The fetal middle cerebral artery (MCA) pulsatility index (PI) is a key parameter used in fetal middle cerebral arterial Doppler assessment. It is calculated by subtracting the end diastolic velocity (EDV) from the peak systolic velocity (PSV) and then dividing by the time averaged (mean) velocit...
A fetal (origin of the) posterior cerebral artery is a common variant in the posterior cerebral circulation, estimated to occur in 20-30% of individuals 2.
The posterior communicating artery (PCOM) is larger than the P1 segment of the posterior cerebral artery (PCA) and supplies the bulk of the...
Fibrinous pericarditis results from fine granular roughening of the pericardium.
Pericardial friction rub may be heard.
acute rheumatic fever
myocardial infarction: Dressler syndrome
chronic renal fail...
Fibro-adipose vascular anomaly (FAVA) is a recently-described intramuscular vascular anomaly consisting of phlebectasia (dilatation of veins) and fibrofatty replacement of muscle.
Though the term FAVA has recently been advocated, patients with similar clinical and radio-pathologica...
Fibromuscular dysplasia (FMD) is a heterogeneous group of vascular lesions characterised by an idiopathic, non-inflammatory, and non-atherosclerotic angiopathy of small and medium-sized arteries.
The prevalence is unknown 7. It is most common in young women with a female to male r...
Fibromuscular dysplasia is classified into 5 categories according to the vessel wall layer affected:
intimal fibroplasia (1%)
medial dysplasia (70%, the commonest type)
perimedial (subadventitial) fibroplasia (15-20%)
medial hyperplasia (8-10%)
The fibular or peroneal artery is one of the three arteries of the leg, along with the anterior and posterior tibial arteries.
Origin and course
arises from the tibioperoneal trunk approximately 2.5 cm distal to popliteus and passes obliquely to the fibula, descending along its ...
The figure 3 sign is seen in aortic coarctation and is formed by prestenotic dilatation of the aortic arch and left subclavian artery, indentation at the coarctation site (also known as the "tuck"), and post-stenotic dilatation of the descending aorta.
On barium studies of the oesophagus in pat...
The Fisher scale is the initial and best known system of classifying the amount of subarachnoid haemorrhage on CT scans, and is useful in predicting the occurrence and severity of cerebral vasospasm, highest in grade 3 2.
Numerous other scales have been proposed, incorporating various paramete...
The floating aorta sign refers to displacement of the abdominal aorta away from the vertebral column.
It is a radiographic/CT sign of retroperitoneal masses.
On lateral lumbar spine radiographs, the expected location of the posterior aortic wall is expected to be ≤10 mm ...
The floating viscera sign is an angiographic sign that occurs when there is visualisation of branches of the abdominal aorta (e.g. coeliac axis, superior mesenteric artery, and renal arteries) during aortography with little or no visualisation of the aortic lumen.
it indicates the presence of a...
Focussed Assessment with Sonography for Trauma (FAST) scan is a point-of-care ultrasound examination performed at the time of presentation of a trauma patient.
It is invariably performed by a clinician, who should be formally trained, and is considered as an 'extension' of the trauma clinical ...
Foix-Alajouanine syndrome refers to presentation of spinal AVMs with progressive neurological deterioration.
Initially, patients have a spastic paraplegia which progresses to flaccidity, loss of sphincter control and ascending sensory level. It is thought to be due to venous hypertension.
The Fontan procedure is a repair surgical strategy for congenital cardiac anomalies. It is not usually used in isolation, but in combination with other repair procedures in a staged manner in an attempt to correct the underlying cardiac pathology.
The procedure attempts to bypass the...
F. P. Weber syndrome (FPWS) is a traditional eponymous denomination of a certain type of angiodysplasia, that would nowadays rather be called a mixed haemolymphatic congenital vascular malformation (CVM) with arteriovenous (AV) shunting, based on the Hamburg classification of CVMs.
In his origi...
Free-floating thrombus of the internal carotid artery is an uncommon entity placing the patient at high risk for acute ischemic stroke. It is characterised by intraluminal thrombus within the internal carotid artery (ICA) and aggressively managed with surgical, medical, or combined therapy.
The French gauge (Fr) (also known as the French scale or system) is used to size catheters, and other instruments, in interventional radiology and surgery. In some parts of the world, the Charrière (Ch) is used as the name of the unit, in honour of its inventor.
The French syste...
The frontopolar artery is a branch of the A2 segment of the anterior cerebral artery (ACA), commonly arising after the medial frontobasal artery and coursing obliquely across the medial surface of the cerebral hemisphere towards the frontal pole.
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...
Gastric varices are an important portosystemic collateral pathway, occurring in ~20% of patients with portal hypertension. They are considered distinct from esophageal varices in that they have a propensity to hemorrhage at comparatively lower portal pressures 1, and are also associated with hig...
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 s...
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 (or internal spermatic 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 anteri...
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...
Hepatic venous pressure gradient measurement is a safe and minimally invasive method to indirectly measure portal vein pressure in chronic liver disease patients suspected of developing portal vein hypertension.
diagnosis of liver fibrosis and risk stratification
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 valves, orga...
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 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 longi...
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...
IgG4-related cardiovascular disease is one of the many manifestations of IgG4-related disease and may present as:
aortitis and periaortitis
arteritis and periarteritis of small to medium-sized arteries
coronary arteritis and periarteritis
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...