Medical app minefield: radiologists use of medical apps for education and reporting and do they require regulation?

AIM: To evaluate the use of apps in radiology and consider advised changes to practice. MATERIALS AND METHODS: A survey was conducted of all radiology consultants and specialty trainees within Devon and Cornwall. The responses were collated, including the list of all medical applications used. These were assessed using the Medicine & Healthcare Products Regulatory Agency (MHRA) "Medical device stand-alone software including apps" guidance. RESULTS: The response rate was 88/150 (59%) radiologists who responded with the majority 48/88 (54.4%) using apps. Forty-four of 66 (67%) states that they did not assess the reliability or accuracy of these devices prior to use with 71/81 (88%) indicating that they were unaware of any regulations. Thirty-three items were identified of which 27 functioning apps were identified and three of these were considered medical devices and did not have complete and recognisable CE marking as required by the MHRA. CONCLUSION: This study highlights that application use is widespread. The vast majority of these applications are not considered medical devices; however, there are some devices that, according to the MHRA flow chart, are used in a way that classifies them as medical devices and should therefore be CE marked. This highlights the need for guidance and regulation of the medical application market with recommendations provided.

Systematic evaluation of radiological findings in the assessment of resectability of peri-ampullary cancer by CT using different contrast phase protocols.

AIMS: To determine the relative significance of radiological signs in determining the resectability of peri-ampullary cancer (PC) and to assess the value of multi-phase imaging in detecting these findings. MATERIALS AND METHODS: Blinded, double re-reporting of preoperative imaging from five hospitals was undertaken of 411 patients undergoing surgery for PC over an 8-year period, of whom 119 patients were found to be inoperable at the time of surgery. RESULTS: The median tumour size was 26.7 mm and the proportion of patients reported to have regional lymphadenopathy (RL), venous (VI) and arterial involvement (AI) was 24.7%, 11.5%, and 3.9%, respectively and was similar regardless of the number of contrast phases undertaken. Significant associations were, however, noted between individual risk factors: VI was closely associated with tumour size (p=0.002) and AI (p<0.0001). In multivariate analysis AI, VI, and RL were independently associated with resectability (relative risk of resection=0.05, 0.31, and 0.51, respectively). Tumour size, however, was not associated with resectability when VI was included in the multivariate model. CONCLUSIONS: The use of multiple vascular contrast phases has no measureable impact on the rate of determination of tumour resectability of PC. In preoperative staging, AI is the most significant adverse finding for resectability. Large tumour diameter is not an adverse finding in isolation from other risk factors.

The safe practice of CT coronary angiography in adult patients in UK imaging departments.

Computed tomography coronary angiography is increasingly used in imaging departments in the investigation of patients with chest pain and suspected coronary artery disease. Due to the routine use of heart rate controlling medication and the potential for very high radiation doses during these scans, there is a need for guidance on best practice for departments performing this examination, so the patient can be assured of a good quality scan and outcome in a safe environment. This article is a summary of the document on 'Standards of practice of computed tomography coronary angiography (CTCA) in adult patients' published by the Royal College of Radiologists (RCR) in December 2014.

Determining the haemodynamic significance of arterial stenosis: the relationship between CT angiography, computational fluid dynamics, and non-invasive fractional flow reserve.

Coronary artery disease causes significant morbidity and mortality worldwide. Invasive coronary angiography (ICA) is currently the reference standard investigation. Fractional flow reserve (FFR) complements traditional ICA by providing extra information on blood flow, which has convincingly led to better patient management and improved cost-effectiveness. Computed tomography coronary angiography (CTCA) is suitable for the investigation of chest pain, especially in the low- and intermediate-risk groups. FFR generated using CT data (producing FFRCT) may improve the positive predictive value of CTCA. The basic science of FFRCT is like a "black box" to most imaging professionals. A fundamental principle is that good quality CTCA is likely to make any post-processing easier and more reliable. Both diagnostic and observational studies have suggested that the accuracy and the short-term outcome of using FFRCT are both comparable with FFR in ICA. More multidisciplinary research with further refined diagnostic and longer-term observational studies will hopefully pinpoint the role of FFRCT in existing clinical pathways.

Diagnostic accuracy of high-definition CT coronary angiography in high-risk patients.

AIM: To assess the diagnostic accuracy of computed tomography coronary angiography (CTCA) using a combination of high-definition CT (HD-CTCA) and high level of reader experience, with invasive coronary angiography (ICA) as the reference standard, in high-risk patients for the investigation of coronary artery disease (CAD). MATERIALS AND METHODS: Three hundred high-risk patients underwent HD-CTCA and ICA. Independent experts evaluated the images for the presence of significant CAD, defined primarily as the presence of moderate (≥ 50%) stenosis and secondarily as the presence of severe (≥ 70%) stenosis in at least one coronary segment, in a blinded fashion. HD-CTCA was compared to ICA as the reference standard. RESULTS: No patients were excluded. Two hundred and six patients (69%) had moderate and 178 (59%) had severe stenosis in at least one vessel at ICA. The sensitivity, specificity, positive predictive value, and negative predictive value were 97.1%, 97.9%, 99% and 93.9% for moderate stenosis, and 98.9%, 93.4%, 95.7% and 98.3%, for severe stenosis, on a per-patient basis. CONCLUSION: The combination of HD-CTCA and experienced readers applied to a high-risk population, results in high diagnostic accuracy comparable to ICA. Modern generation CT systems in experienced hands might be considered for an expanded role.

High-dose intravenous metoprolol usage for reducing heart rate at CT coronary angiography: efficacy and safety.

AIM: To evaluate the usage, safety, and efficacy of high-dose intravenous metoprolol for heart rate reduction in computer tomographic (CT) coronary angiography. MATERIALS AND METHODS: As this was retrospective analysis of anonymous data, medical ethics committee approval was waived by the regional health research authority. Patients, who had known iodinated contrast medium allergy, contraindications to ß-blockers, atrial fibrillation, and indications other than suspected coronary artery disease, were excluded from analysis. The ultimate study population of 662 were analysed with details of intravenous metoprolol doses, complications, heart rate before administration of intravenous metoprolol (resting heart rate, RHR), heart rate at acquisition of scan (acquisition heart rate, AHR), and usage of low radiation dose protocols. RESULTS: Of the ultimate study population of 662 patients, 183 had no intravenous metoprolol with mean acquisition heart rate (AHR) of 58 beats per minute (bpm), 257 had 1-15 mg intravenous metoprolol with mean AHR of 57 bpm, 114 had 16-29 mg intravenous metoprolol with mean AHR of 62 bpm and 108 had ≥30 mg intravenous metoprolol with mean AHR of 66 bpm. In the group receiving intravenous metoprolol, average usage was 19 mg (maximum 67 mg) with average reduction in HR of 15 bpm. There were no clinical incidents in relation to the use of high-dose intravenous metoprolol. CONCLUSION: Higher doses of intravenous metoprolol are beneficial in achieving target heart rates to facilitate usage of low radiation dose protocols. With appropriate exclusion criteria, higher doses of intravenous metoprolol, well in excess of 15 mg, can be safely administered when carefully titrated.

Transcatheter aortic valve insertion (TAVI): a review.

The introduction of transcatheter aortic valve insertion (TAVI) has transformed the care provided for patients with severe aortic stenosis. The uptake of this procedure is increasing rapidly, and clinicians from all disciplines are likely to increasingly encounter patients being assessed for or having undergone this intervention. Successful TAVI heavily relies on careful and comprehensive imaging assessment, before, during and after the procedure, using a range of modalities. This review outlines the background and development of TAVI, describes the nature of the procedure and considers the contribution of imaging techniques, both to successful intervention and to potential complications.

The role of multidetector computed tomography coronary angiography in imaging complications post-cardiac surgery.

There have been numerous advances in the field of cardiac imaging. The advent of multidetector computed tomography coronary angiography (MDCT-CA) and in particular electrocardiographic (ECG)-gated acquisition has revolutionized the investigation of the complete spectrum of complications of common cardiothoracic surgical procedures. Generic complications, such as mediastinitis, pericardial effusion, sternal osteomyelitis, and mediastinal fibrosis, are discussed with illustrative examples of multiplanar and volume-rendered three-dimensional reconstructions. Graft-related complications of both coronary artery bypass grafts and aortic root grafts are reviewed. The role of MDCT-CA in the investigation of prosthetic valve endocarditis and root abscesses is outlined. We present a complete illustration of the detailed images that are obtained when investigating a full range of graft-related complications from both aortic and coronary surgery using ECG-gated MDCT-CA. MDCT-CA has the potential to become established as the optimal technique with which to image a multitude of complications post-cardiac surgery.

Computed tomography to diagnose coronary artery disease: a reduction in radiation dose increases applicability.

AIM: To assess the effects of dose-saving algorithms on the radiation dose in an established computed tomography coronary angiography (CTCA) clinical service. MATERIALS AND METHODS: A 3 year retrospective analysis of all patients attending for a clinically indicated CTCA was performed. The effective dose was calculated using a cardiac-specific conversion factor [0.028 mSv(mGy·cm)(-1)]. Patients were stratified by the advent of new scanning technology and dose-saving protocols. RESULTS: Between September 2007 and August 2010, 1736 examinations were performed. In the first 6 months, 150 examinations were performed with a mean effective dose of 29.6 mSv (99% CI 26.6-33 mSv). In March 2008 prospective electrocardiogram (ECG) gating was installed; reducing the effective dose to 13.6 mSv (99% CI 12.5-14.9 mSv). In March 2009, the scanner parameters were set to a minimal exposure time and 100 kV in patients with a body mass index (BMI) of <30. This reduced the mean dose to 7.4 mSv (99% CI 6.8-8 mSv). For the final six months the mean radiation dose for a cardiac scan was 5.9 mSv (99% CI 5.4-6.5 mSv) this figure incorporates all examinations performed irrespective of the protocol used. CONCLUSION: With the implementation of evidence-based protocols, the effective dose from cardiac CT has significantly reduced. As CTCA services develop dose-saving algorithms should be adopted to keep the radiation dose as low as reasonably practical.

Pulmonary venous evaluation using electrocardiogram-gated 64-detector row cardiac CT.

OBJECTIVES: Radiofrequency ablation of the pulmonary veins is an accepted treatment for atrial fibrillation. An accurate knowledge of pulmonary venous anatomy and dimensions is desirable prior to such a procedure. The objective of this study was to use 64-detector row cardiac CT to investigate the changes in pulmonary venous dimensions during the cardiac cycle. METHODS: Data from 44 consecutive patients with no significant cardiovascular pathology who underwent electrocardiogram (ECG)-gated 64-detector row coronary angiography were retrospectively analysed. Average diameter and cross-sectional area were measured at 5 mm intervals from each pulmonary vein ostium, in ventricular end-diastole and ventricular end-systole, using curved multiplanar reformats. RESULTS: 4 (9.1%) patients had pulmonary vein anomalies and were excluded. In the remaining 40 patients, pulmonary vein diameter and area at the ostium were significantly larger in end-systole in all four veins, with the largest differences in the superior pulmonary veins. Dimensional changes for diameter (millimetres) and area (square millimetres) were as follows: left superior pulmonary vein, 2.5 (p<0.001), 65.48 (p<0.001); right superior pulmonary vein, 1.63 (p<0.001), 56.27 (p<0.001); left inferior pulmonary vein, 1.1 (p<0.001), 30.41 (p<0.001); and right inferior pulmonary vein, 0.68 (p=0.005), 30.14 (p=0.005). Less marked changes were seen at measurement sites further from the atrium. Interobserver correlation was high (all but one measurement >0.9). CONCLUSION: Pulmonary vein dimensions change significantly between end-systole and end-diastole, and the ostia of the superior pulmonary veins are potentially the most vulnerable to dimensional inaccuracies. ECG-gated cardiac CT may provide a more precise method of pulmonary venous dimensional measurement than non-gated techniques. Knowledge of change in pulmonary vein diameter offers interesting potential research into the effect of pulmonary vein function.

Practical dosimetry methods for the determination of effective skin and breast dose for a modern CT system, incorporating partial irradiation and prospective cardiac gating.

OBJECTIVE: For CT coronary angiography (CTCA), a generic chest conversion factor returns a significant underestimate of effective dose. The aim of this manuscript is to communicate new dosimetry methods to calculate weighted CT dose index (CTDIw), effective dose, entrance surface dose (ESD) and organ dose to the breast for prospectively gated CTCA. METHODS: CTDIw in 32 cm diameter Perspex phantom was measured using an adapted technique, accounting for the segmented scan characteristic. Gafchromic XRCT film (International Speciality Products, New Jersey, NJ) was used to measure the distribution and magnitude of ESD. Breast dose was measured using high sensitivity metal oxide semiconductor field-effect transistors and compared to the computer based imaging performance assessment of CT scanners (ImPACT) dosimetry calculations. RESULTS: For a typical cardiac scan the mean ESD remained broadly constant (7-9 mGy) when averaged over the circumference of the Perspex phantom. Typical absorbed dose to the breast with prospectively gated protocols was within the range 2-15 mGy. The subsequent lifetime attributable risk (LAR) of cancer incidence to the breast was found at 0.01-0.06 for a 20-year-old female. This compares favourably to 100 mGy (LAR ~0.43) for a retrospectively gated CTCA. CONCLUSIONS: Care must be taken when considering radiation dosimetry associated with prospectively gated scanning for CTCA and a method has been conveyed to account for this. Breast doses for prospectively gated CTCA are an order of magnitude lower than retrospectively gated scans. Optimisation of cardiac protocols is expected to show further dose reduction.

The role of non-invasive imaging in patients with suspected acute coronary syndrome.

This article gives an overview of the role of imaging in the diagnosis and management of acute coronary syndrome.

Cardiac CT: are we underestimating the dose? A radiation dose study utilizing the 2007 ICRP tissue weighting factors and a cardiac specific scan volume.

AIM: To calculate the effective dose from cardiac multidetector computed tomography (MDCT) using a computer-based model utilizing the latest International Commission on Radiation Protection (ICRP) 103 tissue-weighting factors (2007), to compare this dose with those calculated with previously published chest conversion factors and to produce a conversion factor specific for cardiac MDCT. MATERIALS AND METHODS: An observational study of 152 patients attending for cardiac MDCT as part of their usual clinical care in a university teaching hospital. The dose for each examination was calculated using the computer-based anthropomorphic ImPACT model (the imaging performance assessment of CT scanners) and this was compared with the dose derived from the dose-length product (DLP) and a chest conversion factor. RESULTS: The median effective dose calculated using the ImPACT calculator (4.5 mSv) was significantly higher than the doses calculated with the chest conversion factors (2.2-3 mSv). CONCLUSION: The use of chest conversion factors significantly underestimates the effective dose when compared to the dose calculated using the ImPACT calculator. A conversion factor of 0.028 would give a better estimation of the effective dose from prospectively gated cardiac MDCT.

Imaging of illicit drug use.

Illicit drug abuse is a continuing menace of epidemic proportions associated with serious medical and social problems. Drug abuse can have a wide variety of presentations some of which can be life-threatening. The clinical diagnosis can be challenging as the history is usually limited or absent. Radiologists need to be familiar with varied imaging presentations and the related complications of illicit drug abuse to ensure correct diagnosis and appropriate timely treatment. This review will illustrate the imaging spectrum of illicit drug abuse involving several organ systems and also discuss the pathophysiological consequences of drug abuse.

Radiation-reduction strategies in cardiac computed tomographic angiography.

Ionizing radiation has long been known to increase the risk of cancer. X-rays and γ-rays are officially classified as a carcinogen by the World Health Organization's International Agency for Research on Cancer.(1) Of the 5 billion imaging investigations performed worldwide two-thirds employ ionizing radiation.(2) Diagnostic x-rays are the largest man-made source of radiation exposure to the general population, and computed tomography (CT) represents the largest proportion of these.(3) Diagnostic CT has seen a dramatic increase in applications in the last two decades, not least in the higher dose applications. Whilst the increased use of CT has undoubtedly been of patient benefit, it inevitably will be associated with an increase in malignancy due to medical exposure. In fact a recent study from the USA has estimated that the CT examinations performed in 2007 could result in 29,000 future cancers based on current risk estimations.(4) Whilst the numbers in the UK will be less (only 4 million examinations are performed compared to 70 million), it is clear that it is the responsibility of all radiologists to carefully examine their CT techniques and protocols with the aim to reduce the dose of examinations without compromising their accuracy. Cardiac computed tomographic angiography (CTA) initially was a very high dose application. However, both clinicians and CT system manufacturers have done a large amount of work to reduce dose. Dramatic changes have been achieved and the aim of this review is to highlight these. However, such developments are not exclusively applicable to cardiac CTA and many can be utilized in CT in general.

A comparison of radiation doses between state-of-the-art multislice CT coronary angiography with iterative reconstruction, multislice CT coronary angiography with standard filtered back-projection and invasive diagnostic coronary angiography.

OBJECTIVE: To accurately compare the radiation dose between prospectively gated cardiac multidetector CT (with and without iterative reconstruction) and diagnostic invasive coronary angiography using the latest International Commission on Radiological Protection 103 (ICRP) tissue weightings. DESIGN, SETTING AND PATIENTS: A retrospective analysis of consecutive patients presenting to a university teaching hospital for investigation of coronary artery disease. Radiation doses for each technique were calculated using computational Monte Carlo modelling of a standard Cristy phantom rather than the application of previously published conversion factors. While these have frequently been used in other studies, they are based on out-dated ICRP tissue weightings (ICRP 60) and are for the whole chest rather than for structures irradiated in cardiac imaging. In order to allow a comparison, doses were calculated and expressed in terms of effective dose in millisieverts (mSv). RESULTS: From a population presenting for angiography within a clinical service, the median radiation dose from cardiac CT with standard filtered back-projection (84 patients, 5.4 mSv) was comparable with the dose from invasive diagnostic coronary angiography (94 patients, 6.3 mSv). The dose for cardiac CT using iterative reconstruction was significantly lower (39 patients, 2.5 mSv). CONCLUSION: The median effective dose from cardiac CT with standard filtered back-projection was comparable with the effective dose from invasive coronary angiography, even with application of the most contemporary ICRP tissue weightings and use of cardiac specific volumes. Cardiac CT scanning incorporating iterative reconstruction resulted in a significant reduction in the effective dose.