Fusiform intracranial aneurysms are a type of intracranial aneurysms with an elongated fusiform shape caused by atherosclerotic disease most common in the vertebrobasilar circulation.
3%-13% of all intracranial aneurysms
They can be incidental or asymptomat...
Gadofosveset trisodium (also known as AblavarTM or VasovistTM) is an intravenous blood pool contrast agent used in magnetic resonance imaging. The manufacturer discontinued production in 2017 due to poor sales.
It was designed as an agent for contrast-enhanced MR angiography since it exhibits s...
The gastroduodenal artery (GDA) is a terminal branch of the common hepatic artery which mainly supplies the pylorus of the stomach, proximal duodenum, and the head of the pancreas. Due to its proximity to the anterior wall of the first part of the duodenum, the gastroduodenal artery is one of th...
Generalised lymphatic anomaly, previously known as lymphangiomatosis, is a systemic condition characterized by multifocal lymphatic malformations with systemic distribution. Distribution of lymphatic malformations is variable; there can be cutaneous, thoracic and abdominal viscera, and osseous i...
The Giacomini vein or thigh extension of the small saphenous vein refers to a variation in lower limb venous anatomy where the small saphenous vein (SSV) continues through to the thigh as a distinct branch.
The persistence of this vein may play a contributory role in the development of chronic ...
Giant cell arteritis (GCA) is a common granulomatous vasculitis affecting medium- to large-sized arteries. It may also be known as temporal arteritis or cranial arteritis, given its propensity to involve the extracranial carotid artery branches such as the temporal artery.
Giant cerebral aneurysms are ones that measure >25 mm in greatest dimension.
Giant cerebral aneurysms account for ~5% of all intracranial aneurysms 1,3. They occur in the 5th-7th decades and are more common in females 2.
Patients can present with symptoms ...
The Glenn shunt, also known as Glenn procedure, is a palliative surgical procedure for a variety of cyanotic congenital heart diseases.
In this procedure, the systemic venous return is re-directed to the pulmonary circulation, bypassing the right heart 1-3.
It can be used in a varie...
Glomangiomas, also known as glomus tumours, are benign vascular tumours typically seen at the distal extremities.
On imaging, they characteristically present as small hypervascular nodules under the finger nail.
These tumours should not be confused with paragangliomas, which are...
The glomus body is a component of the dermis that is involved in thermoregulation.
It consists of a specialised arteriovenous anastomosis surrounded by a connective tissue capsule. They are most numerous in the fingers and toes and exist to shunt blood from the skin surface when...
Glomus jugulare paraganglioma is a paraganglioma of the head and neck that is confined to the jugular fossa. While it is a rare tumour, it is the most common of the jugular fossa tumours.
The relative prevalence of glomus jugulare with respect to other head and neck paraganglioma ...
The gonadal arteries are the paired primary vascular supply to the ovaries in the female and the testes in the male. As the anatomy of the gonadal arteries differs substantially between the sexes, they are covered separately:
The gonadal veins are paired structures that drain the gonads in males and females. In males it is called the testicular vein and in females it is called the ovarian vein. The gonadal veins ascend with the gonadal arteries in the abdomen along the psoas muscle anterior to the ureters. Like the s...
Gradman and Steinburg inferior vena cava aneurysm classification is one method of classing aneurysmal dilatation of the inferior vena cava, which is an uncommon finding. When present it can be often associated with other caval anomalies. Gradman and Steinburg method classifies them as 1:
The great cardiac vein (GCV) runs in the anterior interventricular groove and drains the anterior aspect of the heart where it is the venous complement of the left anterior descending artery. It is the main tributary of the coronary sinus.
It begins on the anterior surface of th...
The greater pancreatic artery, also known as the pancreatica magna artery, is a branch of the splenic artery that supplies the pancreatic tail and body.
It arises approximately two thirds the way along the splenic artery and descends a short distance to run to the left along the posterior margi...
The great saphenous vein (GSV) forms part of the superficial venous system of the lower limb.
Great saphenous vein is the preferred terminology over other variants such as long saphenous vein (LSV), greater saphenous vein or internal saphenous vein 5.
Origin and c...
Griesinger sign, named after Wilhelm Griesinger, a German psychiatrist and neurologist (1817-1868) refers to oedema of the postauricular soft tissues overlying the mastoid process as a result of thrombosis of the mastoid emissary vein. It is a complication of acute otomastoiditis and may be asso...
The Griffiths point (or Griffiths critical point) refers to the site of watershed anastomosis between the ascending left colic artery and the marginal artery of Drummond occurring in the region of the splenic flexure. Most anatomy texts describe the location as two-thirds along the transverse co...
A haemangioendothelioma is a tumour derived from blood vessels.
Subtypes dependent on location include
haemangioendothelioma of liver
Haemangiomas are benign tumours of vascular origin usually seen in early childhood, divided into
Unfortunately, the term haemangioma has been widely misused to apply to many non-neoplastic vascular malformations, particularly the com...
Haemangiopericytoma is a term formerly used to describe a continuum of mesenchymal tumours with elevated cellularity found throughout the body in soft tissue and bone. After many years of controversy, haemangiopericytomas have been shown to not only share histological features similar to solitar...
Haemangiopericytomas of the spleen are very rare vascular neoplasm with only a few case reports available at the time of writing.
Splenic haemangiopericytomas are typically asymptomatic or can result in splenomegaly.
These are soft tissue vascular neoplasms ar...
Haematomas are the name given to localised collections of blood and they can form virtually anywhere in the body. They often form secondary to trauma or surgery but spontaneous formation is also not uncommon, especially in those with coagulation disorders or on anticoagulant therapy.
An acquired arm arteriovenous fistula (AVF) creation is a procedure performed for haemodialysis access in those with end stage renal failure. It connects and artery to a vein in the vein. This can either be a native connection or a connection using a PTFE (polytetrafluoroethylene) graft.
Haemoptysis refers to coughing out blood. Generally, it appears bright red in colour as opposed to blood from the gastrointestinal tract which appears dark red. It is considered an alarming sign of a serious underlying aetiology.
Massive haemoptysis is referred to as expectoration ...
Haemosuccus pancreaticus, also known as pseudohaemobilia or haemoductal pancreatitis, is defined as upper gastrointestinal tract haemorrhage originating from the pancreatic duct into the duodenum via the ampulla of Vater, or major pancreatic papilla.
male:female ratio is 7:1
Hamburg classification system of vascular malformations is one of the more commonly used systems to describe the wide range of vascular malformations, largely replacing the many various eponymous syndromes traditionally used. It accounts for the underlying anatomical, histological, and pathophys...
Head and neck anatomy is important when considering pathology affecting the same area. In radiology, the 'head and neck' refers to all the anatomical structures in this region excluding the central nervous system, that is, the brain and spinal cord and their associated vascular structures and en...
The hemiazygos vein is the asymmetric counterpart to the azygos vein and forms part of the azygos venous system.
The hemiazygos vein is formed by the confluence of the left ascending lumbar and left subcostal veins.
The hemiazygos vein enters the thorax either ...
The resistive index (RI) is the commonest Doppler parameter used for hepatic arterial evaluation. The usual range in normal, as well as post-transplant individuals, is between 0.55 and 0.8.
It is measured by:
RI = (peak systolic velocity - end diastolic velocity)/peak systolic velocity
The hepatic artery proper (or proper hepatic artery) is the continuation of the common hepatic artery after it gives off the gastroduodenal artery.
The hepatic artery proper runs anteromedial to the portal vein and medial to the common bile duct to form the portal triad w...
A hepatic lymphangioma is a rare benign condition that corresponds to focally dilated lymphatic channels in the liver.
Most cases are asymptomatic.
A lymphangioma is a benign lesion that can occur at almost any location in the body. Hepatic involvement is les...
The hepatic veins are three large intraparenchymal veins which drain the liver substance into the inferior vena cava (IVC), named the right hepatic vein, middle hepatic vein and left hepatic vein. The veins are important landmarks, running in between and hence defining the segments of the liver....
Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), is a condition arising from occlusion of hepatic venules.
right upper quadrant pain
abnormal liver function tests
Toxic injury to liver s...
Hereditary connective tissue diseases are a group of connective tissue disease that have a degree of inheritance risk. They include :
Marfan syndrome - genetic disease causing abnormal fibrillin
Ehlers-Danlos syndrome - progressive deterioration of collagen and affects joints, heart v...
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.
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...
Hickman catheters (or Hickman lines) are a type of tunnelled central venous access device.
chemotherapy administration 2
parenteral nutrition 2
long-term parenteral antibiotic administration 2
arrhythmia (most common) 1
The high attenuating crescent sign represents an acute haematoma within either the mural thrombus or the aneurysm wall, especially when detected on unenhanced CT scans. It is a specific sign of impending abdominal aortic aneurysm (AAA) rupture or so-called contained rupture.
Blood vessels, namely arteries and veins, are composed of endothelial cells, smooth muscle cells and extracellular matrix (including collagen and elastin). These are arranged into three concentric layers (or tunicae): intima, media and adventitia.
the intima (or tunica intima)
inner layer abut...
The Hoffman-Rigler sign is a sign of left ventricular enlargement inferred from the distance between the inferior vena cava (IVC) and left ventricle (LV).
On a lateral chest radiograph, if the distance between the left ventricular border and the posterior border of IVC e...
Hughes-Stovin syndrome (HSS) is a vasculitis that predominantly affects large vessels. The disease bears some resemblance to Behcet disease.
It predominantly occurs predominantly between the 2nd to 4th decades. There is a recognised male predilection.
The Hunt and Hess scale describes the severity of subarachnoid haemorrhage, and is used as a predictor of survival.
asymptomatic or minimal headache and slight neck stiffness
moderate to severe headache; neck stiffness; no neurologic deficit except cranial nerve...
The hyperdense MCA sign refers to focal increased density of the middle cerebral artery (MCA) on CT and is a direct visualisation of thromboembolic material within the lumen. It is thus the earliest visible sign of MCA infarction as it is seen within 90 minutes after the event 1. It is the long...
Hyperperfusion syndrome after carotid endarterectomy (CEA) or carotid artery stenting (CAS) is a rare complication.
Hyperperfusion occurs in ~7.5% (range 1-14%) of patients but only a minority (~1.5%) of patients are symptomatic 1,2, with incidence being reported slightly more af...
Hyper-reninaemic hypertension may have many causes including:
renal artery stenosis
renal secreting tumour, e.g. renal cell carcinoma, reninoma
renal compression: large renal mass, subcapsular haemorrhage (Page kidney)
Hypertension refers to an increase in blood pressure above the 'normal' for the age, sex and ethnicity of the patient. This can be specified according to the vascular system involved.
Hypervascular liver lesions may be caused by primary liver pathology or metastatic disease.
hepatocellular carcinoma (HCC)
most common hypervascular primary liver malignancy
early arterial phase enhancement and then rapid wash out
rim enhancement of c...
Hypothenar hammer syndrome occurs from trauma to the distal ulnar artery or proximal portion of superficial palmar arch as a result of repetitive trauma to the hypothenar eminence. Originally described in patients using hammers and screwdrivers, it is also seen in various athletes such as basket...
Idiopathic dilatation of the pulmonary trunk is a rare congenital anomaly comprising of pulmonary trunk enlargement with or without dilatation of the right and left pulmonary arteries.
For this diagnosis, exclusion of pulmonary and cardiac diseases (mainly pulmonary valve stenosis) and confirma...
Idiopathic pauci immune pulmonary capillaritis (IPIPC) is considered a rare type of pulmonary vasculitis. Some authors consider this due be an organ specific subset of microscopic polyangiitis 3. It can result in diffuse alveolar haemorrhage.
It is an isolated small vessel vasculitis...
Idiopathic portal hypertension (non-cirrhotic portal hypertension or Banti syndrome) is a term that has been given to portal hypertension occurring without hepatic cirrhosis, parasitic infection, or portal venous thrombosis.
Rare condition. More common in India and Japan.
Idiopathic pulmonary arterial hypertension is uncommon, representing only a tiny fraction of all cases of pulmonary arterial hypertension, which has a very long list of secondary causes (see causes of pulmonary arterial hypertension).
Older terms for this entity include primary pul...
Idiopathic retroperitoneal fibrosis (IRF) is a subtype of retroperitoneal fibrosis where no obvious cause is found. It includes a spectrum of diseases which are characterized by fibroinflammatory tissue encasing the abdominal aorta and the iliac arteries. This process may extend into the retrope...
IgA vasculitis (formerly known as Henoch-Schonlein purpura (HSP)) is a type of non-thrombocytopenic immune-mediated small vessel acute leukocytoclastic vasculitis.
It tends to occur in the paediatric population (peak incidence 3-10 years) 3.
In order to differentiate from other types of vascul...
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...
Iliac arterial aneurysms are focal dilatations of the iliac artery.
Although the dimensions that define the aneurysm are dependent on the sex of the patient and the portion of the artery involved, a common iliac artery (CIA) with a diameter ≥1.7 cm in males or ≥1.5 cm in females is considered ...
Iliac artery endofibrosis is a rare condition that affects young endurance athletes, characterised by a non-atherosclerotic stenosis of the iliac artery.
It is a rare entity that affects highly trained endurance athletes, mostly cyclists and long-distance runners 4. The disease ha...
Iliac vein occlusion can be due to the variety of causes including:
catheter dissection injuries
IVC filter insertion
direct tumour invasion
enlarged lymph nodes
Iliofemoral deep vein thrombosis (iliofemoral DVT) occurs when a thrombus in the iliac vein (common, external or internal) or common femoral vein obstructs the venous outflow from the lower limb leading to marked oedema; DVT of the IVC or the more distal lower limb veins may be present.
The iliolumbar artery is one of three branches of the posterior division of the internal iliac artery.
origin: posterior division of the internal iliac artery
supply: ilium, iliacus muscle, psoas major muscle, quadratus lumborum muscle, erector spinae muscle, anterio...
Incomplete double aortic arch is a rare vascular ring anomaly wherein a segment of the minor aortic arch, usually the left, is atretic.
As in the case of other vascular rings, this anomaly can cause 1:
Some patients may reach adulthood with...
Infantile haemangiomas are benign vascular neoplasms that are the most common head and neck tumours of infancy. They can occur virtually anywhere, but the majority are found in the head and neck regions.
This article aims to be a generic discussion of the condition, for detailed and more specif...
The infarct core denotes the part of an acute ischaemic stroke which has already infarcted, or is irrevocably destined to infarct regardless of reperfusion. It is also referred as established infarct and is in distinction from the penumbra which remains potentially salvageable.
The inferior adrenal (suprarenal) artery is one of three adrenal arteries that supplies the adrenal gland.
Ipsilateral renal artery (usually before the terminal division of the renal artery)
The course of the inferior suprarenal artery depends on its origin. Re...
The inferior alveolar artery is a branch of the maxillary artery. It runs with the inferior alveolar nerve as it descends through the infratemporal fossa and enters the mandibular canal and supplies mandibular teeth. In the region of the first premolar it bifurcates into the incisive and mental ...
The inferior epigastric artery arises from the external iliac artery and is an important artery supplying the anterior abdominal wall. If a superficial inferior epigastric artery is present, as seen in about two-thrids of cases, then the inferior epigastric artery is referred to as the deep infe...
The inferior gluteal artery is a branch of the anterior division of the internal iliac artery. It originates in the pelvis and supplies the gluteal region and thigh.
origin: anterior division of the internal iliac artery
location: pelvis, gluteal region, back of thigh
The inferior hypophyseal arterial circle, also known as the inferior capsular arterial rete, is an anastamotic arterial network formed around the base of the pituitary gland by branches from three vessels, themselves branches off the cavernous portion of the carotid artery. They are:
The inferior hypophyseal artery is a branch from the meningohypophyseal trunk, a branch of the C4 segment of the internal carotid artery. It is usually single on each side and divides into medial and lateral branches contributing to the inferior hypophyseal arterial circle.
The inferior hypoph...
The inferior interventricular artery (also known as the posterior interventricular artery or posterior descending artery, PDA) is an artery that extends along the inferior interventricular sulcus. The artery supplies the posterior third of the interventricular septum through posterior septal per...
The inferior mediastinum is the box-shaped space in the mediastinum below the transthoracic plane of Ludwig between the wedge-shaped superior mediastinum above and the diaphragm and inferior thoracic aperture below. There are no physical structures that divide the superior and inferior mediastin...
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.
Inferior mesenteric artery aneurysms are among the rarest of all visceral artery aneurysms.
Aneurysms of the inferior mesenteric artery (IMA) only account for <1% of all visceral artery aneurysms 1,2. These aneurysms are more common in men than in women 3.
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), 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...
The inferior petrosal sinus is one of the dural venous sinuses. It is often a plexus of venous channels rather than a true sinus and drains blood from the cavernous sinus to the jugular foramen (pars nervosa) or sometimes via a vein which passes through the hypoglossal canal to the suboccipital ...
The inferior phrenic arteries (IPA) are paired branches of the abdominal aorta / coeliac trunk supplying the diaphragm. Their importance lies with the fact that the right IPA is the most common extrahepatic arterial supply of a hepatocellular carcinoma.
origin: abdominal aorta or coel...
The inferior rectal artery is an artery that supplies the lower anal canal including the external anal sphincter.
origin: from internal pudendal artery, just after it enters the pudendal canal
course: runs anteromedially through the ischioanal fossa to reach the deep portion of the ex...
The inferior sagittal sinus is one of the dural venous sinuses and runs along the inferior edge of the falx cerebri. It runs from front to back (same as the superior sagittal sinus) and drains into the straight sinus. It receives tributaries from the falx itself as well as some small veins from ...
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 ...
The inferior thyroid artery is a branch of the thyrocervical trunk (85%) or subclavian artery (15%) and ascends to enter the thyroid gland on its posterior surface, as well as supplying both the superior and inferior parathyroid glands 1. The nerve is closely related to the ascending limb of the...
The inferior ulnar collateral artery is a vessel arising from the brachial artery at the distal-most part of the upper arm.
origin: branch of the brachial artery superior to the medial epicondyle 1
location: distal lower arm
supply: brachialis, biceps brachii, and coracobrachialis 1
The inferior vena cava (IVC) drains venous blood from the lower trunk, abdomen, pelvis and lower limbs to the right atrium of the heart.
The IVC is formed by the confluence of the two common iliac veins at the L5 vertebral level. The IVC has a retroperitoneal course within the ab...
Inferior vena cava filter, or just IVC filter, is an endovascular device which is typically placed in the infrarenal inferior vena cava (IVC) to prevent pulmonary embolism in selected patients. This procedure is most often performed by interventional radiologists under fluoroscopic guidance.
Inferior vena caval (IVC) thrombosis is an essential diagnosis while evaluating any neoplastic lesion, or portal hypertension. It is also important to differentiate bland thrombus from tumour thrombus.
Patient can present with many features which include
bilateral pedal oede...
Inferior vena cava (IVC) webs are an uncommon condition characterised by obstruction of the hepatic segment of the inferior vena cava by a membrane or fibrous band. This is often associated with occlusion of one or more of the hepatic veins.
If there is hepatic vein invol...
The inferior vesical artery is a branch of the anterior division of the internal iliac artery.
Some texts state it is only present in males and may be replaced by a vaginal artery in females. Note, the vaginal artery which is most commonly described, is often a branch of the uterine artery.
The inferolateral trunk, along with the meningohypophyseal trunk, is a branch of the C4 segment of the internal carotid artery. It is identified in up to 80% of dissection specimens but is less frequently seen on imaging.
It is also referred to as the artery to the inferior cavernous sinus, ari...
Inflammatory abdominal aortic aneurysm (IAAA) is a variant of abdominal aortic aneurysm (AAA) characterised by inflammatory thickening of the aneurysm wall, perianeurysmal fibrosis and adherence to surrounding structures.
They account for ~5 to 10% of all AAAs.
The infraorbital artery is a branch of the third part of the maxillary artery. It runs through the inferior orbital fissure, orbit, infraorbital canal then the infraorbital foramen. Here it gives off the anterior superior alveolar artery which supplies the anterior teeth and the anterior part of...
An infundibulum (plural: infundibula) is a conical outpouching from an artery (usually intracranial), with a broad base narrowing to an apex from which a vessel originates. The most common location for an infundibulum is the origin of the posterior communicating artery (PCOM) from the supraclino...