An enlarged/dilated azygos vein may result from a number of physiological as well as pathological causes. The enlarged azygos vein may be seen as a widened right paratracheal/paraspinal stripe on a frontal chest radiograph.
Spelling it "azygous" when referring to the vein is incorr...
The differential of an enlarged pulmonary trunk/main pulmonary artery on chest radiography includes:
may appear prominent in young patients especially women
rotation of the heart
left lower lobe collapse
pulmonary arterial hyp...
Epithelioid hemangioendothelioma (EHE) is a rare relatively low grade vascular tumor. It occurs around medium to large venous structures.
It consists of rounded or slightly spindle-shaped eosinophilic endothelial (epitheloid) cells with rounded nuclei and prominent cytoplasmic vacuol...
The external carotid artery (ECA) is one of the two terminal branches of the common carotid artery. The other terminal branch is the internal carotid (ICA), which is somewhat larger than the ECA.
origin: bifurcation of the common carotid artery
course: under the submandibular gland an...
The external iliac artery (EIA) is the larger of the two terminal branches of the common iliac artery (CIA).
The common iliac artery bifurcates into the internal iliac artery and external iliac artery at the level of the pelvic brim anterior to the sacroiliac joint.
The external iliac vein (EIV) is located along the pelvic brim between the inguinal ligament and the sacroiliac joint.
posterior to inguinal ligament within lacuna vasorum 1 as continuation of femoral vein
The external iliac vein unites with the internal il...
The external jugular vein (EJV) drains the head, face and part of the pectoral region.
The posterior division of the retromandibular vein and posterior auricular vein unite within the parotid gland to form the external jugular vein, at the angle of the mandible.
A mnemonic to remember external jugular vein (formed by the retromandibular and posterior auricular veins) tributaries is:
P: posterior external jugular vein
A: anterior jugular vein
S: suprascapular vein
T: transverse cervical vein
Extracorporeal membrane oxygenation (ECMO) is used as a modified pulmonary or cardiopulmonary bypass technique in those with severe cardiac and/or respiratory failure refractory to conventional ventilatory support and medical intervention 1,3. There are two access paths for extracorporeal life s...
Extra-hepatic portal vein obstruction is the most common cause of noncirrhotic portal hypertension in children and young adults in developing countries. It may or may not extend into the intrahepatic portal vein.
It usually occurs in children and young adults, presenting ...
The facial artery is one of the branches of the external carotid artery and supplies blood to the structures of the face.
origin: branch of the external carotid artery a little above the level of the lingual artery, in the carotid triangle of the neck
course: passes deep to the poster...
The facial-cavernous anastomoses are the communications of the facial and deep facial veins with the cavernous sinus.
At the medial canthus of the eye there is a communication with the ophthalmic veins, which drain into the cavernous sinus. Blood from the frontal scalp normally f...
The facial vein (previously known as the anterior facial vein) is the continuation of the angular vein and joins the anterior branch of the retromandibular vein to form the common facial vein 1-3.
At the level of the lower margin of the orbit, the angular vein becomes the facial ...
The falciform artery, also known as the hepatic falciform artery (FHA) is an uncommon vascular anatomic variant that most commonly arises as the terminal branch of the middle hepatic artery which courses anteriorly through the falciform ligament into and supplying the supraumbilical anterior abd...
False aneurysms, also known as a pseudoaneurysm, is when there is a breach in the vessel wall such that blood leaks through the wall but is contained by the adventitia or surrounding perivascular soft tissue. A direct communication of blood flow exists between the vessel lumen and the aneurysm l...
Familial multiple cavernous malformation syndrome is uncommon, accounting for only a minority of cavernous malformations.
It has been more frequently reported in patients of Hispanic descent 1.
The presentation is most commonly with seizures (38-55%) 1 and ...
Femoral artery pseudoaneurysms are usually iatrogenic, as the femoral artery is the vessel of choice for most endovascular arterial interventions.
inadequate compression following femoral arterial puncture for endovascular intervention
The femoral canal is the medial compartment of the femoral sheath, an inverted cone-shaped fascial space medial to the common femoral vein within the upper femoral triangle. It is only 1-2 cm long and opens superiorly as the femoral ring. It serves two purposes:
allows the femoral vein to expan...
Femoral nerve neuropathy is an uncommon peripheral neuropathy, which most commonly occurs when the femoral nerve is compressed as it passes under the inguinal ligament, anterior to the iliopsoas muscle.
loss of power of hip flexion and knee extension
The femoral ring is the superior opening of the femoral canal. Its boundaries are:
medial: lacunar ligament
anterior: medial part of the inguinal ligament
lateral: femoral vein within the intermediate compartment of the femoral sheath
posterior: pectineal ligament overlying the pectineus mus...
The femoral sheath is the funnel-shaped fascial space that extends from the abdomen, inferior to the inguinal ligament, into the femoral triangle. It has variable length and terminates by blending in with the adventitia of the femoral vessels. It is formed from the transversalis and psoas fascia...
The femoral vein is the main deep vein of the thigh and accompanies the superficial femoral artery and common femoral artery.
The term "superficial femoral vein" or its abbreviation, "SFV" should not be used as it is a misnomer (i.e. it is not a superficial vein), and can be especi...
Fetal circulation differs from the adult circulation due to the presence of certain vessels and shunts.
These shunts close after birth, and most of the fetal vessels are visible as remnants in the adult circulation. The function of these shunts is to direct oxygen-rich venous blood to the syst...
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 characterized 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 esophagus in pati...
The Fisher scale is the initial and best known system of classifying the amount of subarachnoid hemorrhage 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 parameter...
A fistula (plural: fistulae) is an abnormal connection between two epithelial surfaces such as between hollow organs, skin or vessels. Conventionally, the name of a specific fistula type is a combination of the two organs
For discussions of specific fistulae please refer to individual articles....
The floating aorta sign refers to the displacement of the abdominal aorta away from the vertebral column.
It is a radiographic 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 visualization of branches of the abdominal aorta (e.g. celiac axis, superior mesenteric artery, and renal arteries) during aortography with little or no visualization of the aortic lumen.
The floating viscera sign indic...
Focused 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 a...
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 hemolymphatic congenital vascular malformation (CVM) with arteriovenous (AV) shunting, based on the Hamburg classification of CVMs.
In his original...
Free-floating thrombus of the internal carotid artery is an uncommon entity placing the patient at high risk for acute ischemic stroke. It is characterized 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 honor of its inventor.
The French system...
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...
The abbreviation GCA can refer to:
giant cell arteritis
global cortical atrophy scale
Generalized lymphatic anomaly, previously known as lymphangiomatosis or cystic angiomatosis, is a systemic condition characterized by multifocal lymphatic malformations with systemic distribution. The distribution of lesions is variable; there can be cutaneous, thoracic and abdominal viscera and...
The Giacomini vein or thigh extension of the small saphenous vein refers to a variation in lower limb venous anatomy whereby 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 chroni...
Giant cell arteritis (GCA) is a common granulomatous vasculitis affecting medium- to large-sized arteries. It is also known as temporal arteritis or cranial arteritis, given its propensity to involve the extracranial external carotid artery branches such as the superficial 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 tumors, are benign vascular tumors typically seen at the distal extremities. On imaging, they characteristically present as small hypervascular nodules under the fingernail.
These tumors should not be confused with paragangliomas, which are somet...
The glomus body is a component of the dermis that is involved in thermoregulation.
It consists of a specialized 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 tumor, it is the most common of the jugular fossa tumors.
The relative prevalence of glomus jugulare with respect to other head and neck paraganglioma va...
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 classifying 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.
The great saphenous vein is the preferred term over other variants such as long saphenous vein (LSV), greater saphenous vein or internal saphenous vein 5.
Origin and cours...
The Griesinger sign refers to edema 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 associated with dural sinus occlusive disease (DSOD). It is said to be a pathognomon...
The Griffiths point, also known as 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 tr...
A hemangioendothelioma is a tumor derived from blood vessels.
Subtypes dependent on location include
hemangioendothelioma of liver
Hemangiomas are benign tumors of vascular origin usually seen in early childhood, divided into:
Unfortunately, the term hemangioma has been widely misused to apply to many non-neoplastic vascular malformations, particularly the common ...
Hemangiopericytoma is a term formerly used to describe a continuum of mesenchymal tumors with elevated cellularity found throughout the body in soft tissue and bone. After many years of controversy, hemangiopericytomas have been shown to not only share histological features similar to solitary f...
Hemangiopericytomas of the spleen are very rare vascular neoplasm with only a few case reports available at the time of writing.
Splenic hemangiopericytomas are typically asymptomatic or can result in splenomegaly.
These are soft tissue vascular neoplasms aris...
Hematomas are the name given to localized 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.
Haemodialysis vascular access is required in patients with end-stage renal failure. Usually, it is an upper limb vascular access on the non-dominant side. Central venous access and lower limb access (less frequent) are other options.
Types of vascular access
Native arteriovenous fistula (AVF)...
Hemoptysis (plural: hemoptyses) refers to coughing up of blood. Generally, it appears bright red in color as opposed to blood from the gastrointestinal tract which appears dark red. It is considered an alarming sign of a serious underlying etiology.
Massive hemoptysis is referred t...
Haemosuccus pancreaticus, also known as pseudohaemobilia or haemoductal pancreatitis, is defined as upper gastrointestinal tract hemorrhage originating from the pancreatic duct into the duodenum via the ampulla of Vater, or major pancreatic papilla.
male:female ratio is 7:1
The hair on end sign refers to a radiographic appearance of the diploic space of the skull vault which results from a thickening of trabeculae as the diploic space expands. These trabeculae are perpendicular in orientation, interspersed by radiolucent marrow hyperplasia along the skull vault.
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.
Spelling it "hemiazygous" when referring to the vein is incorrect, regardless of whether British or American English 7. In the context of anatomy, see Terminologia Anat...
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, also known as the proper hepatic artery (PHA), is the continuation of the common hepatic artery after it gives off the gastroduodenal artery. Just prior to the porta hepatis it divides into the left and right hepatic arteries.
The hepatic artery...
Hepatic lymphangiomas are a rare benign condition that corresponds to focally dilated lymphatic channels in the liver.
For a general discussion on this topic, please refer to the parental article on lymphangioma.
Most cases are asymptomatic.
A lymphangioma ...
Hepatic vascular and perfusion disorders are a broad group of conditions that radiologists should be familiar with, as some of them are quite frequently seen in the daily practice. The aim of this article is to be a collection of articles that represent the core knowledge in the matter.
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 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.
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...
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...
Hickman catheters (or Hickman lines) are a type of tunnelled central venous access line.
chemotherapy administration 2
parenteral nutrition 2
long-term parenteral antibiotic administration 2
arrhythmia (most common) 1
The high attenuating crescent sign represents an acute hematoma 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.
A high division of the brachial artery is an unusually proximal bifurcation of the brachial artery into its ulnar and radial branches in the upper arm.
It is an anatomical variant of the arterial branching pattern of the upper limb.
In general, the brachial artery bifurcates into...
A high-riding brachiocephalic artery (now preferred to innominate artery) is a rare anomaly of the neck vessels in which the brachiocephalic artery passes much more superiorly than normally. It is a clinically important variant, as mistaking it for a neck lump and sampling it or neck surgery in ...
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...