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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.

972 results found
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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 ...
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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 (disambiguation)

The napkin ring sign may refer to either of the following imaging findings: napkin ring sign (colon): colonic stenosis such as due to colon cancer napkin ring sign (coronary): coronary artery vulnerable plaque A napkin ring is a decorative household item used in some Western societies to hold...
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Napkin-ring sign (heart)

The napkin-ring sign is a feature of high-risk coronary artery atherosclerotic plaque on CT coronary angiogram (coronary CTA). 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.  It is n...
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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...
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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 ...
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Northern exposure sign (sigmoid volvulus)

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...
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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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O'Donoghue unhappy triad

O'Donoghue unhappy triad or terrible triad often occurs in contact and non-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 an abduction-external rotation mechanism of injury ("pivot s...
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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 a histopathologic finding in hypertrophic neuropathies such as Charcot-Marie-Tooth type 1A (CMT1A) and chronic inflammatory demyelinating polyneuropathy (CIDP). Pathology Onion bulb formations are concentric layers of Schwann cell processes and collagen surrounding axon...
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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 ...
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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 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 (epicardial ...
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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 ...
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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 (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...
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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...
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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...
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Parrot beak meniscal tear

Parrot beak meniscal tear is a type of radial meniscal tear with a more oblique course, which on axial images gives the characteristic appearance of a curved V, similar to a parrot's beak. As it is obliquely oriented in relation to the coronal and sagittal plane, it results in a marching cleft s...
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Patellotrochlear index

Patellotrochlear index (PTI) is one of the methods to determine patellar height. Measurement Patellotrochlear index is measured on a sagittal MR image with the maximal patellar cartilage thickness and the maximal craniocaudal diameter of the patella. Two measurements are made:  A: the length...
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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 ...
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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...
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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 ...
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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...
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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...
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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...
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Pelvic brim sign

The pelvic brim sign is seen in the AP view of the pelvis and refers to a thickening of the pelvic brim outlined by the iliopectineal line. It is due to an osteoblastic reaction seen and first described in Paget disease, which leads to cortical thickening and sclerosis 1.
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Pelvic teardrop

The pelvic teardrop, also known as U-figure or Köhler​ 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 plat...
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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...
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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...
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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...
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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. Clinical presentation Symptoms of perilymphatic ...
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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 tract perforation. See also bowel perforation (summary) pneumoperitoneum
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Periportal halo (CT/US)

Periportal halo or periportal collar sign refers to a zone of low attenuation seen around the intrahepatic portal veins on contrast-enhanced CT or hypoechogenicity on liver ultrasound. It likely represents periportal edema, which is often used as a synonymous term. Periportal haloes may occur ar...
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Periportal halo sign (MRI)

The periportal halo sign on liver MRI is a specific sign of primary biliary cholangitis (formerly primary biliary cirrhosis) that is characterized by rounded low signal intensity around portal venous branches, 5-10 mm in size, on T1- and T2-weighted images. These lesions are usually numerous, in...
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Perirenal cobweb

Perirenal cobwebs are the presence of prominent perinephric septa. It is best appreciated on CT images. Pathology The cobweb is considered to be due to engorged venous collaterals or due to edema and fluid extravasation into the perirenal space 1. Perirenal cobwebs may be seen in many benign ...
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Peritoneal stripe sign (pneumoperitoneum)

The peritoneal stripe sign in abdominal ultrasonography is considered indicative of intraperitoneal free air, present in pneumoperitoneum. Free air in the abdomen will collect in an anti-dependent manner, typically the anterior prehepatic space in the supine patient, settling against the parieta...
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Peritoneal to abdominal height ratio (PAR)

Peritoneal to abdominal height ratio (PAR) ≥ 0.52 is a statistically associated sign for raised intra-abdominal pressure > 12 mmHg in the context of abdominal compartment syndrome in critically ill patients in CT.   It can be calculated by dividing the distance from the linea alba to the poster...
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Periwinkle sign (supratentorial ependymoma)

The periwinkle sign has been coined to describe what has been claimed to be a characteristic appearance of intraparenchymal supratentorial ependymomas on non-enhanced CT axial images. The central solid component with centripetal calcification surrounding central necrotic area resembles a flower...
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Persistent nephrogram

Persistent nephrograms occur when intravenous contrast media is retained by both kidneys for more than 3 minutes. Terminology Persistent nephrograms are characteristically bilateral and are usually distinguished from delayed nephrograms, which occur unilaterally.  Pathology Etiology hypoten...
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Phantom calyx

A phantom calyx is a solitary calyx which fails to opacify with contrast amidst an otherwise well-opacified pelvicalyceal system. It is due to an intrarenal process which has infiltrated and caused obliteration of the involved collecting system element. It may be seen in: tumor: especially tra...
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Phantom organ sign

The phantom organ sign is a term used when a large mass arises from a small organ and as a consequence, it is impossible to detect the affected organ. The identification of this sign and other radiological signs such as the embedded organ sign, beak sign, and prominent feeding artery sign on CT...
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Phemister triad (tuberculosis)

The triad of Phemister refers to three radiographic features seen classically with tuberculous arthroplasty 4: juxta-articular osteopenia/osteoporosis peripheral osseous erosions gradual narrowing of joint space History and etymology Named after Dallas Burton Phemister (1882-1951), American...
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Phrygian cap

Phrygian caps are the most common congenital anatomic variant of the gallbladder. It denotes folding of the fundus back upon the gallbladder body and is asymptomatic with no pathological significance. Radiographic findings A Phrygian cap may be identified on ultrasound, multiphase CT/MRI or ch...
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Picture frame vertebral body

Picture frame vertebral body is a radiologic appearance in which the cortex of the vertebral body is thickened. This sign can be seen in patients with Paget disease.  It is a result of disorganized new cortical bone formation after excessive osteoclastic activity causes the resorption of normal...
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Piece of pie sign (wrist)

The piece of pie sign refers to an abnormal triangular appearance of the lunate on a PA image of the wrist representing either lunate dislocation or perilunate dislocation 1,2. A lateral image will help differentiate whether there is lunate or perilunate dislocation, with lunate dislocation demo...
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Piglet sign (osmotic demyelination)

The piglet sign is seen in osmotic demyelination syndrome. It refers to the appearance of the upper pons in axial T2 and FLAIR images. The areas of coalescent T2 signal increase are reminiscent of a pig's snout, with other features on axial MR images resembling the rest of the face of a piglet w...
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Pine cone bladder

A pine cone bladder or Christmas tree bladder is a cystographic appearance in which the bladder is elongated and pointed with a thickened, trabeculated wall. It is typically seen in severe neurogenic bladder with increased sphincter tone (detrusor sphincter dyssynergia) due to suprasacral lesion...
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Pistol grip deformity (hip)

The pistol grip deformity is considered a typical radiographic sign of cam-type femoroacetabular impingement. The shape of the proximal femur is reminiscent of a flintlock pistol known from old pirate movies. History and etymology It was first described by American orthopedic surgeon S David S...
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Pitt pit

Pitt pit refers to an oval or round lucency in the anterosuperior aspect of the femoral neck, just distal to the articular surface. It represents a herniation of synovium or soft tissues into the bone through a cortical defect, hence the alternate name synovial herniation pit. They are usually a...
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Pivot shift test

The pivot shift test forms part of the orthopedic examination of a post-traumatic knee. A positive test shows high specificity for injury of the anterior cruciate ligament. Procedure The pivot shift test is performed on a supine patient.  At the start the subject's knee is permitted to droop ...
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Plankton sign (ultrasound)

The plankton sign refers to swirling, punctiform internal echoes within an otherwise anechoic pleural effusion which demonstrate slow, whirling dynamics, occasionally buffered by cardiac and respiratory impulses. When present, one may rule out a transudative effusion, and should be highly suspic...
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Pleural mouse

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

Pleural pointillism is multiple high signal regions on b=1000 diffusion-weighted imaging but not at lower b-values. It can be a reliable tool allowing differentiation of malignant from benign pleural lesions and can help guide biopsy 1-3.  Its sensitivity is reported to be 93-100% and specificit...
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Pneumolipohaemarthrosis

Pneumolipohaemarthrosis is the presence of intra-articular gas in a lipohemarthrosis. It indicates an open intra-articular fracture. 
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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...
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Pneumothorax (ultrasound)

Pneumothorax is a serious potential consequence of blunt thoracic trauma and, if misdiagnosed, it may quickly become life-threatening. For a discussion on epidemiology, clinical presentation, pathology, and treatment and prognosis please see the main pneumothorax article.  Radiographic feature...
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Polka-dot sign (vertebral hemangioma)

The polka-dot sign is the result of the replacement of the normal cancellous bone by thickened vertical trabeculae surrounded by fat marrow or vascular lacunae in vertebral intraosseous hemangiomas 2. It is the axial equivalent of the corduroy sign seen on sagittal and coronal images. On CT the ...
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Polo mint sign (venous thrombosis)

The polo mint sign is a description given to a venous thrombosis on contrast-enhanced CT imaging.  When viewed in the axial plane, a thin rim of contrast persists around a central filling defect due to thrombus. This gives an appearance like that of the popular UK mint sweet, the Polo (figure 1)...
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Polycoria

Polycoria is the presence of more than one true pupil in the iris, each possessing their own fully functional sphincter pupillae muscle, which responds appropriately to light and drugs. It is a very rare entity with only a few case reports in the global literature 1,2. Pseudopolycoria occurs whe...
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Pool sign (intracranial; metastatic adenocarcinoma)

The pool sign is a recently described brain MRI appearance where an intracranial mass exhibits a T2 hyperintense rim adjacent to a solid mass surrounded by peritumoral edema. This appearance has been recently suggested to be a feature characteristic of metastatic adenocarcinoma (with various pri...
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Pooping duck sign

Pooping duck sign indicates the presence of a triquetral fracture in a lateral wrist radiograph, where an avulsed fracture fragment from the dorsal cortex of the triquetrum projects along the dorsal aspect of the osseous structures of the wrist. In this sign, the fracture fragment represents th...
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Popcorn calcification

Popcorn calcification refers to amorphous calcifications often with rings and arcs that resemble popped corn kernels. This type of calcification may be seen in many radiological settings including 1: chondroid lesions (e.g. enchondroma, chondrosarcoma) fibrous dysplasia pulmonary hamartomas ...
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Popcorn calcification within the breast

Popcorn calcification in the breast is the classical description for the calcification seen in involuting fibroadenomas which, as the name suggests, has a popcorn-like appearance.  Pathology A fibroadenoma in the long run may degenerate and calcify. Initially, there are a few punctate peripher...
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Popeye sign

Popeye sign is a pronounced bulging muscle in the distal aspect of the biceps region of the arm. It is clinically apparent with a complete long head of biceps tendon tear which causes distal migration of the long head of biceps muscle.   Terminology Defined by the distal migration of the long ...
Article

Porcelain gallbladder

Porcelain gallbladder refers to extensive calcium encrustation of the gallbladder wall. The term has been used to emphasize the blue discolouration and brittle consistency of the gallbladder wall at surgery but is often an incidental finding on multiple different imaging modalities.  Clinical p...
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Porcelain left atrium

Porcelain left atrium, also known as 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 ren...
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Positive bronchus sign

The positive bronchus sign is seen on CT chest, and refers to the presence of a bronchus leading directly to a peripheral lung lesion 1,2. In one study, four types of tumor-bronchi relationships were described 3: patent bronchus leads directly to the tumor mass bronchus is within the tumor ma...
Article

Positive carpal sign

The positive carpal sign is a useful radiographic sign for the diagnosis of Turner syndrome in association with the other musculoskeletal manifestations. Radiographic features Abnormality in the shape of the proximal carpal row in the dorsopalmar radiographs of the wrist and hand (taking in th...
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Positive metacarpal sign

In the metacarpal sign, a line drawn along the heads of the 4th and 5th metacarpals will intersect the head of the 3rd metacarpal if shortening is present. The shortened 4th metacarpal is the key to the sign. The sign is positive in up to 9.6% of normal individuals 3. It is however seen in a va...
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Positive PCL line sign

The positive PCL line sign is an indirect sign of anterior cruciate ligament (ACL) tear based on secondary changes of the posterior cruciate ligament (PCL) on MRI images. A line tangent to the upper border of the PCL should normally intersect the medullary cavity of the distal femur, if it does ...
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Posterior fat pad sign (elbow)

The posterior fat pad sign is the visualization of a lucent crescent of fat located in the olecranon fossa on a true lateral view of an elbow joint with the elbow flexed at a right angle indicating an elbow joint effusion. Normally, the posterior fat pad will not be seen in this view.  In the s...
Article

Posterior pituitary bright spot

The posterior pituitary bright spot is an MRI feature of the normal pituitary gland wherein the posterior pituitary appears bright on non-contrast T1 weighted images.  Pathology The posterior pituitary bright spot, having intrinsically high signal on T1 weighted images is believed to be from t...
Article

Posterior wall sign (femoroacetabular impingement)

Posterior wall sign is a radiographic sign used to assess the morphology of posterior acetabular wall. A deficient posterior acetabular wall is often associated with acetabular retroversion or acetabular dysplasia, while a too-prominent posterior acetabular wall is a predisposing factor for post...
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Potato nodes

Potato nodes are a classical moniker for the large nodes seen in the lung hila and mediastinum on the chest radiograph in pulmonary sarcoidosis. This name is derived from the characteristic bulky irregular morphology of the nodes which is reminiscent of large lumpy potatoes. Although this appear...
Article

Powers ratio

The Powers ratio is a measurement of the relationship of the foramen magnum to the atlas, used in the diagnosis of atlanto-occipital dissociation injuries. The ratio, AB/CD, is measured as the ratio of the distance in the median (midsagittal) plane between the: basion (A) and the posterior spi...
Article

Pretzel sign (serpentine aneurysm)

The pretzel sign is seen on DSA and is indicative of a serpentine aneurysm 1. The sign refers to the sinusoid configuration of the intra-aneurysmal vascular channel seen in serpentine aneurysms, giving it the appearance of a pretzel.
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Prévost sign (eyes)

The Prévost sign, also known as the Vulpian sign, refers to conjugate ocular deviation in patients with acute cortical hemiparetic stroke. The direction is variable, depending on the location of the stroke 3. In a hemispheric stroke, the eyes usually deviate towards the lesion (away from the h...
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Pronator quadratus sign

The pronator quadratus sign can be an indirect sign of distal forearm trauma. It relies on displacement of the fat pad that lies superficial to the pronator quadratus muscle. Pathology Displacement, anterior bowing, or obliteration of the fat plane in the setting of trauma may indicate a dista...
Article

Pseudoboutonniere deformity

The pseudoboutonniere deformity is the result of an untreated hyperextension injury of the proximal interphalangeal joint. It is due to an uncommon avulsion of the volar plate from the proximal phalanx causing a flexion deformity of the PIP joint, while the central slip of the extensor tendon r...
Article

Pseudocalculus sign (common bile duct)

The pseudocalculus sign is a term coined to describe a mimic of a distally impacted common bile duct (CBD) stone on ERCP, MRCP and the various forms of cholangiography, including T-tube, CT, intraoperative, and percutaneous 1. It results from the forceful contraction of the choledochal sphincte...

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