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11 results found

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 oesophageal rupture.  It is seen as a V-shaped air collection. One limb of the V is produced by mediastinal air outlining the left lower lateral mediastinal border. The...

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...

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. ...

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 ileocaecal valve or with small-bowel follow-through. Although classically described with ...

Nightstick fracture

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...

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 ...

Non-accidental injuries

Non-accidental injuries (NAI) represent both ethical and legal challenges to treating physicians. Radiologists are often the first to suspect NAI when confronted with particular injury patterns, and a knowledge of these is essential if the opportunity to save a child from future neglect is not ...

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.

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...

Nubbin sign

Nubbin sign (also called as cystic duct sign) is an important sign in a HIDA scan (cholescintigraphy using iminodiacetic acid analogues) 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 tr...

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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