Sex-based inequalities in contemporary UK hospital management of stable chest pain.

OBJECTIVE: We surveyed UK practice of National Institute for Health and Care Excellence (NICE) "Recent onset chest pain" guidance (CG95, 2016), stratified by sex. We looked for sex-related differences in referral to computed tomographic coronary angiography (CTCA) and subsequent functional imaging (FI), invasive coronary angiography (ICA) and revascularisation. METHODS: This was a prospective analysis of CTCA practice in 8 UK centres between 2018 and 2020. Coronary artery disease (CAD) was recorded with the CAD-reporting and data system. Local electronic records/archiving/communication systems were used to collect data regarding subsequent FI, ICA and revascularisation. RESULTS: 2301 women, 2326 men underwent CTCA; women were older (58±11 vs 55±12 years, p<0.001) but more likely to have normal coronary arteries (46% (1047) vs 29% (685); p<0.001) and less likely to have severe stenosis (7% (169) vs 13% (307); p<0.001). FI was used less for 4% (93) women, 5% (108) men; ICA was also used less for women (8% (182) vs 14% (321)), as was revascularisation (4% (83) vs 8% (177), p<0.001 for all), including those with ≥moderate CTCA stenosis undergoing ICA (53% (79) vs 61% (166); p<0.001). CONCLUSIONS: Women referred for a NICE CG95 (2016) CTCA are more likely to have normal coronary arteries and men more likely to have CAD. More men than women will then undergo ICA and revascularisation even after adjustments for CTCA disease severity. Raised awareness of these inequalities may improve contemporary chest pain care.

Downstream testing after CT coronary angiography: time for a rethink?

OBJECTIVE: We surveyed UK practice and compliance with the National Institute for Health and Care Excellence (NICE) 'recent-onset chest pain' guidance (Clinical Guideline 95, 2016) as a service quality initiative. We aimed to evaluate the diagnostic utility and efficacy of CT coronary angiography (CTCA), NICE-guided investigation compliance, invasive coronary angiography (ICA) use and revascularisation. METHODS: A prospective analysis was conducted in nine UK centres between January 2018 and March 2020. The reporter decided whether the CTCA was diagnostic. Coronary artery disease was recorded with the Coronary Artery Disease-Reporting and Data System (CAD-RADS). Local electronic records and picture archiving/communication systems were used to collect data regarding functional testing, ICA and revascularisation. Duplication of coronary angiography without revascularisation was taken as a surrogate for ICA overuse. RESULTS: 5293 patients (mean age, 57±12 years; body mass index, 29±6 kg/m²; 50% men) underwent CTCA, with a 96% diagnostic scan rate. 618 (12%) underwent ICA, of which 48% (298/618) did not receive revascularisation. 3886 (73%) had CAD-RADS 0-2, with 1% (35/3886) undergoing ICA, of which 94% (33/35) received ICA as a second-line test. 547 (10%) had CAD-RADS 3, with 23% (125/547) undergoing ICA, of which 88% (110/125) chose ICA as a second-line test, with 26% (33/125) leading to revascularisation. For 552 (10%) CAD-RADS 4 and 91 (2%) CAD-RADS 5 patients, ICA revascularisation rates were 64% (221/345) and 74% (46/62), respectively. CONCLUSIONS: While CTCA for recent-onset chest pain assessment has been shown to be a robust test, which negates the need for further investigation in three-quarters of patients, subsequent ICA overuse remains with almost half of these procedures not leading to revascularisation.

Challenges in delivering computed tomography coronary angiography as the first-line test for stable chest pain.

OBJECTIVE: The National Institute for Health and Care Excellence (NICE) clinical guidelines 'chest pain of recent onset: assessment and diagnosis' (update 2016) state CT coronary angiography (CTCA) should be offered as the first-line investigation for patients with stable chest pain. However, the current provision in the UK is unknown. We aimed to evaluate this and estimate the requirements for full implementation of the guidelines including geographical variation. Ancillary aims included surveying the number of CTCA-capable scanners and accredited practitioners in the UK. METHODS: The number of CTCA scans performed annually was surveyed across the National Health Service (NHS). The number of percutaneous coronary interventions performed for stable angina in the NHS in 2015 was applied to a model based on SCOT-HEART (CTCA in patients with suspected angina due to coronary heart disease: an open-label, parallel-group, multicentre trial) data to estimate the requirement for CTCA, for full guideline implementation. Details of CTCA-capable scanners were obtained from manufacturers and formally accredited practitioner details from professional societies. RESULTS: An estimated 42 340 CTCAs are currently performed annually in the UK. We estimate that 350 000 would be required to fully implement the guidelines. 304 CTCA-capable scanners and 198 accredited practitioners were identified. A marked geographical variation between health regions was observed. CONCLUSIONS: This study provides insight into the scale of increase in the provision of CTCA required to fully implement the updated NICE guidelines. A small specialist workforce and limited number of CTCA-capable scanners may present challenges to service expansion.

A prospective national survey of coronary CT angiography radiation doses in the United Kingdom.

BACKGROUND: Little real-world radiation dose data exist for the majority of cardiovascular CT. Some data have been published for coronary CT angiography (coronary CTA) specifically, but they invariably arise from high-volume centres with access to the most recent technology. OBJECTIVE: The aim of this study was to document real-world radiation doses for coronary CTA in the United Kingdom, and to establish their relationship to clinical protocol selection, acquisition heart rate, and scanner technology. METHODS: A dose survey questionnaire was distributed to members of the British Society of Cardiovascular Imaging and other UK cardiac CT units. All participating centres collected data for consecutive coronary CTA cases over one month. The survey captured information about the exam conducted, patient demographics, pre-scan details such as beta-blocker administration, acquisition heart rate and scan technique, and post-scan dose indicators - series volumetric CT dose index (CTDIvol), series dose-length product (DLP), and exam DLP. RESULTS: Fifty centres provided data on a total of 1341 coronary CTA exams. Twenty-nine centres (58%) performed at least 20 coronary CTA scans in the collection period. The median BMI, acquisition heart rate and exam DLP were 28 kg/m2, 60 bpm and 209 mGycm respectively. The corresponding effective dose was estimated as 5.9 mSv using a conversion factor of 0.028 mSv/mGycm. There was no statistically significant difference in radiation dose between low and high-volume centres. Median exam DLP increased with the acquisition heart rate due to the selection of wider temporal windows. The highest exam DLPs were obtained on the older scanner technology. CONCLUSION: This study provides baseline data for benchmarking practice, optimizing radiation dose and improving service quality locally.

National Institute for Health and Care Excellence updates the stable chest pain guideline with radical changes to the diagnostic paradigm.

In the 2016 update of the stable chest pain guideline, the National Institute for Health and Care Excellence (NICE) has made radical changes to the diagnostic paradigm that it-like other international guidelines-had previously placed at the centre of its recommendations. No longer are quantitative assessments of the disease probability considered necessary to determine the need for diagnostic testing and the choice of test. Instead, the recommendation is for no diagnostic testing if chest pain is judged to be 'non-anginal' and CT coronary angiography (CTCA) in patients with 'typical' or 'atypical' chest pain with additional perfusion imaging only if there is uncertainty about the functional significance of coronary lesions. The new emphasis on anatomical-as opposed to functional-testing is driven in large part by cost-effectiveness analysis and despite inevitable resource implications NICE calculates that annual savings for the population of England will be significant. In making CTCA the default diagnostic testing strategy in its updated chest pain guideline, NICE has responded emphatically to calls from trialists for CTCA to have a greater role in the diagnostic pathway of patients with suspected angina.

Recommendations for accurate CT diagnosis of suspected acute aortic syndrome (AAS)--on behalf of the British Society of Cardiovascular Imaging (BSCI)/British Society of Cardiovascular CT (BSCCT).

Accurate and timely assessment of suspected acute aortic syndrome is crucial in this life-threatening condition. Imaging with CT plays a central role in the diagnosis to allow expedited management. Diagnosis can be made using locally available expertise with optimized scanning parameters, making full use of recent advances in CT technology. Each imaging centre must optimize their protocols to allow accurate diagnosis, to optimize radiation dose and in particular to reduce the risk of false-positive diagnosis that may simulate disease. This document outlines the principles for the acquisition of motion-free imaging of the aorta in this context.

Image comparative assessment using iterative reconstructions: clinical comparison of low-dose abdominal/pelvic computed tomography between adaptive statistical, model-based iterative reconstructions and traditional filtered back projection in 65 patients.

OBJECTIVES: The objective of this study was to compare image quality (objective and subjective parameters) and confidence in lesion detection between 3 image reconstruction algorithms in computed tomographic (CT) examinations of the abdomen/pelvis. MATERIALS AND METHODS: This prospective institutional review board-approved study included 65 patients (mean [SD] age, 71.3 ± 9 years; mean [SD] body mass index, 24.4 [4.8] kg) who underwent routine CT examinations of the abdomen/pelvis followed immediately by 2 low-dose scans. Raw data sets were reconstructed by using filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and a model-based iterative reconstruction (MBIR). Measurements of objective noise and CT numbers were compared using repeated-measures analysis of variance. Six subjective image quality parameters were scored. Diagnostic confidence and accuracy in detection of various elementary lesions were performed. RESULTS: Objectively, mean image noise for MBIR was significantly superior at all dose levels (P < 0.001). Subjectively, standard-dose ASIR and low-dose MBIR scans were better than standard-dose FBP scan in all parameters assessed (P < 0.05). Low-dose MBIR scans were comparable with standard-dose ASIR scans in all parameters except at noise index of 70 (approximately 85% dose reduction), where, in this case, the detection of liver lesions less than 5 mm were rated inferior (P < 0.05) with diagnostic accuracy reducing to 77.4%. CONCLUSIONS: Low-dose MBIR scan shows superior objective noise reduction compared with standard-dose FBP and ASIR. Subjectively, low-dose MBIR scans at 76% dose reduction were also superior compared with standard-dose FBP and ASIR. However, at dose reductions of 85%, small liver lesions may be missed.

Comparison of image quality between filtered back-projection and the adaptive statistical and novel model-based iterative reconstruction techniques in abdominal CT for renal calculi.

OBJECTIVES: To compare image quality on computed tomographic (CT) images acquired with filtered back-projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) techniques in CT kidney/ureter/bladder (KUB) examination. METHODS: Eighteen patients underwent standard protocol CT KUB at our institution. The same raw data were reconstructed using FBP, ASIR and MBIR. Objective [mean image noise, contrast-to-noise ratio (CNR) for kidney and mean attenuation values of subcutaneous fat] and subjective image parameters (image noise, image contrast, overall visibility of kidneys/ureters/bladder, visibility of small structures, and overall diagnostic confidence) were assessed using a scoring system from 1 (best) to 5 (worst). RESULTS: Objective image measurements revealed significantly less image noise and higher CNR and the same fat attenuation values for the MBIR technique (P < 0.05). MBIR scored best in all the subjective image parameters (P < 0.001) with averages ranging between 2.05-2.73 for MBIR, 2.95-3.10 for ASIR and 3.08-3.31 for FBP. No significant difference was observed between FBP and ASIR (P > 0.05), while there was a significant difference between ASIR vs. MBIR (P < 0.05). The mean effective dose was 3 mSv. CONCLUSION: MBIR shows superior reduction in noise and improved image quality (both objective and subjective analysis) compared with ASIR and FBP CT KUB examinations. MAIN MESSAGES: • There are many reconstruction options in CT. • Novel model-based iterative reconstruction (MBIR) showed the least noise and optimal image quality. • For CT of the kidneys/ureters/bladder, MBIR should be utilised, if available. • Further studies to reduce the dose while maintaining image quality should be pursued.

Image quality assessment of standard- and low-dose chest CT using filtered back projection, adaptive statistical iterative reconstruction, and novel model-based iterative reconstruction algorithms.

OBJECTIVE: The purpose of this article is to compare image quality between filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR) at standard dose and two preselected low-dose scans. SUBJECTS AND METHODS: Thirty patients (16 men and 14 women; mean age, 67 years) were prospectively recruited. Patients underwent three scans (one standard-dose scan and two low-dose scans at noise indexes [NIs] of 33, 60, and 70, respectively). All three scans were reconstructed with FBP, ASIR, and MBIR. Objective and subjective image qualities were compared. Dose-length products and effective doses for each scans were recorded. Mean image noise and attenuation values were compared between different reconstruction algorithms using repeated-measures analysis of variance and paired Student t tests. The interobserver variation between the two radiologists for subjective image quality and lesion assessment was estimated by using weighted kappa statistics. RESULTS: Objective image analysis supports significant noise reduction with low-dose scans using the MBIR technique (p < 0.05). There was no significant change in mean CT numbers between different reconstructions (p > 0.05). Subjective analysis reveals no significant difference between image quality and diagnostic confidence between low-dose MBIR scans compared with standard-dose scans reconstructed using ASIR (p > 0.05). Average effective doses were 3.7, 1.2, and 0.9 mSv for standard scans at NIs of 33, 60, and 70, respectively. CONCLUSION: MBIR shows superior noise reduction and improved image quality. Substantial dose reduction can be achieved by increasing the NI parameters as tested in this study without affecting image quality and diagnostic confidence.

Assessment of image quality on effects of varying tube voltage and automatic tube current modulation with hybrid and pure iterative reconstruction techniques in abdominal/pelvic CT: a phantom study.

OBJECTIVES: The objective of this study was to compare image quality on abdominal/pelvic computed tomographic images acquired with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and novel model-based iterative reconstruction (MBIR) techniques with varying levels of automatic tube current modulation and tube voltages. METHODS: A 2-phase study was performed. In phase 1, a torso phantom was scanned at 17 different noise levels of automatic current modulation (selected using noise index [NI]) at 120 kilovolt (peak) (kVp). Images reconstructed with FBP, ASIR, and MBIR underwent objective analysis. In phase 2, additional scans were performed at 3 different kVp (80, 100, and 120 kVp at 3 different NIs (33, 50, and 70). Objective and subjective image qualities were assessed. Computed tomography dose index and dose-length products were recorded. RESULTS: The objective image analysis supports significant noise reduction with MBIR compared with ASIR and FBP (P < 0.05) at all 17 NI tested at 120 kVp. When lowering the kVp, the subjective image quality was improved, but when this is performed in conjunction with increasing NI, image quality was maintained only at moderately high NI of 50 but was degraded at higher NIs despite improving contrast-to-noise ratio. CONCLUSIONS: Our results represent the first exploration in the utility of MBIR technique with alteration of kVp in conjunction with tube current modulation in comparison with traditional methods. Objective image noise for MBIR is superior. Subjective image quality is only moderately improved. Scanning at low kVp and moderately high NI with MBIR can ensure that a balance of improved image noise and contrast can be achieved as well as reducing dose.

Image Quality Assessment in Torso Phantom Comparing Effects of Varying Automatic Current Modulation with Filtered Back Projection, Adaptive Statistical, and Model-Based Iterative Reconstruction Techniques in CT.

OBJECTIVES: To compare image quality on computed tomographic (CT) images acquired with different levels of automatic tube current modulation reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and novel model-based iterative reconstruction (MBIR) techniques. METHODS: A torso phantom was scanned at 17 different noise levels of automatic current modulation and images were reconstructed with FBP, ASIR, and MBIR. Objective and subjective image qualities were assessed. Effective dose was also calculated. RESULTS: Objective image analysis supports significant noise reduction and superior contrast to noise ratio with new a MBIR technique. Subjective image parameters were maximally rated for MBIR followed by ASIR then FBP. The reconstruction algorithms were evaluated over effective doses ranging from 0.7 to 3 mSv. CONCLUSION: MBIR shows superior reduction in noise and improved image quality (both objective and subjective analysis) compared with ASIR and FBP. It was possible to achieve meaningful image quality even at the highest noise index of 70 achieving substantial dose reduction to as low as 0.7 mSv.

Pictorial review: computed tomography features of cardiovascular emergencies and associated imminent decompensation.

Multi-detector computed tomography (MDCT) scanner is available in most hospitals and is increasingly being used as the first line imaging in trauma and suspected cardiovascular emergencies, such as acute coronary syndrome, pulmonary artery thrombo-embolism, abdominal aortic aneurysm and acute haemorrhage (Ryan et al. Clin Radiol 60:599-607, 2005). A significant number of these patients are haemodynamically unstable and can rapidly progress into shock and death. Recognition of computed tomography (CT) signs of imminent cardiovascular decompensation will alert the clinical radiologist to the presence of shock. In this review, the imaging findings of cardiovascular emergencies in both acute traumatic and non-traumatic settings with associated signs of imminent decompensation will be described and illustrated.

Popliteal pseudoaneurysm secondary to a tibial osteochondroma: diagnosis with multi-detector row computed tomographic angiography.

A 17-year-old male presented with right knee pain following mild trauma whilst playing badminton. He subsequently developed a popliteal pseudoaneurysm secondary to trauma from a tibial osteochondroma. This is a recognised though very rare occurrence. Its appearance is reported for the first time using multidetector row computed tomographic angiography (MDCTA). The clinical presentation and management of the popliteal pseudoaneurysm are outlined and the imaging findings are illustrated. There is increasing usefulness of MDCTA as an accessible, accurate, noninvasive clinical tool in the emergency diagnostic setting. Its use in the management of this unusual condition is demonstrated with emphasis on 3D, multi-planar reconstruction post-processing techniques.

Hyperdense pericardial effusion in dermatomyositis and contrast induced nephropathy.

Pericardial involvement in dermatomyositis is rare and usually asymptomatic. In many instances, a diagnosis of pericardial involvement is not found until autopsy. Renal failure associated with connective tissue disorders can result in or potentially exaggerate pericardial inflammation. We report an unusual case of high-density pericardial effusion in a patient with dermatomyositis consequent upon contrast nephropathy as demonstrated by computed tomography. High-density pericardial effusion can be a result of an insidious cause such as pericardial inflammation rather than the more usual causes such as coronary or cardiac perforation.

Dilatation of the aorta in pure, severe, bicuspid aortic valve stenosis.

BACKGROUND: Aortic complications are more frequent after bicuspid aortic valve (BAV) replacement (AVR), than tricuspid aortic valve replacement. We studied the size of the proximal thoracic aorta in patients with BAV undergoing AVR for pure, severe aortic stenosis, looking for dilatation in comparison with patients with a matched tricuspid aortic valve (TAV) and normograms of aortic size. METHODS: Aortic root and ascending aortic diameter measurements were taken at 3 levels, from electrocardiographic-gated multidetector row computed tomograms, in 28 patients with pure, severe aortic stenosis before AVR. The patients were divided in 2 groups (BAV, n = 10; TAV, n = 18). Patients with greater than mild aortic regurgitation or who were scheduled for aortic root replacement were excluded. RESULTS: Although patients in the BAV group were younger (P <.0001) and less likely to have hypertension (P <.005), their aortic diameters were larger than those of patients in the TAV group at all levels measured (aortic sinus, 41.1 +/- 8.1 mm vs 33.8 +/- 3.3 mm; sino-tubular junction, 39.0 +/- 7.8 mm vs 31.1 +/- 3.8 mm; right pulmonary artery level, 42.8 +/- 7.1 mm vs 33.7 +/- 4.3 mm; P <.005 for all). Whereas 60% (6/10) of patients in the BAV group had >/=1 aortic diameter measurements greater than the 95th age-adjusted percentile, 0% (0/18) of patients in the TAV group did. CONCLUSIONS: Patients with BAV undergoing AVR with pure, severe aortic stenosis commonly have moderate dilatation of the thoracic aorta, whereas matched patients with a TAV do not. This finding may contribute to the increased frequency of aortic complications seen in follow up of patients with a BAV after AVR.

Calcified patent ductus arteriosus diagnosed following aortic valve replacement.

A 71-year-old woman underwent aortic valve replacement for severe, symptomatic aortic stenosis. The left ventricle filled rapidly when the left ventricular vent was switched off and postoperatively she was slow to recover with bilateral pleural effusions. These findings prompted early reinvestigation, initially with echocardiography and subsequently with multi-detector row computed tomography. Using a retrospectively electrocardiographic-gated acquisition, adapted from a noninvasive coronary angiography protocol, a calcified, persistently patent ductus arteriosus was identified as the cause for her perioperative and postoperative condition. The defect has since been closed successfully using a transcatheter technique.

Thoracic aorta at multi-detector row CT: motion artifact with various reconstruction windows.

The authors assessed motion artifact of the thoracic aorta in 25 patients who underwent multi-detector row computed tomography (CT) with retrospective electrocardiographic (ECG) gating. CT reconstructions centered at four phases of diastole were compared for five different levels of the thoracic aorta. A significant positive correlation was observed between heart rate and motion artifact (r = 0.72, P <.001). The optimal reconstruction phase varied between patients, and this was directly related to heart rate. For patients with a heart rate of 70 beats per minute, the reconstruction phase centered at 75% of the R-R interval had the significantly least motion artifact (P =.004). Conversely, the optimal reconstruction phase for patients with heart rates above 70 beats per minute was centered at 50% of the R-R interval (P =.09).