured in three ROIs at the level of the carina. Three observers visually scored the images using a fivestep scale. A Wilcoxon Signed-Rank test was used for statistical analysis of differences.RESULTS: Using the GE revolution CT scanner, dose reductions between 1.10 mSv (12%) and 1.56 mSv (24%) (p < 0.01) were found in the anterior segment and no differences posteriorly and laterally. Total dose reductions between 0.64 (8%) and 0.91 mSv (13%) were found across kVp levels (p < 0.00001). Maximum noise increase with OBTCM was 0.8 HU. With the Canon system, anterior dose reductions of 6-10% and total dose reduction of 0.74-0.76 mSv across kVp levels (p < 0.001) were found with a maximum noise increase of 1.1 HU. For the Siemens system, dose increased by 22-51% anteriorly; except at 100 kVp where no dose difference was found. Noise decreased by 1 to 1.5 HU.CONCLUSION: Organ based tube current modulation is capable of anterior and total dose reduction with minimal loss of image quality in vendors that do not increase posterior dose.IMPLICATIONS FOR PRACTICE: This research highlights the importance of being familiar with dose reduction technologies.

The purpose was to examine if scatter correction software could replace a grid while maintaining image quality and reducing radiation dose for pelvic DR examinations. Grid images was produced with 70 kV and 16mAs. Anthropomorphic- and Contrast Detail RADiography (CDRAD) non-grid images were produced with 60 kV, 80 kV and 90 kV combined with five different mAs and scatter correction software. The anthropomorphic images were analyzed by absolute Visual Grading Analysis (VGA). The CDRAD images were analyzed using the CDRAD analysis software. The results showed a total of 54.6% non-grid images were evaluated as unsuitable for diagnostic use by the VGA. The CDRAD grid images showed that the IQF_inv values were significantly different (p = 0.0001) when compared to every group of non-grid images. Hereby, the conclusion stated that the scatter correction software did not compensate for the loss in image quality due to scattered radiation at the exposure levels included in a pelvic examination.

Background: Distal radius fracture characterization and treatment are mainly based on radiographic measurements but with contradictory findings on the correlation of those measurements to clinical outcome. Before applying radiographic measurement to the treatment decision and before correlating the measurements to clinical outcome, an accuracy of measurements must be established. Purpose: To summarize existing evidence on accuracy of the radiographic measurements of: (i) dorsal/volar tilt of the distal radius; (ii) radial shortening; (iii) ulnar variance; (iv) radial inclination; and (v) articular step-off of the distal radius. We conducted a systematic critical review of the literature. Material and Methods: MEDLINE, EMBASE, and the Cochrane Library database were searched. The Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines were followed. Quality of included studies was assessed using a tailored version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Results: A total of 5908 publications were screened and five studies met the inclusion criteria. Four studies assessed accuracy of articular step-off but with contradictory outcomes. Radiographic measurements of step-off were accurate in two studies and inaccurate in one study. In the last step-off study, some of their measurements varied significantly but accuracy was not reported. The radiographic measurements of ulnar variance were significantly underestimated when compared to the true variance. We were not able to include studies that assessed accuracy of radial shortening, radial inclination, or dorsal/volar tilt against a reference standard. Conclusion: Currently, evidence is not available to support accuracy of the radiographic measurements commonly used to characterize distal radius fractures.

Introduction\ud \ud Radiographers routinely undertake many initiatives to balance image quality with radiation dose (optimisation). For optimisation studies to be successful image quality needs to be carefully evaluated. Purpose was to 1) discuss the strengths and limitations of a Visual Grading Analysis (VGA) method for image quality evaluation and 2) to outline the method from a radiographer's perspective.\ud \ud Methods\ud A possible method for investigating and discussing the relationship between radiographic image quality parameters and the interpretation and perception of X-ray images is the VGA method. VGA has a number of advantages such as being low cost and a detailed image quality assessment, although it is limited to ensure the images convey the relevant clinical information and relate the task based radiography.\ud \ud Results\ud Comparing the experience of using VGA and Receiver Operating Characteristic (ROC) it is obviously that less papers are published on VGA (Pubmed n=1.384) compared to ROC (Pubmed n=122.686). Hereby the scientific experience of the VGA method is limited compared to the use of ROC. VGA is, however, a much newer method and it is slowly gaining more and more attention.\ud \ud Conclusion\ud The success of VGA requires a number of steps to be completed, such as defining the VGA criteria, choosing the VGA method (absolute or relative), including observers, finding the best image display platforms, training observers and selecting the best statistical method for the study purpose should be thoroughly considered.\ud \ud Implication for practice\ud Detailed evaluation of image quality for optimisation studies related to technical definition of image quality.

Purpose: Improve mapping and registration of longitudinal view on histopathology vessels in a three-dimensional alignment procedure for postmortem quantitative coronary plaque analyses. This new procedure is applied and results shown using calcified coronary plaque analyses within post-mortem computed tomography angiography (PMCTA), optical coherence tomography (OCT) and the gold standard of histopathology.Results: In total, 338 annotated histopathology images were included, 166 PMCTA transversal images and 285 OCT images were aligned in the comparison. The results from the comparison using the alignment procedure showed overall that the calcified plaques seem to be overestimated by PMCTA and underestimated by OCT.Conclusions: The 3D fusion approach, aligning the images of PMCTA, OCT and histopathology as gold standard allowed for a slice-based comparison of the different modalities. The results showed that PMCTA overestimates the calcified plaques while OCT underestimates these, compared to histopathology. (C) 2018 Elsevier Inc. All rights reserved.

Purpose: Organ-based tube current modulation (OBTCM) is designed for anterior dose reduction in CT. This study assessed the dose reduction capability of using organ dose modulation from two vendors at a range of kVp settings in chest CT. The secondary purpose was to assess noise between dose-modulation systems. Methods and Materials: A Lungman phantom with Thermo-Luminescent Dosimeters circumferentially attached around the phantom surface was scanned with and without OBTCM at 80-135/140 kVp using a Toshiba Aquillion Prime and a GE Revolution CT scanner. Equivalent dose was measured. Noise was measured in ROIs in the vertebral body, pulmonary trunk and in free air anterior to the phantom at the level of the carina. Comparisons were performed using Wilcoxon Signed-Rank test. Results: Using GE, dose reductions between 1.1 mSv (12%) and 1.56 mSv (24%) (p

Purpose: To evaluate the effect on skin dose and image quality when decentering in the y- and x-direction for abdominal CT scans.Methods: Patient centering data in CT were collected retrospectively from dose management software (DoseWatch, GE Healthcare) from a single university hospital (n=4 scanners) in 2017. Deviations from the isocentre were categorized for both vertical (±1.5cm, ±3.0cm, ±4.5cm) and horizontal (±1.5cm, ±3cm) planes on 498 patients. An anthropomorphic phantom (PBU-60) was subsequently scanned using each deviation on two scanners (Toshiba Prime, GE HD750) to allow dose and image quality (noise and visual grading assessment) comparisons. Results: Significant skin dose increases (4.3mSv/50%) were detected anteriorly for both scanners when centered above the isocenter and reductions (2.0mSv, 24%) when below the isocenter. For the HD750, dose decreased up to 8.3mSv in four locations at the -4.5 position with increases (2.0mSv) noted on the right side with horizontal deviation. With upward vertical deviation noise increased from 13HU (isocenter) to 15HU. No change in standard deviation (SD) was detected with the phantom below isocenter. With left horizontal deviation SD increased by 12HU while SD decreased by 12HU dextro-laterally. VGA-score was lowest at the largest vertical ISO-center deviation. Conclusion: Positioning above ISO-center may increase noise and skin dose. Similarly, horizontal deviation may increase dose. Subjective image quality is negatively affected by extreme vertical ISO-center deviation.

Purpose To investigate whether software optimisation can improve an observers' perception of image quality in low dose paediatric pelvic examinations. Methods Twenty-five consecutive patients (3–7 years old) were referred for a pelvic digital radiography (DR) examination. They were prospectively enrolled in the study over a 3-month period. Images were taken at 80 kV and 2–4 mAs depending on pelvic thickness (9–15 cm). A small focal spot, 130 cm SID: 10 cm air gap and 1 mm Al and 0.2 mm Cu additional filtration were also utilised. Images were acquired on a Canon DR detector and optimised using five different combinations of the multi-frequency processing software (Canon DR system version NE, Version 7.1 with SPECTRA) to comply with the ALARA principle. Image quality was blindly evaluated using the subjective Visual Grading Analysis (VGA) by five experienced musculoskeletal radiologists, including the evaluation of six anatomical image quality criteria (scored from 1 to 5). Results Consistently, the VGA results indicated that by using software optimised parameters, image quality was suitable for diagnosis in 48–71% of all images. Based on a VGC analysis all software optimised images did have significant better image quality then the one with just the clinical settings. Noise reduction was the software setting which influenced the image quality the most, area under the curve (AUC) of 0.8172 95%CI 0.7953–0.8375. Conclusion Software optimisation improve the radiologists' perception of image quality and should thus be thoroughly considered within clinical practise. Noise reduction is the software parameter which has the greatest influence.

Digital radiography is widely seen to be forgiving of poor exposure technique and to provide consistent high quality diagnostic images. Optimal quality images are however not universal; sub-optimal images are encountered. Evaluators on hip dysplasia schemes encounter images from multiple practices produced on equipment from multiple manufacturers. For images submitted to the Danish Kennel Club for hip dysplasia screening, a range of quality is seen and the evaluators are of the impression that variations in image quality area associated with particular equipment. This study was undertaken to test the hypothesis that there is an association between image quality in digital radiography and the manufacturer of the detector equipment, and to demonstrate the applicability of visual grading analysis (VGA) for image quality evaluation in veterinary practice. Data from 16,360 digital images submitted to the Danish Kennel Club were used to generate the hypothesis that there is an association between detector manufacturer and image quality and to create groups for VGA. Image quality in a subset of 90 images randomly chosen from 6 manufacturers to represent high and low quality images, was characterized using VGA and the results used to test for an association between image quality and system manufacturer. The range of possible scores in the VGA was −2 to +2 (higher scores are better). The range of the VGA scores for the images in the low image quality group (n = 45) was −1.73 to +0.67, (median −1.2). Images in the high image quality group (n = 44) ranged from −1.52 to +0.53, (median −0.53). This difference was statistically significant (p < 0.001). The study shows an association between VGA scores of image quality and detector manufacturer. Possible causes may be that imaging hardware and/or software are not equal in terms of quality, that the level of support sought and given differs between systems, or a combination of the two. Clinicians purchasing equipment should be mindful that image quality can differ across systems. VGA is practical for veterinarians to compare image quality between systems or within a system over time.

PURPOSE: The purpose of this study was to study the effect of iterative reconstruction (IR) software on quantitative plaque measurements in coronary computed tomography angiography (CCTA).METHODS: Thirty patients with a three clinical risk factors for coronary artery disease (CAD) had one CCTA performed. Images were reconstructed using FBP, 30% and 60% adaptive statistical IR (ASIR). Coronary plaque analysis was performed as per patient and per vessel (LM, LAD, CX and RCA) measurements. Lumen and vessel volumes and plaque burden measurements were based on automatic detected contours in each reconstruction. Lumen and plaque intensity measurements and HU based plaque characterization were based on corrected contours copied to each reconstruction.RESULTS: No significant changes between FBP and 30% ASIR were found except for lumen- (-2.53 HU) and plaque intensities (-1.28 HU). Between FBP and 60% ASIR the change in total volume showed an increase of 0.94%, 4.36% and 2.01% for lumen, plaque and vessel, respectively. The change in total plaque burden between FBP and 60% ASIR was 0.76%. Lumen and plaque intensities decreased between FBP and 60% ASIR with -9.90 HU and -1.97 HU, respectively. The total plaque component volume changes were all small with a maximum change of -1.13% of necrotic core between FBP and 60% ASIR.CONCLUSIONS: Quantitative plaque measurements only showed modest differences between FBP and the 60% ASIR level. Differences were increased lumen-, vessel- and plaque volumes, decreased lumen- and plaque intensities and a small percentage change in the individual plaque component volumes.

Purpose Investigate the influence of adaptive statistical iterative reconstruction (ASIR) and the model-based IR (Veo) reconstruction algorithm in coronary computed tomography angiography (CCTA) images on quantitative measurements in coronary arteries for plaque volumes and intensities. Methods Three patients had three independent dose reduced CCTA performed and reconstructed with 30% ASIR (CTDI vol at 6.7 mGy), 60% ASIR (CTDI vol 4.3 mGy) and Veo (CTDI vol at 1.9 mGy). Coronary plaque analysis was performed for each measured CCTA volumes, plaque burden and intensities. Results Plaque volume and plaque burden show a decreasing tendency from ASIR to Veo as median volume for ASIR is 314 mm 3 and 337 mm 3–252 mm 3 for Veo and plaque burden is 42% and 44% for ASIR to 39% for Veo. The lumen and vessel volume decrease slightly from 30% ASIR to 60% ASIR with 498 mm 3–391 mm 3 for lumen volume and vessel volume from 939 mm 3 to 830 mm 3. The intensities did not change overall between the different reconstructions for either lumen or plaque. Conclusion We found a tendency of decreasing plaque volumes and plaque burden but no change in intensities with the use of low dose Veo CCTA (1.9 mGy) compared to dose reduced ASIR CCTA (6.7 mGy & 4.3 mGy), although more studies are warranted.

Background Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose. Purpose To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT angiography (CCTA) in detailed image quality. Material and Methods A total of 160 CCTA were reconstructed as follows: 55 scans with filtered back projection (FBP) (650 mA), 51 scans (455 mA) with 30% ASIR (ASIR30), and 54 scans (295 mA) with 60% ASIR (ASIR60). For each reconstruction, subjective image quality was assessed by five independent certified cardiologists using a visual grading analysis (VGA) with five predefined image quality criteria consisting of a 5-point scale. Objective measures were contrast, noise, and contrast-to-noise ratio (CNR). Results The CTDIvol resulted in 10.3 mGy, 7.4 mGy, and 4.6 mGy for FBP, ASIR30, and ASIR60, respectively. Homogeneity of the left ventricular lumen was the sole aspect in which reconstruction algorithms differed with a decreasing effect for ASIR60 compared to FBP (estimated odds ratio [OR] = 0.49 [95% confidence interval (CI) = 0.32–0.76; P = 0.001]). Decreased sharpness and spatial- and low-contrast resolutions were observed when using ASIR instead of FBP, but differences were not statistically significant. Concerning objective measurements, noise increased significantly for ASIR30 (OR = 1.08; 95% CI = 1.02–1.14; P = 0.006) and ASIR60 (OR = 1.06; 95% CI = 1.01–1.12; P = 0.034) compared to FBP. Conclusion ASIR significantly decreased the subjectively assessed homogeneity of the left ventricular lumen and increased the objectively measured noise compared to FBP. Considering these results, ASIR at a reduced radiation dose should be implemented with caution.

Background Coronary computed tomography angiography (CCTA) requires high spatial and temporal resolution, increased low contrast resolution for the assessment of coronary artery stenosis, plaque detection, and/or non-coronary pathology. Therefore, new reconstruction algorithms, particularly iterative reconstruction (IR) techniques, have been developed in an attempt to improve image quality with no cost in radiation exposure. Purpose To evaluate whether adaptive statistical iterative reconstruction (ASIR) enhances perceived image quality in CCTA compared to filtered back projection (FBP). Material and Methods Thirty patients underwent CCTA due to suspected coronary artery disease. Images were reconstructed using FBP, 30% ASIR, and 60% ASIR. Ninety image sets were evaluated by five observers using the subjective visual grading analysis (VGA) and assessed by proportional odds modeling. Objective quality assessment (contrast, noise, and the contrast-to-noise ratio [CNR]) was analyzed with linear mixed effects modeling on log-transformed data. The need for ethical approval was waived by the local ethics committee as the study only involved anonymously collected clinical data. Results VGA showed significant improvements in sharpness by comparing FBP with ASIR, resulting in odds ratios of 1.54 for 30% ASIR and 1.89 for 60% ASIR ( P = 0.004). The objective measures showed significant differences between FBP and 60% ASIR ( P Conclusion ASIR improved the subjective image quality of parameter sharpness and, objectively, reduced noise and increased CNR.

Introduction Coronary atherosclerosis is a leading cause of mortality. New technological developments in computed tomography (CT), including dual energy, iterative reconstructions and high definition scanning, could significantly improve the non-invasive identification of atherosclerosis plaques. Here, a new method for optimising cardiac coronary CT with optical coherence tomography (OCT) and histopathology is presented. Materials and methods Twenty human hearts obtained from autopsies were used. A contrast agent that solidifies after cooling was injected into the coronary arteries. CT scanning was performed on the heart alone as well as with the heart in a chest phantom. We used eight different CT protocols and the newest CT technique to image every heart. The OCT and CT images were compared with their corresponding histological sections. A procedure for ensuring the correct alignment of the images was also developed. Results We have succeeded in developing a new method for post-mortem coronary CT angiography in which an autopsy heart is placed in a chest phantom to simulate clinical CT. Conclusion The new method permits comparison of CT with OCT and histopathology. This method can also be used for evaluating coronary artery disease, including characterising plaques, and will eventually allow for the detection of rupture-prone plaques, which we will assess in a future study. Clinical testing is our ultimate goal.

Intravascular optical coherence tomography (IVOCT) is an imaging technique that is used to analyze the underlying cause of cardiovascular disease. Because a catheter is used during imaging, the intensities can be affected by the catheter position. This work aims to analyze the effect of the catheter position on IVOCT image intensities and to propose a compensation method to minimize this effect in order to improve the visualization and the automatic analysis of IVOCT images. The effect of catheter position is modeled with respect to the distance between the catheter and the arterial wall (distance-dependent factor) and the incident angle onto the arterial wall (angle-dependent factor). A light transmission model incorporating both factors is introduced. On the basis of this model, the interaction effect of both factors is estimated with a hierarchical multivariant linear regression model. Statistical analysis shows that IVOCT intensities are significantly affected by both factors with p

BACKGROUND: New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults. OBJECTIVE: To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. MATERIALS AND METHODS: A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. RESULTS: Optimal image-quality was maintained at a dose reduction of 61% with MLT(S) optimized images. Even for images of diagnostic quality, MLT(S) provided a dose reduction of 88% as compared to the reference image. Software impact on image quality was found significant for dose (mAs), dynamic range dark region and frequency band. CONCLUSION: By optimizing image processing parameters, a significant dose reduction is possible without significant loss of image quality.

Sir, In a prior issue of this journal we published an article titled “Digital radiography: Optimization of image quality and dose using multi-frequency software” [1]. Knowledge of software optimization is clinically important because it offers possibilities for enhancing the visual diagnostic outcome of the image to obtain images with different visual signal-to-noise ratio [2–4] and, hence, achieve the lowest possible dose. As image quality may differ from one examination to another, this technique allows for individual presettings, defined by the size of the patient and the indication for that particular examination [4]. As the required image quality differs among clinical conditions [5–8], a close dialogue between radiologist, radiographer and physicist is essential in the optimization process. Based on these opportunities we performed another study to examine whether multifrequency software could allow for dose reduction based on differentiated image quality, whilst maintaining an acceptable diagnostic image quality for follow-up examinations in pediatric femur examinations, using similar methods as in the primary study [1]. Three significant factors for visual grading analysisscores were found: first of all dose (mAs), but also the imaging processing parameters “dynamic range—dark region” and “edge enhancement” (Table 1). The generalized odds ratios and their 95% confidence intervals were estimated at 1.39 (1.16, 1.66) for dose, 0.87 (0.78, 0.96) for dynamic range—dark region, and 1.12 (1.03, 1.23) for edge enhancement (Table 1). Compared to the primary article [1], these results showed different significant software parameters than for the primary examination demanding optimal image quality. To differentiate image quality defined

A newly developed Digital Radiography (DR) detector has smaller pixel size and higher fill factor than earlier detector models. These technical advantages should theoretically lead to higher sensitivity and higher spatial resolution, thus making dose reduction possible without scarifying image quality compared to previous DR detector versions. To examine whether the newly developed Canon CXDI-70C DR detector provides an improved image quality and/or allows for dose reductions in hand and pelvic bone examinations as well as premature chest examinations, compared to the previous (CXDI-55C) DR detector version. A total of 450 images of a technical Contrast-Detail phantom were imaged on a DR system employing various kVp and mAs settings, providing an objective image quality assessment. In addition, 450 images of anthropomorphic phantoms were taken and analyzed by three specialized radiologists using Visual Grading Analysis (VGA). The results from the technical phantom studies showed that the image quality expressed as IQFINV values was on average approximately 45 % higher with the CXDI-70C detector compared to the CXDI-55C detector. Consistently, the VGA results from the anatomical phantom studies indicated that by using the CXDI-70C detector, diagnostic image quality could be maintained at a dose reduction of in average 30 %, depending on anatomy and kVp level. This indicates that the CXDI-70C detector is significantly more sensitive than the previous model, and supports a better clinical image quality. By using the newly developed DR detector a significant dose reduction is possible while maintaining image quality.