Migration of the Nellix endoprosthesis England, Andrew, PhD; Torella, Francesco, MD, FRCS; Fisher, Robert K., MD, FRCS ...
Journal of vascular surgery,
08/2016, Letnik:
64, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Background This study reports the incidence and sequelae of migration of the Nellix (Endologix Inc, Irvine, Calif) endoprosthesis after endovascular aneurysm sealing. Methods A review was performed ...of the follow-up imaging of all endovascular aneurysm sealing patients in a university hospital endovascular program who had a minimum follow-up of 1 year. The first postoperative and latest follow-up computed tomography scans were used to measure the distances between the proximal and distal borders of the stent grafts relative to reference vessels using a previously validated technique. Device migration was based on previously established criteria and defined as any stent graft movement of ≥4 mm related to a predefined reference vessel. Device movement in a caudal direction was given a positive value, and movement in a cranial direction was denoted by a negative value. Results Eighteen patients (35 stent grafts) were eligible for inclusion in this retrospective review. The mean preoperative abdominal aortic aneurysm diameter was 57 mm (standard deviation SD, 5; range, 50-67 mm) and aortic neck length was 30 mm (SD, 16; range, 6-62 mm). Proximal migration, according to study definitions, was identified in six stent grafts (17%), all in a caudal direction. At 1 year the mean proximal migration distance was +6.6 mm (SD, 1.6; range, +4.7-+9.2 mm). Migration occurred in a single stent graft in four patients and bilaterally in one. No distal migration occurred. Conclusions Proximal migration of the Nellix endoprosthesis does occur and was without any sequelae in our series. Further investigations into the long-term positional stability of the Nellix device, together with a more thorough understanding of the etiology and consequences of migration, are required.
The design life of welded structures and components extends into the very high cycle fatigue (VHCF) regime across various applications. However, the availability of data on the fatigue behaviour of ...welded joints in the VHCF regime is limited, particularly when compared to the low and high cycle fatigue regimes. The development of ultrasonic fatigue testing equipment has accelerated fatigue testing and allowed for the VHCF properties of welds to be investigated in a feasible timeframe. In the present review, the emerging research concerning the VHCF behaviour of welds of various steels and non-ferrous alloys are individually explored. Overall, it is observed that welded joints have significantly lower fatigue strength than the base metal in the VHCF regime and that welding defects have a considerable influence on fatigue strength. Through the discussion of the relevant literature, important findings concerning the effects of specimen geometry and fatigue improvement methods are underlined. Furthermore, the guidance provided within design standards is compared, and some examples of VHCF failures of in-service components are highlighted. Finally, perspectives on future directions of investigation are put forward with the aim of encouraging further research in the field of VHCF of welds.
Patients with dementia frequently present to the Radiology Department. However, stigmas have been recorded amongst radiographers surrounding imaging persons with dementia (PwD). This study aimed to ...investigate the impact of PwD attending the Radiology Department for imaging and the resultant effects to all patients, radiographers, and the Department from the perspectives of the examining radiographer.
A paper-based questionnaire of radiographers’ perceptions and experiences of individual examinations ‘termed an interaction form’ was created and made available in a public hospital in Ireland for a period of eight weeks. Radiographers completed the interaction form collecting data regarding individual imaging examinations of PwD. The form comprised sixteen closed and one open-ended question on the radiographers’ individual perspectives of PwDs’ abilities and distress levels, carers and comforters and their role in the examination, what the radiographer found helpful in the interaction, and any adverse events. Data were analysed using a combination of descriptive analysis and thematic content analysis.
Thirty-three interaction forms were completed by the participating radiographers. The modality most commonly represented in the survey was general X-ray (58%). Radiographers reported 84% of examinations for PwD required extra time, with 27% of examinations required repeat imaging and 69% of patients appeared distressed. A carer helped facilitate the completion of 77% of examinations. Qualitative data indicated that distractive and communicative techniques were used by radiographers to make the patient feel more comfortable and help with examination success.
PwD often require more time for radiological examinations, they often need repeat imaging and re-scheduling of an examination at a more appropriate time. These factors need to be considered when scheduling and performing radiological examinations. Patient distress was frequently encountered, this area may benefit from further research and dedicated practitioner training which could help drive improvements in patient experience.
Les patients atteints de démence se présentent fréquemment au service de radiologie. Cependant, des stigmates ont été relevés chez les radiographes concernant l'imagerie des personnes atteintes de démence (PaD). Cette étude visait à examiner l'incidence de la présence de PaD dans le service de radiologie et les effets qui en résultent pour tous les patients, les radiographes et le service, du point de vue du radiographe examinateur.
Un questionnaire papier sur les perceptions et les expériences des radiographes en matière d'examens individuels, appelé « formulaire d'interaction », a été créé et mis à disposition dans un hôpital public irlandais pendant une période de huit semaines. Les radiographes ont rempli le formulaire d'interaction en recueillant des données sur les examens d'imagerie individuels des PaD. Le formulaire comprenait seize questions fermées et une question ouverte sur les perspectives individuelles des radiographes concernant les capacités et les niveaux de détresse des PaD, les soignants et les réconfortants et leur rôle dans l'examen, ce que le radiographe a trouvé utile dans l'interaction, et tout événement indésirable. Les données ont été analysées à l'aide d'une combinaison d'analyse descriptive et d'analyse thématique du contenu.
Trente-trois formulaires d'interaction ont été remplis par les radiographes participants. La modalité la plus représentée dans l'enquête était la radiographie générale (58%). Les radiographes ont indiqué que 84% des examens pour les PaD ont nécessité plus de temps, que 27% des examens ont nécessité une nouvelle imagerie et que 69% des patients semblaient en détresse. Un soignant a facilité la réalisation de 77% des examens. Les données qualitatives indiquent que les radiographes utilisent des techniques de distraction et de communication pour mettre le patient à l'aise et contribuer à la réussite de l'examen.
Les PaD ont souvent besoin de plus de temps pour les examens radiologiques, l'examen doit souvent être repris ou reprogrammé à un moment plus approprié. Ces facteurs doivent être pris en compte lors de la programmation et de la réalisation des examens radiologiques. La détresse des patients était fréquente, ce domaine pourrait bénéficier d'une recherche plus approfondie et d'une formation spécialisée des praticiens, ce qui pourrait contribuer à améliorer l'expérience des patients.
Cannabis usage in recent years has increased due to the legalization of both recreational and medical use. The CB1cannabinoid receptor (CB1R) is a G‐protein coupled receptor (GPCR) found in the ...central nervous system and modulates neuroprogenitor development, neural commitment and migration, and neurotransmitter release. Cannabinoid receptor interacting protein 1a (CRIP1a) is a beta‐barrel protein that interacts with CB1R. Fluorescence polarization studies demonstrated that CRIP1a interacts directly with myristoylated Gαi (Booth et. al. 2021). We hypothesized that this occurs through the intercalation of the myristoyl moiety into the interior of the barrel through a gapped site that is bordered by the C‐terminal β‐strand. We tested this hypothesis by immunoprecipitation of CRIP1a with antibodies developed to two different epitopes of CRIP1a: to the loop‐helix‐loop motif that is located at a distance from the proposed myristoylated peptide access site, and to the C‐terminal β‐strand of CRIP1a which is directly adjacent to this region. We immunoprecipitated CRIP1a from N18TG2 mouse neuroblastoma cell homogenates without the addition of detergent for solubilization. We then probed for CRIP1a and determined if the either the Gαi subunit or the Gβγ dimer were associated with CRIP1a. Immunoprecipitation using the antibody to CRIP1a directed at the loop‐helix‐loop motif revealed complexes with Gai1 and Gai3 and not Gβγ. In contrast, immunoprecipitation of CRIP1a using the antibody directed at the C‐terminal β‐strand co‐immunoprecipitated Gβ and not Gαi1 or Gαi3. Collectively, these data suggest CRIP1a is a cargo‐carrying protein capable of carrying the G‐protein α‐subunit, but also exhibits an interaction with the β‐subunit.
The purpose of this study was to evaluate the effect of outside-field-of-view (FOV) lead shielding on the entrance surface dose (ESD) of the breast on an anthropomorphic X-ray phantom for a variety ...of axial skeleton X-ray examinations.
Using an anthropomorphic phantom and radiation dosimeter, the ESD of the breast was measured with and without outside-FOV shielding in anterior-posterior (AP) abdomen, AP cervical spine, occipitomental 30° (OM30) facial bones, AP lumbar spine, and lateral lumbar spine radiography. The effect of several exposure parameters, including a low milliampere-seconds technique, grid use, automatic exposure control use, wraparound lead (WAL) use, trolley use, and X-ray table use, on the ESD of the breast with and without outside-FOV shielding was investigated. The mean ESD (μSv) and standard deviation for each radiographic protocol were calculated. A one-tailed Student's t-test was carried out to evaluate whether ESD to the breast was reduced with the use of outside-FOV shielding.
A total of 920 breast ESD measurements were recorded across the different protocol parameters. The largest decrease in mean ESD of the breast with outside-FOV shielding was 0.002 μSv (
= 0.084), recorded in the AP abdomen on the table with a grid, OM30 on the table with a grid, OM30 standard protocol on the trolley, and OM30 on the trolley with WAL protocols. This decrease was found to be statistically non-significant.
This study found no significant decrease in the ESD of the breast with the use of outside-FOV shielding for the AP abdomen, AP cervical spine, OM30 facial bones, AP lumbar spine, or lateral lumbar spine radiography across a range of protocols.
Introduction
Differences in patient size often provide challenges for radiographers, particularly when choosing the optimum acquisition parameters to obtain radiographs with acceptable image quality ...(IQ) for diagnosis. This study aimed to assess the effect of body part thickness on IQ in terms of low‐contrast detail (LCD) detection and radiation dose when undertaking adult chest radiography (CXR).
Methods
This investigation made use of a contrast detail (CD) phantom. Polymethyl methacrylate (PMMA) was utilised to approximate varied body part thicknesses (9, 11, 15 and 17 cm) simulating underweight, standard, overweight and obese patients, respectively. Different tube potentials were tested against a fixed 180 cm source to image distance (SID) and automatic exposure control (AEC). IQ was analysed using bespoke software thus providing an image quality figure inverse (IQFinv) value which represents LCD detectability. Dose area product (DAP) was utilised to represent the radiation dose.
Results
IQFinv values decreased statistically (P = 0.0001) with increasing phantom size across all tube potentials studied. The highest IQFinv values were obtained at 80 kVp for all phantom thicknesses (2.29, 2.02, 1.8 and 1.65, respectively). Radiation dose increased statistically (P = 0.0001) again with increasing phantom thicknesses.
Conclusion
Our findings demonstrate that lower tube potentials provide the highest IQFinv scores for various body part thicknesses. This is not consistent with professional practice because radiographers frequently raise the tube potential with increased part thickness. Higher tube potentials did result in radiation dose reductions. Establishing a balance between dose and IQ, which must be acceptable for diagnosis, can prevent the patient from receiving unnecessary additional radiation dose.
This study aimed to assess the effect of body part thickness on image quality in terms of low‐contrast detail detection and radiation dose when undertaking adult chest radiography. Findings of our study show that image quality decreased significantly with increasing body part thickness and the highest values of image quality were observed at lower tube potentials (80 and 85 kVp). Higher kVp settings did result in dose reductions.
Background
Artifacts caused by metal implants are challenging when undertaking computed tomography (CT). Dedicated algorithms have shown promising results although with limitations. Tin filtration ...(Sn) in combination with high tube voltage also shows promise but with limitations. There is a need to examine these limitations in more detail. The purpose of this study was to investigate the impact of different metal artefact reduction (MAR) algorithms, tin filtration, and ultra-high-resolution (UHR) scanning, alone or in different combinations in both phantom and clinical settings.
Methods
An ethically approved clinical and phantom study was conducted. A modified Catphan® phantom with titanium and stainless-steel inserts was scanned with six different MAR protocols with tube voltage ranging from 80 to 150 kVp. Other scan parameters were kept identical. The differences (∆) in mean HU and standard deviation (SD) in images, with and without metal, were measured and compared. In the clinical study, three independent readers performed visual image quality assessments on eight different protocols using retrospectively acquired images.
Results
Iterative MAR had the lowest ∆HU and ∆SD in the phantom study. For images of the forearm, the soft tissue noise for Sn-based 150-kVp UHR protocol with was significantly higher (
p
= 0.037) than for single-energy MAR protocols. All Sn-based 150-kVp protocols were rated significantly higher (
p
< 0.046 than the single-energy MAR protocols in the visual assessment.
Conclusions
All Sn-based 150-kVp UHR protocols showed similar objective MAR in the phantom study, and higher objective MAR and significantly improved visual image quality than single-energy MAR.
Relevance statement
Images with less metal artifacts and higher visual image quality may be more clinically optimal in CT examination of musculoskeletal patients with metal implants.
Key points
• Metal artifact reduction algorithms and Sn filter combined with high kVp reduce artifacts.
• Metal artifact reduction algorithms introduce new artifacts in certain metals.
• Sn-based protocols alone may be considered as low metal artifact protocols.
Graphical Abstract
INTRODUCTION: The SARS-CoV-19 (COVID-19) pandemic has become a global problem but has affected the paediatric population less so than in adults. The clinical picture in paediatrics can be different ...to adults but nonetheless both groups have been subject to frequent imaging. The overall aim of this study was to comprehensively summarise the findings of the available literature describing the chest radiograph (CXR) findings of paediatric patients with confirmed COVID-19. The COVID-19 landscape is rapidly changing, new information is being constantly brought to light, it is therefore important to appraise clinicians and the wider scientific community on the radiographic features of COVID-19 in children. METHODS: Four databases, which included, PubMed; Medline; CINAHL; ScienceDirect were searched from the 30 November 2020 to the 5 March 2021. The review was conducted using the “Preferred Reporting Items for Systematic Reviews and Meta-Analysis, PRISMA” guidelines. Studies were included for (1) publications with full text available, (2) patients with confirmed COVID-19 diagnoses, (3) CXR imaging features of COVID-19 were reported, (4) the age of patients was 0–18 years, (5) studies were limited to human subjects and (6) a language restriction of English was placed on the search. Quality assessment of included articles used the National of Health Quality Assessment Tool for Case Series Studies. RESULTS: Eight studies met our criteria for inclusion in the review. All eight studies documented the number of CXRs obtained, along with the number of abnormal CXRs. Seven out of the eight studies noted greater than 50% of the CXRs taken were abnormal. Opacification was the number one feature that was recorded in all eight studies, followed by pleural effusion which was seen in six studies. Consolidation and peri-bronchial thickening features were both evident in four studies. Opacification was sub-divided into common types of opacities i.e., consolidation, ground glass opacities, interstitial, alveolar and hazy. Consolidation was reported in half of the studies followed by ground glass opacities and interstitial opacities which was seen in three out of the eight studies. CONCLUSION: This systematic review provides insight into the common COVID-19 features that are seen on CXRs in paediatric patients. Opacification was the most common feature reported, with consolidation, ground glass and interstitial opacities the top three opacifications seen. Peri-bronchial thickening is reported. in the paediatric population but this differs from the adult population and was not reported as a common radiographic finding typically seen in adults. ADVANCES IN KNOWLEDGE: This systematic review highlights the CXR appearances of paediatric patients with confirmed SARS-CoV-19, to gain insight into the disease pathophysiology and provide a comprehensive summary of the features for clinicians aiding optimal management.
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