Understanding the factors influencing acceptability of AI in medical imaging domains among healthcare professionals: A scoping review.

BACKGROUND: Artificial intelligence (AI) technology has the potential to transform medical practice within the medical imaging industry and materially improve productivity and patient outcomes. However, low acceptability of AI as a digital healthcare intervention among medical professionals threatens to undermine user uptake levels, hinder meaningful and optimal value-added engagement, and ultimately prevent these promising benefits from being realised. Understanding the factors underpinning AI acceptability will be vital for medical institutions to pinpoint areas of deficiency and improvement within their AI implementation strategies. This scoping review aims to survey the literature to provide a comprehensive summary of the key factors influencing AI acceptability among healthcare professionals in medical imaging domains and the different approaches which have been taken to investigate them. METHODS: A systematic literature search was performed across five academic databases including Medline, Cochrane Library, Web of Science, Compendex, and Scopus from January 2013 to September 2023. This was done in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. Overall, 31 articles were deemed appropriate for inclusion in the scoping review. RESULTS: The literature has converged towards three overarching categories of factors underpinning AI acceptability including: user factors involving trust, system understanding, AI literacy, and technology receptiveness; system usage factors entailing value proposition, self-efficacy, burden, and workflow integration; and socio-organisational-cultural factors encompassing social influence, organisational readiness, ethicality, and perceived threat to professional identity. Yet, numerous studies have overlooked a meaningful subset of these factors that are integral to the use of medical AI systems such as the impact on clinical workflow practices, trust based on perceived risk and safety, and compatibility with the norms of medical professions. This is attributable to reliance on theoretical frameworks or ad-hoc approaches which do not explicitly account for healthcare-specific factors, the novelties of AI as software as a medical device (SaMD), and the nuances of human-AI interaction from the perspective of medical professionals rather than lay consumer or business end users. CONCLUSION: This is the first scoping review to survey the health informatics literature around the key factors influencing the acceptability of AI as a digital healthcare intervention in medical imaging contexts. The factors identified in this review suggest that existing theoretical frameworks used to study AI acceptability need to be modified to better capture the nuances of AI deployment in healthcare contexts where the user is a healthcare professional influenced by expert knowledge and disciplinary norms. Increasing AI acceptability among medical professionals will critically require designing human-centred AI systems which go beyond high algorithmic performance to consider accessibility to users with varying degrees of AI literacy, clinical workflow practices, the institutional and deployment context, and the cultural, ethical, and safety norms of healthcare professions. As investment into AI for healthcare increases, it would be valuable to conduct a systematic review and meta-analysis of the causal contribution of these factors to achieving high levels of AI acceptability among medical professionals.

Benchmarking the diagnostic test accuracy of certified AI products for screening pulmonary tuberculosis in digital chest radiographs: Preliminary evidence from a rapid review and meta-analysis.

BACKGROUND AND OBJECTIVE: The global market for AI systems used in lung tuberculosis (TB) detection has expanded significantly in recent years. Verifying their performance across diverse settings is crucial before medical organisations can invest in them and pursue safe, wide-scale deployment. The goal of this research was to synthesise the clinical evidence for the diagnostic accuracy of certified AI products designed for screening TB in chest X-rays (CXRs) compared to a microbiological reference standard. METHODS: Four databases were searched between June to September 2022. Data concerning study methodology, system characteristics, and diagnostic accuracy metrics was extracted and summarised. Study bias was evaluated using QUADAS-2 and by examining sources of funding. Forest plots for diagnostic odds ratio (DOR) and summary receiver operating characteristic (SROC) curves were constructed for the AI products individually and collectively. RESULTS: 10 out of 3642 studies satisfied the review criteria however only 8 were subject to meta-analysis following bias assessment. Three AI products were evaluated with a 95 % confidence interval producing the following pooled estimates for accuracy rankings: qXR v2 (sensitivity of 0.944 [0.887-0.973], specificity of 0.692 [0.549-0.805], DOR of 3.63 [3.17-4.09], Lunit INSIGHT CXR v3.1 (sensitivity of 0.853 [0.787-0.901], specificity of 0.646 [0.627-0.665], DOR of 2.37 [1.96-2.78]), and CAD4TB v3.07 (sensitivity of 0.917 [0.848-0.956], specificity of 0.371 [0.336-0.408], DOR of 1.91 [1.4-2.47]). Overall, the products had a sensitivity of 0.903 (0.859-0.934), specificity of 0.526 (0.409-0.641), and DOR of 2.31 (1.78-2.84). CONCLUSION: Current publicly available evidence indicates considerable variability in the diagnostic accuracy of available AI products although overall they have high sensitivity and modest specificity which is improving with time. These preliminary results are limited by the small number of studies and poor coverage for low TB burden settings. More research is needed to expand the clinical evidence base for the performance of AI products.

Reduction of scan duration and radiation dose in cerebral CT perfusion imaging of acute stroke using a recurrent neural network.

Objective. Cerebral CT perfusion (CTP) imaging is most commonly used to diagnose acute ischaemic stroke and support treatment decisions. Shortening CTP scan duration is desirable to reduce the accumulated radiation dose and the risk of patient head movement. In this study, we present a novel application of a stochastic adversarial video prediction approach to reduce CTP imaging acquisition time.Approach. A variational autoencoder and generative adversarial network (VAE-GAN) were implemented in a recurrent framework in three scenarios: to predict the last 8 (24 s), 13 (31.5 s) and 18 (39 s) image frames of the CTP acquisition from the first 25 (36 s), 20 (28.5 s) and 15 (21 s) acquired frames, respectively. The model was trained using 65 stroke cases and tested on 10 unseen cases. Predicted frames were assessed against ground-truth in terms of image quality and haemodynamic maps, bolus shape characteristics and volumetric analysis of lesions.Main results. In all three prediction scenarios, the mean percentage error between the area, full-width-at-half-maximum and maximum enhancement of the predicted and ground-truth bolus curve was less than 4 ± 4%. The best peak signal-to-noise ratio and structural similarity of predicted haemodynamic maps was obtained for cerebral blood volume followed (in order) by cerebral blood flow, mean transit time and time to peak. For the 3 prediction scenarios, average volumetric error of the lesion was overestimated by 7%-15%, 11%-28% and 7%-22% for the infarct, penumbra and hypo-perfused regions, respectively, and the corresponding spatial agreement for these regions was 67%-76%, 76%-86% and 83%-92%.Significance. This study suggests that a recurrent VAE-GAN could potentially be used to predict a portion of CTP frames from truncated acquisitions, preserving the majority of clinical content in the images, and potentially reducing the scan duration and radiation dose simultaneously by 65% and 54.5%, respectively.

Chest CT in COVID-19 patients: A clinical need.

INTRODUCTION: The COVID-19 pandemic caused by the coronavirus SARS-CoV-2 has resulted in a global healthcare crisis. The provision of computed tomography (CT) imaging services by radiology departments for COVID-19 patients poses multiple challenges. Consequently, it is important to explore the clinical need and indications for thoracic CT and whether they subsequently alter patient management. METHODS: We report our experience in this single-centre retrospective cohort study of all confirmed COVID-19 cases admitted during the peak of the 'Delta' variant wave in Australia, and who underwent a chest CT. Clinical indication and patient management plan pre- and post-CT were ascertained. RESULTS: A total of 92 out of 1403 patients who were admitted with COVID-19 underwent a thoracic CT (73 CT pulmonary angiogram (CTPA), 14 CT Chest and five high-resolution CT (HRCT) studies). 72.8% of studies were to evaluate for pulmonary emboli, 16.2% for assessment of COVID-19 pneumonia complications, 5.4% for tuberculosis and 6.5% for other indications. 21 (23%) of these studies resulted in a change in management with two patients having a major change in management (thrombolysis, CT-guided aspiration). Management was altered due to diagnosis of pulmonary embolism (PE), pneumonia, cryptogenic organising pneumonia and other reasons. Of 73 CTPA studies, 11 (15%) patients had evidence of PE. CONCLUSION: In our centre, thoracic CT in COVID-19 patients were predominantly for the evaluation of PE with other indications being for COVID-19 complications and other cardiopulmonary pathologies. 23% of studies subsequently altered patient management, suggesting there is good clinical need for CT chests for these indications.

Head movement during cerebral CT perfusion imaging of acute ischaemic stroke: Characterisation and correlation with patient baseline features.

PURPOSE: To quantitatively characterise head motion prevalence and severity and to identify patient-based risk factors for motion during cerebral CT perfusion (CTP) imaging of acute ischaemic stroke. METHODS: The head motion of 80 stroke patients undergoing CTP imaging was classified retrospectively into four categories of severity. Each motion category was then characterised quantitatively based on the average head movement with respect to the first frame for all studies. Statistical testing and principal component analysis (PCA) were then used to identify and analyse the relationship between motion severity and patient baseline features. RESULTS: 46/80 (58%) of patients showed negligible motion, 19/80 (24%) mild-to-moderate motion, and 15/80 (19%) considerable-to-extreme motion sufficient to affect diagnostic/therapeutic accuracy even with correction. The most prevalent movement was "nodding" with maximal translation/rotation in the sagittal/axial planes. There was a tendency for motion to worsen as scan proceeded and for faster motion to occur in the first 15 s. Statistical analyses showed that greater stroke severity (National Institutes of Health Stroke Scale (NIHSS)), older patient age and shorter time from stroke onset were predictive of increased head movement (p < 0.05 Kruskal-Wallis). Using PCA, the combination of NIHSS and patient age was found to be highly predictive of head movement (p < 0.001). CONCLUSIONS: Quantitative methods were developed to characterise CTP studies impacted by motion and to anticipate patients at-risk of motion. NIHSS, age, and time from stroke onset function as good predictors of motion likelihood and could potentially be used pre-emptively in CTP scanning of acute stroke.

Quality of radiology training and role of Royal Australian and New Zealand College of Radiology in supporting radiology trainees in NSW: Results of the first radiology trainee survey.

INTRODUCTION: The Royal Australian and New Zealand College radiology training programme is a 5-year programme with a vast curriculum including reporting and research requirements. Undertaking training can be stressful for trainees who must balance their educational needs and work responsibilities. We undertook the first independent survey of New South Wales (NSW) radiology trainees to evaluate their perceptions about the quality of their training. METHODS: Focus groups with trainees from multiple NSW training sites were conducted to construct a survey which was then distributed to all NSW Radiology trainees (n = 118). Data from the survey were analysed, and factors correlating to the overall satisfaction with the programme were explored using Spearman's correlation. RESULTS: Survey response rate was 70.3%. Eighty-nine per cent of trainees were satisfied with their career choice, and 73% were satisfied with the training programme. Majority felt they had a good exposure to cases, modalities and access to resources to complete their training. Trainee satisfaction significantly correlated with a supportive work environment (rs  = 0.83, P < 0.0001), which involved supportive consultants (rs  = 0.75, P < 0.0001), good peer support (rs  = 0.60, P < 0.0001) and their training site respecting work/life balance (rs  = 0.62, P < 0.0001). As trainees progressed through the training programme, they became less satisfied, with trainees in years 3 and above being the most dissatisfied. CONCLUSION: NSW radiology trainees are generally satisfied with their training programme and career choices. Trainee satisfaction correlated most strongly with supportive work environment, good consultant support, peer relationships and good work/life balance; satisfaction decreased for senior trainees.

Quality use of diagnostic imaging in trauma, and the impact on emergency medical practice-a retrospective clinical audit.

PURPOSE: The current study aimed to evaluate the appropriateness of the decisions made to order diagnostic imaging for emergency trauma patients. METHODS: A retrospective audit of 642 clinical decisions for 370 non-consecutive trauma cases was conducted at a level 1 adult trauma centre. Radiographs and computed tomography investigations were compared for compliance with the American College of Radiology/European Society of Radiology (ACR/ESR) imaging guidelines. The non-compliant imaging orders were evaluated for the following medical officer ranks: Junior Medical Officer (JMO), Senior Resident Medical Officer (SRMO), Emergency Medicine Registrar (EMR) and Consultants/Career Medical Officer (CMO). The time of imaging order (day/evening or night shift), whether the imaging led to conservative or surgical patient management, and whether the imaging order decisions led to a change in the clinical management of the patient were also considered. RESULTS: Non-compliance with the ACR/ESR guidelines was low. At least half of non-compliant decisions made by each level of medical officer resulted in a change in patient management. In total, 11 (65%), 25 (53%), 12 (63%) and 11 (52%) of non-compliant imaging orders placed by JMOs, SRMOs, EMRs and Consultants, respectively, resulted in change of patient management. JMOs and SRMOs ordered a significantly higher proportion of non-compliant imaging studies for conservatively managed patients in comparison to surgically managed patients. CONCLUSION: This study highlighted that most non-compliant imaging orders benefited the patient.

Efficient radiation dose reduction in whole-brain CT perfusion imaging using a 3D GAN: performance and clinical feasibility.

Dose reduction in cerebral CT perfusion (CTP) imaging is desirable but is accompanied by an increase in noise that can compromise the image quality and the accuracy of image-based haemodynamic modelling used for clinical decision support in acute ischaemic stroke. The few reported methods aimed at denoising low-dose CTP images lack practicality by considering only small sections of the brain or being computationally expensive. Moreover, the prediction of infarct and penumbra size and location-the chief means of decision support for treatment options-from denoised data has not been explored using these approaches. In this work, we present the first application of a 3D generative adversarial network (3D GAN) for predicting normal-dose CTP data from low-dose CTP data. Feasibility of the approach was tested using real data from 30 acute ischaemic stroke patients in conjunction with low dose simulation. The 3D GAN model was applied to 643voxel patches extracted from two different configurations of the CTP data-frame-based and stacked. The method led to whole-brain denoised data being generated for haemodynamic modelling within 90 s. Accuracy of the method was evaluated using standard image quality metrics and the extent to which the clinical content and lesion characteristics of the denoised CTP data were preserved. Results showed an average improvement of 5.15-5.32 dB PSNR and 0.025-0.033 structural similarity index (SSIM) for CTP images and 2.66-3.95 dB PSNR and 0.036-0.067 SSIM for functional maps at 50% and 25% of normal dose using GAN model in conjunction with a stacked data regime for image synthesis. Consequently, the average lesion volumetric error reduced significantly (p-value <0.05) by 18%-29% and dice coefficient improved significantly by 15%-22%. We conclude that GAN-based denoising is a promising practical approach for reducing radiation dose in CTP studies and improving lesion characterisation.

Blunt thoracic aorta injuries, an Australian single centre's perspective.

BACKGROUND: Blunt thoracic aortic injuries (BTAI) are potentially life-threatening emergencies. The management paradigm has shifted from open repair to a predominantly endovascular approach. We evaluated the trends in managing BTAI at our centre over the last decade and compared them to current international guidelines. METHODS: We retrospectively reviewed all patients who presented with BTAI to our level one trauma centre, Westmead Hospital, New South Wales, Australia between 1 January 2010 and 31 December 2019. Patient demographics, injury grade and location, imaging features, management details and outcomes were analysed. RESULTS: BTAI is rare, with 39 patients identified at our institute over the last 10 years. Of these, seven died in the emergency department from their associated injuries (17.9%). Of the 32 survivors, 27 underwent surgical management with an endovascular stent-graft placement, and the remaining five patients were treated non-operatively. No patients were treated via an open surgical approach. All patients were diagnosed via computed tomography angiography. There were one death and two endoleaks amongst patients who underwent Thoracic endovascular aortic repair (TEVAR). The death occurred secondary to severe traumatic brain injury. Two patients illustrated neurological changes however these were associated with the original injury. No patients failed non-operative management. CONCLUSION: This study demonstrates that at our level one trauma centre, patients with BTAI are managed in accordance with international guidelines. All patients underwent computed tomography angiography for diagnosis and grading of injury. All patients requiring surgical management underwent TEVAR. Furthermore, our data support that select patients with grade I injuries can safely be managed non-operatively.

Early experiences of COVID-19 infected, middle-aged patients.

This case report describes our early radiological experiences of middle-aged patients with COVID-19 at Westmead Hospital, Sydney. We found limited relationship between initial CT imaging appearances and progression to severe disease. The most effective use of imaging in COVID-19 is yet to be determined.

Adaptive tutorials versus web-based resources in radiology: a mixed methods analysis in junior doctors of efficacy and engagement.

BACKGROUND: Radiology education is limited in undergraduate Medicine programs. Junior doctors might not have the necessary background to effectively order and interpret diagnostic imaging investigations. Furthermore, junior doctors are often time-poor, balancing clinical commitments with ongoing learning, leadership and teaching responsibilities. Previous studies have demonstrated the efficacy of radiology-themed online adaptive tutorials for senior medical students. Such adaptive tutorials might therefore be an efficient and effective form of radiology education for junior doctors. METHODS: A randomised controlled crossover trial was performed to evaluate the impact of adaptive tutorials on learning the indications for, and interpretation of, basic imaging studies, compared with peer-reviewed web-based resources. Ninety-one volunteer junior doctors, comprising 53 postgraduate year 1 (PGY 1) and 38 postgraduate year 2 (PGY 2), were randomly allocated into two groups. In the first phase of the trial, focusing on head CT, one group accessed adaptive tutorials while the other received web-based resources. In the second phase of the trial, focusing on chest CT, the groups crossed over. Following each phase of the trial, participants completed exam-style online assessments. At the conclusion of the study, participants also completed an online questionnaire regarding perceived engagement and efficacy of each type of educational resource. RESULTS: Junior doctors completed the adaptive tutorials significantly faster than the relevant web-based resources for both head CT and chest CT (p = 0.03 and < 0.01 respectively). Mean quiz scores were higher in the groups receiving adaptive tutorials on head CT and chest CT (86.4% vs 83.5 and 77.7% vs 75% respectively). However, in contrast to previous studies in senior medical students, these differences were not statistically significant. Participants reported higher engagement and perceived value of adaptive tutorials, compared with web-based resources. CONCLUSIONS: Adaptive tutorials are more time-efficient than existing web-based resources for learning radiology by junior doctors, while both types of resources were equally effective for learning in this cohort. Junior doctors found the adaptive tutorials more engaging and were more likely to recommend these resources to their colleagues.

Adaptive Tutorials Versus Web-Based Resources in Radiology: A Mixed Methods Analysis of Efficacy and Engagement in Senior Medical Students.

RATIONALE AND OBJECTIVES: Radiology education is suited to delivery via e-learning which may be used to fill gaps in knowledge and help prepare medical students for internship. There is limited evidence of effectiveness of adaptive tutorials, a form of e-learning in a senior medical student cohort. MATERIALS AND METHODS: A randomized mixed methods crossover trial was performed to assess effectiveness of adaptive tutorials on engagement and understanding of appropriate use and interpretation of basic imaging studies. Eighty-one volunteer medical students from years 5 and 6 of a 6-year program were randomly allocated to one of two groups. In the first phase of the trial on head CT, one group received access to adaptive tutorials and the other to peer-reviewed web-based resources. A cross over was performed and the second phase of the trial addressing chest CT commenced. Examination style assessments were completed at the end of each phase. At the trial's conclusion, an online questionnaire was provided to evaluate student perceptions of engagement and efficacy of each educational resource. RESULTS: Adaptive tutorial groups in both phases achieved higher mean scores than controls which were statistically significant in the first phase only. Students reported higher engagement and overall perceived value of the adaptive tutorials than controls. CONCLUSION: Adaptive tutorials are overwhelmingly supported by senior medical students. Questionnaire responses suggest the engaging nature of the tutorials efficiently aids participation and knowledge retention which is in principle supported by test results.

A Case of Placenta Percreta Managed with Sequential Embolisation Procedures.

BACKGROUND: The incidence of morbidly adherent placenta, including placenta percreta, has increased significantly over recent years due to rising caesarean section rates. Historically, abnormally invasive placenta has been managed with caesarean hysterectomy; however nonsurgical interventions such as uterine artery embolisation (UAE) are emerging as safe alternative management techniques. UAE can be utilised to decrease placental perfusion and encourage placental resorption, thereby reducing the risk of haemorrhage and other morbidities. CASE: We describe one of the very few reported cases of placenta percreta which was successfully treated primarily with sequential artery embolisation. Our patient underwent four embolisation procedures over a period of 248 days, with no major morbidity or complications. CONCLUSION: Repeat UAE may be a beneficial primary management modality in cases of placenta percreta with bladder involvement.

Adaptive Tutorials Versus Web-Based Resources in Radiology: A Mixed Methods Comparison of Efficacy and Student Engagement.

RATIONALE AND OBJECTIVES: Diagnostic imaging is under-represented in medical curricula globally. Adaptive tutorials, online intelligent tutoring systems that provide a personalized learning experience, have the potential to bridge this gap. However, there is limited evidence of their effectiveness for learning about diagnostic imaging. MATERIALS AND METHODS: We performed a randomized mixed methods crossover trial to determine the impact of adaptive tutorials on perceived engagement and understanding of the appropriate use and interpretation of common diagnostic imaging investigations. Although concurrently engaged in disparate blocks of study, 99 volunteer medical students (from years 1-4 of the 6-year program) were randomly allocated to one of two groups. In the first arm of the trial on chest X-rays, one group received access to an adaptive tutorial, whereas the other received links to an existing peer-reviewed Web resource. These two groups crossed over in the second arm of the trial, which focused on computed tomography scans of the head, chest, and abdomen. At the conclusion of each arm of the trial, both groups completed an examination-style assessment, comprising questions both related and unrelated to the topics covered by the relevant adaptive tutorial. Online questionnaires were used to evaluate student perceptions of both learning resources. RESULTS: In both arms of the trial, the group using adaptive tutorials obtained significantly higher assessment scores than controls. This was because of higher assessment scores by senior students in the adaptive tutorial group when answering questions related to topics covered in those tutorials. Furthermore, students indicated significantly better engagement with adaptive tutorials than the Web resource and rated the tutorials as a significantly more valuable tool for learning. CONCLUSIONS: Medical students overwhelmingly accept adaptive tutorials for diagnostic imaging. The tutorials significantly improve the understanding of diagnostic imaging by senior students.

Integration of medical imaging including ultrasound into a new clinical anatomy curriculum.

In 2008 a new clinical anatomy curriculum with integrated medical imaging component was introduced into the University of Sydney Medical Program. Medical imaging used for teaching the new curriculum included normal radiography, MRI, CT scans, and ultrasound imaging. These techniques were incorporated into teaching over the first two years of the program as a part of anatomy practical sessions, in addition to dedicated lectures and tutorials given by imaging specialists. Surveys were conducted between 2009 and 2012 to evaluate the student acceptance of the integration. Students were asked to rate individual activities as well as provide open-ended comments. The number of students who responded to the surveys varied from 40% to 98%. Over 90% of the respondents were satisfied with the overall quality of teaching in the anatomy units. In summary, 48% to 63% of the responding students thought that the specialist imaging lectures helped them learn effectively; 72% to 77% of students thought that the cross-sectional practical sessions helped them to better understand the imaging modalities of CT, MRI, and ultrasound; 76% to 80% of students considered hands-on ultrasound session to be useful in understanding the application of ultrasound in abdominal imaging. The results also revealed key similarities and differences in student perceptions of the new integrated curriculum for students with both a high and low prior exposure to anatomy. Further evaluation will aid in refining the integrated medical imaging program and providing its future direction.

Immediate hypersensitivity reactions to IV non-ionic iodinated contrast in computed tomography.

BACKGROUND: With use of computed tomography (CT), intravenous contrast media is used routinely to help define anatomy and identify any pathology. Non-ionic iodinated contrast agents have largely replaced ionic agents and although rare, reactions to contrast are still important and more so with the continual increase in CT examinations in the last decade. OBJECTIVE: To examine the incidence, severity and risk factors of immediate hypersensitivity reactions to intravenous non-ionic iodinated contrast in CT. METHODS: Data of consecutive patients in an Australian tertiary hospital who developed immediate hypersensitivity reactions to intravenous iopromide during CT were collected and compared with the results of all contrast CTs performed over a four year period. Chi-square statistics and odds ratio are calculated on the variables of age, gender, referral source and seasons of the study. RESULTS: Forty-seven patients had immediate hypersensitivity reactions of 29,962 patients who underwent contrast CT (0.16%). Thirty-three patients (70%) had a mild reaction, 11 (23%) moderate and three (7%) severe. Sixteen (34%) were male and 31 (66%) were female. Sixty-eight percent were under 55-years of age. Reactions occurred in 0.35% (34 patients) of all outpatients, 0.07% (6 patients) of all emergency patients, and 0.06% (7 patients) of all in-patients. Eighteen (38%) occurred in spring, seven (15%) in summer, 17 (36%) in autumn and five (11%) in winter. There is a statistically significant higher risk of contrast reactions in females (Odds Ratio [OR] 2.41 p = 0.005), patients younger than 55-years old (OR 2.46, p = 0.005), outpatients (OR 5.42, p < 0.001) and CTs performed in spring and autumn (OR 2.77, p = 0.002). CONCLUSION: The incidence of immediate hypersensitivity reactions in contrast CT is low and mostly mild. Risk factors include female, younger than 55-years of age, outpatients and CT examinations performed in spring and autumn. This is the first study to observe such a seasonal variation.

Study of patients with intravenous contrast extravasation on CT studies, with radiology staff and ward staff cannulations.

INTRODUCTION: Intravenous (IV) contrast extravasation is an adverse outcome of computed tomography (CT) studies. This study evaluates for any differences in rates of extravasation between radiology (radiographer) staff and ward medical staff cannulations, and secondarily by cannula size and study type. METHOD: A prospective study of 26,854 studies in adults between September 2004 and April 2008 accumulated 119 extravasations. Patients were divided into two groups, those cannulated by radiology staff and those cannulated by non-radiology staff. Patients with extravasations were followed for treatment outcomes. Statistical analysis between our groups was undertaken. RESULTS: The total extravasation rate was 0.44%. The extravasation rate for those patients cannulated by radiology staff was 0.34% (n= 11,470 cannulations) and those cannulated by non-radiology staff was 0.52% (n = 15,384 cannulations). This was not statistically significantly different. The site where most extravasations occurred was at the elbow (71.4%). The injection rate where most extravasations occurred was in the 1-2 mL/s range (42%). No patient required surgical intervention or had any significant morbidity. CONCLUSION: Radiology radiographer staff can provide safe administration of IV contrast in CT scanning with low rates of extravasation. Extravasation may occur with high or low injection rates and when small or large size cannulas are used.

Correlation of CT findings remote from prime area of interest: a multitrauma study.

BACKGROUND: Multitrauma patients represent a difficult cohort of patients from a diagnostic standpoint. Current trauma recommendations do not advise whole-body computed tomography (CT) in hemodynamically stable patients. OBJECTIVE: To measure the prevalence of abnormal CT findings in areas other than the prime area of clinical interest in multitrauma patients. METHOD: The records of 462 consecutive adult patients who underwent whole-body CT scans between 2004 and 2005 at Westmead Hospital, a Level 1 trauma center, were assessed. Clinical parameters, including suspected clinical injury, regional tenderness, bruising, loss of consciousness, scalp laceration, and unequal chest air entry, were examined. Correlation was made with CTs performed from the brain to symphysis pubis, on a Toshiba 16 slice machine, with evaluation of clinically significant findings. RESULTS: The prevalence of abnormal CT findings distant to the prime area of concern varied between anatomical areas: brain (10.3%-88.7%), skull (6.7%-39.7%), facial bones (4.4%-54.3%), cervical spine (5.6%-13.7%), thoracolumbar spine (5.6%-26.7%), chest (30.8%-54.4%), and abdomen/pelvis (20%-27.2%). CONCLUSION: There is a high prevalence of injuries remote from the prime area of clinical concern in multitrauma patients. Whole-body CT is a rapid, accurate, and systematic imaging modality that provides an early, complete, clinical picture for the treating physician.