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.

1,079 results found
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Hereditary breast and ovarian cancer syndrome

Hereditary breast and ovarian cancer (HBOC) syndrome is caused by a mutation to either BRCA1 or BRCA2 genes. These patients have an increased risk of breast cancer, ovarian cancer, pancreatic cancer and prostate cancer. However, these gene mutations are not the only cause of hereditary breast ca...
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Hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterised by abnormal blood vessel formation in the skin, mucous membranes, and organs including the lungs, liver, and central nervous system. Epidemiology Worldwide prevale...
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Hereditary non-polyposis colorectal cancer

Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an inherited condition which predisposes to a host of malignancies, including colorectal carcinoma. It is considered the most frequent form of hereditary colorectal cancer. Diagnosis requires evaluation using cl...
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Hereditary pancreatitis

Hereditary pancreatitis is a rare subtype of chronic pancreatitis that has an autosomal dominant inheritance. Imaging plays a role in excluding underlying abnormalities. Clinical presentation As a congenital condition, presentation with acute pancreatitis attacks typically occurs in childhood,...
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Herpes oesophagitis

Herpes oesophagitis is one of the infectious oesophagitis that usually affects immunocompromised patients.  Epidemiology  It occurs as an opportunistic infection in immunocompromised patients, particularly those with AIDS. It has also been described in immunocompetent individuals 3. Pathology...
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Heyde syndrome

Heyde syndrome is an association between aortic valve stenosis and gastrointestinal haemorrhage. The aetiology of the gastrointestinal bleeding in this setting is uncertain, but it is thought to be related to intestinal angiodysplasia. The strength of this association independent of age-related...
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Hiatus hernia

Hiatus hernias occur when there is herniation of abdominal contents through the oesophageal hiatus of the diaphragm into the thoracic cavity. Epidemiology The prevalence of hiatus hernia increases with age, with a slight female predilection. Clinical presentation Many patients with hiatus he...
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Hiccups

Hiccups (or hiccoughs), medical term singultus (rarely used), are an unpleasant phenomenon, experienced by everyone on occasion, and usually self-limiting. However the much rarer intractable chronic form can be extremely debilitating. Epidemiology Hiccups are a symptom that has probably been e...
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Hide-bound sign (bowel)

The hide-bound bowel sign refers to an appearance on a barium study of the small bowel in patients with scleroderma. The sign describes the narrow separation between the valvulae conniventes which are of normal thickness despite dilatation of the bowel lumen.   Although the term hide-bound is u...
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High-grade appendiceal mucinous neoplasms

High-grade appendiceal mucinous neoplasms (HAMN) are rare mucinous tumours of the appendix showing high-grade cytologic atypia, cf. low-grade appendiceal mucinous neoplasms (LAMN). The distinction between both LAMN and HAMN is done on histological grounds and these tumours look the same on imagi...
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Hinchey classification of acute diverticulitis

E J Hinchey et al. 3 proposed a classification for acute diverticulitis, that has been variously adapted, and is useful not only in academia but also in outlining successive stages of severity. Classification stage 1a: phlegmon stage 1b: diverticulitis with pericolic or mesenteric abscess st...
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Hirschsprung disease

Hirschsprung disease is the most common cause of neonatal colonic obstruction (15-20%). It is commonly characterised by a short segment of colonic aganglionosis affecting term neonates, especially boys.  Epidemiology Hirschsprung disease affects approximately 1:5000-8000 live births. In short ...
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HIV/AIDS

Acquired immunodeficiency syndrome (AIDS) is an immunosuppressed state, caused by infection with the human immunodeficiency virus (HIV). It is characterised by opportunistic infections, neoplasms and neurological manifestations. Epidemiology According to the United Nations programme on HIV/AID...
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HIV/AIDS: gastrointestinal manifestations

Gastrointestinal manifestations of AIDS are protean and can be broadly divided into opportunistic infections and tumours: Infections viral  cytomegalovirus (CMV) herpes simplex virus (HSV) primary infection with HIV fungal candidiasis histoplasmosis bacterial tuberculosis mycobacteriu...
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HIV associated neoplasms

HIV-associated neoplasms are numerous and can be broadly divided into two groups: AIDS-defining malignancies associated but not AIDS defining malignancies AIDS-defining malignancies The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4: Ka...
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HIV oesophagitis

HIV oesophagitis is a possible cause of odynophagia in immunosuppressed patients with HIV. Epidemiology The actual incidence and prevalence of Idiopathic oesophagitis of HIV are unknown. Most of the patients have acquired immunodeficiency syndrome (AIDS) and CD4 count <100 3. Clinical present...
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Hydatid disease

Hydatid cysts result from infection by the Echinococcus, and can result in cyst formation anywhere in the body.  Pathology There are two main species of the Echinococcus tapeworm 1,2: Echinococcus granulosus commoner pastoral: dog is a main host; most common form sylvatic: wolf is a main h...
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Hyoscine-N-butylbromide (Buscopan)

Hyoscine-N-butylbromide, more commonly known by its brand name, Buscopan®, is an antimuscarinic agent, widely used in radiology as an antispasmodic agent. It is employed to freeze bowel motion as part of many fluoroscopic, CT and MRI studies (its main use for many years was for barium GI studies...
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Hyperattenuating ring sign in epiploic appandagitis

The hyperattenuating ring sign is a sign that has been described with epiploic appendagitis and refers to a hyperattenuating ring of visceral peritoneum surrounding an inflamed epiploic appendage 1. On CT it can be seen as a ring of soft tissue surrounding a region of fat attenuation adjacent to...
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Hypercontracting (nutcracker) oesophagus

Hypercontracting (nutcracker) oesophagus is a motility disorder of the oesophagus. This condition is primarily diagnosed with manometry with high intra-oesophageal pressure and normal peristalsis. Most patients will have a normal barium swallow.  Hypercontracting oesophagus ("nutcracker oesopha...
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Hypertriglyceridaemia-induced pancreatitis

Hypertriglyceridaemia-induced pancreatitis is an uncommon form of acute pancreatitis caused by high levels of circulating triglycerides in the blood. Epidemiology Hypertriglyceridaemia-induced pancreatitis accounts for around 1-4% of cases of acute pancreatitis and is the third most common cau...
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Hypertrophic pyloric stenosis (ultrasound measurements mnemonic)

Hypertrophic pyloric stenosis can be characterised in ultrasound studies by the measurements of the hypertrophic muscle. Although the criteria can vary from publication to publication, an easy way to keep in mind those values is remembering the first digits of the number "pi", also represented b...
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Ice pick sign

The ice pick sign is a smooth tapered narrowing of the upstream pancreatic duct distal to the pancreatic lesion seen frequently in benign pancreatic lesions such as a focal autoimmune pancreatitis, this is due to the extrinsic narrowing of the duct secondary to periductal fibrosis and inflammati...
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Idiopathic eosinophilic oesophagitis

Idiopathic eosinophilic oesophagitis is an inflammatory disease of the oesophagus characterised by eosinophilia that can involve all the layers of the oesophagus.  Epidemiology It is most commonly seen in males aged 20-40. It is an uncommon disease; however not rare.  Clinical presentation P...
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IgG4-related disease

IgG4-related disease (IgG4-RD) is a systemic disease that is characterised by extensive IgG4-positive plasma cells and T-lymphocyte infiltration of various organs. Terminology This condition has been known by many other names in the past, such as IgG4-related sclerosing disease, IgG4-related s...
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Ileal atresia

Ileal atresia is a congenital abnormality where there is significant stenosis or complete absence of a portion of the ileum. There is an increased incidence in those with chromosomal abnormalities. This article will focus on ileal atresia alone but bear in mind that some cases correspond to jej...
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Ileocaecal valve

The ileocaecal valve separates the terminal ileum from the caecum and functions to regulate flow between these two structures and prevent reflux from the caecum into the small intestine.  Gross anatomy The ileocaecal valve consists of two muscular layers of ileum, an upper and lower lip, that ...
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Ileocolic artery

The ileocolic artery is a branch of the superior mesenteric artery (SMA) that runs obliquely to the ileocaecal junction. It divides into an ileal branch that supplies the terminal ileum and anastomoses with the terminal SMA and a colic branch that supplies the proximal ascending colon and anast...
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Ileovesicostomy

Ileovesicostomy (also known as "cutaneous ileocystostomy", "ileal chimney", or "bladder chimney") is an uncommon urologic diversion in which a loop of small bowel is anastomosed/augmented to the dome of the bladder. This loop of bowel then exits through a urostomy. The diversion is not continent...
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Ileum

The ileum is the final part of the small intestine, following the duodenum and jejunum. Terminology The ileum is not to be confused with the ilium - the associated plural/adjectival forms are ilea/ileal and ilia/ilial respectively. Gross anatomy The ileum is 2-4 m in length and is separated ...
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Ilium vs ileum

The medical terms ileum and ilium have been causing great confusion to medical students and junior doctors alike for decades now. Only separated by one letter, the second vowel, the pronunciation may be identical, or differ slightly with the i sound resembling that in "bit" for ilium (ɪlɪəm) or ...
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Incidental splenic lesion (an approach)

The majority of splenic lesions are benign and when an incidental splenic lesion is found in an asymptomatic patient, it may pose a dilemma in workup because imaging findings are often nonspecific. benign imaging features: no follow up imperceptible wall well-marginated homogeneous <10-20 H...
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Incisional hernia

Incisional hernias are relatively common and along with parastomal hernias, umbilical hernias, paraumbilical hernias and spigelian hernias, they are usually anterior abdominal hernias. Epidemiology Usually develop within a few months of surgery but a small proportion can remain clinically sile...
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Indeterminate colitis

Indeterminate colitis is considered a somewhat controversial term. It was originally used by pathologists when no specific features for either Crohn disease (CD) or ulcerative colitis (UC) were seen. Over the years the term has been adopted to describe patients in whom a diagnosis of UC or CD ca...
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Indirect inguinal hernia

Indirect inguinal hernias are the most common type of abdominal hernias. Epidemiology It is five times more common than a direct inguinal hernia, and is seven times more frequent in males, due to the persistence of the processus vaginalis during testicular descent.  In children, the vast majo...
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Indium-111 OncoScint

Indium-111 OncoScint is a radiopharmaceutical used in SPECT imaging. It is a labelled monoclonal antibody that is directed against TAG-72, which is a tumour-associated antigen associated with ~95% of colorectal carcinomas and 100% of ovarian carcinomas 1,2. Background hepatic uptake limits sensi...
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Infectious colitis

Infectious colitis refers to inflammation of the colon due to an infective cause, including bacterial, viral, fungal, or parasitic infections. Epidemiology In Western countries, bacterial infection is the most common cause, while in developing countries parasitic infection is much more common....
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Inferior lumbar triangle

The inferior lumbar triangle, also known as the Petit triangle, is an anatomical space through which inferior lumbar hernias can occur. Gross anatomy Boundaries inferiorly: iliac crest anteriorly: external oblique muscle  posteriorly: latissimus dorsi muscle floor: internal oblique muscle ...
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Inferior mesenteric artery

The inferior mesenteric artery (IMA) is one of the three non-paired major visceral arteries in the abdominal cavity arising from the abdominal aorta and supplying the hindgut. It is the smallest of the three anterior visceral branches of the abdominal aorta. Gross anatomy Location Located wit...
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Inferior mesenteric vein

The inferior mesenteric vein drains blood from the distal portion of the colon as well as the rectum (i.e. the hindgut).  Gross anatomy Origin and course The inferior mesenteric vein drains the mesenteric arcade of the hindgut (comprising of distal transverse, descending, and sigmoid colon). ...
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Inferior pancreaticoduodenal artery

The inferior pancreaticoduodenal artery is the first branch of the superior mesenteric artery (SMA), though it often arises from the first jejunal branch. It anastomoses with branches of the superior pancreaticoduodenal artery (from the gastroduodenal artery) and it supplies the head of the pan...
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Inferior thoracic aperture

The inferior thoracic aperture connects the thorax with the abdomen. Gross anatomy The inferior thoracic aperture is irregular in shape and is more oblique and much larger than the superior thoracic aperture. The diaphragm occupies and closes the inferior thoracic aperture, thereby separating ...
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Inflammatory bowel disease

Inflammatory bowel disease (IBD), although occasionally used to encompass a variety of infective and purely inflammatory bowel conditions, usually refers to two idiopathic conditions Crohn disease ulcerative colitis Indeterminate colitis is added to the list, and represents approximately 6% o...
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Inflammatory bowel disease (summary)

This is a basic article for medical students and other non-radiologists Inflammatory bowel disease is a generic term used to describe diseases of the GI tract that have an inflammatory cause. Crohn disease (CD) and ulcerative colitis (UC) are the commonest causes of inflammatory bowel disease. ...
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Inflammatory bowel disease (thoracic manifestations)

Thoracic manifestations of both ulcerative colitis and Crohn disease can be variable and cannot be used to differentiate between these entities. They can develop at any time with respect to the clinical onset of the underlying disease. Actually, they can also predate the colonic disease or deve...
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Inflammatory pseudopolyp

An inflammatory pseudopolyp is an island of normal colonic mucosa which only appears raised because it is surrounded by atrophic tissue (denuded ulcerative mucosa). It is seen in long-standing ulcerative colitis. It must be distinguished from inflammatory polyps, which are regions of inflamed a...
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Inframesocolic space

The inframesocolic space is the peritoneal space below the root of the transverse mesocolon. The supramesocolic space lies above the transverse mesocolon's root. Gross anatomy The compartment can be divided into two unequal spaces posteriorly by the mesentery of the small bowel as it runs from...
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Ingested bones

Ingested bones that become lodged in the throat or gastrointestinal tract are a common presentation to the emergency department. Recognition is important because these cases can be potentially fatal.  Pathology Patients may present with a 'foreign body' feeling in the throat after eating fish ...
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Ingested foreign bodies in children

Ingested foreign bodies in children are common as the world is a curious place to young children, who will put anything and everything into their mouth, and will often inadvertently swallow.  The usual practice is for plain films of the chest/abdomen to identify a foreign body. Epidemiology P...
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Inguinal canal

The inguinal canal is a passage in the anterior abdominal wall that transmits structures from the pelvis to the perineum formed by the fetal migration of the gonad from the abdomen into the labioscrotal folds. Gross anatomy The inguinal canal has an oblique course, is 4 cm in length and has tw...
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Inguinal canal lipoma

Inguinal canal lipomas, also known as spermatic cord or round ligament lipomas,  are a relatively common but often under-recognised finding on imaging. Clinical presentation Lipomas are usually asymptomatic but can sometimes cause pain and discomfort. They can present as a mass lesion.  Patho...
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Inguinal hernia

Inguinal hernia is a type of abdominal wall hernia 1. Epidemiology They are the commonest type of abdominal wall herniation (up to 80% 3) and are most often acquired. There is a recognised male predilection with an M:F ratio of up to 7:1 3. Clinical presentation Patients most commonly presen...
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Insulinoma

Insulinomas are the most common sporadic endocrine tumour of the pancreas. On imaging, they usually present as small well-defined hypervascular tumours that may be found anywhere along the pancreas.  Epidemiology Account for 40% of syndromic pancreatic endocrine tumours. The overall incidence ...
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Internal hernia

Internal hernias are protrusions of the viscera through the peritoneum or mesentery but remaining within the abdominal cavity. Epidemiology Internal hernias have a low incidence of <1% and represent a relatively small amount of presentations, of ~5% 1. Clinical presentation The most common p...
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Internal hernias due to gastric bypass surgery

Internal hernias due to gastric bypass surgery are more common after laparoscopic gastric bypass than after an open procedure.  Clinical presentation It is a particularly sinister complication with variable, nonspecific clinical presentations. Most patients report a combination of postprandial...
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Internal iliac lymph nodes

The internal iliac lymph nodes can be found adjacent to the internal iliac artery and its branches and drain the regions supplied by these vessels. This encompasses a large area from the genitalia anteriorly, the psoas muscle posteriorly and medial thigh inferiorly (see internal iliac artery for...
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Internal oblique muscle

The internal oblique muscle (IOM) is one of the muscles that form the anterior abdominal wall. Inferiorly, it contributes towards the formation of the inguinal ligament. Summary origin: originates along the whole length of the lumbar fascia, from the anterior two-thirds of the iliac crest and ...
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Interstitial oedematous pancreatitis

Interstitial oedematous pancreatitis is one of the two subtypes of acute pancreatitis. It is normally referred to as "acute pancreatitis" or "uncomplicated pancreatitis" in day-to-day use. Please refer to the article on acute pancreatitis for further details. 
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Intestinal angioedema

Intestinal angioedema is oedema into the submucosal space of the bowel wall following protein extravasation from "leaky" vessels. It can affect both the small and large bowel. Clinical presentation Patients often present with non-specific findings of abdominal pain, nausea, and vomiting. Path...
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Intestinal failure

Intestinal failure is when a patient's native bowel is unable to digest and absorb  the food, electrolytes and fluids needed for normal growth and development.  Clinical presentation This often includes intractable diarrhoea, weight loss, dehydration, electrolyte imbalance, and malnutrition. ...
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Intestinal ischaemia

Intestinal ischaemia refers to vascular compromise of the bowel which in the acute setting has a very high mortality if not treated expediently. Diagnosis is often straightforward, provided appropriate imaging is obtained and sometimes subtle findings sought out. The disease can be arbitrarily c...
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Intestinal ischaemia (summary)

This is a basic article for medical students and other non-radiologists Intestinal ischaemia refers to vascular compromise of the bowel which in the acute setting has a very high mortality if not treated expediently. Diagnosis is often straight forward provided appropriate imaging is obtained. ...
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Intestinal lymphangiectasia

Intestinal lymphangiectasia is a condition characterised by dilated intestinal lacteals causing loss of lymph into the lumen of the small intestine. This can result in hypoproteinemia, hypogammaglobulinemia, hypoalbuminemia and reduced number of circulating lymphocytes or lymphopaenia.  Epidemi...
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Intestinal malrotation

Intestinal malrotation is a congenital anatomical anomaly that results from an abnormal rotation of the gut as it returns to the abdominal cavity during embryogenesis. Although some individuals live their entire life with malrotated bowel without symptoms, the abnormality does predispose to mid...
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Intestinal nonrotation

Intestinal nonrotation is a congenital anomaly of the intestines that results in the small bowel occupying the right side of the peritoneal cavity and the colon predominantly on the left. It is sometimes thought of as a subtype of intestinal malrotation. Epidemiology Nonrotation is estimated ...
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Intestinal transplant

Intestinal transplantation is a surgical treatment for intestinal failure. It is one of the most rarely performed transplant procedures performed, exclusively involving the transplantation of donor small bowel to a recipient, with an ileostomy formation.  Due to the high risk of complications w...
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Intestinal volvulus

Intestinal volvulus is a broad term that describes the torsion of bowel around its mesentery. Torsion results in narrowing of the lumen at the point of rotation and compromise of the vessels that supply the torted gut.  In order for a vessel to be compressed and obstructed, the force that the t...
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Intra-abdominal calcification

Intra-abdominal calcification is common and the causes may be classified into four broad groups based on morphology: Concretions These are discrete precipitates in a vessel or organ. They are sharp in outline but the density and shape vary but in some cases they may be virtually pathognomonic:...
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Intra-abdominal calcification (neonatal)

Intra-abdominal calcification in a neonate can be caused by a number of pathologies that cause calcification within the peritoneal space or within organs. Pathology Aetiology Meconium peritonitis The commonest cause is meconium peritonitis which is the result of aseptic peritonitis secondary...
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Intraductal papillary mucinous neoplasm

Intraductal papillary mucinous neoplasms or tumours (IPMNs or IMPTs) are cystic tumours of the pancreas. Epidemiology These tumours are most frequently identified in older patients (50-60 years of age) 6, and thus are sometimes colloquially referred to as the "grandfather lesion". Main duct ty...
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Intramural bowel gas

Intramural bowel gas, also known as pneumatosis intestinalis, refers to the clinical or radiological finding of gas within the wall of the bowel. Terminology There are different terminologies in the medical literature, such as pneumatosis intestinalis, pneumatosis coli, and pneumatosis cystoid...
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Intraperitoneal focal fat infarction

Intraperitoneal focal fat infarction (IFFI) refers to a group of self-limiting abdominal diseases where the primary insult is acute inflammation of intraperitoneal fat. They commonly mimic the more common causes of acute abdomen such as acute diverticulitis and acute appendicitis. The group incl...
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Intussusception

Intussusception occurs when one segment of bowel is pulled into itself or a neighbouring loop of bowel by peristalsis. It is an important cause of an acute abdomen in children and merits timely ultrasound examination and reduction to preclude significant sequelae including bowel necrosis. When o...
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Inverted "V" sign (pneumoperitoneum)

The inverted "V" sign, also known as the lateral umbilical ligament sign, is a sign of pneumoperitoneum manifested by the visualisation of an inverted "V"  shape in the pelvis on supine view of abdominal radiographs. It represent free gas outlining the lateral umbilical ligaments. In infants, th...
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Investigating abdominal pain (summary)

This is a basic article for medical students and other non-radiologists Investigating abdominal pain is a common request from clinical teams throughout most hospitals. Causes of abdominal pain are vast and as such, appropriate history and examination are necessary to initiate appropriate initia...
Article

Investigating jaundice (summary)

This is a basic article for medical students and other non-radiologists Investigation of jaundice is heavily reliant on radiology, from the simplest of investigations (the ultrasound) through to much more complicated MRI-based test and intervention. It is important to determine whether jaundic...
Article

Investigating nausea and vomiting (summary)

This is a basic article for medical students and other non-radiologists Nausea and vomiting (often abbreviated in medical notes to N&V) are non-specific physical manifestations of disease. They may occur together, or in isolation and may be the result of obstructive pathology or as a general ma...
Article

Investigating PR bleeding (summary)

This is a basic article for medical students and other non-radiologists Investigating PR bleeding radiologically may help to make a diagnosis or give more information after a diagnosis has been established. Radiology should not replace appropriate physical examination or appropriate use of sigm...
Article

Irish node

An Irish node is an enlarged axillary lymph node, often associated with advanced gastric cancer1.
Article

Iron deficiency anaemia

Iron deficiency anaemia is a common cause of anaemia and a common precipitant to radiological investigation. Epidemiology Amongst men and postmenopausal women, the incidence in the developed world is around 2%. Among premenopausal women, the incidence is greater and in most cases, investigatio...
Article

Ischaemic colitis

Ischaemic colitis refers to inflammation of the colon secondary to vascular insufficiency and ischaemia. It is sometimes considered under the same spectrum as intestinal ischaemia. The severity and consequences of the disease are highly variable. Epidemiology Ischaemic bowel is typically a dis...
Article

Ischioanal fossa

The ischioanal (or ischiorectal) fossa is a fat-filled space of the perineum.  Gross anatomy The ischioanal fossa is a paired triangular-shaped space lateral to the anal canal with an apex directed anteromedially towards the pubic symphysis. Each ischioanal fossa is separated from the other by...
Article

Ishikawa classification of venous involvement by pancreatic ductal adenocarcinoma

Ishikawa classification system describes the degree of involvement of adjacent portal vein and SMV by pancreatic ductal adenocarcinoma based on calibre of the vein: type I: normal  type II: smooth shift/displacement with normal calibre   type III: unilateral narrowing  type IV: bilateral nar...
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Isolated free fluid in trauma

Isolated free fluid in trauma may or may not represent a significant injury, and this creates a diagnostic dilemma in determining appropriate treatment for these patients.  Epidemiology The presence of isolated free fluid in trauma occurs in 3-5% of blunt trauma patients 1-4. Pathology The c...
Article

Ivor Lewis procedure

Ivor Lewis procedure (also known as a gastric pull-up) is a type of oesophagectomy, an upper gastrointestinal tract operation performed for mid and distal oesophageal pathology, usually oesophageal cancer. Due to the necessity of removing a significant length of the oesophagus, the stomach is "...
Article

Jejunal and ileal branches of the superior mesenteric artery

The jejunal and ileal branches of the superior mesenteric artery are variable in number. They pass in the two layers of the mesentery to the jejunum and ileum and progressively divide and join in a series of anastomosing arcades. From the arcades, straight arteries (also known as the vasa recta...
Article

Jejunal atresia

Jejunal atresia is a congenital anomaly characterised by obliteration of the lumen of the jejunum. The site of the atresia can be anywhere from the ligament of Treitz to the jejunoileal junction. There can be more than one atretic segment. This article will focus on jejunal atresia alone but be...
Article

Jejunocolic bypass

Jejunocolic bypass was an early form of bariatric surgery. It is no longer performed due to severe side effects. For this bypass, the proximal small bowel (jejunum) is transected and anastomosed to the colon (such as the transverse colon). The other end of the small bowel is closed and the dist...
Article

Jejunoileal bypass

Jejunoileal bypass is an older form of bariatric surgery that was developed to be an improvement on jejunocolic bypass. It is no longer performed due to severe side effects. For this bypass, the proximal small bowel (jejunum) is divided ~35 cm past the ligament of Treitz, and the proximal end i...
Article

Jejunoileal diverticula

Jejunoileal diverticula, also referred to as jejunal diverticula or diverticulosis as most of the diverticula are located in the jejunum, are outpouchings from the jejunal and ileal wall on their mesenteric border that represent mucosal herniation through sites of wall weakening 1. See also Pl...
Article

Jejunoileal fold pattern reversal

Jejunoileal fold pattern reversal (a.k.a. jejunisation of the ileum) is one of the signs of coeliac disease, and is seen on small bowel follow-through studies as well as CT. The pattern is one of increased number of ileal folds and reduced number of jejunal folds 1,2, and is considered positive ...
Article

Jejunum

The jejunum is arbitrarily defined as the proximal two-fifths of the small intestine and is, on average, about 3 m in length. Gross anatomy Compared to the ileum, the jejunum has more valvulae conniventes and fewer folds per unit length. Like the ileum, the normal jejunal wall thickness is les...
Article

Jejunum vs ileum

There are a few differences that can help differentiate jejunum and ileum 1-3: location jejunum: upper left part of the peritoneal cavity ileum: lower right part of the peritoneal cavity gross appearance jejunum: greater calibre (<3 cm), thicker walls and more vascular  ileum: lesser calib...

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