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.

1,922 results found
Article

Melioidosis

Melioidosis is an infectious disease caused by the bacterium Burkholderia pseudomallei (previously known as Pseudomonas pseudomallei) and is a multisystem disorder which may affect the lungs, brain, visceral organs, or musculoskeletal system. Epidemiology Melioidosis is a disease of the monsoo...
Article

Steeple sign (trachea)

The steeple sign, also called the wine bottle sign, refers to the tapering of the upper trachea on a frontal chest radiograph reminiscent of a church steeple. The appearance is suggestive of croup, which should be obvious clinically. A corresponding lateral x-ray would show narrowing of the subg...
Article

Rib notching

Rib notching refers to deformation of the superior or inferior surface of the rib. It can affect a single rib (from trauma or solitary masses e.g. schwannoma) or can affect multiple ribs. Differential diagnosis The differentials differ according to whether it is the superior or inferior surfac...
Article

Tree-in-bud sign (lung)

Tree-in-bud sign or pattern describes the CT appearance of multiple areas of centrilobular nodules with a linear branching pattern. Although initially described in patients with endobronchial tuberculosis, it is now recognized in a large number of conditions. Pathology Pathogenesis Simply put...
Article

Sarcoidosis (thoracic manifestations)

Pulmonary and mediastinal involvement of sarcoidosis is extremely common, seen in over 90% of patients with sarcoidosis. Radiographic features are variable depending on the stage of the disease.  For a general discussion, please refer to the parent article: sarcoidosis. Epidemiology Pulmonary...
Article

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...
Article

Cystic lung disease

Cystic lung disease is an umbrella term used to group the conditions coursing with multiple lung cysts.  Clinical presentation The clinical presentation is an important clue to the differential diagnosis of cystic lung diseases 12. Diseases that present with insidious dyspnea or spontaneous p...
Article

Pulmonary Langerhans cell histiocytosis

Pulmonary Langerhans cell histiocytosis (PLCH) may be seen as part of widespread involvement in patients with disseminated Langerhans cell histiocytosis or more frequently as a distinct entity in young adult smokers. This article focuses on the latter.  Epidemiology Pulmonary Langerhans cell h...
Article

Asbestosis

Asbestosis refers to later development of diffuse interstitial fibrosis secondary to asbestos fiber inhalation and should not be confused with other asbestos related diseases. Epidemiology Asbestosis typically occurs 10-15 years following the commencement of exposure to asbestos and is dose re...
Article

Tracheomalacia (differential)

A dilated trachea has numerous causes, and in almost all cases represents tracheomalacia (increased size and increased compliance). As is almost always the case, various diameters have been used. Typical figures include >26 mm in men, >23 mm in women or >3 cm for both genders. Although many of...
Article

Thoracic sarcoidosis (staging)

Thoracic sarcoidosis can be staged on a chest radiograph with implications for prognosis although HRCT and FDG-PET provide more information to help guide treatment.   Usage Chest radiographs have been the mainstay of staging thoracic sarcoidosis for many decades with fair interobserver concord...
Article

Unilateral hypertranslucent hemithorax

Unilateral hypertranslucent hemithorax has many potential causes. It may be the result of rotation away from an optimal position or because of pathology. Rotation A unilateral hypertranslucent hemithorax may be caused by the positioning of the patient. Rotation away from the radiation beam alt...
Article

Peripheral lung opacities (mnemonic)

Mnemonics for peripheral lung opacities seen on chest x-ray or CT are useful to remember differentials. Examples include: AEIOU SIC CUE Mnemonics AEIOU A: alveolar sarcoidosis E: eosinophilic pneumonia I: infarction O: organizing pneumonia (including COP) U: usual interstitial pneumonit...
Article

Pneumothorax in supine projection

A pneumothorax does not display classical signs when a patient is positioned supine for a chest radiograph as commonly occurs in acute trauma or the critical care setting. Of course, pneumothoraces are common in both these scenarios and even relatively small pneumothoraces may be significant due...
Article

Solitary pulmonary nodule

Solitary pulmonary nodule (SPN) is defined as a relatively well defined round or oval pulmonary parenchymal lesion equal to or smaller than 30 mm in diameter. It is surrounded by pulmonary parenchyma and/or visceral pleura and is not associated with lymphadenopathy, atelectasis, or pneumonia 9. ...
Article

CT angiogram sign (lungs)

The CT angiogram sign refers to vessels appearing prominent on contrast-enhanced CT as they traverse an airless low attenuation portion of consolidated lung 1,2. This sign has been associated with 1,2: lung adenocarcinoma 3 pulmonary lymphoma infectious and post-obstructive pneumonia
Article

Flat waist sign

The flat waist sign refers to flattening of the left heart border, specifically the contours of the aortic arch and adjacent pulmonary trunk. It is seen in severe left lower lobe collapse and is caused by leftward displacement and rotation of the heart. It is different to the straight left hear...
Article

Hydatid disease

Hydatid cysts result from infection by the Echinococcus tapeworm species and can result in cyst formation anywhere in the body. Epidemiology Cystic echinococcosis has a worldwide geographical distribution. The Mediterranean basin is an important endemic area 6,7. Pathology There are two main...
Article

Pedunculated intratracheal mass

A pedunculated intratracheal mass has a variety of differential diagnoses: benign tumor, e.g. hamartoma, chondroma, lipoma hemangioma inspissated mucus metastasis to tracheal mucosa, e.g. renal cell carcinoma, melanoma polyp, e.g. inflammatory, antrochoanal papilloma post-intubation trach...
Article

Pneumomediastinum

Pneumomediastinum is the presence of extraluminal gas within the mediastinum. Gas may originate from the lungs, trachea, central bronchi, esophagus, and peritoneal cavity and track from the mediastinum to the neck or abdomen. Terminology In the setting of trauma, if pneumomediastinum is visibl...
Article

Pulmonary hamartoma

Pulmonary hamartomas (alternative plural: hamartomata) are benign neoplasms composed of cartilage, connective tissue, muscle, fat, and bone. It is one of the most common benign tumors of the lung and accounts for ~8% of all lung neoplasms and 6% of solitary pulmonary nodules. Terminology Pulmo...
Article

Pneumothorax

Pneumothorax, sometimes abbreviated to PTX, (plural: pneumothoraces) refers to the presence of gas (often air) in the pleural space. When this collection of gas is constantly enlarging with resulting compression of mediastinal structures, it can be life-threatening and is known as a tension pneu...
Article

Subcutaneous emphysema

Subcutaneous emphysema (also known commonly, although less correctly, as surgical emphysema), strictly speaking, refers to gas in the subcutaneous tissues. But the term is generally used to describe any soft tissue emphysema of the body wall or limbs since the gas often dissects into the deeper ...
Article

Thoracic aortic stenosis (differential)

The differential for thoracic aortic stenosis includes: atherosclerosis aortitis (especially Takayasu arteritis) radiotherapy coarctation pseudocoarctation Williams syndrome: supravalvular aortic stenosis congenital rubella syndrome: supravalvular aortic stenosis
Article

Thoracic aortic dilatation (differential)

There is a broad differential for thoracic aortic dilatation. Differential diagnosis senile ectasia hypertension post-stenotic dilatation, e.g. bicuspid aortic valve thoracic aortic aneurysm atherosclerosis (usually descending thoracic aorta) collagen disorders Marfa...
Article

Granulomatosis with polyangiitis

Granulomatosis with polyangiitis (GPA), previously known as Wegener granulomatosis, is a multisystem necrotizing non-caseating granulomatous c-ANCA positive vasculitis affecting small to medium-sized arteries, capillaries, and veins, with a predilection for the respiratory system and kidneys. T...
Article

Water-lily sign (hydatid cyst)

The water-lily sign, also known as the camalote sign, is seen in hydatid infections when there is detachment of the endocyst membrane which results in floating membranes within the pericyst that mimic the appearance of a water lily. It is classically described on plain radiographs (mainly chest...
Article

Upper lobe bronchiectasis

Distribution of bronchiectasis can help in narrowing the differential diagnosis. Upper lobe bronchiectasis is typically seen in: cystic fibrosis tuberculosis Rarely it may be seen with non-tuberculous mycobacterial infection (e.g. MAC infection 2). Traction bronchiectasis in the upper lobes c...
Article

Tuberous sclerosis

Tuberous sclerosis (TS), also known as tuberous sclerosis complex (TSC) or Bourneville disease, is a phakomatosis (neurocutaneous disorder) characterized by the development of multiple benign tumors of the embryonic ectoderm (e.g. skin, eyes, and nervous system). Epidemiology Tuberous sclerosi...
Article

Tuberculosis

Tuberculosis (commonly abbreviated to TB, short for tubercle bacillus) encompasses an enormously wide disease spectrum affecting multiple organs and body systems predominantly caused by the organism Mycobacterium tuberculosis. A small proportion can also be caused by Mycobacterium bovis.  Epide...
Article

Transient tachypnea of the newborn

Transient tachypnea of the newborn, also known as retained fetal fluid or wet lung disease, presents in the neonate as tachypnea for the first few hours of life, lasting up to one day. The tachypnea usually resolves within 48 hours.  Epidemiology Transient tachypnea is one of the most common c...
Article

Tracheal masses

The differential for tracheal masses can be rather wide. For a single mass consider: metastasis  direct invasion from adjacent organ (lung, thyroid, esophagus and larynx) distant metastasis (e.g. melanoma, breast, renal, and colon cancer)  primary neoplasms squamous cell carcinoma: commone...
Article

Tracheal diverticulum

Tracheal diverticula, also known as tracheoceles, are usually an incidental finding. Occasionally it may mimic pneumomediastinum, so-called pseudopneumomediastinum. Terminology There is an overlap in the use and description of the terms paratracheal air cyst and a tracheal diverticulum in the ...
Article

Thoracic outlet syndrome

Thoracic outlet syndrome refers to a group of clinical syndromes caused by congenital or acquired compression of the brachial plexus or subclavian vessels as they pass through the superior thoracic aperture 11.  Clinical presentation Clinical presentation will depend on the structure compresse...
Article

Thoracic aortic injury

Thoracic aortic injury is the most common type of traumatic aortic injury and is a critical life-threatening, and often life-ending event.  Clinical presentation Approximately 80% of patients with thoracic aortic injury die at the scene of the trauma. In those who make it to hospital, clinical...
Article

Takayasu arteritis

Takayasu arteritis (TAK), also known as idiopathic medial aortopathy or pulseless disease, is a granulomatous large vessel vasculitis that predominantly affects the aorta and its major branches. It may also affect the pulmonary arteries. The exact cause is not well known but the pathology is tho...
Article

String of pearls sign (disambiguation)

String of pearls sign can refer to: string of pearls sign on an abdominal radiograph of fluid-filled dilated small bowel loops string of pearls sign on cerebral MRI in deep border zone infarction string of pearls sign on ultrasound in polycystic ovarian syndrome string of pearls sign for ang...
Article

Straight back syndrome

Straight back syndrome refers to decreased thoracic kyphosis ("flattening") and decreased anteroposterior thoracic diameter, such that there is compression of cardiovascular or bronchial structures.  It should not be confused with flat back syndrome, which refers to decreased lumbar lordosis, o...
Article

Stanford classification of aortic dissection

The Stanford classification, along with the DeBakey classification, is used to separate aortic dissections into those that need surgical repair, and those that usually require only medical management 7. Both the Stanford and DeBakey systems can be used to describe all forms of an acute aortic s...
Article

Situs inversus

Situs inversus, (rare plural: sitūs inversi) short form of the Latin “situs inversus viscerum”, is a term used to describe the inverted position of chest and abdominal organs. Terminology The condition is called situs inversus totalis when there is a total transposition of abdominal and thorac...
Article

Situs classification

Situs classification (plural: sitūs) or body situs can be a daunting topic, but it falls into three main groups: situs solitus: the normal configuration of thoracic and abdominal organs situs inversus: mirror image of the normal configuration situs ambiguus (heterotaxy): an intermediate confi...
Article

Signet ring sign

The signet ring sign is seen in bronchiectasis when the dilated bronchus and accompanying pulmonary artery branch are seen in cross-section. The bronchus and artery should be the same size, whereas in bronchiectasis, the bronchus is markedly dilated. The signet ring analogy has also been applie...
Article

Scleroderma

Scleroderma, also known as systemic sclerosis, is an autoimmune connective tissue disorder characterized by multisystem fibrosis and soft tissue calcification. As such, it affects many separate organ systems, which are discussed separately: musculoskeletal manifestations of scleroderma pulmona...
Article

Scimitar syndrome (lungs)

Scimitar syndrome, also known as hypogenetic lung syndrome, is characterized by a hypoplastic lung that is drained by an anomalous pulmonary vein into the systemic venous system. It is a type of partial anomalous pulmonary venous return and is one of the several findings in congenital pulmonary ...
Article

Sarcoidosis

Sarcoidosis is a non-caseating granulomatous multisystem disease with a wide range of clinical and radiographic manifestations.  Individual systemic manifestations are discussed in respective articles:  pulmonary and mediastinal manifestations cardiac manifestations  musculoskeletal manifest...
Article

Saber-sheath trachea

Saber-sheath trachea refers to a diffuse coronal narrowing of the intrathoracic portion of the trachea with the concomitant widening of the sagittal diameter. It is not uncommon and is pathognomonic for chronic obstructive pulmonary disease (COPD) 1.  The sagittal:coronal diameter is over 2:1 2...
Article

Superior vena caval duplication

Superior vena caval (SVC) duplication is the most common form of a left-sided SVC, where the normal right-sided SVC remains. The right SVC, however, can be smaller in approximately two-thirds of such cases 3. Pathology Results from failure of the embryonic left anterior cardinal vein to regres...
Article

Reverse bat wing pulmonary opacities

Reverse bat wing pulmonary opacities refer to peripheral opacities of the lungs, sparing the perihilar region. It is a relatively unusual appearance with a fairly narrow differential 1: chronic eosinophilic pneumonia organizing pneumonia (formerly bronchiolitis obliterans with organizing pneum...
Article

Pulmonary interstitial emphysema

Pulmonary interstitial emphysema (PIE) refers to the abnormal location of gas within the pulmonary interstitium and lymphatics usually due to positive pressure ventilation. It typically results from rupture of overdistended alveoli following barotrauma in infants with respiratory distress syndro...
Article

Pulmonary edema grading

One pulmonary edema grading based on chest radiograph appearances and pulmonary capillary wedge pressure (PCWP) is as follows: grade 0: normal chest radiograph, PCWP 8-12 mmHg grade 1: shows evidence of upper lobe diversion on a chest radiograph, PCWP 13-18 mmHg grade 2: shows interstitial ed...
Article

Pulmonary embolism

Pulmonary embolism (PE) refers to embolic occlusion of the pulmonary arterial system. The majority of cases result from thrombotic occlusion, and therefore the condition is frequently termed pulmonary thromboembolism which is what this article mainly covers. Non-thrombotic pulmonary emboli sour...
Article

Pulmonary arteriovenous malformation

Pulmonary arteriovenous malformations (PAVMs) are rare vascular anomalies of the lung, in which abnormally dilated vessels provide a right-to-left shunt between the pulmonary artery and vein. They are generally considered direct high flow, low-resistance fistulous connections between the pulmona...
Article

Pulmonary artery stenosis types

A pulmonary arterial stenosis refers to a narrowing of the pulmonary artery or pulmonary trunk can be classified into several types 1,2: type I: involving main pulmonary artery (pulmonary trunk) type II: involving bifurcation type III: multiple peripheral stenoses type IV: central and periph...
Article

Pulmonary sequestration

Pulmonary sequestration, also called accessory lung, refers to the aberrant formation of segmental lung tissue that has no connection with the bronchial tree or pulmonary arteries. It is a bronchopulmonary foregut malformation (BPFM). There are two types: intralobar sequestration (ILS) extral...
Article

Psammoma bodies

Psammoma bodies are round microscopic calcific collections. It is a form of dystrophic calcification. Necrotic cells form the focus for surrounding calcific deposition. They have a lamellated concentric calcified structure, sometimes large enough to be seen on CT.  Psammoma bodies are found in ...
Article

Pulmonary Pneumocystis jiroveci infection

Pulmonary Pneumocystis jiroveci infection, also known as Pneumocystis jiroveci pneumonia (PJP) or Pneumocystis pneumonia (PCP), is an atypical pulmonary infection and the most common opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). Terminology Classically, "P...
Article

Pleural mouse

A pleural mouse (plural: pleural mice), also known as a fibrin body is a 1-2 cm mobile rounded clump of fibrin left over after resolution of a pleural effusion 1.
Article

Phrenic nerve palsy

Phrenic nerve palsy (also known as phrenic nerve paresis or paralysis) has many causes and can be caused by lesions anywhere along the course of the phrenic nerve, as it travels from the neck, to pierce the diaphragm adjacent to the pericardium. Epidemiology No single demographic is affected, ...
Article

Pericardial calcification

Pericardial calcification is usually seen in individual patients with a history of pericarditis and may be associated with constrictive pericarditis.  Pathology Although historically infective pericarditis was the most common cause, a wide variety of insults can lead to calcification of the pe...
Article

Pectus excavatum

Pectus excavatum, also known as funnel chest or trichterbrust 13, is a congenital chest wall deformity characterized by concave depression of the sternum, resulting in cosmetic and radiographic alterations. Epidemiology It is the most common chest wall deformity, accounting for approximately 9...
Article

Paraganglioma

Paragangliomas, sometimes called glomus tumors, are rare neuroendocrine tumors arising from paraganglia.  Terminology Paraganglia are clusters of neuroendocrine cells dispersed throughout the body and closely related to the autonomic nervous system, with either parasympathetic or sympathetic f...
Article

Recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis, also known as squamous cell papillomatosis, refers to the occurrence of multiple squamous cell papillomas involving respiratory epithelium, most commonly in the larynx (laryngeal papillomatosis) and less commonly the trachea and bronchial tree (tracheobronch...
Article

Pancoast tumor

Pancoast tumor, also known as superior sulcus tumor, refers to a relatively uncommon situation where a primary lung cancer arises in the lung apex and invades the surrounding soft tissues. Classically a Pancoast syndrome results, but in actuality this is only seen in one quarter of cases.  Term...
Article

Pancoast syndrome

Pancoast syndrome (historically known as Ciuffini-Pancoast-Tobías syndrome, Hare syndrome or variation thereof) results from involvement of the brachial plexus and sympathetic chain by a Pancoast tumor or, less commonly, from other tumors - or even non-malignant disease - involving the lung apex...
Article

Paget-Schrötter syndrome

Paget-Schrötter syndrome, alternatively spelled Paget-Schroetter syndrome and also known as effort thrombosis, refers to primary thrombosis of the axillary and/or subclavian vein. It can be thought of as a venous equivalent of thoracic outlet syndrome (i.e. venous thoracic outlet syndrome). Epi...
Article

Esophageal stricture

Esophageal stricture refers to any persistent intrinsic narrowing of the esophagus.  Terminology The term peptic stricture refers specifically to those benign esophageal strictures caused by chronic acid reflux, although some - incorrectly - use it more loosely to refer to any benign esophagea...
Article

Esophageal and esophagogastric junction squamous cell carcinoma (staging)

Esophageal and esophagogastric junction squamous cell carcinoma staging refers to TNM staging of squamous cell carcinoma originating in the esophagus or esophagogastric junction (including tumors whose center is within the proximal 2 cm of the gastric cardia). Related histologies included in th...
Article

Esophageal carcinoma

Esophageal carcinoma is relatively uncommon. It tends to present with increasing dysphagia, initially to solids and progressing to liquids as the tumor increases in size, obstructing the lumen of the esophagus. Epidemiology Esophageal cancer is responsible for <1% of all cancers and 4-10% of a...
Article

Esophageal web

Esophageal webs refer to an esophageal constriction caused by a thin mucosal membrane projecting into the lumen. Epidemiology Esophageal webs tend to affect middle-aged females. Clinical presentation Patients are usually asymptomatic and the finding may be incidental and unimportant. However...
Article

Monod sign (lungs)

The Monod sign simply describes gas that surrounds a mycetoma (most commonly an aspergilloma) in a pre-existing pulmonary cavity 1-3. It should not be confused with the air crescent sign which is seen in recovering angioinvasive aspergillosis 4. The air crescent sign heralds improvement in the ...
Article

Mitral annular calcification

Mitral annular calcification refers to the deposition of calcium (along with lipid) in the annular fibrosa of the mitral valve. Epidemiology Annular calcification is seen in up to 35% of elderly patients. It is common in females over 65 years, in those with myxomatous degeneration of the mitra...
Article

Miliary opacities (lungs)

The term miliary opacities refers to innumerable, small 1-4 mm pulmonary nodules scattered throughout the lungs. It is useful to divide these patients into those who are febrile and those who are not. Additionally, some miliary opacities are very dense, narrowing the differential - see multiple...
Article

Middle lobe bronchiectasis

Middle lobe bronchiectasis is an imaging an imaging descriptor when bronchiectasis is confined to the middle lobe. When it (predominantly) involves the middle lobe it is sometimes is termed right middle lobe predominant (RMLP) bronchiectasis 2. Middle lobe bronchiectasis may be seen in: non-tu...
Article

Hemorrhagic intracranial metastases (mnemonic)

A mnemonic for primary malignancies responsible for hemorrhagic intracranial metastases is: MR CT BB MR CT HBO Mnemonic MR CT BB M: melanoma R: renal cell carcinoma C: choriocarcinoma T: thyroid carcinoma, teratoma B: bronchogenic carcinoma B: breast carcinoma MR CT HBO M: melanoma ...
Article

Lymphangitic carcinomatosis

Lymphangitic carcinomatosis, or lymphangitis carcinomatosa, is the term given to tumor spread through the lymphatics of the lung and is most commonly seen secondary to adenocarcinoma. Epidemiology The demographics will reflect that of the underlying malignancy (see below). Clinical presentati...
Article

Lung hernia

Lung hernias (alternative plural: herniae) are defined as a herniation of the lung beyond the confines of the thoracic cage. They are uncommon, mostly seen post trauma or thoracotomies.  Clinical presentation Hernias which are symptomatic may cause dyspnea, chest wall pain or a visible or palp...
Article

Lung abscess

Lung abscesses are circumscribed collections of pus within the lungs. They are often complicated to manage and difficult to treat and, in some cases, maybe life-threatening. Epidemiology As a result of the widespread availability of antibiotics, the incidence of lung abscesses has been dramati...
Article

Lung cancer (staging - IASLC 7th edition - superseded)

The IASLC (International Association for the Study of Lung Cancer) 7th edition lung cancer staging system was proposed in 2010 and has now been updated and superseded by the 8th edition, published in 2016. Small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) used to be staged di...
Article

Lower lobe bronchiectasis

The distribution of bronchiectasis can help in narrowing the differential diagnosis. Lower lobe bronchiectasis is the commonest zonal predilection in bronchiectasis 2. It is mostly idiopathic but can be typically seen in post infective bronchiectasis recurrent childhood infections aspiration ...
Article

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a rare multisystem disease with a wide and heterogeneous clinical spectrum and variable extent of involvement.  Terminology Langerhans cell histiocytosis was previously known as histiocytosis X. The newer term is preferred as it is more descriptive of its...
Article

Septal lines in lung

Septal lines, also known as Kerley lines, are seen when the interlobular septa in the pulmonary interstitium become prominent. This may be because of lymphatic engorgement or edema of the connective tissues of the interlobular septa. They usually occur when pulmonary capillary wedge pressure rea...
Article

Idiopathic interstitial pneumonias

The 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 Over the years many attempts have...
Article

Respiratory distress syndrome

Respiratory distress syndrome (RDS) is a relatively common condition that occurs in preterm neonates resulting from insufficient production of surfactant.  Terminology RDS is also known as hyaline membrane disease (not favored as reflects non-specific histological findings), neonatal respirato...
Article

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) that are usually subpleural, peripheral and basal in distribution. They can be subdivided into: microcystic honeycombing macrocystic honeycombing ...
Article

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...
Article

Hiatus hernia

Hiatus hernias (alternative plural: herniae) occur when there is herniation of abdominal contents through the esophageal hiatus of the diaphragm into the thoracic cavity. Epidemiology The prevalence of hiatus hernia increases with age, with a slight female predilection. Clinical presentation ...
Article

Hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterized by abnormal blood vessel formation in the skin, mucous membranes, and organs including the lungs, liver, and central nervous system. Epidemiology Worldwide prevalen...
Article

Hemithorax white-out (differential)

Complete white-out of a hemithorax on the chest x-ray has a limited number of causes. The differential diagnosis can be shortened further with one simple observation: the position of the trachea. Is it central, pulled or pushed from the side of opacification? Is there pulmonary volume loss or vo...
Article

Varicella pneumonia

Varicella pneumonia is a type of viral pneumonia. It is a common cause of multiple small round calcific lung lesions. Varicella-zoster virus most commonly causes self-limited benign disease (chickenpox) in children. However, in adults it tends to cause significant complications including varicel...
Article

Head cheese sign (lungs)

The head cheese sign or three-density pattern refers to a juxtaposition of regions with three (or sometimes more) different densities/regions of different attenuation within the lungs: ground-glass opacities (high attenuation) mosaic attenuation pattern (low attenuation) normal lung tissue (n...
Article

Hypertension

Hypertension refers to an increase in blood pressure above the 'normal' for the age, sex, and ethnicity of the patient. This can be specified according to the vascular system involved. Although generally when it is not specified it is assumed to refer to the systemic type. systemic hypertension...
Article

Ground-glass opacification

Ground-glass opacification/opacity (GGO) is a descriptive term referring to an area of increased attenuation in the lung on computed tomography (CT) with preserved bronchial and vascular markings. It is a non-specific sign with a wide etiology including infection, chronic interstitial disease an...
Article

Golden S-sign (lung lobe collapse)

The Golden S-sign is seen on both PA chest radiographs and on CT scans. It is named because this sign resembles a reverse S shape, and is therefore sometimes referred to as the reverse S-sign of Golden. Although typically seen with right upper lobe collapse, the S-sign can also be seen with the...

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.