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.

194 results found
Article

Acute airspace opacification with lymphadenopathy (differential)

Acute airspace opacification with lymphadenopathy is a subset of the differential diagnosis for generalized airspace opacification and includes: post-obstructive causes (usually chronic, but 'new' changes can occur) primary lung cancer pulmonary metastases lymphoma/leukemia infection prim...
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Acute bilateral airspace opacification (differential)

Acute bilateral airspace opacification is a subset of the larger differential diagnosis for airspace opacification. An exhaustive list of all possible causes of acute bilateral airspace opacities is long, but a useful way to consider the huge list is via the material within the airways: infecti...
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Acute unilateral airspace opacification (differential)

Acute unilateral airspace opacification is a subset of the differential diagnosis for airspace opacification.   Differential diagnosis The exhaustive list of all possible causes would be huge, but a useful framework includes: pus, i.e. infection bacterial pneumonia fungal pneumonia viral p...
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Air space opacification

Air space opacification is a descriptive term that refers to filling of the pulmonary tree with material that attenuates x-rays more than the surrounding lung parenchyma. It is one of the many patterns of lung opacification and is equivalent to the pathological diagnosis of pulmonary consolidati...
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Air space opacities

The differential for air space opacities is extensive, and needs to be interpreted in context of chronicity (previous imaging) and clinical context. It is therefore useful to divide airspace opacities as follows: acute airspace opacities with lymph node enlargement acute airspace opacities: un...
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Apical pleural cap

Apical pleural cap refers to a curved density at the lung apex seen on chest radiograph. Epidemiology The frequency of apical pleural thickening increases with age 3. Pathology It arises from a number of causes: pleural thickening/scarring idiopathic: chronic ischemic etiology is favored f...
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Ascending aorta dilatation

Dilatation of the ascending aorta is a common finding in the elderly but unusual in younger patients. Pathology In adults, an ascending aortic diameter greater than 4 cm is considered to indicate dilatation 4. Aneurysmal dilatation is considered when the ascending aortic diameter reaches or ex...
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Bat wing opacities (lungs)

Bat wing or butterfly pulmonary opacities refer to a pattern of bilateral perihilar shadowing. It is classically described on a frontal chest radiograph but can also refer to appearances on chest CT 3,4. Differential diagnosis Bat wing pulmonary opacities can be caused by: pulmonary edema (es...
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Bilateral axillary lymphadenopathy (differential)

Bilateral axillary lymphadenopathy can result from a number of causes and generally implies a systemic process. They include: autoimmune diseases, e.g.: rheumatoid arthritis scleroderma dermatomyositis 5 systemic lupus erythematosus (SLE) psoriasis Sjögren syndrome lymphoma leukemia di...
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Bronchial wall thickening

Bronchial wall thickening is an imaging descriptor used to describe abnormal thickening of bronchial walls and can arise from a vast number of pathological entities. It is one of the causes of peribronchial cuffing. The presence of bronchial wall thickening usually (but not always) implies infl...
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Calcified mediastinal lymph nodes (differential)

There are numerous causes of calcified mediastinal lymph nodes. Common causes include: infectious granulomatous diseases tuberculosis histoplasmosis sarcoidosis silicosis treated lymphoma Uncommon causes include: Pneumocystis jiroveci (PCP) pneumonia metastases thyroid carcinoma: papi...
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Calcified pulmonary densities (differential)

Calcified pulmonary (lung parenchymal) densities can occur in a number of conditions. Micronodules healed varicella pneumonia 1 pulmonary alveolar microlithiasis occupational lung diseases silicosis coal workers pneumoconiosis stannosis baritosis See the main article on calcified pulmon...
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Calcified pulmonary embolus

Calcification associated with pulmonary emboli is usually associated with chronic pulmonary embolism. Calcification is occasionally related to prior congenital cardiac repairs 1. Differential diagnosis If it is purely high attenuating, consider polymethylmethacrylate (PMMA) embolism into the ...
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Calcified pulmonary nodules

Calcified pulmonary nodules are a subset of hyperdense pulmonary nodules and a group of nodules with a relatively narrow differential. Pathology Etiology The most common cause of nodule calcification is granuloma formation, usually in the response to healed infection.   healed infection cal...
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Calcifying pulmonary metastases

Calcifying pulmonary metastases are rare. These should not be confused with metastatic pulmonary calcification. Pathology Calcification in metastases can arise through a variety of mechanisms: bone formation in tumors osteoid origin, calcification and ossification of tumor cartilage, dystrophi...
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Cardiophrenic angle lesions

The cardiophrenic space is usually filled with fat. However, lesions originating above or lower to the diaphragm can present as cardiophrenic angle lesions. The more common lesions encountered include: pericardial fat pad pericardial cyst pericardial fat necrosis Morgagni's hernia lymphade...
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Causes of ascending aorta calcification

There are relatively few causes of calcification of the ascending aorta 1-3: atherosclerosis (this usually spares the ascending aorta) aortitis syphilis Takayasu arteritis idiopathic
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Cavitating pneumonia

Cavitating pneumonia is a complication that can occur with severe necrotizing pneumonia and in some publications, it is used synonymously with the latter term 2.  It is a rare complication in both children and adults. Cavitation associated with Mycobacterium tuberculosis is separately discussed...
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Cavitating pulmonary metastases

Cavitating pulmonary metastases refer to pulmonary metastases which then tend to cavitate. The term is similar but may not be identical to cystic pulmonary metastases in which the wall of the former may be thicker. Epidemiology Cavitation is thought to occur in around 4% of lung metastases 2. ...
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Central bronchiectasis

Distribution of bronchiectasis can help in narrowing the differential diagnosis. Central bronchiectasis is typically seen in: allergic bronchopulmonary aspergillosis (ABPA) congenital tracheobronchomegaly (a.k.a. Mounier Kuhn syndrome) cystic fibrosis Williams Campbell syndrome (rare) See a...
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Centrilobular lung nodules

Centrilobular lung nodules refer to an HRCT chest imaging descriptor for small 5-10 mm lung nodules which are anatomically located centrally within secondary pulmonary lobules. The term is applied on the basis of location of the nodule and not its morphology that is they may be well defined or p...
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Chronic bilateral airspace opacification (differential)

Chronic bilateral airspace opacification is a subset of the differential diagnosis for airspace opacification. An exhaustive list of all possible causes of chronic bilateral airspace opacities is long, but a useful framework is as follows: inflammatory sarcoidosis granulomatosis with polyangi...
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Chronic interstitial pneumonitis

Chronic interstitial pneumonitis is a broad descriptive term where an interstitial pneumonia has a prolonged course. It can arise of a range of etiologies. The term does not usually imply a specific radiographic pattern and includes UIP, NSIP or other pattern. As a general rule there is little o...
Article

Chronic suppurative lung disease

Chronic suppurative lung disease (CSLD) refers to a group of conditions which includes: cystic fibrosis  bronchiectasis primary ciliary dyskinesia This term is usually used in the context of pediatric patients.
Article

Chronic unilateral airspace opacification (differential)

Chronic unilateral airspace opacification is a subset of the differential diagnoses for airspace opacification. An exhaustive list of all possible causes of chronic unilateral airspace opacities is long, but a useful framework is as follows: neoplastic post obstructive lymphoma lymphocytic ...
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Cicatrisation atelectasis

Cicatrisation atelectasis is a form of lung atelectasis which occurs as a result of scarring or fibrosis that reduces lung expansion. Cicatrisation atelectasis is classic in tuberculosis. The term is closely related to cicatrisation collapse when an entire lobe is collapsed from the same process...
Article

Coin lesion (lung)

A coin lesion refers to a round or oval, well-circumscribed solitary pulmonary lesion. It is usually 1-5 cm in diameter and calcification may or may not be present 1,3. Typically but not always the patient is asymptomatic 1.  Differential diagnosis The differential diagnosis for such lesions i...
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Compressive atelectasis

Compressive atelectasis refers to a form of lung atelectasis due to compression by a space-occupying process. Some authors describe it as a subtype of compressive (relaxation) atelectasis where the reduction in lung volume is greater than its normal relaxed state 1. Whereas others describe it a...
Article

Crazy paving

Crazy paving refers to the appearance of ground-glass opacity with superimposed interlobular septal thickening and intralobular septal thickening, seen on chest HRCT. It is a non-specific finding that can be seen in a number of conditions.  Pathology Etiology Common causes: acute respiratory...
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Cyanotic congenital heart disease

A number of entities can present as cyanotic congenital heart disease. These can be divided into those with increased (pulmonary plethora) or decreased pulmonary vascularity : increased pulmonary vascularity total anomalous pulmonary venous return (TAPVR) (types I and II) transposition of the...
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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...
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Cystic lung lesions (pediatric)

Cystic lesions in pediatric patients are usually congenital lesions and, as such, can be seen antenatally and following delivery. Pathology Etiology Congenital These congenital lesions are predominantly covered by the overarching diagnosis of bronchopulmonary foregut malformation. This is a ...
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Cystic mediastinal masses

The differential diagnosis for cystic masses of the mediastinum include: bronchogenic cyst esophageal duplication cyst neuroenteric cyst pericardial cyst meningocele lymphangioma thymic cyst cystic teratoma of mediastinum cystic degeneration of an intrathoracic tumor mediastinal thorac...
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Cystic (necrotic) lymph nodes

Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions: Systemic squamous cell carcinoma metastases treated lymphoma leukemia plasmacytoid T-cell leukemia acute myeloid leukemia viral lymphadenitis herpes simplex lymphadenit...
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Cystic pulmonary metastases

Cystic pulmonary metastases are atypical morphological form on pulmonary metastases where lesions manifest as distinct cystic lesions. It is slightly different from the term cavitating pulmonary metastases in that the lesions are extremely thin walled. Pathology It has been reported with many ...
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Cystic retroperitoneal lesions

Cystic retroperitoneal lesions can carry a relatively broad differential, which includes: retroperitoneal lymphangioma retroperitoneal mucinous cystadenoma retroperitoneal cystic teratoma retroperitoenal cystic mesothelioma pseudomyxoma retroperitonei with cystic change perianal mucinous c...
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Dextrocardia

Dextrocardia is a congenital cardiac malrotation in which the heart is situated on the right side of the body (dextroversion) with the apex pointing to the right. Terminology Dextrocardia merely refers to the laterality of the heart, it says nothing about the orientation of the patient's other...
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Diaphragmatic paralysis

Diaphragmatic paralysis (also considered very similar to the term diaphragmatic palsy) can be unilateral or bilateral. Clinical presentation Clinical features are highly variable according to underlying etiological factor: unilateral paralysis: asymptomatic in most of the patients as the othe...
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Diaphragmatic rupture

Diaphragmatic rupture often results from blunt abdominal trauma. The mechanism of injury is typically a motor-vehicle collision. Epidemiology Given that the most common mechanism is motor vehicle collisions, it is perhaps unsurprising that young men are most frequently affected. The estimated ...
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Differential diagnosis for a small cardiothoracic ratio

A small cardiothoracic ratio (CTR) is defined as <42%/0.42 when assessed on a PA chest radiograph, and is often called small heart syndrome. A pathologically-small heart is also known as microcardia.It can be due to/associated with a number of entities: adrenal insufficiency, e.g. Addison disea...
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Differential for an anterosuperior mediastinal mass

An anterosuperior mediastinal mass can be caused by neoplastic and non-neoplastic pathology. As their name suggests, they are confined to the anterior mediastinum, that portion of the mediastinum anterior to the pericardium and below the level of the clavicles.  The differential diagnosis for a...
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Diffuse airway narrowing

Diffuse airway narrowing can occur from a number of pathologies. These include relapsing polychondritis ulcerative colitis amyloidosis: tracheobronchial sarcoidosis granulomatosis with polyangiitis tracheopathia osteochondroplastica various infections including tracheobronchial papilloma...
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Diffuse alveolar hemorrhage

Diffuse alveolar hemorrhage (DAH) is a subset of diffuse pulmonary hemorrhage when bleeding is diffuse and directly into the alveolar spaces. It can occur in a vast number of clinical situations and can be life-threatening. Pathology Blood tends to fill alveolar spaces at multiple sites. Etio...
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Diffuse pleural thickening

Diffuse pleural thickening refers to a morphological type of pleural thickening. It can occur from malignant as well as nonmalignant causes, which include: diffuse pleural fibrosis / fibrothorax 6 asbestos related pleural disease: typically seen a continuous sheet of pleural thickening often i...
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Diffuse pulmonary hemorrhage

Diffuse pulmonary hemorrhage (DPH) is a subtype of pulmonary hemorrhage where bleeding into the lung is diffuse. If the bleeding is into the alveolar spaces this can be further subclassified as diffuse alveolar hemorrhage (DAH). Clinical presentation While the exact presentation can vary is ha...
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Diffuse pulmonary nodules

Diffuse pulmonary nodules are usually seen as multiple pulmonary nodular opacifications on a HRCT chest scan. They can signify disease processes affecting either the interstitium or the airspace. They can range from a few millimeters to up to 1 cm and when very small and numerous there can be so...
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Diffuse tracheal narrowing

Conditions associated with diffuse tracheal narrowing or collapse include (in alphabetical order): amyloidosis chronic obstructive pulmonary disease (COPD): saber sheath trachea granulomatosis with polyangiitis tracheobronchial tuberculosis 3 tracheomalacia/tracheobronchomalacia (due to col...
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Drug and toxin induced pulmonary hypertension

Drug and toxin induced pulmonary hypertension is one of the causes of pulmonary arterial hypertension. It falls under group 1.3 under the Dana point classification system of pulmonary hypertension.  Pathology A wide range of difference drugs have been associated with developing pulmonary hyper...
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Drug-induced lung disease

Drug-induced lung disease can result from a number of agents and may have a myriad of presentations, ranging from an adult respiratory distress syndrome type picture to established pulmonary fibrosis. Due to this, it can be extremely difficult to pinpoint the offending agent on imaging appearan...
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Dynamic tracheal collapse

Dynamic tracheal collapse refers to collapse of the trachea during expiration. It is perhaps best assessed on CT in the end expiratory phase. An inspiratory series is also useful for comparative purposes. The term excessive dynamic airway collapse (EDAC) refers to abnormal and exaggerated bulgin...
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Dysphagia

Dysphagia refers to subjective awareness of difficulty or obstruction during swallowing. It is a relatively common and increasingly prevalent clinical problem. Odynophagia is the term for painful swallowing. Fluoroscopy is the mainstay of imaging assessment but manometry can help evaluate the e...
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Echogenic fetal lung lesions

Echogenic fetal lung lesions on antenatal ultrasound can be detected in a number of situations. They include: Airway obstructions: lung are often enlarged and echogenic bilaterally congenital high airways obstruction syndrome (CHAOS) tracheal atresia congenital tracheal stenosis laryngeal a...
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Elevated diaphragm

Elevated diaphragm refers to the symmetrical elevation of both domes of the diaphragm. Pathology Etiology There is some overlap with causes of an elevated hemidiaphragm.  Technical  supine position poor inspiratory effort Patient factors obesity pregnancy Diaphragmatic pathology paral...
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Elevated hemidiaphragm

An elevated hemidiaphragm may result from direct and indirect causes which include: above the diaphragm 1 decreased lung volume atelectasis/collapse prior lobectomy or pneumonectomy pulmonary hypoplasia diaphragm 3-7 phrenic nerve palsy diaphragmatic eventration contralateral stroke: ...
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Empyema

Empyemas are purulent inflammatory collections within a body cavity. Contrast this with abscesses, which arise within parenchymal tissue, rather than occupying a pre-existing anatomical space. Terminology Colloquially, the standalone term empyema is used to refer to thoracic empyemas but there...
Article

Endobronchial metastases

Endobronchial metastases are an uncommon form of intrathoracic metastases. They are much less common than intrapulmonary metastases. Clinical presentation The clinical presentation varies and includes: hemoptysis cough post-obstructive pneumonitis from distal obstruction Pathology Frequen...
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Enlargement of the cardiac silhouette

Enlargement of the cardiac silhouette on a frontal (or PA) chest x-ray can be due to a number of causes 1: cardiomegaly (most common cause by far) pericardial effusion anterior mediastinal mass prominent epicardial fat pad expiratory radiograph AP projection (from supine radiographs taken ...
Article

Fat containing solitary pulmonary nodule

The differential of a fat containing solitary pulmonary nodule is very narrow. In a well circumscribed smooth or lobulated mass (especially if it has been largely stable in size over time) presence of fat is essentially pathognomonic of a pulmonary hamartoma, and usually not further assessment ...
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Fat containing thoracic lesions

There is a long list of fat containing thoracic lesions. They may involve the mediastinum, lung, pleura or chest wall. Differential diagnosis includes:  intrapulmonary: fat containing pulmonary lesions pulmonary hamartoma endobronchial lipoma intrapulmonary lipoma lipoid pneumonia myeloli...
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Fatty mediastinal masses (differential)

Fatty mediastinal masses are relatively uncommon, and the differential diagnosis is brief, including 1-4: lipoma liposarcoma thymolipoma benign mature teratoma lipoblastoma extravasation of lipid-rich hyperalimentation fluid 3 fibrofatty replacement of the central portion of mediastinal l...
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Foregut duplication cyst

Foregut duplication cysts are a type of congenital duplication cyst. They are sometimes classified under bronchopulmonary foregut malformations. Entities classified as foregut duplication cysts include: bronchogenic cysts neurenteric cysts other enteric cysts esophageal duplication cysts l...
Article

Granulomatous lung disease

Granulomatous lung disease refers to a broad group of infectious and non-infections conditions characterized by the formation of granulomas. The spectrum includes infectious mycobacterial pulmonary tuberculosis pulmonary non-tuberculous mycobacterial infection fungal pulmonary coccidioido...
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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...
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Hemopneumothorax

A hemopneumothorax (plural: hemopneumothoraces) (or, less commonly, haematopneumothorax or pneumohemothorax) is a term given when there is concurrent presence of a hemothorax and pneumothorax. It is a variant of a hydropneumothorax.  Epidemiology Approximately 5% of patients with pneumothorax ...
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Hemoptysis

Hemoptysis (plural: hemoptyses) refers to coughing up of blood. Generally, it appears bright red in color as opposed to blood from the gastrointestinal tract which appears dark red. It is considered an alarming sign of a serious underlying etiology. Terminology Massive hemoptysis is referred t...
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Hemothorax

A hemothorax (plural: hemothoraces), or rarely hematothorax, literally means blood within the chest, is a term usually used to describe a pleural effusion due to accumulation of blood. If a hemothorax occurs concurrently with a pneumothorax it is then termed a hemopneumothorax.  A tension hemot...
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Hematopoietic stem cell transplantation (thoracic complications)

There are many thoracic complications that can occur following hematopoietic stem cell transplantation. These can precipitate during various stages following transplantation and can be either infectious or noninfectious. Complications Early pulmonary edema engraftment syndrome diffuse alveo...
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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...
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High attenuation lymphadenopathy

High attenuation lymphadenopathy (or adenopathy) variably refers to abnormal lymph nodes with attenuation on CT usually higher compared to muscle, either on a noncontrast exam or following contrast administration (i.e., hyperenhancement) 5. High attenuation nodes may be due to calcifications or...
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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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Hyperattenuating pulmonary abnormalities

Hyperattenuating pulmonary abnormalities refer to lung parenchymal opacities/lesions that are generally higher attenuation on CT than most soft tissues. An exact definition is usually not provided 1-3, while some authors focus on abnormalities that are as subjectively opaque as bony structures 4...
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Hyperattenuating pulmonary consolidation

Hyperattenuating pulmonary consolidation refers to a region of lung parenchyma with air space opacification that has higher attenuation on CT than muscle or than expected with typical causes of consolidation such as pneumonia (fluid attenuation) or cancer (soft tissue attenuation). The differen...
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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 tumors pulmonary metastases mucoid calcification of mucinous adenocarcinoma breast carcinoma gastrointestinal tract aden...
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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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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

Incomplete border sign (chest)

The incomplete border sign is useful to depict an extrapulmonary mass on chest radiograph. An extrapulmonary mass will often have an 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...
Article

Interstitial lung disease

Interstitial lung disease (ILD) is an umbrella term that encompasses a large number of disorders that are characterized by diffuse cellular infiltrates in a periacinar location. The spectrum of conditions included is broad, ranging from occasional self-limited inflammatory processes to severe de...
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Interstitial lung pattern (radiograph)

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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Large unilateral pleural effusion

When a pleural effusion is large and unilateral, concern for an underlying abnormality should be raised. Causes include: tumor bronchogenic carcinoma mesothelioma pleural metastases lymphoma pleural lymphoma primary effusion lymphoma infection parapneumonic effusion empyema extension ...
Article

Left paramediastinal catheter position (differential)

When a central venous catheter that is supposed to terminate in the superior vena cava or right atrium is abnormally located to the left of the mediastinum and below the level of the brachiocephalic vein, a limited differential of left paramediastinal catheter position should be considered 1: l...
Article

Linear atelectasis

Linear atelectasis refers to a focal area of subsegmental atelectasis that has a linear shape. Depending on its shape, it is also known as plate, discoid or band atelectasis. Linear atelectasis may appear to be horizontal, oblique or perpendicular and is very common. It usually occurs as a conse...
Article

Lobar consolidation

Lobar consolidation is the term used to describe consolidation in one of the lobes of the lung. It infers an alveolar spread of disease and is most commonly due to pneumonia. Pathology Consolidation refers to the alveolar airspaces being filled with fluid (exudate/transudate/blood), cells (inf...
Article

Lobar lung collapse

Lobar collapse refers to the collapse of an entire lobe of the lung. As such it is a subtype of atelectasis (collapse is not entirely synonymous with atelectasis, which is a more generic term for 'incomplete expansion').  Individual lobes of the lung may collapse due to obstruction of the supply...
Article

Localized pulmonary hemorrhage

Localized pulmonary hemorrhage is a descriptive term for a pulmonary hemorrhage restricted to a particular focal region of the lung. It can range from involving a small focus of hemorrhage to a whole lobe. Pathology Etiology Focal pulmonary hemorrhage can occur from a number of causes: pulmo...
Article

Mediastinal lymph node enlargement

Mediastinal lymph node enlargement can occur from a wide range of pathologies. It may occur on its own or in association with other lung pathology. Terminology Although mediastinal lymphadenopathy is used interchangeably - by some - with "mediastinal lymph node enlargement", they are not synon...
Article

Mediastinal mass

Mediastinal mass may be caused by a wide variety of neoplastic and non-neoplastic pathologies. It is helpful to identify the location of the mass since this significantly reduces the breadth of the differential diagnosis.  There are four conceptual compartments of the mediastinum which are larg...
Article

Mediastinal widening (differential)

The differential diagnoses for mediastinal widening include: traumatic aortic injury vascular anomalies unfolded aorta double SVC aberrant right subclavian artery azygos continuation of the IVC pneumomediastinum lung atelectasis pulmonary masses abutting the mediastinum mediastinal ly...
Article

Medical devices in the thorax

Medical devices in the thorax are regularly observed by radiologists when reviewing radiographs and CTs. Extrathoracic devices tubing, clamps, syringes lying on or under the patient rubber sheets, foam mattresses, clothing, hair braids, nipple piercings etc. may also be visible These devices...
Article

Megaesophagus

Megaesophagus or diffuse esophageal dilatation can be caused by a variety of conditions.  Pathology Etiology Some of the more common causes are given below 1-3: esophageal dysmotility achalasia Chagas disease scleroderma distal obstruction malignant stricture, e.g. esophageal cancer, ca...
Article

Middle mediastinal mass

The differential diagnosis for a middle mediastinal mass includes 1-3: lymphadenopathy aneurysm e.g. aortic, pulmonary artery, bronchial artery congenital cyst pericardial cyst foregut duplication cyst (e.g. esophageal, bronchial) pericardial tumor primary/secondary cardiac tumor neuroge...
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

Mosaic attenuation pattern in lung

Mosaic attenuation is a descriptive term used in describing a patchwork of regions of differing pulmonary attenuation on CT imaging.  It is a non-specific finding, although is associated with the following: obstructive small airways disease: low attenuation regions are abnormal and reflect decr...
Article

Mucoid impaction (lung)

Mucoid impaction, also referred to as mucus plugging, mucous plugging,  bronchial mucocele or bronchocele formation, refers to airway filling by mucoid secretions and can be obstructive or non-obstructive. It is a common pathological finding in chest imaging. Pathology Etiology Mucoid impacti...

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