Training novice users to assess stroke aetiology in remote settings using transcranial ultrasound: pilot study.

INTRODUCTION: Emergency care delivery to patients in remote and rural areas is limited by diagnostic restrictions and long transport times to major centres of care. People with suspected acute stroke living long distances from a hospital are unlikely to receive time-critical reperfusion therapy for these reasons. Basic brain imaging assessing blood flow in the major intracranial arteries could facilitate such care in remote settings. A 3-hour training package for novice transcranial ultrasound users has been piloted on a small group of volunteers to investigate whether they could acquire transcranial ultrasound images and video clips to potentially allow remote interpretation and optimise pre-hospital management of acute stroke. METHODS: A pilot training project was set up in a university setting in Inverness, Scotland. Volunteer clinicians and students of nursing or medicine with no practical experience in transcranial ultrasound were recruited. Participants received three 1-hour training sessions combining theoretical aspects and hands-on practice on healthy volunteers provided by a qualified neurologist with more than 2 years of experience in transcranial ultrasound. Transcranial greyscale and colour-coded duplex sonography was performed to visualise midline structures and major intracranial vessels, and to measure blood flow velocity in the middle cerebral artery, followed by an unsupervised assessment. Qualitative analysis of the anonymised feedback from participants on the training experience and its potential application was also performed. RESULTS: A total of 11 volunteers were recruited in the current pilot study. The average time to complete transcranial ultrasound assessment was approximately 40 minutes. The brain midline and cerebral peduncles were correctly labelled by 64% (7/11) and 91% (10/11) of volunteers, respectively. Participants demonstrated a good performance in detecting major intracranial vessels. The correct labelling rate for the middle cerebral artery was 73% (8/11), and 64% (7/11) for the anterior and posterior cerebral arteries. There was agreement between the trainer and the participants on rating the quality of scans as assessed using a visual analogue scale. All participants gave positive feedback on the provided training and time allocated for each session. Generally, volunteers thought that operating the ultrasound machine and the probe simultaneously was difficult. It was also suggested that further follow-up training, with possible supervision, would be useful to retain the acquired skills. CONCLUSIONS: Transcranial ultrasound scans of a quality to allow expert interpretation can be acquired by inexperienced transcranial ultrasound operators after receiving a brief training. This could potentially be used by medical staff working in remote and rural areas to facilitate acute care for stroke patients, but further work with a larger sample is needed.

The use of transcranial ultrasound and clinical assessment to diagnose ischaemic stroke due to large vessel occlusion in remote and rural areas.

Rapid endovascular thrombectomy, which can only be delivered in specialist centres, is the most effective treatment for acute ischaemic stroke due to large vessel occlusion (LVO). Pre-hospital selection of these patients is challenging, especially in remote and rural areas due to long transport times and limited access to specialist clinicians and diagnostic facilities. We investigated whether combined transcranial ultrasound and clinical assessment ("TUCA" model) could accurately triage these patients and improve access to thrombectomy. We recruited consecutive patients within 72 hours of suspected stroke, and performed non-contrast transcranial colour-coded ultrasonography within 24 hours of brain computed tomography. We retrospectively collected clinical information, and used hospital discharge diagnosis as the "gold standard". We used binary regression for diagnosis of haemorrhagic stroke, and an ordinal regression model for acute ischaemic stroke with probable LVO, without LVO, transient ischaemic attacks (TIA) and stroke mimics. We calculated sensitivity, specificity, positive and negative predictive values and performed a sensitivity analysis. We recruited 107 patients with suspected stroke from July 2017 to December 2019 at two study sites: 13/107 (12%) with probable LVO, 50/107 (47%) with acute ischaemic stroke without LVO, 18/107 (17%) with haemorrhagic stroke, and 26/107 (24%) with stroke mimics or TIA. The model identified 55% of cases with probable LVO who would have correctly been selected for thrombectomy and 97% of cases who would not have required this treatment (sensitivity 55%, specificity 97%, positive and negative predictive values 75% and 93%, respectively). Diagnostic accuracy of the proposed model was superior to the clinical assessment alone. These data suggest that our model might be a useful tool to identify pre-hospital patients requiring mechanical thrombectomy, however a larger sample is required with the use of CT angiogram as a reference test.

Diagnostic value of transcranial ultrasonography for selecting subjects with large vessel occlusion: a systematic review.

INTRODUCTION: A number of pre-hospital clinical assessment tools have been developed to triage subjects with acute stroke due to large vessel occlusion (LVO) to a specialised endovascular centre, but their false negative rates remain high leading to inappropriate and costly emergency transfers. Transcranial ultrasonography may represent a valuable pre-hospital tool for selecting patients with LVO who could benefit from rapid transfer to a dedicated centre. METHODS: Diagnostic accuracy of transcranial ultrasonography in acute stroke was subjected to systematic review. Medline, Embase, PubMed, Scopus, and The Cochrane Library were searched. Published articles reporting diagnostic accuracy of transcranial ultrasonography in comparison to a reference imaging method were selected. Studies reporting estimates of diagnostic accuracy were included in the meta-analysis. RESULTS: Twenty-seven published articles were selected for the systematic review. Transcranial Doppler findings, such as absent or diminished blood flow signal in a major cerebral artery and asymmetry index ≥ 21% were shown to be suggestive of LVO. It demonstrated sensitivity ranging from 68 to 100% and specificity of 78-99% for detecting acute steno-occlusive lesions. Area under the receiver operating characteristics curve was 0.91. Transcranial ultrasonography can also detect haemorrhagic foci, however, its application is largely restricted by lesion location. CONCLUSIONS: Transcranial ultrasonography might potentially be used for the selection of subjects with acute LVO, to help streamline patient care and allow direct transfer to specialised endovascular centres. It can also assist in detecting haemorrhagic lesions in some cases, however, its applicability here is largely restricted. Additional research should optimize the scanning technique. Further work is required to demonstrate whether this diagnostic approach, possibly combined with clinical assessment, could be used at the pre-hospital stage to justify direct transfer to a regional thrombectomy centre in suitable cases.

Diagnostic accuracy of clinical tools for assessment of acute stroke: a systematic review.

INTRODUCTION: Recanalisation therapy in acute ischaemic stroke is highly time-sensitive, and requires early identification of eligible patients to ensure better outcomes. Thus, a number of clinical assessment tools have been developed and this review examines their diagnostic capabilities. METHODS: Diagnostic performance of currently available clinical tools for identification of acute ischaemic and haemorrhagic strokes and stroke mimicking conditions was reviewed. A systematic search of the literature published in 2015-2018 was conducted using PubMed, EMBASE, Scopus and The Cochrane Library. Prehospital and in-hospital studies with a minimum sample size of 300 patients reporting diagnostic accuracy were selected. RESULTS: Twenty-five articles were included. Cortical signs (gaze deviation, aphasia and neglect) were shown to be significant indicators of large vessel occlusion (LVO). Sensitivity values for selecting subjects with LVO ranged from 23 to 99% whereas specificity was 24 to 97%. Clinical tools, such as FAST-ED, NIHSS, and RACE incorporating cortical signs as well as motor dysfunction demonstrated the best diagnostic accuracy. Tools for identification of stroke mimics showed sensitivity varying from 44 to 91%, and specificity of 27 to 98% with the best diagnostic performance demonstrated by FABS (90% sensitivity, 91% specificity). Hypertension and younger age predicted intracerebral haemorrhage whereas history of atrial fibrillation and diabetes were associated with ischaemia. There was a variation in approach used to establish the definitive diagnosis. Blinding of the index test assessment was not specified in about 50% of included studies. CONCLUSIONS: A wide range of clinical assessment tools for selecting subjects with acute stroke has been developed in recent years. Assessment of both cortical and motor function using RACE, FAST-ED and NIHSS showed the best diagnostic accuracy values for selecting subjects with LVO. There were limited data on clinical tools that can be used to differentiate between acute ischaemia and haemorrhage. Diagnostic accuracy appeared to be modest for distinguishing between acute stroke and stroke mimics with optimal diagnostic performance demonstrated by the FABS tool. Further prehospital research is required to improve the diagnostic utility of clinical assessments with possible application of a two-step clinical assessment or involvement of simple brain imaging, such as transcranial ultrasonography.

The effectiveness of ultrasound in the detection of fractures in adults with suspected upper or lower limb injury: a systematic review and subgroup meta-analysis.

BACKGROUND: The aim of the present review is to assess the effectiveness of ultrasound (US) in the detection of upper and lower limb bone fractures in adults compared to a diagnostic gold standard available in secondary and tertiary care centres (e.g. radiography, CT scan or MRI). METHODS: The review followed PRISMA guidelines and used a database-specific search strategy with Medline, EMBASE and The Cochrane Library plus secondary sources (see supplementary material for completed PRISMA checklist). Diagnostic performance of ultrasound was assessed with a qualitative synthesis and a meta-analysis of two data subgroups. RESULTS: Twenty-six studies were included (n = 2360; fracture prevalence =5.3 % to 75.0%); data were organised into anatomical subgroups, two of which were subjected to meta-analysis. Sensitivity and specificity ranged from 42.11 - 100% and 65.0 - 100%, with the highest diagnostic accuracy in fractures of the foot and ankle. The pooled sensitivity and specificity of US was 0.93 and 0.92 for upper limb fractures (I2 = 54.7 % ; 66.3%), and 0.83 and 0.93 for lower limb fractures (I2 = 90.1 % ; 83.5%). CONCLUSION: Ultrasonography demonstrates good diagnostic accuracy in the detection of upper and lower limb bone fractures in adults, especially in fractures of the foot and ankle. This is supported by pooled analysis of upper and lower limb fracture subgroups. Further research in larger populations is necessary to validate and strengthen the quality of the available evidence prior to recommending US as a first-line imaging modality for prehospital use. TRIAL REGISTRATION: The protocol is registered with the PROSPERO International register of systematic reviews: ID = CRD42017053640 .

Paramedic and physician perspectives on the potential use of remotely supported prehospital ultrasound.

INTRODUCTION: During remotely supported prehospital ultrasound (RSPU), an ultrasound operator performs a scan and sends images to a remote expert for interpretation. This novel technology has been undergoing investigation in the randomised controlled SatCare trial, which seeks to assess the capability of RSPU to improve patient outcomes and standard of prehospital care in the Highlands of Scotland. This study aimed to explore the views of emergency medicine physicians and paramedics prior to starting the trial. METHODS: An interview schedule was prepared a priori and was based upon normalisation process theory (NPT), which can be used to assess ways in which practitioners work to embed novel technologies in clinical practice. Semi-structured interviews were conducted with four consultant physicians and eight paramedics, who were recruited using purposive sampling until theoretical saturation. Analysis used open and hierarchical axial coding, and NPT as a framework to assist in the management and analysis of codes. RESULTS: The prospect of RSPU evoked significantly different responses from emergency care physicians and paramedics. Paramedics thought of RSPU as a logical progression of prehospital care, which addresses core prehospital challenges such as lack of decision-making support and a limited ability to identify life-threatening occult conditions. Paramedics saw RSPU as part of a trend to increase their skills and responsibilities, and viewed ultrasound as a validated tool within emergency medicine. Paramedics felt that ultrasound was simple to learn and would be practical for use within the prehospital arena. In contrast, physicians expressed a greater spectrum of views; most saw limited value to prehospital diagnosis and were concerned that RSPU would distract both paramedics and physicians from their existing roles (particularly in the context of the increasing demand and workload within Scotland's publicly funded National Health Service). Physicians were also concerned that ultrasound skills were poorly incorporated into training and practice in the British emergency medicine system. Furthermore, they believed that ultrasound was difficult to learn, prone to misinterpretation and easy to become deskilled in. Both sets of participants believed that the relational skills required between the two groups and the practical complexities of RSPU may pose challenges in its implementation. In particular, concerns were raised regarding the time that would be required to conduct the ultrasound scans and difficulties with transmission and communication in the Highlands. Both groups questioned the likelihood of measurable benefits from RSPU for patients. Furthermore, both groups were unsure how the technology would benefit those patients in urban areas close to the emergency department or whether RSPU would be effectively utilised in rural areas where serious emergencies are infrequent. CONCLUSION: There are substantial differences in emergency physician and paramedic perspectives on RSPU; however, both parties were willing to engage with the research process. Both groups have reservations, especially the emergency physicians who perceive significant barriers to the acquisition of skills, as well as the relational and contextual integration of RSPU. This study demonstrates the importance of conversations with physicians and paramedics throughout the research process, particularly as the role of prehospital care remains controversial.

Telesonography in emergency medicine: A systematic review.

Ultrasound is an efficacious, versatile and affordable imaging technique in emergencies, but has limited utility without expert interpretation. Telesonography, in which experts may remotely support the use of ultrasound through a telecommunications link, may broaden access to ultrasound and improve patient outcomes, particularly in remote settings. This review assesses the literature regarding telesonography in emergency medicine, focussing on evidence of feasibility, diagnostic accuracy and clinical utility. A systematic search was performed for articles published from 1946 to February 2017 using the Cochrane, Medline, EMBASE, and CINAHL databases. Further searches utilising Scopus, Google Scholar, and citation lists were conducted. 4388 titles were identified and screened against inclusion criteria which resulted in the inclusion of 28 papers. These included feasibility, diagnostic accuracy and clinical pilot studies. Study design, methodology and quality were heterogeneous. There was good evidence of feasibility from multiple studies. Where sufficient bandwidth and high quality components were used, diagnostic accuracy was slightly reduced by image transmission. There was evidence of clinical utility in remote hospitals and low-resource settings, although reliability was infrequently reported. Further exploratory research is required to determine minimum requirements for image quality, bandwidth, frame rate and to assess diagnostic accuracy. Clinical trials in remote settings are justifiable. Telecommunication options will depend on local requirements; no one system conveys universal advantages. The methodological quality of research in this field must improve: studies should be designed to minimise bias, and must include details of their methods to allow replication. Analysis of cost effectiveness and sustainability should be provided.

Remotely supported prehospital ultrasound: A feasibility study of real-time image transmission and expert guidance to aid diagnosis in remote and rural communities.

Introduction Our aim is to expedite prehospital assessment of remote and rural patients using remotely-supported ultrasound and satellite/cellular communications. In this paradigm, paramedics are remotely-supported ultrasound operators, guided by hospital-based specialists, to record images before receiving diagnostic advice. Technology can support users in areas with little access to medical imaging and suboptimal communications coverage by connecting to multiple cellular networks and/or satellites to stream live ultrasound and audio-video. Methods An ambulance-based demonstrator system captured standard trauma and novel transcranial ultrasound scans from 10 healthy volunteers at 16 locations across the Scottish Highlands. Volunteers underwent brief scanning training before receiving expert guidance via the communications link. Ultrasound images were streamed with an audio/video feed to reviewers for interpretation. Two sessions were transmitted via satellite and 21 used cellular networks. Reviewers rated image and communication quality, and their utility for diagnosis. Transmission latency and bandwidth were recorded, and effects of scanner and reviewer experience were assessed. Results Appropriate views were provided in 94% of the simulated trauma scans. The mean upload rate was 835/150 kbps and mean latency was 114/2072 ms for cellular and satellite networks, respectively. Scanning experience had a significant impact on time to achieve a diagnostic image, and review of offline scans required significantly less time than live-streamed scans. Discussion This prehospital ultrasound system could facilitate early diagnosis and streamlining of treatment pathways for remote emergency patients, being particularly applicable in rural areas worldwide with poor communications infrastructure and extensive transport times.

Combining transcranial ultrasound with intelligent communication methods to enhance the remote assessment and management of stroke patients: Framework for a technology demonstrator.

With over 150,000 strokes in the United Kingdom every year, and more than 1 million living survivors, stroke is the third most common cause of death and the leading cause of severe physical disability among adults. A major challenge in administering timely treatment is determining whether the stroke is due to vascular blockage (ischaemic) or haemorrhage. For patients with ischaemic stroke, thrombolysis (i.e. pharmacological 'clot-busting') can improve outcomes when delivered swiftly after onset, and current National Health Service Quality Improvement Scotland guidelines are for thrombolytic therapy to be provided to at least 80 per cent of eligible patients within 60 min of arrival at hospital. Thrombolysis in haemorrhagic stroke could severely compound the brain damage, so administration of thrombolytic therapy currently requires near-immediate care in a hospital, rapid consultation with a physician and access to imaging services (X-ray computed tomography or magnetic resonance imaging) and intensive care services. This is near impossible in remote and rural areas, and stroke mortality rates in Scotland are 50 per cent higher than in London. We here describe our current project developing a technology demonstrator with ultrasound imaging linked to an intelligent, multi-channel communication device - connecting to multiple 2G/3G/4G networks and/or satellites - in order to stream live ultrasound images, video and two-way audio streams to hospital-based specialists who can guide and advise ambulance clinicians regarding diagnosis. With portable ultrasound machines located in ambulances or general practices, use of such technology is not confined to stroke, although this is our current focus. Ultrasound assessment is useful in many other immediate care situations, suggesting potential wider applicability for this remote support system. Although our research programme is driven by rural need, the ideas are potentially applicable to urban areas where access to imaging and definitive treatment can be restricted by a range of operational factors.

Implementing transnational telemedicine solutions: a connected health project in rural and remote areas of six Northern Periphery countries Series on European collaborative projects.

This is the first article in a Series on collaborative projects between European countries, relevant for general practice/family medicine and primary healthcare. Telemedicine, in particular the use of the Internet, videoconferencing and handheld devices such as smartphones, holds the potential for further strides in the application of technology for the delivery of healthcare, particularly to communities in rural and remote areas within and without the European Union where this study is taking place. The Northern Periphery Programme has funded the 'Implementing Transnational Telemedicine Solutions' (ITTS) project from September 2011 to December 2013, led by the Centre for Rural Health in Inverness, Scotland. Ten sustainable projects based on videoconsultation (speech therapy, renal services, emergency psychiatry, diabetes), mobile patient self-management (physical activity, diabetes, inflammatory bowel disease) and home-based health services (medical and social care emergencies, rehabilitation, multi-morbidity) are being implemented by the six partner countries: Scotland, Finland, Ireland, Northern Ireland, Norway and Sweden. In addition, an International Telemedicine Advisory Service, created for the project, provides business expertise and advice. Community panels contribute feedback on the design and implementation of services and ensure 'user friendliness'. The project goals are to improve accessibility of healthcare in rural and remote communities, reducing unnecessary hospital visits and travel in a sustainable way. Opportunities will be provided for comparative research studies. This article provides an introduction to the ITTS project and how it aims to fulfil these needs. The ITTS team encourage all healthcare providers to at least explore possible technological solutions within their own context.

Recommendations for research design and reporting in computer-assisted diagnosis to facilitate meta-analysis.

Computer-assisted diagnosis (CAD) describes a diverse, heterogeneous range of applications rather than a single entity. The aims and functions of CAD systems vary considerably and comparing studies and systems is challenging due to methodological and design differences. In addition, poor study quality and reporting can reduce the value of some publications. Meta-analyses of CAD are therefore difficult and may not provide reliable conclusions. Aiming to determine the major sources of heterogeneity and thereby what CAD researchers could change to allow this sort of assessment, this study reviews a sample of 147 papers concerning CAD used with imaging for cancer diagnosis. It discusses sources of variability, including the goal of the CAD system, learning methodology, study population, design, outcome measures, inclusion of radiologists, and study quality. Based upon this evidence, recommendations are made to help researchers optimize the quality and comparability of their trial design and reporting.

A systematic review of computer-assisted diagnosis in diagnostic cancer imaging.

OBJECTIVES: This study reviews the evidence for the effectiveness of computer-assisted diagnosis (CAD) in cancer imaging. Diagnostic applications were studied to estimate the impact of CAD on radiologists' detection and diagnosis of cancer lesions. METHODS: Online databases were searched and 48 studies from 1992 to 2010 were included: 16 with radiologists using CAD to detect lesions (CADe) and 32 with radiologists using CAD to classify or diagnose lesions (CADx). Weighted means, statistics, summary receiver operating characteristics (SROC) curves, and related measures were used for analysis. RESULTS: There is evidence that CADx significantly improves diagnosis in mammography and breast ultrasound. In contrast, studies of CADx applied to lung CT and dermatologic imaging show an adverse impact on diagnosis. Overall, there is no evidence of a benefit due to the use of CADe. The area under the SROC curves was not significantly increased for radiologists using either CADe or CADx. CONCLUSIONS: From this analysis it seems CADx can offer some benefit to radiologists in specific imaging applications for breast cancer diagnosis. There is no evidence of a beneficial effect in other applications of CAD and some evidence of a detrimental one.

The effect of image colour distortion on evaluation of donor liver suitability for transplantation.

Some medical applications rely on the use of colour in the diagnostic process, even when poor colour reproduction can affect diagnosis. In this paper, we investigate the effect colour distortion can have on assessment of livers for possible transplantation. We compare the diagnostic effects for the likely colour shifts when illuminant and camera remain uncalibrated or when a monitor is incorrectly calibrated. We describe methods that can result in accurate reproduction of image colour on visual displays and determine whether accurate colour reproduction is necessary for effective liver assessment.