Radiologists differ markedly in the estimation of pneumothorax risk for a patient undergoing co-axial lung biopsy. Identifying individual patients developing pneumothorax was only possible when risk was estimated at > or =50%. Pulmonary haemorrhage was uncommon and difficult to predict accurately.

Pulmonary arterial hypertension (PAH) is an uncommon condition associated with significant morbidity and mortality. It has diverse aetiology with differing clinical presentations, imaging features and treatments that range from surgical treatment of proximal chronic thromboembolic disease to targeted medical therapies in small vessel disease. Current classification of pulmonary hypertension (PH) is clinically based and groups diseases with similar pathophysiological mechanisms and therapeutic approaches. Groupings include conditions characterised by diffuse small vessel diseases such as idiopathic PAH, PH secondary to chronic hypoxic lung disease, left sided cardiac disease, chronic large vessel obstruction such as chronic thromboembolic disease and a miscellaneous group of diseases. The physiological manifestation of all of these diseases is increased pulmonary vascular resistance and PAH and while clinical features may provide a clue to diagnosis imaging plays a fundamental role in establishing a precise diagnosis and therefore guides therapy. A broad range of imaging modalities is available for the patient with suspected PH including chest radiograph, echocardiography, ventilation/perfusion scintigraphy, catheter pulmonary angiography as well as cross-sectional CT and MRI. Each modality has its strengths and limitations and different techniques may be used at different stages of diagnostic investigation and frequently complement each other. For example, while MRI and echocardiography permit cardiac structural and functional assessment, CT pulmonary angiography provides exquisite morphological information about the proximal pulmonary vasculature and lung parenchyma but little functional information. Modern cross-sectional imaging techniques (CT and MRI) hold the promise of a comprehensive evaluation of the heart, circulation and lung parenchyma in PH. The authors present a multimodality-imaging algorithm for the investigation of patients with suspected PH though it is acknowledged that there is some variation in practice depending on availability of resources and expertise.

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Neurological complications are well described in SARS-CoV-2, but for the first time we report a case of unilateral diaphragm paralysis occurring early in mechanical ventilation for respiratory failure due to such an infection. The patient subsequently required tracheostomy and ventilator support for 37 days, and had increased breathlessness and an elevated diaphragm at clinic review 9 months later. Dynamic chest radiography demonstrated persistent diaphragm paralysis with an accompanying postural change in lung volumes, and he subsequently underwent surgical plication. This case demonstrates that although persistent dyspnoea is a common feature following SARS-CoV-2 infection and is usually due to deconditioning or persistent parenchymal involvement, it can be due to other causes and needs to be investigated appropriately.

Pulmonary hypertension is defined by physiological parameters but there are numerous causes that differ in their pathogenesis, management and prognosis. Causes include chronic cardiac or pulmonary diseases and diffuse small vessel disease but also a range of large vessel obstructive diseases. The physiological manifestation of all these diseases is increased pulmonary vascular resistance and pulmonary arterial hypertension, and while clinical features may provide a clue to diagnosis, imaging plays a fundamental role in establishing a precise diagnosis and therefore guiding therapy. Chronic thromboembolic pulmonary hypertension (CTEPH) is the most common large vessel cause of pulmonary hypertension. It is increasingly recognised as a major cause of morbidity and mortality which is underdiagnosed and often diagnosed late. The importance of CTEPH is that for patients in whom the distribution of disease lies predominantly in the proximal vasculature there is potential for symptomatic and physiological cure by surgical pulmonary endarterectomy. More distal disease may be suitable for medical management. Increased awareness on behalf of both clinicians and imagers is therefore paramount. However, there are other rare causes or large vessel obstruction/stenosis such as large vessel vasculitis, pulmonary artery tumour, fibrosing mediastinitis, congenital stenosis or extrinsic compression of the pulmonary arteries/veins. Atypical imaging appearance such as unilateral central pulmonary artery obstruction should lead to consideration of a diagnosis other than CTEPH.