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Purpose: To systematically review studies on the effectiveness of supplementary imaging for breast cancer screening in women with dense breasts., Materials and Methods: A systematic search of peer-reviewed publications in English (January 2000 to March 2021) was carried out. Eight databases were used to retrieve the studies: MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials, Cochrane Clinical Answers, Cochrane Database of Systematic Reviews, Cochrane Methodology Register, PubMed, and Web of Science. Two radiographers and an academic independently reviewed the articles to determine if the studies met inclusion criteria. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Summary estimates of diagnostic accuracy were obtained by using proportion and diagnostic metanalysis., Results: From 3764 studies that underwent title and abstract screening, 221 studies underwent full-text screening. Of these 42 were included in the qualitative and quantitative synthesis. Results for sensitivity, specificity, positive and negative predictive values, cancer detection rates, recall and biopsy rates in women with dense breasts undergoing supplementary imaging were reported. Studies included in this review were heterogeneous, as was the proportion of women undergoing prevalence and incidence screening rounds., Conclusions: Supplementary screening among women with dense breasts who had recent negative mammograms can consistently identify additional cancers and lead to further recalls and biopsies., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Purpose: To evaluate the perception and 5-year application of anatomic side markers (ASMs) by radiographers in Malta., Methods and Materials: Phase 1 involved a longitudinal, retrospective observation of a stratified sample of radiographs over 5 years, using a self-designed data record sheet to record features of the placement of ASMs. Phase 2 consisted of a cross-sectional, prospective self-designed questionnaire evaluating the radiographers' perception on the use of ASMs in professional practice., Results: In phase 1, radiographs (n = 500) were selected from 234,105 taken over the 5-year period (error: ±4.38%; 95% confidence level). Four hundred thirty radiographs (86%) had evidence of markers, of which 110 (25.6%) had a pre-exposure marker and 320 (74.4%) had a postprocessed marker. The remaining 14% had no evidence of any markers. Two hundred eighty two (56.4%) of the radiographs had ASMs placed according to recommended guidelines by Ballinger, Frank, and Merrill. In phase 2, most radiographers (84.6%) preferred using postprocessing markers, with 15.4% preferring pre-exposure markers (76.6% of radiographers found applying pre-exposure markers time consuming). Sixty percent (60.5%) of radiographers gave correct answers on use of markers as recommended in the guidelines., Conclusions: Radiographer preference in using postprocessing markers was evident, while the use of pre-exposure markers was seen to be influenced by time of examination, projection executed, and patient positioning. Radiographer awareness and continuous training are recommended., (Copyright © 2016 Canadian Association of Medical Radiation Technologists. Published by Elsevier Inc. All rights reserved.)

This study investigated radiation dose and image quality differences for computed tomography (CT) head examinations across centres with matched CT equipment. Radiation dose records and imaging protocols currently employed across three European university teaching hospitals were collated, compared and coded as Centres A, B and C from specification matched CT equipment models. Patient scans (n = 40) obtained from Centres A and C were evaluated for image quality, based on the visualisation of Commission of European Community (CEC) image quality criteria using visual grading characteristic (VGC) analysis, where American Board of Radiology examiners (n = 11) stated their confidence in identifying anatomical criteria. Mean doses in terms of CT dose index (CTDI vol -mGy) and dose length product (DLP-mGy cm) were as follows: Centre A-33.12 mGy and 461.45 mGy cm; Centre B -101 mGy (base)/32 mGy (cerebrum) and 762 mGy cm and Centre C-71.98 mGy and 1047.26 mGy cm, showing a significant difference (p ≤ 0.05) in DLP across centres. VGC analysis indicated better visualisation of CEC criteria on Centre C images (VGC AUC 0.225). All three imaging protocols are routinely used clinically, and image quality is acceptable in each centre. Clinical centres with identical model CT scanners have variously customised their protocols achieving a range of dose savings and still resulting in clinically acceptable image quality., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Tendons are visco-elastic structures that connect bones to muscles and perform the basic function of force transfer to and from the skeleton. They are essential for positioning as well as energy storing when involved in more abrupt movements such as jumping. Unfortunately, they are also prone to damage, and when injuries occur, they may have dilapidating consequences. For instance, there is consensus that injuries of tendons such as Achilles tendinopathies, which are common in athletes, are difficult to treat. Here we show, through in vivo and ex vivo tests, that healthy tendons are highly anisotropic and behave in a very unconventional manner when stretched, and exhibit a negative Poisson's ratio (auxeticity) in some planes when stretched up to 2% along their length, i.e. within their normal range of motion. Furthermore, since the Poisson's ratio is highly dependent on the material's microstructure, which may be lost if tendons are damaged or diseased, this property may provide a suitable diagnostic tool to assess tendon health., Statement of Significance: We report that human tendons including the Achilles tendons exhibits the very unusual mechanical property of a negative Poisson's ratio (auxetic) meaning that they get fatter rather than thinner when stretched. This report is backed by in vivo and ex vivo experiments we performed which clearly confirm auxeticity in this living material for strains which correspond to those experienced during most normal everyday activities. We also show that this property is not limited to the human Achilles tendon, as it was also found in tendons taken from sheep and pigs. This new information about tendons can form the scientific basis for a test for tendon health as well as enable the design of better tendon prosthesis which could replace damaged tendons., (Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Objectives: To evaluate visual grading characteristics (VGC) and ordinal regression analysis during head CT optimisation as a potential alternative to visual grading assessment (VGA), traditionally employed to score anatomical visualisation., Methods: Patient images (n = 66) were obtained using current and optimised imaging protocols from two CT suites: a 16-slice scanner at the national Maltese centre for trauma and a 64-slice scanner in a private centre. Local resident radiologists (n = 6) performed VGA followed by VGC and ordinal regression analysis., Results: VGC alone indicated that optimised protocols had similar image quality as current protocols. Ordinal logistic regression analysis provided an in-depth evaluation, criterion by criterion allowing the selective implementation of the protocols. The local radiology review panel supported the implementation of optimised protocols for brain CT examinations (including trauma) in one centre, achieving radiation dose reductions ranging from 24 % to 36 %. In the second centre a 29 % reduction in radiation dose was achieved for follow-up cases., Conclusions: The combined use of VGC and ordinal logistic regression analysis led to clinical decisions being taken on the implementation of the optimised protocols. This improved method of image quality analysis provided the evidence to support imaging protocol optimisation, resulting in significant radiation dose savings., Main Messages: • There is need for scientifically based image quality evaluation during CT optimisation. • VGC and ordinal regression analysis in combination led to better informed clinical decisions. • VGC and ordinal regression analysis led to dose reductions without compromising diagnostic efficacy.

The impact of optimisation methods on dose reductions for head computerised tomography was undertaken in three phases for two manufacturer models. Phase 1: a Catphan(®)600 was employed to evaluate protocols where the impact of parameter manipulation on dose and image quality was gauged by psychophysical measurements of contrast and spatial resolution in terms of contrast discs and line pairs. mA, kV and pitch were systematically altered until the optimisation threshold was identified. Phantom studies provide dose comparisons during optimisation but lack anatomical detail. Phase 2: optimised protocols were tested on a porcine model permitting further dose reductions over phantom findings providing anatomical structures for image quality evaluation using relative visual grading analysis of anatomical criteria. Phase 3: patient images using pre- and post-optimised protocols were clinically audited using visual grading characteristic analysis and ordinal regression analysis providing a robust analysis of image quality data prior to clinical implementation., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Purpose: To evaluate and compare image quality and radiation dose of sequential computed tomography (CT) examinations of the brain and spiral CT examinations of the brain imaged on a GE HiSpeed NX/I Dual Slice 2CT scanner., Methods: A random sample of 40 patients referred for CT examination of the brain was selected and divided into 2 groups. Half of the patients were scanned using the sequential technique; the other half were scanned using the spiral technique. Radiation dose data—both the computed tomography dose index (CTDI) and the dose length product (DLP)—were recorded on a checklist at the end of each examination. Using the European Guidelines on Quality Criteria for Computed Tomography, 4 radiologists conducted a visual grading analysis and rated the level of visibility of 6 anatomical structures considered necessary to produce images of high quality., Results: The mean CTDI(vol) and DLP values were statistically significantly higher (P <.05) with the sequential scans (CTDI(vol): 22.06 mGy; DLP: 304.60 mGy • cm) than with the spiral scans (CTDI(vol): 14.94 mGy; DLP: 229.10 mGy • cm). The mean image quality rating scores for all criteria of the sequential scanning technique were statistically significantly higher (P <.05) in the visual grading analysis than those of the spiral scanning technique., Discussion: In this local study, the sequential technique was preferred over the spiral technique for both overall image quality and differentiation between gray and white matter in brain CT scans. Other similar studies counter this finding., Conclusion: The radiation dose seen with the sequential CT scanning technique was significantly higher than that seen with the spiral CT scanning technique. However, image quality with the sequential technique was statistically significantly superior (P <.05).

Objectives: To evaluate the diagnostic efficacy of different oral contrast media (OCM) for abdominopelvic CT examinations performed for follow-up general oncological indications. The objectives were to establish anatomical image quality criteria for abdominopelvic CT; use these criteria to evaluate and compare image quality using positive OCM, neutral OCM and no OCM; and evaluate possible benefits for the medical imaging department., Methods: Forty-six adult patients attending a follow-up abdominopelvic CT for general oncological indications and who had a previous abdominopelvic CT with positive OCM (n = 46) were recruited and prospectively placed into either the water (n = 25) or no OCM (n = 21) group. Three radiologists performed absolute visual grading analysis (VGA) to assess image quality by grading the fulfilment of 24 anatomical image quality criteria., Results: Visual grading characteristics (VGC) analysis of the data showed comparable image quality with regards to reproduction of abdominal structures, bowel discrimination, presence of artefacts, and visualization of the amount of intra-abdominal fat for the three OCM protocols., Conclusion: All three OCM protocols provided similar image quality for follow-up abdominopelvic CT for general oncological indications., Key Points: • Positive oral contrast media are routinely used for abdominopelvic multidetector computed tomography • Experimental study comparing image quality using three different oral contrast materials • Three different oral contrast materials result in comparable CT image quality • Benefits for patients and medical imaging department.

Purpose: To evaluate potential radiation dose savings and resultant image quality effects with regard to optimization of commonly performed computed tomography (CT) studies derived from imaging a porcine (pig) model., Methods: Imaging protocols for 4 clinical CT suites were developed based on the lowest milliamperage and kilovoltage, the highest pitch that could be set from current imaging protocol parameters, or both. This occurred before significant changes in noise, contrast, and spatial resolution were measured objectively on images produced from a quality assurance CT phantom. The current and derived phantom protocols were then applied to scan a porcine model for head, abdomen, and chest CT studies. Further optimized protocols were developed based on the same methodology as in the phantom study. The optimization achieved with respect to radiation dose and image quality was evaluated following data collection of radiation dose recordings and image quality review. Relative visual grading analysis of image quality criteria adapted from the European guidelines on radiology quality criteria for CT were used for studies completed with both the phantom-based or porcine-derived imaging protocols., Results: In 5 out of 16 experimental combinations, the current clinical protocol was maintained. In 2 instances, the phantom protocol reduced radiation dose by 19% to 38%. In the remaining 9 instances, the optimization based on the porcine model further reduced radiation dose by 17% to 38%., Conclusion: The porcine model closely reflects anatomical structures in humans, allowing the grading of anatomical criteria as part of image quality review without radiation risks to human subjects. This study demonstrates that using a porcine model to evaluate CT optimization resulted in more radiation dose reduction than when imaging protocols were tested solely on quality assurance phantoms.

This work recommends dose reference levels (DRLs) for abdomen, chest and head computerised tomography (CT) examinations in Malta as the first step towards national CT dose optimisation. Third quartiles volume CT dose index  values for abdomen: 12.1 mGy, chest: 13.1 mGy and head: 41 mGy and third quartile dose-length product values for abdomen: 539.4, chest: 492 and head: 736 mGy cm(-1) are recommended as Maltese DRLs derived from this first Maltese CT dose survey. These values compare well with DRLs of other European countries indicating that CT scanning in Malta is consistent with standards of good practice. Further work to minimise dose without affecting image quality and extending the establishment of DRLs for other CT examinations is recommended.

The purpose of this survey was to provide details and frequency data on CT examinations in Malta, and identify commonly requested CT examinations. Future work will establish Diagnostic Reference Levels (DRLs) in these areas. Participation of 57% was garnered encompassing CT units from both public and private hospitals comparing well with other surveys. Three major CT manufacturers were included encompassing four different models. A broad classification using European guidelines was adopted to enable international comparison of frequencies. Data were collected by a questionnaire based on the internationally recognized NRPB W67 guideline, and obtained from the Radiology Information Systems of the hospitals for the period January to December 2008. CT comprised 8.85% of the total ionizing radiation examinations. CT of the head is the most frequently requested examination at 43%. This is higher than in Spain (38%), the United Kingdom (35%), and Ireland (41%) but less than in Wales (50%). The abdomen and pelvis in Malta (33%) is much more frequently requested than in other countries (12%-22%), whereas the thorax is similar to other countries (9%). CT distribution data in Malta has identified differences to other countries. Ongoing work on DRLs will further elucidate the causal factors and enable the establishment of collective doses. The abdomen and pelvis examinations demonstrate a larger frequency and hence a large potential for optimization. A comparison with European and worldwide examination distributions has demonstrated discrepancies in certain CT examinations indicating areas for dose reduction., (Copyright © 2011. Published by Elsevier Inc.)

Purpose: This article is intended as a review of the methods of establishing dose reference levels (DRLs) in relation to computerized tomography (CT) and their role in the standardization and auditing of radiation dose in CT., Discussion: CT is considered a high radiation dose examination. The potential for dose reduction resulting from the establishment of DRLs is discussed. The rationale for the use of DRLs in relation to the use of appropriate radiation measurements and CT dose descriptors are discussed. The estimation of the radiation risk to the irradiated individual is given by the effective dose, which takes into consideration the type of radiation and the radiosensitivity of the irradiated tissues. The collective dose is used to describe the radiation exposure of a population from low doses of different sources of radiation., Conclusion: Dose comparison between individual imaging sites is a vital part of DRL establishment and facilitates standardization of radiation dose levels for patients attending for a CT examination. Measurements of both effective and collective dose are difficult to achieve in practice. CT dose descriptors such as CT dose index and dose length product provide the means of comparing and monitoring the effect of optimized CT scanning protocols on the radiation dose., (Copyright © 2009 Elsevier Inc. All rights reserved.)

The ingenuity that has characterized the fabrication of provisional prostheses has been readily adapted to the osseointegration technique. Implant abutments do not need protection during final prosthesis fabrication stages as teeth do. However, compelling arguments can be made in favor of esthetic, comfortable, and functional provisional prostheses supported by implants, even if they are worn for only a few weeks. The prosthodontic contribution to a patient's quality of life throughout all stages of treatment is thereby enhanced.

Osseointegration is a clinical application of a biologically investigated host bone response to the placement of threaded unalloyed titanium implants using a meticulous surgical procedure. Its documented successful use as an analogue for the periodontal ligament in endentulous patients has already profoundly altered the predicament of being edentulous. Its application as a treatment modality for partial edentulism offers exciting challenges for the dentist. This article reviewed preliminary experiences from the University of Toronto's Clinical Osseointegration Unit in this area. Although it is tempting to extrapolate the successful longitudinal clinical applications with edentulous patients to partially edentulous ones, discretion and prudence demand that dentists remember that osseointegration for routine treatment of partially edentulous patients is still in its infancy. Until the results from long-term clinical trials in different centres are published, the dental profession cannot yet subsume the versatility and routine application of this exciting technique.