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.

18 results found
Article

Atrial escape

Atrial escape refers to a chest x-ray sign of massive left atrial enlargement and is an exaggerated version of the double density sign.   Normally, the right border of the left atrium is not visible. As it enlarges it forms a distinct border projecting through the right heart shadow, medial to ...
Article

Beck triad

Beck triad is a collection of three clinical signs associated with pericardial tamponade which is due to excess accumulation of fluid within the pericardial sac. The three signs are: low blood pressure (weak pulse or narrow pulse pressure) muffled heart sounds  raised jugular venous pressure ...
Article

Box-shaped heart

A 'box-shaped' heart is a radiographic description given to the cardiac silhouette in some cases of Ebstein anomaly. The classic appearance of this finding is caused by the combination of the following features: huge right atrium that may fill the entire right hemithorax shelved appearance of ...
Article

Double density sign of left atrial enlargement

Double-density sign is seen on frontal chest radiograph in the presence of left atrial enlargement, and occurs when the right side of the left atrium pushes behind the right cardiac shadow, indenting the adjacent lung and forming its own distinct silhouette 1-3.  If large enough, the left atriu...
Article

Double density sign of osteoid osteoma

The double density sign, also sometimes clumsily referred to as the hotter spot within hot area sign, is a bone scan sign of an osteoid osteoma. It refers to a central focus of intense uptake (the nidus) within a surrounding lower, but nonetheless increased uptake, rim. See also double densit...
Article

Earth-heart sign

The earth-heart sign is a newly recognised sign of cardiac compromise that may be seen on chest radiographs of patients with tension pneumomediastinum. The substantial pressure exerted on the heart by the air trapped in mediastinum with subsequent impairment of central venous return and obstruc...
Article

Egg-on-a-string sign

Egg-on-a-string sign, also referred as egg on its side, refers to the cardiomediastinal silhouette seen in transposition of the great arteries (TGA). The heart appears globular due to an abnormal convexity of the right atrial border and left atrial enlargement and therefore appears like an egg...
Article

Fetal cardio thoracic circumference ratio

Fetal cardio-thoracic (C/T) circumference ratio is parameter than can be used in assessment of fetal cardiac and thoracic/chest wall anomalies. It is essentially the ratio of the cardiac circumference of the thoracic circumference and may be easily measured on ultrasound/fetal echocardiography. ...
Article

Figure of eight appearance

Following lesions may resemble a figure of eight (sometimes referred to as snowman shaped): supracardiac variety of total anomalous pulmonary venous return (TAPVR) 1 pituitary macroadenoma with suprasellar extension2 intraspinal neurofibroma with extraspinal extension through neural foramina ...
Article

Napkin-ring sign

The napkin-ring sign (cardiac) is a recently described sign encountered on CT-coronary angiogram (coronary CTA) performed on modern MDCT (number of rows 64 or higher). It has been shown to possess a high predictive value in predicting future cardiac events and is considered one of the imaging co...
Article

Panzerherz

Panzerherz (or armoured heart) is a term used to describe the appearance of the heart in calcified constrictive pericarditis. The pericardium becomes circumferentially thickened with calcification, limiting the ability of the heart to contract. The rim of dense calcification describes how the h...
Article

Porcelain left atrium

Porcelain left atrium (or coconut left atrium) is a term used when a large part of or the entire left atrial wall becomes calcified. It can occur as a rare consequence of endocarditis (with underlying rheumatic heart disease). It has also been described in the setting of end stage renal disease ...
Article

Septal bounce

Septal bounce is a sign of ventricular interdependence on echocardiography, cardiac CT, and cardiac MRI, manifested by reduced or paradoxical interventricular septal movement during diastole (i.e. initial septal movement towards and then away from the left ventricle) during early diastole second...
Article

Shmoo sign

Shmoo sign refers to the appearance of a prominent, rounded left ventricle and dilated aorta on a plain AP chest radiograph giving the appearance of Shmoo, a fictional cartoon character in the comic strip Li'l  Abner in the 1940s. This sign is indicative of left ventricular hypertrophy.
Article

Snowman sign: total anomalous pulmonary venous return

Snowman sign refers to the configuration of the heart and the superior mediastinal borders resembling a snowman. This is seen in total anomalous pulmonary venous return (TAPVR) type I (supracardiac type). It is an abnormality of the fetal circulation wherein the entire pulmonary venous flow is ...
Article

Third mogul sign

The third mogul sign can be seen on frontal chest radiograph in the presence of left atrial enlargement. It refers to an extra mogul or bump along the upper left cardiac silhouette just below the left main bronchus. The third mogul sign commonly represents the enlarged left atrial appendage, pa...
Article

Transient ischaemic dilatation

Transient ischaemic dilatation is a paradoxical phenomenon seen in myocardial perfusion SPECT imaging.   With severe balanced coronary artery disease, myocardial ischaemia may result in apparent enlargement of the left ventricular cavity during stress. The cause of this is not entirely clear, b...
Article

Walking man sign

The walking man sign is seen on lateral chest radiograph and is a sign of left atrial enlargement. It results from posterior displacement of the left main bronchus such that it no longer overlaps the right bronchus. The left and right bronchus thus appear as an inverted 'V', mimicking the legs o...

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