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Barbell sign (progressive multifocal leukoencephalopathy)

The barbell sign is a radiological sign present in progressive multifocal leukoencephalopathy (PML) on MRI brain. This describes confluent T2/FLAIR parieto-occipital abnormalities with a thin continuation of signal abnormality across the splenium 1,2. Given the lack of mass effect typically exh...

Ball of wool sign (hydatid cyst)

The ball of wool sign, also referred to as the yarn sign or congealed water lily sign, is an ultrasound appearance, representing degeneration of hydatid cysts (WHO class CE 4). The inner side of the cyst detaches from the cyst wall and folds on itself, causing a change from anechoic (fluid) to a...

Bracket sign (disambiguation)

A bracket sign has been named in multiple contexts: bracket sign in CT brain of calcification in tubulonodular pericallosal lipoma bracket sign in MRI brain of of the superior most extent of the pars marginalis of the cingulate sulcus

Radial bands sign (tuberous sclerosis)

The radial bands sign, also known as radial migration bands, refers to linear bands seen on MRI, radiating from the periventricular white matter to the subcortical region, thought to be specific for tuberous sclerosis 1,2. Pathology The exact pathogenesis of radial bands is uncertain, but they...

Obliteration of the retrosternal airspace

Obliteration of the retrosternal airspace is a sign on lateral chest radiographs which can be due to anterior mediastinal mass or right ventricular hypertrophy.

Feeding artery sign (endometrial polyp)

Feeding artery sign (a.k.a. pedicle artery sign) refers to the presence of a single feeding artery to endometrial lesion using color/power Doppler on ultrasonography. It is often seen in endometrial polyps 1. The feeding vessel indicates the stalk attachment of the polyp to the uterus. Endometr...

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. History and etymology Defined by the distal migration of...

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...

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...

Air trapping

Air trapping is the retention of excess gas in lung distal to one or more obstructed airways. Subnormal reduction in volume and subnormal increase in attenuation on end-expiratory CT are diagnostic findings and the affected areas are typically sharply demarcated. Reactive vasoconstriction is oft...

Pronator quadratus sign

The pronator quadratus sign, also known as MacEwan 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 as seen on a lateral wrist radiograph. Pathology Displacement, anterior bowing, or oblitera...

État criblé

État criblé, also known as status cribrosum, is a term that describes the diffusely widened perivascular spaces (Virchow-Robin spaces) in the basal ganglia, especially in the corpus striatum on MRI. It is usually symmetrical, with the perivascular spaces showing CSF signal on all sequences and w...

Cobra head sign (ureter)

The cobra head sign, also known as the spring onion sign, refers to dilatation of the distal ureter, surrounded by a thin lucent line seen in patients with an adult-type ureterocele. The cobra head appearance indicates an uncomplicated ureterocele. During an excretory phase of an intravenous ur...

String of pearls sign (Susac syndrome)

The string of pearls sign is a radiological sign described in Susac syndrome. The string of pearls sign is seen on diffusion-weighted imaging (DWI) whereby there are multiple punctate microinfarcts topographically located along the internal capsule 1-3. These are always accompanied by similar i...

Atoll sign (lungs)

The atoll sign or reversed halo sign refers to focal ground-glass opacity with a peripheral ring of consolidation which may be complete or incomplete. The sign was originally described in organizing pneumonia but can also occur in infections, infarction, granulomatous disease, inflammation and t...

Atoll sign (liver MRI)

The atoll sign in hepatic imaging has been described when a liver lesion shows a peripheral rim of high T2 signal intensity with the center of the lesion appearing isointense to the background of non-cirrhotic liver on T2WI mimicking an atoll. The peripheral rim shows hyperenhancement in the por...

String of pearls sign (disambiguation)

String of pearls sign can refer to: string of pearls sign on an abdominal radiograph of fluid-filled dilated small bowel loops string of pearls sign on brain MRI in deep border zone infarction string of pearls sign on brain MRI in Susac syndrome string of pearls sign on ultrasound in polycys...

Curlicue ureter sign (sciatic hernia)

The curlicue ureter sign 1 was described on intravenous pyelogram studies in cases of ureteral herniation into a sciatic hernia, causing a curled appearance of the herniated ureter. Although very rare, this sign is pathognomonic of ureterosciatic hernias. It can also be seen on CT urogram studies.

Monod sign (lungs)

The Monod sign describes gas that surrounds a mobile fungus ball or mycetoma (most commonly an aspergilloma) in a pre-existing pulmonary cavity 1-3. Terminology In the 2024 edition of the Fleischner glossary, air crescent is the preferred term applying to air crescents seen with both mobile in...

Satellite sign

The satellite sign is a radiological sign seen on non-contrast CT of the brain in the setting of intracerebral hemorrhage, and refers to a small hemorrhage adjacent to, and separate from, the main hematoma. It is a predictor of hemorrhage expansion. Epidemiology The satellite sign can be seen...

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