Pulmonary Thromboembolic Disease Pulmonary Thromboembolic Disease Definition A pulmonary embolus (PE) usually arises from a thrombus within a pelvic or lower limb vein (>90%) ▪ ‘Saddle’ embolus: a thrombus lodged at the main pulmonary arterial bifurcation ▪ Pulmonary infarction: This is relatively rare as there is a second ‘systemic’ arterial supply to the lungs from the bronchial arteries Risk factors for a pulmonary embolism: increasing age…

Acquired Mitral Valve Disease Mitral Regurgitation Definition An incompetent mitral valve allowing regurgitant flow from the left ventricle (LV) into the left atrium (LA) during systole (mid-to-late systolic murmur) ▸ maintaining an adequate stroke volume requires an increased ventricular stroke volume and ejection fraction Clinical presentation Acute regurgitation (e.g. ruptured chordae tendineae): sudden volume loading with acute pulmonary oedema/heart failure Chronic regurgitation (e.g. hypertrophic cardiomyopathy): volume…

Introduction Cardiac Development Between the 2 nd and 7 th week of intrauterine life the primitive cardiac tube grows in length more than the fetal trunk – as the ends of this tube are relatively fixed the rapidly elongating cardiac tube is compelled to bend into a loop and twist and rotate The formed curve is almost always convex to the right of the fetus (the…

Lung Transplantation Lung Transplantation Definition Single lung transplantation This is indicated for non-suppurative lung disease: emphysema ▸ idiopathic pulmonary fibrosis ▸ sarcoidosis ▸ lymphangioleiomyomatosis Bilateral sequential lung transplantation This is indicated for suppurative lung disease: cystic fibrosis ▸ bronchiectasis Preoperative Imaging Typical imaging procedures that are performed: PA and lateral CXR ▸ CT chest ▸ quantitative ventilation–perfusion scintigraphy This can determine the optimum side for a…

Congenital Chest Abnormalities Congenital Pulmonary Airway Malformations (CPAM) Definition Previously known as congenital cystic adenomatoid malformation (CCAM) A rare lesion caused by hamartomatous proliferation of the terminal bronchioles at the expense of alveolar development ▸ it is characterized by a multicystic mass of pulmonary tissue with proliferation of the bronchiolar structures It is usually unilobar and communicates with a normal tracheobronchial tree ▸ it receives its…

Airspace Disease Pulmonary Oedema Definition An excess of extravascular lung water ▪ Cardiogenic oedema: increased hydrostatic pressure moves fluid out of the vascular compartment ▸ this is commonly caused by left heart failure ▸ it is rarely caused by a reduction in plasma osmotic pressure (e.g. hypoalbuminaemia) ▪ Non-cardiogenic oedema: this is caused by an increased alveolar-capillary barrier permeability – Causes: fluid overload ▸ drowning ▸…

Chest Wall and Lung Trauma Chest Wall and Lung Trauma Rib fractures More than 50% of acute fractures are missed on the initial CXR ▸ additional lateral or oblique views are inappropriate in an acute trauma patient – the main priority is to detect complications such as a pneumothorax, haemothorax or a pulmonary contusion Fractures of the 1 st to 3 rd ribs imply a severe…

HRCT Patterns of Diffuse Lung Disease HRCT Technique Thin collimation (1-2 mm) with a high spatial frequency algorithm reconstruction ▸ interspaced versus volumetric acquisition (dose considerations) Reducing slice thickness < 1 mm will not increase spatial resolution but increase image noise A sharp reconstruction algorithm reduces images smoothing making structures visibly sharper (at the cost of increased image noise) IV contrast should be avoided if possible as it…

Evaluation of the Solitary Pulmonary Nodule Evaluation of the Solitary Pulmonary Nodule Definition This is defined as a solitary circumscribed pulmonary opacity with no associated pulmonary, pleural, or mediastinal abnormality ▸ it measures < 3 cm in diameter Many are discovered incidentally (but up to 40% may be malignant) <10% are due to a solitary pulmonary metastasis Benign intrapulmonary lymph nodes: nodules <15 mm from the pleural surface…

Mechanisms and Radiographic Appearances Mechanisms and Causes of Lobar Collapse Lobar collapse: this is divided into those causes due to an endobronchial obstruction (intrinsic or extrinsic) or those causes without obstruction ▪ A segment of atelectatic lung pivots around the central hilum via its attaching bronchovascular structures – any fissures will also influence the direction of collapse Common causes differ between adults and children: ▪ Adults:…

Tracheal Disorders Post-Traumatic Strictures Definition These are usually secondary to damage from external neck trauma or from a cuffed endotracheal or tracheostomy tube CXR/CT A focus of circumferential or eccentric tracheal narrowing associated with a segment of increased soft tissue Postintubation stenosis: this extends for several cm ▸ it typically involves the trachea above the level of the thoracic inlet Post-tracheostomy stenosis: this typically begins 1–1.5 cm…

Lobar Pneumonia Lobar Pneumonia Definition An infection developing within the distal airspaces (and adjacent to the visceral pleura) ▸ it spreads via collateral air drift (pores of Kohn), producing homogeneous opacification of partial or complete lung segments (and occasionally an entire lobe) ▸ any lung opacification is limited by the fissures and is usually unifocal As the airways are not primarily involved and remain patent there…

Mediastinitis Acute Mediastinitis Definition Acute infection of the mediastinum ▸ this is rare It is most commonly due to an oesophageal perforation (e.g. following endoscopy or from a swallowed object) – the alimentary contents serve as an infective source Other causes Boerhaave's syndrome (forceful vomiting that tears the oesophagus) with the tear almost invariably just above the gastro-oesophageal junction ▸ leakage through a necrotic neoplasm ▸…

Chest Wall: Bony and Soft Tissue Lesions Rib Lesions Benign Congenital abnormalities The upper ribs are commonly bifid, splayed, fused, or hypoplastic ▸ they are occasionally associated with syndromes (e.g. basal cell naevus syndrome) or other anomalies (e.g. Sprengel's deformity) Cervical rib: this arises from C7 (affecting 1–2% of the population) and consists of an initially downward sloping rib just lateral to the spine (cf. an…