Hepatic and splenic tuberculosis refers to tuberculosis affecting the liver and the spleen. It generally occurs due to hematogenous spread from the primary site of infection, commonly from pulmonary tuberculosis.
Two types of lesions are known:
The hepatic edge sign is a radiographic sign of pneumoperitoneum seen on a supine plain abdominal radiograph. It is represented by a cigar-shaped pocket of free air in the subhepatic region, which tracks superomedial following the contour of the liver.
Hepatic pseudolesions near the falciform ligament show abnormal attenuation without mass effect. They may be seen on contrast-enhanced CT scans as either a region of high or low attenuation relative to the rest of the liver. They are typically located in the medial segment of the left lobe of th...
The hepatoduodenal ligament is a peritoneal ligament of lesser omentum containing the portal triad 1.
The hepatoduodenal ligament is a thickening of the right edge of the lesser omentum and forms the anterior margin of the epiploic foramen. It extends from the porta hepatis to t...
The hepatogastric (gastrohepatic) ligament is a peritoneal ligament that together with the hepatoduodenal ligament forms the lesser omentum. It derives from the embryonic ventral mesentery.
The hepatogastric ligament extends from the fissure of the ligamentum venosum and porta he...
Hepatorenal syndrome refers to a form of acute kidney injury caused by changes in renal blood flow regulation due to liver pathology 1. Although the syndrome occurs mainly in cirrhotic livers it has been reported in patients with acute fulminant liver failure as well 1.
Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly).
Many, many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive!
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...
Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterized by abnormal blood vessel formation in the skin, mucous membranes, and organs including the lungs, liver, and central nervous system.
Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an autosomal dominant 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...
Hereditary pancreatitis is a rare subtype of chronic pancreatitis that has an autosomal dominant inheritance and is one of the main causes of pancreatitis in childhood.
As a congenital condition, a presentation with acute pancreatitis attacks typically occurs in childhoo...
Hernias (or herniae) are a common pathological entity, in which an anatomical structure passes into an abnormal location via an opening.
The opening may be a normal physiological aperture (e.g. hiatus hernia: stomach passes through the diaphragmatic esophageal hiatus) or pathological. Iatrogeni...
Herpes esophagitis is one of the infectious esophagitis that usually affects immunocompromised patients.
It occurs as an opportunistic infection in immunocompromised patients, particularly those with AIDS. It has also been described in immunocompetent individuals 3.
Heyde syndrome is an association between aortic valve stenosis and gastrointestinal hemorrhage.
The etiology 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 d...
Hiatus hernias (alternative plural: herniae) occur when there is herniation of abdominal contents through the esophageal hiatus of the diaphragm into the thoracic cavity.
The prevalence of hiatus hernia increases with age, with a slight female predilection.
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.
Hiccups are a symptom that has probably been e...
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...
There are several mnemonics to remember the causes of high density lesions in the gastrointestinal tract on CT:
C: chloral hydrate/cocaine packets
H: heavy metals
I: iodinated compounds, e.g. contrast media, iron
High-grade appendiceal mucinous neoplasms (HAMN) are rare mucinous tumors 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 tumors look the same on imaging...
Edward John Hinchey et al. 3 proposed a classification for acute diverticulitis, (anywhere along the bowel, not just the colon) that has been variously adapted, and is useful not only in academia but also in outlining successive stages of severity.
stage Ia: phlegmon
stage Ib: ...
Hirschsprung disease is the most common cause of neonatal colonic obstruction (15-20%). It is commonly characterized by a short segment of colonic aganglionosis affecting term neonates, especially boys.
Hirschsprung disease affects approximately 1:5000-8000 live births. In short ...
The acquired immunodeficiency syndrome (AIDS) is an immunosuppressed state, caused by infection with the human immunodeficiency virus (HIV). It is characterized by opportunistic infections, neoplasms, and neurological manifestations.
According to the United Nations programme on HI...
Gastrointestinal manifestations of AIDS are protean and can be broadly divided into opportunistic infections and tumors:
herpes simplex virus (HSV)
primary infection with HIV
HIV-associated neoplasms are numerous and can be broadly divided into two groups:
associated but not AIDS defining malignancies
The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4:
HIV esophagitis is a possible cause of odynophagia in immunosuppressed patients with HIV.
The actual incidence and prevalence of idiopathic esophagitis of HIV are unknown. Most of the patients have AIDS and a CD4 count <100 cells/mm3 (= <100 cells/μL) 3.
A horseshoe appendix is an extremely rare variant of the vermiform appendix, in which the appendix arises from the cecum and curves back on itself to re-insert into the cecum, similar to a semicircular canal in the inner ear.
Anatomic variation of the appendix is extremely rare. I...
Several normal anatomical structures and rare organ variants have been described as being horseshoe-shaped.
horseshoe pancreas 1
The Howship-Romberg sign refers to obturator nerve neuropathy due to compression of the obturator nerve by an obturator hernia. Patients present with pain and paresthesia along the inner aspect of the thigh, down to the knee.
History and etymology
Named after Moritz Heinrich Romberg (1795-1873...
Hydatid cysts result from infection by the Echinococcus tapeworm species and can result in cyst formation anywhere in the body.
Cystic echinococcosis has a worldwide geographical distribution. The Mediterranean basin is an important endemic area 6,7.
There are two main...
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...
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...
Hypercontracting (nutcracker) esophagus is a motility disorder of the esophagus. This condition is primarily diagnosed with manometry with high intra-esophageal pressure and normal peristalsis. Most patients will have a normal barium swallow.
Hypercontracting esophagus ("nutcracker esophagus")...
Hyperthermic intraperitoneal chemotherapy (often abbreviated as HIPEC) is a form of chemotherapy used for the treatment of peritoneal involvement with malignancy.
It usually involves the instillation of heated (to around 41–43°C) chemotherapy agents directly into the abdominopelvic cavity imme...
Hypertriglyceridemia-induced pancreatitis is an uncommon form of acute pancreatitis caused by high levels of circulating triglycerides in the blood.
Hypertriglyceridemia-induced pancreatitis accounts for around 1-4% of cases of acute pancreatitis and is the third most common cause...
Hypertrophic pyloric stenosis can be characterized on ultrasound by the measurements of the hypertrophic muscle. Although the criteria can vary from publication to publication, an easy way to keep in mind the values is using a mnemonic which relies upon remembering the first digits of the number...
Hypervascular pancreatic lesions may be caused by a broad range of pathologies.
intrapancreatic accessory spleen: should not be overdiagnosed as a malignant tumor
peripancreatic vascular anomalies
arterial aneurysm 1
involves the pancreaticoduodenal and /or gastroduoden...
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...
Idiopathic eosinophilic esophagitis is an inflammatory disease of the esophagus characterized by eosinophilia that can involve all the layers of the esophagus.
It is most commonly seen in males aged 20-40. It is an uncommon disease; however not rare.
IgG4-related disease (IgG4-RD) is a systemic disease that is characterized by fibroinflammatory infiltration of various organs, including by plasma cells that express IgG4 (immunoglobulin G subclass 4).
This condition has been known by many other names in the past, such as IgG4-rel...
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...
Ileal pouch-anal anastomosis (IPAA), also referred to as a J-pouch procedure, is a colorectal surgery technique performed in patients undergoing proctocolectomy or proctectomy, where a reservoir ("neorectum") is made with a segment of distal ileum just before its anastomosis with the anal canal....
Ileocecal tuberculosis is the most common site of gastrointestinal tuberculosis, which in turn is the third most common site of extrapulmonary tuberculosis.
Three morphological types of ileocecal tuberculosis are known:
The ileocecal valve separates the terminal ileum from the cecum and functions to regulate flow between these two structures and prevent reflux from the cecum into the small intestine.
The ileocecal valve consists of two muscular layers of ileum, an upper and lower lip, that are ...
The ileocolic artery is a branch of the superior mesenteric artery (SMA) that runs obliquely to the ileocecal junction. It divides into an ileal branch that supplies the terminal ileum and anastomoses with the terminal SMA and a colic branch. It also gives off anterior and posterior cecal arteri...
An Ileostomy is a surgical method in which loop of the distal small bowel is connected and opened through the outer abdominal wall to artificially created a connection and bypass large bowel loops.
There are two types of ileostomies :
permanent end ileostomy
A permanent end ...
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...
The ileum is the final part of the small intestine, following the duodenum and jejunum.
The ileum is not to be confused with the ilium - the associated plural/adjectival forms are ilea/ileal and ilia/ilial respectively.
The ileum is 2-4 m in length and is separated ...
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 ...
Incarcerated (also referred to as irreducible) is used to describe herniae, in which their contents are unable to pass back through the hernial opening to their anatomical site of origin.
Incarceration is a risk factor for bowel obstruction and strangulation, and therefore usually necessitates...
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
Incisional hernias (alternative plural: herniae) are relatively common and along with parastomal hernias, umbilical hernias, paraumbilical hernias, and Spigelian hernias, they are usually anterior abdominal hernias.
Incisional hernias usually develop within a few months of surgery...
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...
Indirect inguinal hernias (alternative plural: herniae), a type of groin herniation, are the most common type of abdominal hernia.
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 vaginal...
Indium-111 OncoScint is a radiopharmaceutical used in SPECT imaging. It is a labeled monoclonal antibody that is directed against TAG-72, which is a tumor-associated antigen associated with ~95% of colorectal carcinomas and 100% of ovarian carcinomas 1,2. Background hepatic uptake limits sensiti...
Infectious colitis refers to inflammation of the colon due to an infective cause, including bacterial, viral, fungal, or parasitic infections.
In Western countries, bacterial infection is the most common cause, while in developing countries parasitic infection is much more common....
Infective enteritis is a common condition although, routinely, does not require imaging.
Patients can present with fevers, colicky abdominal pain, diarrhea, nausea and vomiting 2,3.
There are numerous organisms that can cause infective enteritis with classically...
The inferior lumbar triangle, also known as the Petit triangle, is an anatomical space through which inferior lumbar hernias can occur. It is not to be confused with the adjacent superior lumbar triangle (of Grynfeltt-Lesshaft).
inferiorly: iliac crest
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.
The inferior mesenteric vein drains blood from the distal portion of the colon as well as the rectum (i.e. the hindgut).
Origin and course
The inferior mesenteric vein drains the mesenteric arcade of the hindgut (comprising of distal transverse, descending, and sigmoid colon). ...
The inferior pancreaticoduodenal artery is the first branch of the superior mesenteric artery (SMA).
It usually arises at the inferior border of the pancreas or with the first jejunal artery as part of the pancreaticoduodenojejunal trunk.
It anastomoses with branches of the superior pancreati...
The inferior thoracic aperture connects the thorax with the abdomen.
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 ...
Inflammatory bowel disease (IBD), although occasionally used to encompass a variety of infective and purely inflammatory bowel conditions, usually refers to two idiopathic conditions:
Indeterminate colitis is added to the list and represents approximately 6% o...
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.
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...
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...
The inframesocolic space is the peritoneal space below the root of the transverse mesocolon. The supramesocolic space lies above the transverse mesocolon's root.
It can be divided into two unequal spaces posteriorly by the mesentery of the small bowel as it runs from the duodenojejunal flexure ...
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.
Fish bones are more commonly ingested than chicken or pork bones. Patie...
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 and/or abdomen to identify a foreign body.
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.
The inguinal canal has an oblique course, is 4 cm in length and has tw...
Inguinal canal lipomas, also known as spermatic cord or round ligament lipomas, are a relatively common but often under-recognized finding on imaging.
Lipomas are usually asymptomatic but can sometimes cause pain and discomfort. They can present as a mass lesion.
Inguinal hernias (herniae also used) are a type of groin herniation, part of a much larger group of abdominal wall hernias 1.
They are the commonest type of abdominal wall herniation (up to 80% 3) and are most often acquired. There is a recognized male predilection with an M:F ra...
Inguinal hernia repair plug refers to a nonabsorbable material such as a polypropylene inserted intraoperatively into an inguinal hernial defect.
Usually located anterior to the iliac vessels at the level of the inguinal canal. Size varies with mean long axis diameter 2.6 cm. Unilate...
Insulinomas are the most common sporadic endocrine tumor of the pancreas.
On imaging, they usually present as small well-defined hypervascular tumors that may be found anywhere in the pancreas.
Account for 40% of syndromic pancreatic endocrine tumors. The overall incidence is of...
Internal hernias (alternative plural: herniae) are protrusions of the viscera through the peritoneum or mesentery but remaining within the abdominal cavity.
Internal hernias have a low incidence of <1% and represent a relatively small amount of presentations, of ~5% 1.
Internal hernias due to gastric bypass surgery are more common after laparoscopic gastric bypass than after an open procedure.
Incidence after a Roux-en-Y gastric bypass may range between 1-16%. The presence of strangulation may be associated with a mortality rate exceeding 50% r...
The internal iliac lymph nodes (often shortened to internal iliac nodes) are the lymph nodes 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...
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.
origin: originates along the whole length of the lumbar fascia, from the anterior two-thirds of the intermediate lin...
Internal supravesical hernias (alternative plural: herniae) are a type of internal hernia in which viscera protrude into the supravesical fossa, occupying the paravesical space.
It is a very rare condition and accounts for less than 4% of all internal herniae 4.
Interstitial edematous 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.
Intestinal angioedema is edema into the submucosal space of the bowel wall following protein extravasation from "leaky" vessels. It can affect both the small and large bowel.
Patients often present with non-specific findings of abdominal pain, nausea, and vomiting.
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.
This often includes intractable diarrhea, weight loss, dehydration, electrolyte imbalance, and malnutrition.
This is a basic article for medical students and other non-radiologists
Intestinal ischemia 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. T...
Intestinal lymphangiectasia is a condition characterized by dilated intestinal lacteals causing loss of lymph into the lumen of the small intestine. This can result in hypoproteinemia, hypogammaglobulinemia, hypoalbuminemia and lymphopenia.
It may present in either children or ad...
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...
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.
Nonrotation is estimated ...
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...
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 torsed gut.
In order for a vessel to be compressed and obstructed, the force that the t...
Intra-abdominal calcification is common and the causes may be classified into four broad groups based on morphology:
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...
Intra-abdominal calcification in a neonate can be caused by a number of pathologies that cause calcification within the peritoneal space or within organs.
The commonest cause is meconium peritonitis which is the result of aseptic peritonitis secondary ...
Intraductal papillary mucinous neoplasms or tumors (IPMNs or IMPTs) are epithelial pancreatic cystic tumors of mucin-producing cells that arise from the pancreatic ducts. They are most commonly seen in elderly patients.
On imaging, particularly MRCP, they are characterized by single or multipl...
Intramural bowel gas, also known as pneumatosis intestinalis, refers to the clinical or radiological finding of gas within the wall of the bowel.
There are different terminologies in the medical literature, such as pneumatosis intestinalis, pneumatosis coli, and pneumatosis cystoid...
An intrapancreatic accessory spleen is a splenunculus within the pancreatic parenchyma.
Differentiating this finding from other pancreatic neoplasms is important to avoid unnecessary surgery.
Intrapancreatic splenunculi are not as rare as previously thought and their incidence ra...
The presence of gas in the pancreatic gland and/or the pancreatic ducts is an uncommon finding.
Causes of gas in the pancreatic ducts
altered function and/or anatomy of the sphincter of Oddi: causes duodenal-pancreatic duct reflux
patulous pancreatic duct opening 2