Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

1,498 results found
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Histoplasmosis

Histoplasmosis is an endemic mycosis caused by Histoplasma capsulatum.  Pulmonary histoplasmosis is the most common manifestation of this infectious disease. Disseminated or extra-pulmonary (pericardial, articular) histoplasmosis is often seen in immunosuppressed patients. As such, these are in...
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HIV/AIDS

Acquired immunodeficiency syndrome (AIDS) is an immunosuppressed state, caused by infection with the human immunodeficiency virus (HIV). It is characterised by opportunistic infections, neoplasms and neurological manifestations. Epidemiology According to the United Nations programme on HIV/AID...
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HIV/AIDS (pulmonary and thoracic manifestations)

Pulmonary manifestations of HIV/AIDS are a major contributor to morbidity and mortality related to the disease. The differential in an HIV patient with a chest complaint is broad. Infectious causes are the most common, however, neoplasms, lymphoma and interstitial pneumonias also play a signific...
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HIV associated follicular bronchiolitis

HIV associated follicular bronchiolitis is a form of bronchiolitis that occurs in those with HIV. Epidemiology It has been described in both HIV-positive children and adults. Pathology It is manifested by bronchial-associated lymphoid tissue hyperplasia thought to be due to repetitive antige...
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HIV associated neoplasms

HIV-associated neoplasms are numerous and can be broadly divided into two groups: AIDS-defining malignancies associated but not AIDS defining malignancies AIDS-defining malignancies The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4: Ka...
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Hodgkin lymphoma (pulmonary manifestations)

Pulmonary manifestations of Hodgkin lymphoma are relatively rare, present in  5-12% of patients at the time of diagnosis. It is relatively more common with the nodular sclerosing subtype. Pulmonary involvement usually indicates stage IV disease.  Radiographic features Bilateral involvement is ...
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Hoffman-Rigler sign (heart)

The Hoffman-Rigler sign is a sign of left ventricular enlargement inferred from the distance between the inferior vena cava (IVC) and left ventricle (LV).​ Radiographic features On a lateral chest radiograph, if the distance between the left ventricular border and the posterior border of IVC e...
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Holly leaf sign

The holly leaf sign refers to the appearance of pleural plaques on chest x-rays. Their irregular thickened nodular edges are likened to the appearance of a holly leaf.
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Holt-Oram syndrome

Holt-Oram syndrome (HOS) is an autosomal dominant syndrome that results in congenital heart defects and upper limb anomalies:  congenital heart defects  atrial septal defect (ASD) (commonest cardiac defect 4) ventricular septal defect (VSD) aortic coarctation upper limb abnormalities radia...
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Honeycombing (lungs)

Honeycombing is a CT imaging descriptor referring to clustered cystic air spaces (between 3-10 mm in diameter but occasionally as large as 2.5 cm) which are usually subpleural and basal in distribution. They can be subdivided into: microcystic honeycombing: macrocystic honeycombing The walls ...
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Horizontal fissure

The horizontal fissure (also called the minor fissure) is a unilateral structure in the right lung that separates the right middle lobe from the right upper lobe. Gross anatomy The horizontal fissure arises from the right oblique fissure and follows the 4th intercostal space from the sternum u...
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Horseshoe lung

Horseshoe lung is one of the rare congenital anomalies of the lung. A band of pulmonary parenchyma is formed extending between the right and left lungs. The pulmonary tissue can be seen either anterior to the aorta or posterior to the pericardium at the caudal end. Pathology Associations card...
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Hospital acquired pneumonia

Hospital-acquired pneumonia (HAP) or nosocomial pneumonia is defined by the American Thoracic Society (ATS) guidelines as pneumonias that occur more than 48 hours after hospital administration but were not present at the time of admission. Epidemiology It can be a common cause of pneumonia in ...
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Hot tub lung

Hot tub lung refers to pulmonary disease in otherwise healthy patients that can occur by secondary exposure to aerosolized non-tuberculous mycobacteria in contaminated hot water-steam (classically described in hot tubs, hence the name).  Clinical presentation It can present as an acute pulmona...
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Hybrid lesion (paediatric chest)

A hybrid lesion in paediatric chest radiology refers to a combination of a congenital pulmonary airways malformation (CPAM) and a pulmonary sequestration (most commonly extralobar). It falls under a type of bronchopulmonary foregut malformation. Due to more sophisticated imaging, they are increa...
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Hydatid cyst signs

There are several signs of hydatid cysts seen associated with hydatid disease: cumbo sign: air is seen between the pericyst and the laminated membrane of the cyst  serpent sign: internal rupture of the cyst with collapse of membranes of the parasite into the cyst spin sign / whirl sign: detac...
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Hydatid disease

Hydatid cysts result from infection by the Echinococcus, and can result in cyst formation anywhere in the body.  Pathology There are two main species of the Echinococcus tapeworm 1,2: Echinococcus granulosus commoner pastoral: dog is a main host; most common form sylvatic: wolf is a main h...
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Hydropneumothorax

Hydropneumothorax is a term given to the concurrent presence of a pneumothorax as well as a hydrothorax (i.e. air and fluid) in the pleural space. Pathology It may arise in various situations which include thoracentesis 1-2 thoracic trauma bronchopleural fistula oesophagopleural fistula R...
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Hyparterial bronchus

A hyparterial bronchus is any bronchus originating inferior to the level of the pulmonary artery. Conversely, the right superior lobar bronchus can be referred to by its anatomical relationship to the pulmonary arteries as being eparterial. The term may be encountered in the classification of ...
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Hyperattenuating pulmonary abnormalities

Hyperattenuating pulmonary abnormalities can result from a variety of processes and have varied radiographic appearances. It is easiest, for the purposes of radiology, to divide them into:  hyperdense linear or reticular opacities hyperdense pulmonary nodules hyperdense pulmonary mass hyperd...
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Hypercontracting (nutcracker) oesophagus

Hypercontracting (nutcracker) oesophagus is a motility disorder of the oesophagus. This condition is primarily diagnosed with manometry with high intra-oesophageal pressure and normal peristalsis. Most patients will have a normal barium swallow.  Hypercontracting oesophagus ("nutcracker oesopha...
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Hyperdense pulmonary mass

There are only a few causes of a pulmonary mass with internal calcification. They include:  granuloma: most common pulmonary hamartoma bronchogenic carcinoma carcinoid tumours pulmonary metastases mucoid calcification of mucinous adenocarcinoma: breast carcinoma gastrointestinal tract ad...
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Hyperdense pulmonary nodules

Hyperdense pulmonary nodules are a subset of pulmonary nodules that have relatively increased attenuation, usually caused by calcification within the nodule. Here, we broadly refer to a nodule as a pulmonary opacity <30 mm. Differential diagnosis calcified pulmonary nodules are a specific grou...
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Hyper IgE syndrome

Hyperimmunoglobulin E (hyper IgE) syndrome (HIES), also known as Job syndrome, consists of a heterogeneous group of complex hereditary combined B- and T-cell immune deficiency diseases characterised by recurrent Staph aureus chest infections, characteristic coarse facial appearance and dental pr...
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Hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, represents a group of pulmonary disorders mediated by an inflammatory reaction to inhalation of an allergen. These may be organic or inorganic particles (microbes, animal or plant proteins, and certain chemicals) tha...
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Hypogammaglobulinaemia

Hypogammaglobulinaemia is an immune disorder characterised by a reduction in all types of gammaglobulins.  Terminology While hypogammaglobulinaemia means some of loss of gammaglobulins, a total loss is termed agammaglobulinaemia which can occur in as an x linked form - X-linked agammaglobuline...
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Ichikado CT scoring of acute respiratory distress syndrome

CT scoring systems have been proposed in patients with acute respiratory distress syndrome (ARDS) to predict clinical outcomes. This scoring system was established by Ichikado et al. in 2006 2 and at the time of writing (July 2016), this is the most widely used CT scoring system. Classification...
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Idiopathic dilatation of the pulmonary trunk

Idiopathic dilatation of the pulmonary trunk is a rare congenital anomaly comprising of pulmonary trunk enlargement with or without dilatation of the right and left pulmonary arteries. For this diagnosis, exclusion of pulmonary and cardiac diseases (mainly pulmonary valve stenosis) and confirma...
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Idiopathic giant bullous emphysema

Idiopathic giant bullous emphysema, also known as vanishing lung syndrome (VLS), is characterised by giant emphysematous bullae, which commonly develop in the upper lobes and occupy at least one-third of a hemithorax. It is a progressive condition that is also associated with several forms of em...
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Idiopathic interstitial pneumonia (mnemonic)

Idiopathic interstitial pneumonias (IIPs) are diffuse interstitial lung diseases of unknown cause. A useful mnemonic for the American Thoracic Society-European Respiratory Society (ATS-ERS) classification of IIPs is: All Idiopathic Chronic Lung Disease aRe Nonspecifically Patterned The mnemoni...
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Idiopathic interstitial pneumonias

Idiopathic interstitial pneumonias (IIPs) are diffuse interstitial lung diseases of unknown cause. They are characterized by cellular infiltration of the interstitial compartment of the lung with varying degrees of inflammation and fibrosis. Classification For many years many attempts have bee...
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Idiopathic interstitial pneumonias: HRCT chest approach

The approach to HRCT chest in patients with suspected idiopathic interstitial pneumonia (IIP) is with the aim to: make sure an appropriate study requested i.e. HRCT chest with optimal individually adjusted protocol and ensure adequacy of the HRCT chest quality (see imaging protocol below) meti...
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Idiopathic pauci immune pulmonary capillaritis

Idiopathic pauci immune pulmonary capillaritis (IPIPC) is considered a rare type of pulmonary vasculitis. Some authors consider this due be an organ specific subset of microscopic polyangiitis 3. It can result in diffuse alveolar haemorrhage. Pathology It is an isolated small vessel vasculitis...
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Idiopathic pneumonia syndrome

Idiopathic pneumonia syndrome (IPS) refers to diffuse lung injury which can occur following haematopeotic stem cell transplantation where neither an infectious nor non-infectious aetiology can be found. Epidemiology The incidence of IPS is thought to be around 12% following haematopoetic stem ...
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Idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a clinical syndrome and considered the most common and the most lethal form of pulmonary fibrosis corresponding to the histologic and imaging pattern of UIP. It is more common in middle age or elderly men and diagnosed by:  histological or imaging pattern ...
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Idiopathic pulmonary haemosiderosis

Idiopathic pulmonary haemosiderosis (IPH) is an uncommon form of pulmonary haemosiderosis. It is characterised by the triad of haemoptysis iron deficiency anaemia diffuse pulmonary infiltrates, usually represented by diffuse pulmonary haemorrhage The diagnosis is usually made by exclusion 1....
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Idiopathic pulmonary ossification

Idiopathic pulmonary ossification (also known as bony metaplasia of lung) is a rare disorder with unknown cause characterised by bony tissue within the lung. Clinical presenation The condition is asymptomatic but mild symptoms, restrictive pulmonary physiology, and impaired transfer factor hav...
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IgG4-related disease

IgG4-related disease (IgG4-RD) is a systemic disease that is characterised by extensive IgG4-positive plasma cells and T-lymphocyte infiltration of various organs. Terminology This condition has been known by many other names in the past, such as IgG4-related sclerosing disease, IgG4-related s...
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IgG4-related lung disease

IgG4-related lung disease is a recently described condition. It may occur with or without systemic involvement. It is considered part of the spectrum of IgG4-related disease. Radiographic features CT On HRCT of the chest, it may be categorised into four major subtypes 5: solid nodular subtyp...
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Immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) is paradoxical deterioration of a pre-existing illness following abrupt improvement in an individual's immune function. It is classically seen in HIV/AIDS patients following initiation of highly active anti-retroviral therapy (HAART). Increasing...
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Implantable loop recorder

Implantable loop recorders, also known as insertable cardiac monitors, are small insertable devices that continuously monitor and record cardiac rhythms. They are placed subcutaneously and used for the evaluation of patients with recurrent unexplained episodes of palpitations or syncope. They sh...
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Incidental lung nodules

Incidental lung nodules are encountered commonly in normal clinical practice on CT. The risk of developing cancer in very small nodules (<5 mm) is very low. However, clear-cut recommendations are still not in place with high variation in practice amongst reporting radiologists 1. As a result, it...
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Incomplete border sign

The incomplete border sign is useful to depict an extrapulmonary mass on chest radiograph. An extrapulmonary mass will often have a inner well-defined border and an ill-defined outer margin 1-3. This can be attributed to the inner margin being tangential to the x-ray beam and has good inherent ...
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Incomplete double aortic arch

Incomplete double aortic arch is a rare vascular ring anomaly wherein a segment of the minor aortic arch, usually the left, is atretic.  Clinical presentation As in the case of other vascular rings, this anomaly can cause 1: stridor wheezing dysphagia Some patients may reach adulthood with...
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Increased cardiothoracic ratio (summary)

This is a basic article for medical students and other non-radiologists Increased cardiothoracic ratio describes widening of the cardiac silhouette on a chest radiograph. This is only of use when making an assessment of a PA chest x-ray since the AP chest x-ray causes the artefactual magnificat...
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Increased retrosternal airspace

Increased retrosternal airspace is an indicator of hyperinflation of the lungs and is usually due to emphysema. The thickness of the space between the ascending aorta and the posterior margin of the sternum (3 cm inferior to the sternomanubrial joint) and is normally no more than 2.5 cm 1 altho...
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Infectious bronchiolitis

Infectious bronchiolitis refers to subtype of bronchiolitis where there is an definite infective precipitant. It falls under the subgroup in inflammatory bronchiolitides and by some authors is considered a type of cellular bronchiolitis 3. It tends to be more clinically severe in children than a...
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Inferior accessory fissure of the lung

The inferior accessory fissure of the lung, also known as Twining's line, divides the medial basal bronchopulmonary segment from the rest of the lower lobe. This accessory fissure is present in around 12% of people when examined with CT and is visible on 5-8% of frontal chest x-rays. It is appr...
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Inferior mediastinum

The inferior mediastinum is the box-shaped space in the mediastinum below the transthoracic plane of Ludwig between the wedge-shaped superior mediastinum above and the diaphragm and inferior thoracic aperture below. There are no physical structures that divide the superior and inferior mediastin...
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Inferior pulmonary ligament

The inferior pulmonary ligament (or just the pulmonary ligament) is a normal anatomical structure that is often seen on chest x-ray and CT chest.  Gross anatomy The inferior pulmonary ligament is a fused triangular-shaped sheet of parietal and visceral pleura that extends from the hilum to the...
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Inferior thoracic aperture

The inferior thoracic aperture connects the thorax with the abdomen. Gross anatomy The inferior thoracic aperture is irregular in shape and is more oblique and much larger than the superior thoracic aperture. The diaphragm occupies and closes the inferior thoracic aperture, thereby separating ...
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Inflammatory bowel disease (thoracic manifestations)

Thoracic manifestations of both ulcerative colitis and Crohn disease can be variable and cannot be used to differentiate between these entities. They can develop at any time with respect to the clinical onset of the underlying disease. Actually, they can also predate the colonic disease or deve...
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Inflammatory bronchiolitis

While the term bronchiolitis in itself implies "inflammation" of the bronchioles by definition, some authors group the term inflammatory bronchiolitis as a specific group in terms of imaging as distinct from the more fibrotic - constrictive type 1. Conditions that are described under this inclu...
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Inflammatory myofibroblastic tumour

Inflammatory myofibroblastic tumours (IMT), also known as plasma cell granulomas, are rare neoplasms that have a diverse spectrum of biological behaviour.  Terminology These tumours were previously referred as inflammatory pseudotumour.   Epidemiology They can occur at any age and there is c...
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Inflammatory myofibroblastic tumour of the lung

Inflammatory myofibroblastic tumours of the lungs are a location-specific type of inflammatory myofibroblastic tumours. Epidemiology They are very rare with their incidence reported at approximately 0.04-1% of all the pulmonary neoplasms 1. While it can affect any age group, around 25% of case...
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Infusothorax

Infusothorax is a complication of central venous catheter malposition where the catheter tip is located in the pleural space and the infusion of the fluid collects inadvertantly in the pleural space in the form of a pleural effusion. Longer term complications depend on the fluid being infused.
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Innermost intercostal muscles

The innermost intercostal muscles are muscles of respiration. They are the deepest intercostal muscles located in the intercostal spaces, and contract along with the internal intercostal muscles to reduce the transverse dimension of the thoracic cavity during expiration. Gross anatomy The inne...
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Innominate artery compression syndrome

Innominate artery compression syndrome, also known as brachiocephalic artery compression syndrome, is a rare cause of tracheal stenosis that occurs in the paediatric population. Pathology It can only occur in the presence of an aberrantly positioned thymus that forces the aortic arch or innomi...
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Inorganic dust

Inorganic dust types are derived from mineral rather than biological elements (organic compounds). Inhalation of these dusts may result in lung disease (pneumoconiosis), often after years of cumulative exposure. The commonest inhaled dusts that cause disease are asbestos, silica and coal dust. ...
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Intercostal catheter

The intercostal catheter (ICC or chest tube) is a tube inserted into the pleural space to drain gas or fluid. It is mainly inserted to treat pneumothorax. Indication The indications are wide and can include 1: pneumothorax chest trauma pleural effusion haemothorax chylothorax bronchopleu...
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Intercostal lung hernia

Intercostal lung hernia is defined as protrusion of the lung beyond the confines of the thoracic cage. It is an uncommon entity. Clinical presentation Hernias which are symptomatic may cause dyspnoea, chest wall pain or a visible or palpable chest bulge (most common in intercostal lung hernias...
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Intercostal muscles

The intercostal muscles are an important group of muscles in the intercostal spaces (between the ribs) that contract during respiration. Three muscles are classically described, from superficial to deep: external intercostal muscles internal intercostal muscles innermost intercostal muscles ...
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Intercostal nerve

The intercostal nerves are the somatic nerves that arise from the anterior divisions of the thoracic spinal nerves from T1 to T11. These nerves in addition to supplying the thoracic wall also supply the pleura and peritoneum. Gross anatomy Intercostal nerves can be divided into atypical and ty...
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Intercostal nerve neurilemmoma

Intercostal nerve neurilemmomas, also known as intercostal nerve schwannoma or neurinoma, are nerve sheath encapsulated tumours affecting intercostal nerves.   Please refer to the article on schwannomas for a broad discussion about these tumours.  Epidemiology They account for less than 10% o...
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Intercostal spaces

The intercostal spaces are the space between the ribs. There are 11 spaces on each side and they are numbered according to the rib which is the superior border of the space.  Gross anatomy The intercostal spaces contain three layers of muscle: the external, internal and innermost layers with t...
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Interface sign (HRCT chest)

The interface sign is a feature seen on HRCT chest imaging and refers to the presence of irregular interfaces at the margins of pulmonary parenchymal structures or the pleural surface of the lung. It suggests interstitial thickening.
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Interlobular septa

The interlobular septa (sing: septum) are located between the secondary pulmonary lobules and are continuous with both the subpleural interstitium (peripheral connective tissue) and the peribronchovascular interstitium (axial connective tissue) as well as the more delicate intralobular septa. T...
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Interlobular septal thickening

There are many causes of interlobular septal thickening, and this should be distinguished from intralobular septal thickening. Thickening of the interlobular septa can be smooth, nodular or irregular, with many entities able to cause more than one pattern. Pathology Causes of septal thickening...
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Internal intercostal muscle

The internal intercostal muscles are important muscles of respiration. They number eleven on each side and are located in the intercostal spaces, reducing the transverse dimension of the thoracic cavity during expiration. Gross anatomy The internal intercostal muscles are the middle muscle of ...
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Internal thoracic artery

The internal thoracic artery (previously called the internal mammary artery) supplies the anterior body wall and its associated structures from the clavicles to the umbilicus.  Gross anatomy Origin The internal thoracic artery arises from the first part of the subclavian artery in the base of...
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Interstitial lung disease

Diffuse interstitial lung disease encompasses a large number of disorders that are characterised by cellular infiltrates in a periacinar location. While some disease processes may cause significant injury to the underlying lung parenchyma (e.g. usual interstitial pneumonia), some do not (e.g. pu...
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Interstitial lung pattern

An interstitial lung pattern is a regular descriptive term used when reporting a plain chest radiograph. It is the result of the age-old attempt to make the distinction between an interstitial and airspace (alveolar) process to narrow the differential diagnosis. A re-read of the timeless work o...
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Interstitial thickening (lung)

Interstitial thickening is pathological thickening of the pulmonary interstitium and can be divided into: interlobular septal thickening intralobular septal thickening See also interlobular septa secondary pulmonary lobules HRCT terminology
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Intralobular septa

The intralobular septa (sing: septum) are delicate strands of connective tissue separating adjacent pulmonary acini and primary pulmonary lobules. They are continuous with the interlobular septa which surround and define the secondary pulmonary lobules.  See also HRCT terminology
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Intralobular septal thickening

Intralobular septal thickening is a form of interstitial thickening and should be distinguished from interlobular septal thickening. It is often seen as fine linear or reticular thickening.  It has been described with any conditions of variable aetiology which include sarcoidosis 2 asbestosis...
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Intrapleural space

The intrapleural or pleural space is the fluid-filled space in between the parietal and visceral layers of the pleura. In normal conditions it contains only a small amount of serous pleural fluid. Related pathology A pleural effusion is the pathological accumulation of pleural fluid, and when ...
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Intrapulmonary lipoma

Intrapulmonary lipomas are rare fat containing benign lung lesions. Epidemiology They mostly occur in the adult population, with occurence in the paediatric population extremely rare. Pathology As with all lipomas they are composed of adipose tissue. The origin of the peripheral intrapulmona...
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Intrapulmonary lymph nodes

Intrapulmonary lymph nodes are a type of intrathoracic lymph nodes. They can be quite common on routine CT examinations of healthy patients. Subtypes perifissural lung nodules 2 Radiographic features CT: HRCT chest around 6 mm in size (usually reported range around 3-8.5 mm) 1 most tend to...
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Intra-thoracic sarcoma

Sarcomatoid neoplasms involving the chest comprise of a broad group of tumours that occur in the lung, mediastinum, pleura, and chest wall. These tumours have mesenchymal component. They include primary sarcomatoid tumours of the chest usually arising from the chest wall Ewing sarcoma of the...
Article

Invasive aspergillosis

Invasive aspergillosis is a form of pulmonary aspergillosis seen in patients with decreased immunity. It comprises a number of entities that are discussed individually: subacute invasive pulmonary aspergillosis (previously known as chronic necrotising aspergillosis (CNA) or semi-invasive asperg...
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Invasive mucinous adenocarcinoma of the lung

Invasive mucinous adenocarcinoma of the lung is a subtype of invasive adenocarcinoma of the lung. It was formerly known as mucinous bronchoalveolar carcinoma. Terminology In 2011, the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European ...
Article

Investigation of haemoptysis (summary)

This is a basic article for medical students and other non-radiologists. Haemoptysis is the coughing up of frank blood or blood-stained mucus/pus from the lungs and it is an important indicator of pathology. Careful assessment of history, clinical examination and investigations will help elicit...
Article

Investigation of pleuritic chest pain (summary)

This is a basic article for medical students and other non-radiologists Pleuritic chest pain is chest pain that is precipitated by movement or forceful breathing and tends to be sharp in nature. It is often accompanied by a perception of dyspnoea which may be secondary to suppression of respira...
Article

Isolated unilateral absence of pulmonary artery

Isolated unilateral absence of the pulmonary artery (IUAPA) is the congenital absence of the left or right pulmonary artery.  When found in combination with other congenital vascular abnormalities it is known as unilateral absence of the pulmonary artery (UAPA). Epidemiology Unilateral absence...
Article

Isomerism

Isomerism is a term which in general means 'mirror-image'. It is used in the context of heterotaxy and is of two types: left isomerism right isomerism Left isomerism Mirror image of the structures on the left side of the chest along the left-right axis of the body, i.e. patients with isomeri...
Article

Juxtaphrenic peak sign

The juxtaphrenic peak sign, also known as diaphragmatic tenting or Kattan sign, refers to the peaked or tented appearance of a hemidiaphragm which can occur in the setting of lobar collapse. It is caused by retraction of the lower end of diaphragm at an inferior accessory fissure (most common 1)...
Article

Kaposi sarcoma

Kaposi sarcoma is a low-to-intermediate grade mesenchymal tumour that involves the lymphovascular system. The tumour can involve the pulmonary, gastrointestinal, cutaneous and musculoskeletal systems. Pathology There are four recognised variants 1: classic (chronic): multiple distal lower ext...
Article

Kartagener syndrome

Kartagener syndrome is a subset of primary ciliary dyskinesia, an autosomal recessive condition characterised by an abnormal ciliary structure or function, leading to impaired mucociliary clearance.  Epidemiology The prevalence of primary ciliary dyskinesia is approximately 1 in 12,000-60,000 ...
Article

Kerley lines in the exam

Getting a film with Kerley lines in the exam is one of the many exam set-pieces that can be prepared for. The film goes up and after a couple of seconds pause, you need to start talking: CXR There are bilateral basal interstitial lines that extend to the pleural surface - these are septal (Ke...
Article

Kirklin sign

The Kirklin sign refers to a deformity of the normal gastric bubble on an upright chest radiograph due to a mass lesion of the gastric cardia or fundus. The differential for a Kirklin sign includes: gastric tumour gastric carcinoma oesophageal carcinoma gastrointestinal stromal tumour (GIST...
Article

Klebsiella pneumonia

Klebsiella pneumonia, also known as Friedländer pneumonia, refers to pneumonia resulting from an infection from the organism Klebsiella pneumoniae.  Epidemiology There tends to be a higher prevalence in older patients with alcoholism and debilitated hospitalised patients 3. Pathology Klebsie...
Article

Knuckle sign (pulmonary embolism)

Knuckle sign refers to the abrupt tapering or cutoff of a pulmonary artery secondary to embolus. It is better visualised on CT pulmonary angiography scan than chest x-ray. This is an important ancillary finding in pulmonary embolism (PE), and often associated with the Fleischner sign of dilated ...
Article

Kveim Stilzbach skin test

The Kveim Stilzbach skin test is a sensitive and specific test for sarcoidosis, requiring the intradermal injection of homogenized spleen or liver material from a patient with known sarcoidosis. In patients with sarcoidosis, a typical sarcoid granuloma will develop at the injection site within 4...

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