An unexpected case of thoracic necrotising fasciitis.

Necrotising fasciitis (NF) is a life-threatening bacterial infection characterised by rapid tissue destruction, which can have severe consequences if not recognised early and treated promptly. It is most commonly caused by group A streptococcus entering the body through breaks in the skin. This case report describes a patient who presented with systemic signs of infection, including right axillary pain, following a recent intramuscular injection. Clinical examination and radiological findings were consistent with NF, and surgical exploration confirmed the diagnosis of thoracic NF. The patient underwent extensive surgical debridement, intensive care management and subsequent reconstructive surgery. This report highlights the importance of early recognition of NF and that this condition is not limited to the limbs but may also affect the torso. It employs consideration of all portals of potential bacterial entry that may prompt a differential of NF through thorough history taking. This case encourages healthcare professionals to maintain awareness of skin infections as a potential though rare complication of procedures such as injections hence the continued value of aseptic techniques to minimise risk. Finally, it emphasises that prompt diagnosis, appropriate antibiotic therapy and immediate surgical intervention remain crucial in managing NF and improving patient outcomes.

Safety, tolerability and viral kinetics during SARS-CoV-2 human challenge in young adults.

Since its emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused hundreds of millions of cases and continues to circulate globally. To establish a novel SARS-CoV-2 human challenge model that enables controlled investigation of pathogenesis, correlates of protection and efficacy testing of forthcoming interventions, 36 volunteers aged 18-29 years without evidence of previous infection or vaccination were inoculated with 10 TCID50 of a wild-type virus (SARS-CoV-2/human/GBR/484861/2020) intranasally in an open-label, non-randomized study (ClinicalTrials.gov identifier NCT04865237 ; funder, UK Vaccine Taskforce). After inoculation, participants were housed in a high-containment quarantine unit, with 24-hour close medical monitoring and full access to higher-level clinical care. The study's primary objective was to identify an inoculum dose that induced well-tolerated infection in more than 50% of participants, with secondary objectives to assess virus and symptom kinetics during infection. All pre-specified primary and secondary objectives were met. Two participants were excluded from the per-protocol analysis owing to seroconversion between screening and inoculation, identified post hoc. Eighteen (~53%) participants became infected, with viral load (VL) rising steeply and peaking at ~5 days after inoculation. Virus was first detected in the throat but rose to significantly higher levels in the nose, peaking at ~8.87 log10 copies per milliliter (median, 95% confidence interval (8.41, 9.53)). Viable virus was recoverable from the nose up to ~10 days after inoculation, on average. There were no serious adverse events. Mild-to-moderate symptoms were reported by 16 (89%) infected participants, beginning 2-4 days after inoculation, whereas two (11%) participants remained asymptomatic (no reportable symptoms). Anosmia or dysosmia developed more slowly in 15 (83%) participants. No quantitative correlation was noted between VL and symptoms, with high VLs present even in asymptomatic infection. All infected individuals developed serum spike-specific IgG and neutralizing antibodies. Results from lateral flow tests were strongly associated with viable virus, and modeling showed that twice-weekly rapid antigen tests could diagnose infection before 70-80% of viable virus had been generated. Thus, with detailed characterization and safety analysis of this first SARS-CoV-2 human challenge study in young adults, viral kinetics over the course of primary infection with SARS-CoV-2 were established, with implications for public health recommendations and strategies to affect SARS-CoV-2 transmission. Future studies will identify the immune factors associated with protection in those participants who did not develop infection or symptoms and define the effect of prior immunity and viral variation on clinical outcome.

Blood culture negative infective endocarditis in adult congenital heart disease patients with prosthetic grafts: a case series.

BACKGROUND: Blood culture negative infective endocarditis (BCNIE) is often a diagnostic challenge in adult congenital heart disease patients leading to misdiagnosis, treatment delay and associated high mortality. Studies of BCNIE in adult congenital heart disease patients repaired with prosthetic cardiovascular grafts are limited. CASE SUMMARY: We report two cases of BCNIE where serology testing, multiple polymerase chain reaction testing of explanted valve material and multi-modality imaging including 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) were utilized not only to confirm the diagnosis but also to guide management strategy and inform prognosis. Both patients were treated successfully with cardiac surgery and prolonged anti-microbial therapy. DISCUSSION: Clinical presentation of BCNIE in repaired CHD patients is highly variable. The symptoms are often non-specific with subacute or chronic presentation. This may mislead initial diagnosis and subsequent management. Multi-modality imaging including PET/CT should be considered to support the diagnosis, define the extent of infection, decide the management strategy and inform prognosis in patients. A thorough history of animal exposure, and consideration of serology and multiple molecular testing to identify the causative organism, is critical in the management of BCNIE.

Premature Structural Failure of Trifecta Bioprosthesis in Midterm Follow-up: A Single-Center Study.

BACKGROUND: A cluster of aortic bioprosthetic valve failures, most of which were Trifecta bioprostheses, was observed in Southampton General Hospital, Southampton, United Kingdom. This study was performed to assess whether the cluster represents a significant failure of this valve model or whether there is a selection bias that can explain the failure of these valves. METHODS: This retrospective study evaluated all bioprosthetic aortic valve replacement operations performed between 2011 and 2016 inclusive in our center. The study compared the performance of the Trifecta valve (Abbott, Abbott Park, IL) with that of Perimount (Edwards Lifesciences, Irvine, CA), Perimount Magna Ease, and Mitroflow (LivaNova, London, United Kingdom) bioprostheses. In addition, the study analyzed patient-related and valve-related risk factors for early failure in the failed valves. RESULTS: A total of 2807 bioprosthetic aortic valve replacements were performed. Of these, 836 were Trifecta valves, 1031 were Perimount, 449 were Perimount Magna Ease, and 351 were Mitroflow valves. A total of 24 Trifecta valves had premature structural failure, a number significantly higher than seen with Perimount or Perimount Magna Ease (no failure, P < .001 and P < .005, respectively) valves and the Mitroflow valve (1 failure, P < .05). There was no difference in the incidence of endocarditis or death. At the time of valve failure, 17 (71%) of the failed Trifecta valves had moderate or severe regurgitation, and the average peak gradient was 61 ± 29 mm Hg. The median failed prosthetic size was 23 mm. One failed valve had severe patient-prosthesis mismatch. The mean time to failure was 4.5 ± 1.7 years. CONCLUSIONS: The Trifecta bioprosthesis has an increased incidence of early structural valve failure, which is significantly higher than that of Perimount, Perimount Magna Ease, or Mitroflow. No patient-related or valve-related cause for the failure could be identified.

Comparison of MOLLI and ShMOLLI in Terms of T1 Reactivity and the Relationship between T1 Reactivity and Conventional Signs of Response during Adenosine Stress Perfusion CMR

Background: One of the most important techniques of cardiac magnetic resonance in assessment of coronary heart diseases is adenosine stress myocardial first-pass perfusion imaging. Using this imaging method, there should be an adequate response to the drug adenosine to make an accurate evaluation. The conventional signs of drug response are not always observed and are often subjective. Methods based on splenic perfusion might possess limitations as well. Therefore, T1 mapping presents as a novel, quantitative and reliable method. There are several studies analyzing this newly discovered property of different T1 mapping sequences. However most of these studies are enrolling only one of the techniques. Aims: To compare modified look-locker inversion recovery and shortened modified look-locker inversion recovery sequences in terms of T1 reactivity and to determine the relationship between T1 reactivity and conventional stress adequacy assessment methods in adenosine stress perfusion cardiac magnetic resonance. Study Design: A cross-sectional study using STARD reporting guideline. Methods: Thirty-four consecutive patients, who were referred for adenosine stress perfusion cardiac magnetic resonance with suspect of myocardial ischemia, were prospectively enrolled into the study. Four patients were disqualified, and thirty patients were included in the final analysis. Using both modified look-locker inversion recovery and shortened modified look-locker inversion recovery, midventricular short axis slices of T1 maps were acquired at rest and during peak adenosine stress before gadolinium administration. Then, they were divided into six segments according to the 17-segment model proposed by the American Heart Association, and separate measurements were made from each segment. Mean rest and mean stress T1 values of remote, ischemic, and infarcted myocardium were calculated individually per subject. During adenosine administration, patients' heart rates and blood pressures are measured and recorded every one minute. Adenosine stress perfusion images were examined for the presence of splenic switch-off. Results: There was a significant difference between rest and stress T1 values of remote myocardium in both modified look-locker inversion recovery and shortened modified look-locker inversion recovery (p<0.001). In both modified look-locker inversion recovery and shortened modified look-locker inversion recovery there was no significant correlation between T1 reactivity and heart rates response (modified look-locker inversion recovery p=0.30, shortened modified look-locker inversion recovery p=0.10), blood pressures response (modified look-locker inversion recovery p=0.062, shortened modified look-locker inversion recovery p=0.078), splenic perfusion (modified look-locker inversion recovery p=0.35, shortened modified look-locker inversion recovery p=0.053). There was no statistically significant difference between modified look-locker inversion recovery and shortened modified look-locker inversion recovery regarding T1 reactivity of remote (p=0.330), ischemic (p=0.068), and infarcted (p=0.116) myocardium. Conclusion: T1 reactivity is independent of the other stress response signs and modified look-locker inversion recovery and shortened modified look-locker inversion recovery do not differ in terms of T1 reactivity.

Frequency and impact of incidental findings on computed tomography during work-up for transcatheter aortic valve implantation: single centre experience and review of the literature.

OBJECTIVE: To assess the frequency and impact of incidental findings (IF) on CT during work-up for transcatheter aortic valve intervention (TAVI). METHODS: A consecutive cohort of patients referred for consideration of TAVI who underwent a CT scan between 2009 and 2018 were studied retrospectively. CT reports were reviewed for the presence of IFs and categorised based upon their clinical significance: (a) insignificant-findings that did not require specific treatment or follow-up; (b) intermediate-findings that did not impact on the decision-making process but required follow-up; (c) significant-findings that either required urgent investigation or meant that TAVI was clinically inappropriate. RESULTS: A total of 652 patients were included, whose median age was 82 years. One or more insignificant IF was found in 95.6% of patients. Intermediate IFs were documented in 5.4%. 91 (14%) patients had at least one significant IF. These included possible malignancy in 67 (74%). The ultimate decision to offer aortic valve intervention was only changed by the presence of an IF in 3.5% of cases. CONCLUSION: Clinically significant IFs are detected in more than 1 in 10 of patients undergoing CT as part of a TAVI work-up, although just over half of these patients still receive aortic valve intervention. ADVANCES IN KNOWLEDGE: This study is the largest UK cohort, which, when combined with a review of existing literature, provides a clear picture of the frequency and clinical impact of IFs found at CT for TAVI assessment.

Using Novel Computed Tomography Analysis to Describe the Contribution and Distribution of Emphysema and Small Airways Disease in Chronic Obstructive Pulmonary Disease.

Rationale: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, caused by emphysema and small airways disease (SAD). Computed tomography (CT) coupled with image analysis enables the quantification of these abnormalities; however, the optimum method for doing so has not been determined.Objectives: This study aims to compare two CT quantitative analysis techniques, disease probability measure (DPM) and parametric response mapping (PRM), and assess their relationship with specific physiological measures of SAD.Methods: Subjects with mild to moderate COPD, never smokers, and healthy ex-smokers were recruited. Each had airway oscillometry and multiple-breath nitrogen washout, measuring peripheral airway resistance, peripheral airway reactance, and acinar airway inhomogeneity. Subjects also had an inspiratory and expiratory chest CT, with DPM and PRM analysis performed by coregistering images and classifying each voxel as normal, emphysema, or nonemphysematous gas trapping related to SAD.Results: Thirty-eight subjects with COPD, 18 never smokers, and 23 healthy ex-smokers were recruited. There were strong associations between DPM and PRM analysis when measuring gas trapping (ρ = 0.87; P < 0.001) and emphysema (ρ = 0.99; P < 0.001). DPM assigned significantly more voxels as emphysema and gas trapped than PRM (P < 0.001). Both techniques showed significantly greater emphysema and gas trapping in subjects with COPD than in never smokers and ex-smokers (P < 0.001). All CT measures had significant associations with peripheral airway resistance and reactance, with disease probability measure of nonemphysematous gas trapping related to SAD having the strongest independent association with peripheral airway resistance (ß = 0.42; P = 0.001) and peripheral airway reactance (ß = 0.41; P = 0.001). Emphysema measures had the strongest associations with acinar airway inhomogeneity (ß = 0.35-0.38).Conclusions: These results provide further validation for the use of DPM/PRM analysis in COPD by demonstrating significant relationships with specific physiological measures of SAD.

Impact of radiologically stratified exacerbations: insights into pneumonia aetiology in COPD.

BACKGROUND: COPD patients have increased risk of developing pneumonia, which is associated with poor outcomes. It can be symptomatically indistinguishable from exacerbations, making diagnosis challenging. Studies of pneumonia in COPD have focused on hospitalised patients and are not representative of the ambulant COPD population. Therefore, we sought to determine the incidence and aetiology of acute exacerbation events with evidence of pneumonic radiographic infiltrates in an outpatient COPD cohort. METHODS: One hundred twenty-seven patients with moderate to very severe COPD aged 42-85 years underwent blood and sputum sampling over one year, at monthly stable visits and within 72 h of exacerbation symptom onset. 343 exacerbations with chest radiographs were included. RESULTS: 20.1% of exacerbations had pneumonic infiltrates. Presence of infiltrate was highly seasonal (Winter vs summer OR 3.056, p = 0.027). In paired analyses these exacerbation events had greater increases in systemic inflammation. Bacterial detection rate was higher in the pneumonic group, with Haemophilus influenzae the most common bacteria in both radiological groups. Viral detection and sputum microbiota did not differ with chest radiograph appearance. CONCLUSIONS: In an outpatient COPD cohort, pneumonic infiltrates at exacerbation were common, and associated with more intense inflammation. Bacterial pathogen detection and lung microbiota were not distinct, suggesting that exacerbations and pneumonia in COPD share common infectious triggers and represent a continuum of severity rather than distinct aetiological events. TRIAL REGISTRATION: Trial registration Number: NCT01360398 .

Relationship of CT-quantified emphysema, small airways disease and bronchial wall dimensions with physiological, inflammatory and infective measures in COPD.

BACKGROUND: COPD is a complex, heterogeneous disease characterised by progressive development of airflow limitation. Spirometry provides little information about key aspects of pathology and is poorly related to clinical outcome, so other tools are required to investigate the disease. We sought to explore the relationships between quantitative CT analysis with functional, inflammatory and infective assessments of disease to identify the utility of imaging to stratify disease to better predict outcomes and disease response. METHODS: Patients from the AERIS study with moderate-very severe COPD underwent HRCT, with image analysis determining the quantity of emphysema (%LAA<- 950), small airways disease (E/I MLD) and bronchial wall thickening (Pi10). At enrolment subjects underwent lung function testing, six-minute walk testing (6MWT), blood sampling for inflammatory markers and sputum sampling for white cell differential and microbiological culture and PCR. RESULTS: 122 subjects were included in this analysis. Emphysema and small airways disease had independent associations with airflow obstruction (ß = - 0.34, p < 0.001 and ß = - 0.56, p < 0.001). %LAA<- 950 had independent associations with gas transfer (ß = - 0.37, p < 0.001) and E/I MLD with RV/TLC (ß = 0.30, p =0.003). The distance walked during the 6MWT was not associated with CT parameters, but exertional desaturation was independently associated with emphysema (ß = 0.73, p < 0.001). Pi10 did not show any independent associations with lung function or functional parameters. No CT parameters had any associations with sputum inflammatory cells. Greater emphysema was associated with lower levels of systemic inflammation (CRP ß = - 0.34, p < 0.001 and fibrinogen ß = - 0.28, p =0.003). There was no significant difference in any of the CT parameters between subjects where potentially pathogenic bacteria were detected in sputum and those where it was not. CONCLUSIONS: This study provides further validation for the use of quantitative CT measures of emphysema and small airways disease in COPD as they showed strong associations with pulmonary physiology and functional status. In contrast to this quantitative CT measures showed few convincing associations with biological measures of disease, suggesting it is not an effective tool at measuring disease activity.

A tertiary centre experience of thoracic CT and cardiac MRI scanning in the presence of a reveal LINQ insertable cardiac monitoring system: a case series review of artefact, patient safety and data preservation.

OBJECTIVE: At our tertiary cardiothoracic centre, cardiac MRI and thoracic CT scans are performed in patients with implanted LINQ devices. The degree of foreign body artefact associated with the LINQ device, and its clinical importance, has not previously been assessed. A case series review was therefore performed with a simultaneous review of patient safety and data loss events, secondary to the MRI environment. METHODS: A local database search identified LINQ device patients who underwent thoracic CT or cardiac MRI scans between March 2014 and December 2016. Images were reviewed by two radiologists, recording the presence of subcutaneous and intrathoracic artefact, and its clinical significance. Furthermore a specialist in cardiac rhythm management reviewed all LINQ data downloads undertaken before and after MRI scanning, and a search of the trust incident reporting system was performed. RESULTS: Minor subcutaneous artefact was present on all scans. Intrathoracic artefact was observed in 25.6% of thoracic CT scans and 33.3% of cardiac MRIs; however no clinically significant artefact was observed. Device downloads were only performed by 53.8% of patients prior to their MRI scan and 56.5% after their MRI scan. No adverse patient safety or data loss events were noted. CONCLUSION: The LINQ device does not produce clinically significant artefact, even when artefact extends into the intrathoracic space, which occurs in a third of MRIs and a quarter of CTs. MRI scanning of the LINQ device is safe with no evidence of inappropriate data loss. Advances in knowledge: This is the first published case series of CT and MRI scanning in LINQ patients and the first performed quantification of artefact related to the LINQ device.

Keeping up appearances: the radiographic evolution of cardiovascular implantable electronic devices.

In recent years, there has been a significant evolution in the field of cardiovascular implantable electronic devices (CIEDs). Pacemakers can now be leadless, implantable cardioverter defibrillators can be entirely subcutaneous and implantable loop recorders have become miniaturized. Driven by technological advances and an ageing population implant numbers have also steadily increased. These highly prevalent systems are all radio-opaque and are frequently observed on chest radiographs, yet the devices are neither well recognized nor understood. We present a pictorial review of CIEDs; describing the chest radiograph appearances of both newer generation systems and their traditional predecessors. Furthermore, we discuss the clinical role of chest radiography in both CIED implantation and follow up, with the aim of improving understanding in this important and expanding field. Finally, we present a collection of interesting and challenging radiographs, where multiple CIED systems have been implanted.

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.

Clot or not? An unusual case of false positive CTPA and an approach to diagnosis.

The case involves a 69-year-old female with severe, longstanding bronchiectasis secondary to childhood pertussis infection. She presented to the hospital and was thought clinically to have a pulmonary embolus. A CT pulmonary angiogram was performed, which was technically satisfactory. This revealed multiple, bilateral filling defects that were fairly convincing for pulmonary emboli. Further review of the CT scan not only revealed the extent of her bronchiectasis but also a number of enlarged bronchial arteries supplying the diseased lung. The pulmonary arterial filling defects arose suspiciously close to the bronchial arteries and the possibility of bronchial to pulmonary artery anastomoses was considered. Could the admixture of highly contrast-opacified pulmonary arterial blood with partially opacified systemic arterial blood cause the apparent filling defects? After further consideration, a second electrocardiography-gated CT angiogram was performed-this time in the systemic arterial phase but planned with two regions of interest sited over the main pulmonary artery and the aorta with the aim of triggering the scan with maximum contrast in the bronchial arteries, and as much contrast washout as possible in the pulmonary arteries. This study revealed a reversal of the CT pulmonary angiogram appearances with contrast now seen in the bronchial arteries and opacifying the sites of the previous filling defects in the pulmonary arteries. Thus, the filling defects were actually false positives caused by an admixture of highly opacified and part-opacified blood via bronchial artery anastomoses. In the context of a false-positive finding of pulmonary embolus on a background of severe bronchiectasis, unnecessary anticoagulation could have increased the risk of complications such as haemoptysis. This case report illustrates the importance of knowledge of potential false-positive findings in CT pulmonary angiography and describes a novel approach based on cardiac CT techniques to prove this.

Distinct emphysema subtypes defined by quantitative CT analysis are associated with specific pulmonary matrix metalloproteinases.

BACKGROUND: Emphysema is characterised by distinct pathological sub-types, but little is known about the divergent underlying aetiology. Matrix-metalloproteinases (MMPs) are proteolytic enzymes that can degrade the extracellular matrix and have been identified as potentially important in the development of emphysema. However, the relationship between MMPs and emphysema sub-type is unknown. We investigated the role of MMPs and their inhibitors in the development of emphysema sub-types by quantifying levels and determining relationships with these sub-types in mild-moderate COPD patients and ex/current smokers with preserved lung function. METHODS: Twenty-four mild-moderate COPD and 8 ex/current smokers with preserved lung function underwent high resolution CT and distinct emphysema sub-types were quantified using novel local histogram-based assessment of lung density. We analysed levels of MMPs and tissue inhibitors of MMPs (TIMPs) in bronchoalveolar lavage (BAL) and assessed their relationship with these emphysema sub-types. RESULTS: The most prevalent emphysema subtypes in COPD subjects were mild and moderate centrilobular (CLE) emphysema, while only small amounts of severe centrilobular emphysema, paraseptal emphysema (PSE) and panlobular emphysema (PLE) were present. MMP-3, and -10 associated with all emphysema sub-types other than mild CLE, while MMP-7 and -8 had associations with moderate and severe CLE and PSE. MMP-9 also had associations with moderate CLE and paraseptal emphysema. Mild CLE occurred in substantial quantities irrespective of whether airflow obstruction was present and did not show any associations with MMPs. CONCLUSION: Multiple MMPs are directly associated with emphysema sub-types identified by CT imaging, apart from mild CLE. This suggests that MMPs play a significant role in the tissue destruction seen in the more severe sub-types of emphysema, whereas early emphysematous change may be driven by a different mechanism. TRIAL REGISTRATION: Trial registration number NCT01701869 .

'The worm that got away': parainfectious atypical optic neuritis associated with schistosomiasis infection.

Although optic neuritis is commonly associated with multiple sclerosis, patients with atypical optic neuritis require further investigations to exclude other associated conditions. We report a woman presenting with cough, fatigue, atypical optic neuritis with chiasmitis. She responded partially to corticosteroids and we subsequently found she had a ground-glass lung nodule. Follow-up CT scan of thorax at 12 months showed new parenchymal lung lesions that suggested schistosomiasis. Further questioning by a respiratory physician identified, in retrospect, a previous exposure history; serological testing confirmed schistosoma infection. She was treated with praziquantel and slowly improved clinically, with radiological improvement in the optic chiasm, regression of the parenchymal lung lesions but with the ground glass nodule unchanged. We diagnosed parainfectious optic neuritis associated with schistosomiasis, based upon exposure history, serological confirmation and radiological features, together with the response to treatment, and having excluded other causes of an atypical optic neuritis.

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.

Relationship between pulmonary matrix metalloproteinases and quantitative CT markers of small airways disease and emphysema in COPD.

BACKGROUND: Matrix metalloproteinases (MMPs) are proteolytic enzymes that can degrade the extracellular matrix and drive tissue remodelling, key processes in the pathogenesis of COPD. The development of small airway disease has been identified as a critical mechanism in the early development of airflow obstruction but the contribution of MMPs in human disease is poorly characterised. OBJECTIVES: We investigated the role of MMPs and inflammatory cytokines in the lung by quantifying levels and determining relationships with the key pathological components of COPD in patients and healthy controls. METHODS: We analysed levels of MMPs and inflammatory cytokines in bronchoalveolar lavage from 24 COPD and 8 control subjects. Each subject underwent spirometry and high-resolution CT. Image analysis quantitatively assessed emphysema, bronchial wall thickening and small airways disease. RESULTS: Multiple MMPs (MMP-1, -2, -3, -8, -9 and -10) and cytokines (interleukin (IL) 6 and IL-8) were elevated in lungs of subjects with COPD. MMP-3, -7, -8, -9, -10 and -12 concentrations closely associated with CT markers of small airways disease. Emphysema severity was also associated with MMP-3, -7 and -10. However, there were no strong relationships between MMPs and bronchial wall thickness of the larger airways. CONCLUSIONS: Pulmonary MMP concentrations are directly associated with the extent of gas trapping and small airways disease identified on CT scan. This study suggests that MMPs play a significant role in small airways remodelling, a key feature in the pathogenesis of COPD. TRIAL REGISTRATION NUMBER: NCT01701869.