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.

903 results found
Article

Lollipop sign (hepatic epithelioid hemangioendothelioma)

The lollipop sign is seen in hepatic epithelioid hemangioendothelioma (HEHE). It represents hepatic/portal vein and/or their tributaries/branches tapering and terminating at or just within the edge of a well defined peripherally enhancing (or non-enhancing) lesion with an avascular core on CT or...
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Loss of normal half-moon overlap sign (shoulder)

Loss of half-moon overlap sign, which does not really roll off the tongue, is a sign of posterior shoulder dislocation on AP radiographs.  On a normal true anteroposterior image, there is a half-moon overlap between the humeral head and the glenoid. In a posteriorly dislocated shoulder, there i...
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Loss of the insular ribbon sign

The loss of the insular ribbon sign refers to a loss of definition of the gray-white interface in the lateral margin of the insular cortex ("insular ribbon") and is considered an early CT sign of MCA infarction. The insular cortex is more susceptible to ischemia following MCA occlusion than oth...
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Low attenuation lymphadenopathy

Low attenuation lymphadenopathy refers to abnormal lymph nodes that on CT appear to have lower attenuation than other soft tissues. This category can be split into two types: cystic (necrotic) lymph nodes metastatic carcinoma (or lymphoma) infections (tuberculous or fungal) cavitating mesent...
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Lower T sign (central sulcus)

The lower T sign is one of the features useful in identifying the central sulcus on cross-sectional imaging.  It relies on identifying the inferior frontal sulcus which intersects the precentral sulcus in a "T" junction, thus defining the precentral gyrus. The central sulcus is the next posteri...
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L sign (brain)

The L sign is one of the features useful in identifying the central sulcus on cross-sectional imaging. On axial images, the superior frontal gyrus at its posterior aspect meets the precentral gyrus in an "L" configuration (forwards on the left, backwards on the right). The central sulcus is the...
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Lucent liver sign

The lucent liver sign is represented by a reduction of hepatic radiodensity on supine radiograph when there is a collection of free intraperitoneal gas located anterior to the liver.
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Luftsichel sign (lungs)

The luftsichel sign is seen in some cases of left upper lobe collapse and refers to the frontal chest radiographic appearance due to hyperinflation of the superior segment of the left lower lobe interposing itself between the mediastinum and the collapsed left upper lobe.   Radiographic feature...
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Lung point sign

The lung point sign is a highly specific ultrasound sign of pneumothorax. It involves visualizing the point where the visceral pleura (lung) begins to separate from the parietal pleural (chest wall) at the margin of a pneumothorax.  In the absence of pneumothorax, the two pleural layers slide a...
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Lying down adrenal sign

The lying down adrenal sign is a cross-sectional imaging sign of renal agenesis or ectopia in which the ipsilateral adrenal gland appears to be 'lying down' on the psoas muscle posteriorly. Due to the linear as opposed to Y-shaped configuration of the gland in such situations, it is also describ...
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Lyre sign (carotid artery)

The lyre sign refers to the splaying of the internal and external carotid by a carotid body tumor. Classically described on angiography it is also visible on CT angiography.
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Macaroni sign (arteries)

The macaroni sign is a sign seen in Takayasu arteritis on ultrasound. It represents the smooth, homogeneous and moderately echogenic circumferential thickening of the arterial wall that occurs in Takayasu arteritis. The sign is highly specific for Takayasu arteritis, more commonly noted in the ...
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Maiden waist deformity

A maiden waist deformity is a name given to the appearance when there is medial deviation of both ureters. This typically occurs in retroperitoneal fibrosis. In this condition, there is medial indrawing of the ureters due to deposition of fibrous tissue in the retroperitoneum at the level of the...
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Manta ray sign (bladder)

The manta ray sign is a radiographic appearance in bladder exstrophy. It describes wide midline separation of the pubic bones simulating the appearance of a manta ray swimming towards you 1. The sacrum and iliac wings recall the manta ray’s head and body, with the widely spaced pubic rami formin...
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Marcus Gunn pupil

A Marcus Gunn pupil, also known as a relative afferent pupillary defect (RAPD), is a non-specific sign on physical examination that indicates partial optic nerve dysfunction. It is mainly due to unilateral optic neuropathy (e.g. optic neuritis), or rarely optic chiasm or optic tract lesions. Th...
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Martini glass sign

The Martini glass sign describes the appearance of the globe in persistent hyperplastic primary vitreous (PHPV). On MRI the retrolenticular tissue characteristic of this condition has a triangular shape, like that of a martini glass appearing as low T2 signal against the normal high T2 signal o...
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Matterhorn sign

The Matterhorn sign is a descriptive sign for a calcified disc herniation that impales the dural sac and sometimes the cord, typically located in the thoracic spine. History and etymology This sign is named after one of the most iconic mountains in the Alps: the Matterhorn.
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MCA dot sign (brain)

The middle cerebral artery (MCA) dot sign, also known as the Sylvian fissure sign, is seen on non-contrast brain CT and represents the cross-sectional M2 equivalent of the hyperdense MCA sign. Rather than imaging a length of middle cerebral artery (typically the M1 segment), the dot sign represe...
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McConnell's sign (echocardiography)

The McConnell's sign describes a regional pattern of acute right ventricular dysfunction on transthoracic echocardiography first observed in a cohort of patients with acute pulmonary thromboembolism. In contrast to the global wall motion abnormalities observed in chronic right ventricular dysfun...
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Medial breast margin sign

The medial breast margin sign is a sign of pectus excavatum seen on the frontal chest radiographs of women. It is one of several described signs of pectus excavatum on frontal chest radiographs.  Radiographic features Plain radiograph Women with pectus excavatum may have a more vertically ori...
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Medial stripe sign

The medial stripe sign refers to an area of increased lucency at the interface of the medial lung and the mediastinum on a chest radiograph in a case of medial pneumothorax. A small pneumothorax generally accumulates anteriorly or medially which may be difficult to detect, hence this sign holds ...
Article

Melting ice cube sign (lungs)

The melting ice cube sign describes the resolution of pulmonary hemorrhage following pulmonary embolism (PE).  When there is pulmonary hemorrhage without infarction following PE, the typical wedge-shaped, pleural-based opacification (Hampton's hump) resolves within a week while preserving its t...
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Mercedes-Benz sign (aorta)

The Mercedes-Benz sign can be seen in the aorta in the context of aortic dissection on CT 1.  It is seen at three distinct intimal flaps that have a triradiate configuration similar to the Mercedes-Benz logo (Figure 1). Two of the three lumens outline by these intimal flaps belong to the false ...
Article

Mercedes-Benz sign (gallbladder)

In the gallbladder, the Mercedes-Benz sign describes a star-shaped pattern of gas-fissuring within gallstones initially described on an abdominal radiograph 2. Fissures, usually fluid-filled, are present in close to 50% of gallstones. Less than half of these fissured gallstones contain some amo...
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Mickey Mouse appearance

In medical imaging literature, a Mickey Mouse appearance has been given to imaging features that depict that of Mickey Mouse when viewed from the front. It has been described in the following: anencephaly 2 progressive supranuclear palsy 1 synonymously with a finger in glove sign the flared ...
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Mickey Mouse sign (ultrasound)

The Mickey Mouse sign is said to represent the normal anatomy of the common femoral artery, common femoral vein and great saphenous vein on ultrasound at the level just inferior the inguinal crease.  See also Mickey Mouse appearance
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Middle cerebellar peduncle sign

The middle cerebellar peduncle (MCP) sign is a feature of a number of conditions, particularly neurodegenerative diseases, and most commonly associated with fragile X-associated tremor/ataxia syndrome (FXTAS) although many other conditions are recognized.  It represents high T2 signal in the mi...
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Moguls of the heart

The 'moguls of the heart' refer to the bulges of the cardiomediastinal contour on frontal chest radiographs. The cardiomediastinal bulges are likened to skiing moguls (bumps of packed snow on a mountainside sculptured by turning skis). Awareness of their usual locations and etiologies is helpful...
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Molar tooth sign (abdomen)

The abdominal molar tooth sign refers to the appearance of contrast media which has spilled out of the urinary bladder on CT cystography after extraperitoneal bladder rupture. Contrast flows out of the ruptured bladder, occupying the preperitoneal cavum Retzii and surrounds the bladder in the s...
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Molar tooth sign (CNS)

The molar tooth sign refers to the appearance of the midbrain in an axial section in which the elongated superior cerebellar peduncles give the midbrain an appearance reminiscent of a molar or wisdom tooth. It was initially described in Joubert syndrome and related disorders (JSRD) 2 but is now...
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Molar tooth sign (disambiguation)

The molar tooth sign may refer to: molar tooth sign (CNS) molar tooth sign (abdomen)
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Mondor sign (foot)

The Mondor sign is a sign seen clinically and on CT, and refers to a hematoma that is formed and extends distally along the sole of the foot 1. Its presence is considered pathognomonic for a calcaneal fracture 1. History and etymology It was named after Henri Mondor (1885-1962), a French surge...
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Monod sign (lungs)

The Monod sign (often misspelt Monad 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...
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Moose head appearance

The moose head appearance refers to the lateral ventricles in coronal projection in patients with dysgenesis of the corpus callosum. The cingulate gyrus is everted into narrowed and elongated frontal horns. An alternative name is the viking helmet sign. Other names include steer-horn, Texas lon...
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More black sign

The more black sign is a normal finding in lateral chest x-ray, and refers to the gradual increased apparent radiolucency (blackness) of the vertebral bodies, when proceeding from upper to lower chest. This is due to the increased proportion of the chest comprised of air containing lungs over di...
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Morning glory sign (midbrain)

Morning glory sign of progressive supranuclear palsy (PSP) and multisystem atrophy, not to be confused with morning glory syndrome, refers to the appearance of the midbrain on axial imaging 1. Graphically this is identified on an axial image at the level of the midbrain by drawing 1:   a horiz...
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Morning glory syndrome (eye)

Morning glory disc anomaly (MGDA), also known as morning glory syndrome, is a rare congenital malformation of the optic nerve which is frequently associated with midline abnormalities of the brain and skull 1. Epidemiology Morning glory disc anomaly is rare and is more commonly found in female...
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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

Mosaic pattern of bone

The mosaic bone pattern, also referred to as the jigsaw pattern of bone is seen in Paget disease, where thickened, disorganized trabeculae lead to areas of sclerosis are interspersed with lucent and more normal bone. See also Other Paget disease related signs: blade of grass sign tam o' shan...
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Mother in law sign

The mother in law sign is perhaps uncharitably (depends on the mother in law I suppose) used to describe lesions that enhance early during the arterial phase and remain opacified well after the venous phase. The joke is that a mother in law comes early and stays late.  It is most frequently equ...
Article

Motor band sign

The motor band sign is a radiological sign described in amyotrophic lateral sclerosis (ALS). It refers to the appearance of the cortex on axial GRE and SWI MRI in patients with ALS 1,2. On these sequences, and in the axial plane, curvilinear bands of low signal may be appreciated within the cor...
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Moulage sign (bowel)

The moulage sign is related to sprue, in particular celiac disease. It occurs where there is a dilated jejunal loop with complete loss of jejunal folds 1. It is said to appear like a tube into which wax has been poured. History and etymology Moulage (French: casting/molding) is the art of appl...
Article

Mount Fuji sign

Mount Fuji sign is seen on cross-sectional imaging and is indicative of a tension pneumocephalus.  The sign refers to the presence of gas (pneumocephalus) between the tips of the frontal lobes with a heaped-up appearance giving the silhouette-like appearance of Mount Fuji 1-3. It suggests that ...
Article

M sign (inferior frontal gyrus)

The M sign refers to the characteristic "M" configuration of the inferior frontal gyrus, as it forms (from front to back) the pars orbitalis, pars triangularis, and, pars opercularis.
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Mulder sign

Mulder sign is a clinical test used to examine causes of metatarsalgia associated with Morton neuroma. It has high specificity (100%) but relatively low sensitivity (62%) 2. Technique With one hand, clasp the metatarsal heads between the thumb and fingers or thenar eminence and fingers. Place ...
Article

Mushroom cap sign

Mushroom cap sign is one of the important signs of deep rectosigmoid endometriosis seen on T2 weighted MRI sequence. It indicates the submucosal involvement in the rectosigmoid colon. The hypertrophic muscularis propria appears as heterogeneous low signal intensity surrounded by the high signal...
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Mushroom sign (pyloric stenosis)

The mushroom sign (also called umbrella sign) is a radiological sign described in pyloric stenosis on barium examination. This sign refers to the impression made by the hypertrophic pylorus on the duodenal cap. See also shoulder sign double track sign caterpillar sign string sign beak sign
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Naclerio V sign

The Naclerio V sign is a sign described on the plain film in patients with a pneumomediastinum occurring often secondary to an esophageal rupture.  It is seen as a V-shaped air collection. One limb of the V is produced by mediastinal gas outlining the left lower lateral mediastinal border. The ...
Article

Naked facet sign (vertebral column)

The naked facet sign (also known as the hamburger sign or reverse hamburger bun sign) refers to the CT appearance of an uncovered vertebral articular facet when the facet joint is dislocated, most often in cases of locked facet.  This CT sign is characteristic of a flexion-distraction injury an...
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Napkin-ring sign (heart)

The napkin-ring sign (heart) is a recently described sign encountered on CT coronary angiogram (coronary CTA) performed on modern MDCT. It has been shown to possess a high predictive value in predicting future cardiac events and is considered one of the imaging correlates of an unstable plaque. ...
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Neuhauser sign (distal ileum)

Neuhauser sign refers to a soap bubble appearance seen in the distal ileum in cases of meconium ileus, related to the air mixed with meconium. It may be seen with barium enema if contrast passes beyond the ileocecal valve or with small-bowel follow-through. Although classically described with m...
Article

Nightstick fracture (ulna)

Nightstick fractures are isolated fractures of the ulna, typically transverse and located in the mid-diaphysis and usually resulting from a direct blow. It is a characteristic defensive fracture when the patient tries to ward off an overhead blow from an assailant (or local law enforcement offic...
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Nodule-in-nodule appearance (liver)

In hepatic imaging, a nodule-in-nodule appearance represents foci of abnormal arterial enhancement within a liver lesion, in cases of a liver regenerative nodule with a focus of hepatocellular carcinoma or high-grade dysplastic nodule. It is so called because of the nodular arterial enhancement ...
Article

Non-accidental injury

Non-accidental injuries (NAI) represent both ethical and legal challenges to treating physicians. Radiologists may be the first clinical staff to suspect non-accidental injuries when confronted with a particular injury pattern. Knowledge of these is essential if the opportunity to save a child ...
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Northern exposure sign

The northern exposure sign has been described as a high specificity sign in sigmoid volvulus. On a supine abdominal radiograph, the apex of the sigmoid volvulus is seen above (cranial to) the transverse colon.
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Notch sign

There are many so-called notch signs. They include: focal notch in the wall (or tail extending from) a 2nd branchial cleft cyst between the internal and external carotid arteries peripheral notches in the contour of a solitary pulmonary nodule (SPN) suggests malignancy thymic notch sign late...
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Nubbin sign

Nubbin sign (also called as cystic duct sign) is an important sign in a HIDA scan (cholescintigraphy using iminodiacetic acid analogs) that may be seen in cases of gallbladder neck obstruction. The "nubbin" refers to a small amount of radiotracer activity in the cystic duct, with absence of trac...
Article

Nutmeg liver

A nutmeg liver appearance is due to a perfusion abnormality of the liver usually as result of hepatic venous congestion. When hepatic veins are congested, contrast is prevented from diffusing through the liver in a normal manner. This results in a mottled pattern of contrast enhancement in the a...
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Obliteration of the retrosternal airspace

Obliteration of the retrosternal airspace is seen in any cause of an anterior mediastinal mass. 
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Occult fracture

Occult fractures are those that are not visible on imaging, most commonly plain radiographs and sometimes CT, either due to lack of displacement or limitations of the imaging study. There may be clinical signs of a fracture without one actually being seen. MRI or nuclear medicine studies are som...
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O'Donoghue unhappy triad

O'Donoghue unhappy triad or terrible triad often occurs in contact sports, such as basketball, football, or rugby, when there is a lateral force applied to the knee while the foot is fixated on the ground. This produces the "pivot shift" mechanism. The O'Donoghue unhappy triad comprises three t...
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Esophageal intubation

Esophageal intubation refers to the incorrect placement of an endotracheal tube in the esophagus. Within minutes its consequences can be catastrophic with the seriousness of its outcome depending largely on the timeliness of its diagnosis. Epidemiology Accidental esophageal intubation can happ...
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Oncocalyx

An oncocalyx is a dilated tumor filled renal calyx, typically seen in patients with transitional cell carcinomas of the renal pelvis.
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Onion bulb formation

Onion bulb formation is seen in hypertrophic neuropathies such as Charcot-Marie-Tooth type 1A (CMT1A) and chronic inflammatory demyelinating polyneuropathy (CIDP). It is the result of proliferation of Schwann cells and deposition of collagen 1.  Radiographic features MRI The nerve roots appea...
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Onion peel sign

The onion peel sign (also called the Cumbo sign or double arch sign) is a feature seen with complicated pulmonary hydatid cyst in which the gas lining between the endocyst and pericyst has the appearance of an onion peel. It is pathognomonic for a ruptured hydatid cyst. History and etymology I...
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Open ring sign

The open ring sign is a relatively specific sign for demyelination, most commonly multiple sclerosis (MS), and is helpful in distinguishing between the causes of ring-enhancing lesions.  Radiographic features The enhancing component is thought to represent advancing front of demyelination and ...
Article

Orbital emphysema

Orbital emphysema is the presence of gas within the orbital soft tissues. It is usually due to orbital fractures communicating with the paranasal sinuses but can be caused by penetrating trauma and infection. It is a common finding also after orbital or ocular surgery.  Location preseptal pos...
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Oreo cookie sign (heart)

The Oreo cookie sign refers to the appearance of a pericardial effusion on lateral radiographs of the chest. A vertical opaque line (pericardial fluid) separating a vertical lucent line directly behind the sternum (paracardial fat) anteriorly from a similar lucent vertical lucent line (epicardia...
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Osborne-Cotterill lesion

Osborne-Cotterill lesions represent a shear or depression fracture of the posteroinferior aspect of the capitellum and an avulsed fragment in posterolateral elbow most commonly seen in patients with chronic posterolateral rotatory instability.  Pathology It is thought to be due to posterolater...
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Owl-eyes sign (spinal cord)

The owl-eyes sign, also referred to as snake-eyes sign or fried-eggs sign, represents bilaterally symmetric circular to ovoid foci of high T2-weighted signals in the anterior horn cells of the spinal cord and is seen on axial MR imaging. The sagittal corollary is a "pencil-like" vertical linear ...
Article

Paint brush borders sign

The paint brush borders sign may be seen on MRI of a giant cell tumor, at the margin between the lesion and the normal bone. The sign specifically refers to the jagged interface as the tumor penetrates into the bone which mimics the profile of the bristles of a paint brush. It has recently been...
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Palla sign

Palla sign is a sign seen on chest radiographs suggestive of pulmonary embolism, usually seen in the acute setting. Although uncommon, it can be seen along with several other described signs of pulmonary embolus on chest radiography. Pathology Palla sign describes an enlarged right descending...
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Pancake brain

Pancake brain, is the classical sign of alobar holoprosencephaly. It is due to fusion of the cerebral hemispheres leaving a single ventricle in its center. It is the most severe form of holoprosencephaly. It is associated with multiple facial abnormalities. See also pancake vertebra vegetable...
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Panda sign (disambiguation)

The humble panda has a few signs to its name: panda sign of the midbrain double panda sign panda sign of sarcoidosis panda eyes (base of skull fracture) See also animal and animal produce inspired signs
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Panda sign (midbrain)

The panda sign in neuroimaging refers to the appearance of the midbrain, when the red nucleus and substantia nigra are surrounded by high T2 signal. It is classically seen in Wilson disease, although whenever the white matter is diffusely abnormal in the region a similar appearance will be perc...
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Panda sign (sarcoidosis)

The panda sign of sarcoidosis is a gallium-67 citrate scan finding. It is due to bilateral involvement of parotid and lacrimal glands in sarcoidosis, superimposed on the normal uptake in the nasopharyngeal mucosa. The presence of perihilar adenopathy adds the lambda distribution of increased up...
Article

Panzerherz (heart)

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

Papilledema

Papilledema is an ophthalmoscopic diagnosis and refers to swelling of the optic disc. The MRI appearance relates to the dural anatomy of the optic nerve, which is continuous with the subarachnoid space, thereby allowing increased intracranial pressure (ICP) to be transmitted to the optic disc. T...
Article

Parrot beak meniscal tear

Parrot beak meniscal tears are a type of oblique meniscal tear which is connected in one plane and displaced in the other plane. Its appearance on axial images is curved like a crescent and is likened to that of a parrot's beak. The tear gap has a curved V-shape.  Some authors advise that the t...
Article

Patent track sign (ultrasound)

Patent track sign is a finding on color Doppler ultrasound, representing blood traveling along the course a biopsy needle track. It can occur after a biopsy of any organ, but is more often seen after liver or kidney biopsies. Radiographic findings linear color Doppler flow along the course of ...
Article

Peaking sign (tension pneumocephalus)

The peaking sign is seen in cross-sectional imaging of the brain suggestive of a tension pneumocephalus. It represents the frontal lobes being pushed together forming a peak in the midline giving a heaped up appearance surrounded by air 1. Later, as the frontal lobes are separated they take on t...
Article

Pearl necklace sign

The pearl necklace sign occurs in adenomyomatosis of the gallbladder, on both oral cholecystograms and MRCP. It represents the contrast/fluid-filled intramural mucosal diverticula (Rokitansky-Aschoff sinuses); lined up, these are reminiscent of pearls on a necklace. It is synonymous with the CT ...
Article

Pear-shaped bladder

Pear-shaped (or teardrop-shaped) bladder is one whose normal round or ovoid shape has been extrinsically compressed to resemble a pear. The pear may be inverted or upright, depending on how the excess pelvic tissue compresses the bladder. Pathology Etiology Causes of a pear-shaped bladder inc...
Article

Peg-like tonsil (cerebellum)

Peg-like tonsils refer to the CT or MR appearances of pointed cerebellar tonsils on sagittal scans. The may help distinguish low-lying tonsils from cerebellar tonsillar ectopia due to a Chiari I malformation.  The terminology of caudally displaced tonsils is discussed in the article on cerebell...
Article

Pellegrini-Stieda lesion

Pellegrini-Stieda lesions are ossified post-traumatic lesions at (or near) the medial femoral collateral ligament adjacent to the margin of the medial femoral condyle. One presumed mechanism of injury is a Stieda fracture (avulsion injury of the medial collateral ligament at the medial femoral c...
Article

Pelvic teardrop

The pelvic teardrop, also known as U-figure or Köhler's​ teardrop, is a radiographic feature seen on pelvic x-rays and results from the end-on projection of a bony ridge running along the floor of the acetabular fossa. This was shown to be the case by demonstrating that sawing away this bony pl...
Article

Penumbra sign (bones)

The penumbra sign represents a rim of vascularized granulation tissue around a bone abscess cavity that has a higher T1 signal intensity than the cavity itself 1.  It should not be confused with the ischemic penumbra of cerebral infarction.  The penumbra is isointense to muscle on T1, enhances...
Article

Peribronchial cuffing

Peribronchial cuffing refers to a radiographic term used to describe haziness or increased density around the walls of a bronchus or large bronchiole seen end-on, both on plain radiographs and on CT. It is sometimes described as a "doughnut sign". When viewed tangentially, it can give the appear...
Article

Pericardial calcification

Pericardial calcification usually occurs in patients with a history of pericarditis.  Pathology Etiology uremia previous trauma or prior pericarditis later sequelae of rheumatic heart disease malignant pericardial involvement (e.g. mediastinal teratoma) post-radiotherapy 5 On chest radio...
Article

Pericardial fat tag sign (pneumothorax)

The pericardial fat tag sign is a sign of pneumothorax on supine CXR where the cardiac border has a lumpy contour. When gas is located in the pleural space between the lung and mediastinum, the pericardial fat is no longer compressed against the mediastinum and therefore can hang or dangle late...
Article

Perilymphatic fistula

A perilymphatic fistula (also known as a labyrinthine fistula) is a pathologic communication between the fluid-filled space of the inner ear and the air-filled space of the middle ear, most commonly occurring at either the round or oval window. The primary manifestations of perilymphatic fistu...
Article

Perinephric stranding

Perinephric stranding refers to the appearance of edema within the fat of the perirenal space on CT or MRI. While a degree of symmetric bilateral perinephric stranding is common, particularly in the elderly, asymmetric or unilateral perinephric stranding is an important sign of renal inflammatio...
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Periportal free gas sign

The periportal free gas sign has been described as being strongly suggestive for upper gastrointestinal hollow viscus perforation. See also bowel perforation (summary) pneumoperitoneum

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