Diagnostic utility of additional whole-chest CT as part of an acute abdominal pain CT imaging pathway during the COVID-19 pandemic.

AIM: To evaluate the diagnostic utility of additional whole-chest computed tomography (CT) in identifying otherwise unheralded COVID-19 lung disease as part of an acute abdominal pain CT imaging pathway in response to the COVID-19 pandemic. MATERIALS AND METHODS: Consecutive patients (n=172) who underwent additional whole-chest CT via a COVID-19 acute abdominal pain CT imaging pathway between 27 March and 3 May 2020 were evaluated in this retrospective single-centre study. Chest CT examinations were graded as non-COVID-19, indeterminate for, or classic/probable for COVID-19. CT examinations in the latter two categories were further divided into one of three anatomical distributions (lung base, limited chest [below carina], whole chest [above carina]) based on location of findings. Reverse transcriptase-polymerase chain reaction (RT-PCR) results and clinical features of COVID-19 were assessed to determine if COVID-19 was clinically suspected at the time of CT referral. RESULTS: Twenty-seven of the 172 (15.7%) patients had CT features potentially indicative of COVID-19 pneumonia, 6/27 (3.5%) demonstrating a classic/probable pattern and 21/27 (12.2%) demonstrating an indeterminate pattern. After correlation with clinical features and RT-PCR 8/172 (4.7%) were defined as COVID-19 positive, of which only 1/172 (0.6%) was clinically unsuspected of COVID-19 at the time of CT referral. All COVID-19 positive cases could be identified on review of the lung base alone. CONCLUSION: Whole-chest CT as part of an acute abdominal pain CT imaging pathway has a very low diagnostic yield for our cohort of patients. All COVID-19-positive patients in our cohort were identified on review of the lung bases on the abdominal CT and this offers an alternative imaging approach in this patient group.

Accuracy and cost-effectiveness of dynamic contrast-enhanced CT in the characterisation of solitary pulmonary nodules-the SPUtNIk study.

INTRODUCTION: Solitary pulmonary nodules (SPNs) are common on CT. The most cost-effective investigation algorithm is still to be determined. Dynamic contrast-enhanced CT (DCE-CT) is an established diagnostic test not widely available in the UK currently. METHODS AND ANALYSIS: The SPUtNIk study will assess the diagnostic accuracy, clinical utility and cost-effectiveness of DCE-CT, alongside the current CT and 18-flurodeoxyglucose-positron emission tomography) (18FDG-PET)-CT nodule characterisation strategies in the National Health Service (NHS). Image acquisition and data analysis for 18FDG-PET-CT and DCE-CT will follow a standardised protocol with central review of 10% to ensure quality assurance. Decision analytic modelling will assess the likely costs and health outcomes resulting from incorporation of DCE-CT into management strategies for patients with SPNs. ETHICS AND DISSEMINATION: Approval has been granted by the South West Research Ethics Committee. Ethics reference number 12/SW/0206. The results of the trial will be presented at national and international meetings and published in an Health Technology Assessment (HTA) Monograph and in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ISRCTN30784948; Pre-results.

MRI in adult patients with aortic coarctation: diagnosis and follow-up.

Aortic coarctation is a disease that usually presents in infancy; however, a proportion of patients present for the first time in adulthood. These lesions generally require repair with either surgery or interventional techniques. The success of these techniques means that increasing numbers of patients are presenting for follow-up imaging in adulthood, whether their coarctation was initially repaired in infancy or as adults. Thus, the adult presenting to the radiologist for assessment of possible coarctation or follow-up of coarctation repair is not an uncommon scenario. In this review, we present details of the MRI protocols and MRI findings in these patients so that a confident and accurate assessment can be made.

Cardiac MR assessment of microvascular obstruction.

Microvascular obstruction (MVO) is usually seen in a proportion of patients with acute myocardial infarction following reperfusion therapy of an occluded coronary artery. It is characterized by damage and dysfunction of the myocardial microvasculature with a no-reflow phenomenon within the infarct zone. While MVO may be demonstrated via a number of different imaging modalities, cardiac MR (CMR) enables accurate identification of MVO and also permits assessment of infarct extent and overall left ventricular function during the same imaging examination. We present a pictorial review of the characteristic appearances of MVO on CMR and highlight the importance of this imaging diagnosis for patient outcome following acute myocardial infarction.

Cardiac MR assessment of cardiac myxomas.

Cardiac myxomas are the most common benign primary cardiac tumour to present in adulthood. While most patients present with symptoms of cardiac obstruction, embolic phenomena or constitutional impairment, up to a fifth of patients remain asymptomatic and are incidentally diagnosed on imaging. Although echocardiography is usually the initial imaging modality used to evaluate these patients, cardiac MRI (CMR) has emerged over the past decade as the primary imaging modality in the assessment of patients with cardiac tumours. The superior tissue characterization capability of CMR means that it is able to determine the nature of some tumours pre-operatively and performs well in differentiating myxomas from thrombus. We present a pictorial review highlighting the key CMR features of myxomas and show how these lesions can be differentiated from thrombus and other cardiac masses.

The role of multidetector-row CT in the diagnosis, classification and management of acute aortic syndrome.

The term "acute aortic syndrome" (AAS) encompasses several non-traumatic life-threatening pathologies of the thoracic aorta presenting in patients with a similar clinical profile. These include aortic dissection, intramural haematoma and penetrating atherosclerotic ulcers. These different pathological entities can be indistinguishable on clinical grounds alone and may be confused with other causes of chest pain, including myocardial infarction. Multidetector-row CT (MDCT) is the current modality of choice for imaging AAS with a sensitivity and specificity approaching 100%. Early diagnosis and accurate radiological classification is associated with improved clinical outcomes in AAS. We review the characteristic radiological features of the different pathologies that encompass AAS and highlight the vital role of MDCT in determining the management of these life-threatening conditions.

Troponin-positive chest pain with unobstructed coronary arteries: definitive differential diagnosis using cardiac MRI.

OBJECTIVE: The purpose of this study was to assess the outcome of cardiac MRI (CMRI) with late gadolinium enhancement (LGE) at outpatient follow-up in a consecutive series of patients with troponin-positive chest pain but unobstructed coronary arteries at the index admission. METHODS: The study group comprised 91 consecutive patients who presented to our institution with cardiac chest pain, elevated troponin I and unobstructed coronary arteries on coronary angiography. All patients underwent an outpatient CMRI with LGE imaging in order to establish a definitive diagnosis. RESULTS: The average time from coronary angiography to LGE-CMRI was 2 months. 73% of patients had no abnormality on their LGE-CMRI, 16% of patients had patchy late enhancement consistent with myocarditis and 11% had focal subendocardial or full thickness late enhancement consistent with myocardial infarction. There were no deaths in this cohort during a mean follow-up of 21 months. CONCLUSION: LGE-CMRI is a useful tool for establishing whether such patients have definitive evidence of non-ST-segment elevation myocardial infarction (NSTEMI), and can make an important contribution to the long-term management strategy of these patients as an inappropriate diagnosis of NSTEMI carries important medical, social and financial implications.

Pericardial disease--anatomy and function.

Imaging of patients with suspected or known pericardial disease remains challenging. Echocardiography is the first-line investigation for pericardial disease but it has specific limitations in terms of its abilities to visualise the pericardium fully and to identify extracardiac pathology. Cardiac cross-sectional imaging by both MRI and CT has developed significantly and now has an important role in the investigation of pericardial disease. This article examines the appearances of both healthy and diseased pericardium using CT and MRI. The typical imaging findings across a wide range of conditions are illustrated and the roles of CT and MRI are reviewed. The relative merits and weaknesses of each modality are explored and the specific functional techniques that are available are introduced.

Cross-sectional imaging appearances of cardiac aneurysms.

Cardiac aneurysms are an uncommon presentation of cardiac disease, but are important to identify and accurately characterise. Traditionally, these aneurysms have been investigated with plain radiography, angiography and echocardiography. With the significant recent technical improvements in cross-sectional cardiac imaging, computed tomography (CT) and magnetic resonance imaging (MRI) are now becoming established as the definitive investigations. This article reviews the spectrum of locations of cardiac aneurysms and their appearance with particular reference to CT and MRI. We describe the relative merits of each technique and discuss how they may be used to direct clinical practice.

Giant left anterior descending coronary artery aneurysm.

Small atherosclerotic coronary artery aneurysms are a relatively frequent incidental finding at angiography. We report an unusual case in that the aneurysm found was extremely large and therefore potentially at risk of rupture.

Ischaemic and non-ischaemic cardiomyopathies--cardiac MRI appearances with delayed enhancement.

Over the past few years, cardiovascular magnetic resonance (CMR) imaging has rapidly developed and is now a robust clinical tool capable of providing high-resolution images of the heart in any desired plane. Delayed contrast-enhanced CMR (DE-CMR) can be used for non-invasive tissue characterization, with differing patterns of hyperenhancement displayed by ischaemic and non-ischaemic cardiomyopathies. This review explains the theory behind delayed hyperenhancement, and demonstrates the potential of DE-CMR in the diagnosis of a wide range of different cardiac disease states.

Computed tomographic coronary angiography: how many slices do you need?

While increasing the number of slices in multislice computed tomography clearly brings benefits in terms of detecting significant coronary disease, heavy calcification remains a problem, as does the high radiation burden.

Relationship between peripheral airway dysfunction, airway obstruction, and neutrophilic inflammation in COPD.

BACKGROUND: Considerable research has been conducted into the nature of airway inflammation in chronic obstructive pulmonary disease (COPD) but the relationship between proximal airways inflammation and both dynamic collapse of the peripheral airways and HRCT determined emphysema severity remains unknown. A number of research tools have been combined to study smokers with a range of COPD severities classified according to the GOLD criteria. METHODS: Sixty five subjects (11 healthy smokers, 44 smokers with stage 0-IV COPD, and 10 healthy non-smokers) were assessed using lung function testing and HRCT scanning to quantify emphysema and peripheral airway dysfunction and sputum induction to measure airway inflammation. RESULTS: Expiratory HRCT measurements and the expiratory/inspiratory mean lung density ratio (both indicators of peripheral airway dysfunction) correlated more closely in smokers with the severity of airflow obstruction (r = -0.64, p<0.001) than did inspiratory HRCT measurements (which reflect emphysema severity; r = -0.45, p<0.01). Raised sputum neutrophil counts also correlated strongly in smokers with HRCT indicators of peripheral airway dysfunction (r = 0.55, p<0.001) but did not correlate with HRCT indicators of the severity of emphysema. CONCLUSIONS: This study suggests that peripheral airway dysfunction, assessed by expiratory HRCT measurements, is a determinant of COPD severity. Airway neutrophilia, a central feature of COPD, is closely associated with the severity of peripheral airway dysfunction in COPD but is not related to the overall severity of emphysema as measured by HRCT.

Endobronchial ultrasound to assess airway wall thickening: validation in vitro and in vivo.

Endobronchial ultrasound (EBUS) allows identification of airway wall structures and could potentially be utilised for in vivo studies of airway thickening in asthma. The present study investigated whether inflation of the fluid-filled balloon sheath over the transducer (necessary to provide sonic coupling with the airway wall) influenced in vitro measurements. In vivo comparability of EBUS with high resolution computed tomography scanning (HRCT), an established method for measuring wall thickness, was determined in control subjects. The airway diameter and wall thickness were studied using EBUS in 24 cartilaginous airways obtained from four sheep, before and after balloon sheath inflation during immersion in saline. To assess EBUS versus HRCT comparability of airway measures in vivo, 12 control subjects underwent imaging of the posterior basal bronchus of the right lower lobe by both techniques. Intra- and interobserver agreement were also assessed. Results with and without the balloon sheath gave comparable measures of airway internal diameter and wall thickness in vitro. Statistical analysis showed agreement between EBUS and HRCT, and intra- and interobserver variability in vivo. The current study concludes that endobronchial ultrasound, which does not present a radiation risk, could be utilised in the in vivo study of cartilaginous airway wall remodelling in respiratory diseases, such as asthma.