String sign
Encyclopedia
String sign, or gastrointestinal string sign, is a medical term for a radiographic finding on an Upper GI series
, in which the patient is given a radio-opaque material, such as barium, to drink. X-ray
s are then taken of the patient's stomach and intestines.
The gastrointestinal string sign represents a severe narrowing of loop of bowel, in which a thin stripe of contrast within the lumen looks like a string.
It may be seen in Crohn's Disease
, Hypertrophic Pyloric Stenosis
(HPS), Carcinoid
and Colon Cancer.
In people with Crohn's Disease, the string sign is caused by incomplete filling of the intestinal lumen, which results from irritability and spasm associated with severe ulceration. In such cases, the string sign is most frequently seen at the terminal ileum.
In infants with Hypertrophic Pyloric Stenosis (HPS), the pylorus is narrowed and the radio-opaque material will take on the appearance of a thin string as it passes through this narrowed channel. Often, there are several of these strings seen (called the "railroad track sign"). The use of the Upper GI series for the diagnosis of HPS, which was the primary diagnostic tool for this condition in the 1980s and 1990s, has been largely replaced by the use of ultrasound
, which is less invasive and can visualize the thickened pylorus, giving actual measurements of this thickening.
Upper GI series
Upper GI series, also upper gastrointestinal tract radiography, is a radiologic examination of the upper gastrointestinal tract. It consists of a series of X-ray images of the esophagus, stomach and duodenum...
, in which the patient is given a radio-opaque material, such as barium, to drink. X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
s are then taken of the patient's stomach and intestines.
The gastrointestinal string sign represents a severe narrowing of loop of bowel, in which a thin stripe of contrast within the lumen looks like a string.
It may be seen in Crohn's Disease
Crohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
, Hypertrophic Pyloric Stenosis
Pyloric stenosis
Pyloric stenosis is a condition that causes severe vomiting in the first few months of life. There is narrowing of the opening from the stomach to the intestines, due to enlargement of the muscle surrounding this opening , which spasms when the stomach empties...
(HPS), Carcinoid
Carcinoid
Carcinoid is a slow-growing type of neuroendocrine tumor, originating in the cells of the neuroendocrine system.In 2000, the World Health Organization redefined "carcinoid", but this new definition has not been accepted by all practitioners. This has led to some complexity in distinguishing...
and Colon Cancer.
In people with Crohn's Disease, the string sign is caused by incomplete filling of the intestinal lumen, which results from irritability and spasm associated with severe ulceration. In such cases, the string sign is most frequently seen at the terminal ileum.
In infants with Hypertrophic Pyloric Stenosis (HPS), the pylorus is narrowed and the radio-opaque material will take on the appearance of a thin string as it passes through this narrowed channel. Often, there are several of these strings seen (called the "railroad track sign"). The use of the Upper GI series for the diagnosis of HPS, which was the primary diagnostic tool for this condition in the 1980s and 1990s, has been largely replaced by the use of ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
, which is less invasive and can visualize the thickened pylorus, giving actual measurements of this thickening.