Cavernous sinus thrombosis (CST) is a rare condition, most commonly infectious in nature, and the diagnosis on imaging is not always straightforward. It has high mortality and morbidity rates.
CST is rare with ~4.5 cases per 1,000,000 per year 5. It is the least common dural venou...
Cavernous transformation of the portal vein (CTPV) is a sequela of portal vein thrombosis and is the replacement of the normal single channel portal vein with numerous tortuous venous channels.
For a discussion of demographics and presentation, please refer to the article on portal vein thrombo...
The central artery of the retina or central retinal artery (CRA) arises from the ophthalmic artery.
The central artery of the retina courses anteriorly and inferior to the optic nerve, It then pierces the dura and the arachnoid of the optic nerve. It then runs in the centre of t...
Central nervous system (CNS) vasculitides represent a heterogeneous group of inflammatory diseases affecting the walls of blood vessels in the brain, spinal cord, and the meninges.
Please refer to the article on vasculitis for a general discussion of that entity.
The aim of this article will ...
Central venous catheters (CVC) or lines (CVL) refer to a wide range of central venous access devices but can broadly be divided into four categories. They may be inserted by medical, surgical, anaesthetic/ITU, or radiology specialists.
peripherally inserted central catheters (PI...
The cephalic vein, along with the basilic vein, is one of the primary superficial veins that drain the upper limb 1. It courses through both the forearm and arm and terminates by draining into the axillary vein.
origin: radial aspect of the superficial venous network of the dorsum of...
Cerebral arteriovenous malformations (CAVMs), also known as classic brain AVMs, are a common form of cerebral vascular malformation and are composed of a nidus of vessels through which arteriovenous shunting occurs.
This article corresponds to the classic form of arteriovenous malf...
Cerebral cavernous venous malformations, commonly known as cavernous haemangioma or cavernoma, are common cerebral vascular malformations, usually with characteristic appearances on MRI.
Cavernous malformations are found throughout the body. This article focuses on cerebral cavernous venous ma...
Cerebral proliferative angiopathy (CPA), previously known as diffuse nidus type AVM, is a cerebral vascular malformation separated from classic brain AVM and characterised by the presence of normal brain parenchyma interspersed throughout the tangle of vessels that corresponds to the nidus 1,2.
Vascular malformations of the central nervous system can be divided, as they can elsewhere, into high and low flow malformations.
arteriovenous malformation (AVM)
cerebral AVM (pial/parenchymal AVM)
cerebral proliferative angiopathy
dural arteriovenous fistula (DAVF)
An understanding of cerebral vascular territories is important in understanding stroke and complications from surgery and endovascular procedures.
Although one could be excused for thinking that within the brain, such a carefully organised organ, blood supply would be constant, the truth is th...
The cerebral veins drain the brain parenchyma and are located in the subarachnoid space. They pierce the meninges and drain further into the cranial venous sinuses.
The cerebral veins lack muscular tissue and valves. The cerebral venous system can be divided into:
superficial (cortical) cerebr...
Cerebral venous infarction is an uncommon form of stroke, and is most commonly secondary to cerebral venous thrombosis.
Cerebral venous infarction is usually the sequelae of cerebral venous thrombosis, complicating both dural venous sinus thrombosis and deep cerebral venous thrombos...
The cerebral venous system, somewhat unlike the majority of the rest of the body, does not even remotely follow the cerebral arterial system.
The cortical veins lie superficially, unlike cortical arteries, and are adherent to the deep surface of the arachnoid mater so that they keep the sulci o...
Cerebral venous thrombosis (CVT) refers to occlusion of venous channels in the cranial cavity, including dural venous thrombosis, cortical vein thrombosis and deep cerebral vein thrombosis. They often co-exist and the clinical presentation among them is very similar and nonspecific. Furthermore,...
Cerebrofacial arteriovenous metameric syndrome (CAMS) encompasses maxillofacial/intracranial vascular malformation complexes including Wyburn-Mason Syndrome and Sturge-Weber syndrome 1-4. Three types are described depending on location 2,6:
CAMS I: medial prosencephalic group with involvement o...
Cervical aortic arch is a rare aortic arch anomaly characterised by an elongated, high-lying aortic arch extending at or above the level of the medial ends of the clavicles.
Patients with cervical aortic arch are usually asymptomatic. Symptomatic patients may present with...
This is a basic article for medical students and other non-radiologists
Chest x-ray PICC (peripherally inserted central catheter) position should be assessed following initial placement and on subsequent radiographs.
This is a summary article; we do have a more in-depth refe...
Chronic hereditary lymphedema or Milroy disease is a condition characterised by lower-limb lymphedema. Patients typically present with pedal oedema at or before birth or soon after. Occasionally, it develops later in life.
Mutations in the FLT4 gene is thought to be present...
Chronic mesenteric ischaemia is an uncommon type of intestinal ischaemia usually affecting elderly patients as a result of significant stenosis of two or more mesenteric arteries.
Normally seen in patients older than 60 years of age and is three times more common in women.
Chronic periaortitis is an inflammatory condition which typically involves the infrarenal portion of the abdominal aorta. It is a rare disease usually occurring in middle-aged men.
It has various clinical presentations:
idiopathic retroperitoneal fibrosis (IRF)
perianeurysmal retroperitoneal ...
Chronic pulmonary emboli are mainly a consequence of incomplete resolution of pulmonary thromboembolism.
vascular CT signs include
direct pulmonary artery signs
calcified thrombus - calcific pulmonary ...
Chronic venous insufficiency (CVI) occurs due to inadequate functioning of venous wall and/or valves in lower limb veins resulting in excessive pooling of blood.
The condition results from venous hypertension which in turn is usually caused by reflux in the superficial venous compart...
The Circle of Willis is an arterial polygon formed as the internal carotid and vertebral systems anastomose around the optic chiasm and infundibulum of the pituitary stalk in the suprasellar cistern. This communicating pathway allows equalization of blood-flow between the two sides of the brain,...
Circumaortic left renal vein, also known as circumaortic renal collar is an anomaly of left renal vein when a supernumerary or accessory left renal vein passes posterior to the aorta, apart from the normal renal vein passing anterior to the aorta. This anomaly is potentially hazardous, if unreco...
The circumflex artery (Cx) is a major coronary artery that divides off the left main coronary artery (the other branch being the left anterior descending (LAD) artery).
The circumflex artery is referred to by multiple terms:
circumflex artery (Cx)
ramus circumflex artery (RCx)
The circumflex fibular artery is a minor artery of the leg.
Origin and course
Most often arises from the posterior tibial artery, passes laterally round the neck of the fibula through the soleus to anastomose with the lateral inferior genicular, medial genicular and anterior tib...
Cirsoid aneurysms are rare arteriovenous malformations of the scalp and extremities.
Patients often present with a slow-growing pulsatile mass and may also experience bleeding, tinnitus and/or a headache 3.
Cirsoid aneurysms develop due to an abnormal arteri...
The cisterna chyli (CC), also known as the receptaculum chyli, is a normal anatomical structure seen as a saccular area of dilatation in the lymphatic channels that is located in the retrocrural space, usually to the immediate right of the abdominal aorta 4.
Endoleaks occur when an aneurysmal sac continues to be pressurised despite endoluminal stent placement.
There are five types:
type I: leak at graft ends (inadequate seal) - most common after repair of thoracic aortic aneurysms 4
Ic: iliac occluder
CNS capillary telangiectasiae(s) are small, asymptomatic low flow vascular lesions of the brain.
As these lesions are asymptomatic, diagnosis usually matches the age of first imaging with MRI, and as such are most frequently found in middle-aged and elderly adults. Their inciden...
Coarctation of the aorta (CoA) refers to a narrowing of the aortic lumen.
Coarctations account for between 5-8% of all congenital heart defects. They are more frequent in males, M:F ratio of ~2-3:1.
Varies accordingly to the degree of stenosis and the assoc...
The cobweb sign is seen in cases of arterial dissection (usually aortic dissection) on CT angiogram (CTA) examinations and represents strands or ribbons of media crossing the false lumen, and appearing as thin filiform filling defects.
Although it is a specific sign for the false lumen, it is i...
Coeliac artery (also known as the coeliac axis or trunk) is a major visceral artery in the abdominal cavity.
Arises anteriorly from abdominal aorta at the T12 level, behind the median arcuate ligament, just as the aorta enters the abdomen.
It is typically a sho...
Coeliac artery aneurysms are a form of visceral artery aneurysm and account for around 4% of such cases (fourth most common visceral arterial aneurysm).
An association with non-visceral arterial aneurysms is considered frequent 2.
While some pat...
Coeliac artery compression syndrome is also known as coeliac axis syndrome, median arcuate ligament syndrome and Dunbar syndrome. It is characterised by upper abdominal angina secondary to compression of the coeliac trunk by the diaphragmatic crurae.
The median arcuate ligament is th...
Coeliac artery dissection is a type of arterial dissection. It is rarely seen as a primary phenomenon and is most often encountered due to propagation of an aortic dissection.
Coeliac artery dissection is usually iatrogenic but may also be secondary to:
Cogan syndrome is a rare vasculitis of children and young adults which primarily characterised by 1,4,6:
inflammatory eye disease (ocular keratitis, uveitis, scleritis, optic neuritis) 6
audiovestibular symptoms (similar to Meniere disease) 6
However, it can potentially affect a multitude of ...
A coil herniation refers to the part of a detachable coil prolapsing out of the aneurysm and into the parent artery. It is an uncommon complication and is typically seen at the end of the embolisation procedure. Contributing factors include 1:
wide aneurysm neck
instability of the coil in the ...
COL4A1-related disorders are a group of autosomal dominant disorders caused by a mutation in the COL4A1 gene.
The exact prevalence is unknown, but the group of disorders is considered to be under-recognised, especially asymptomatic variants 1.
The clinical ...
There are several collateral systems between the celiac trunk and superior mesenteric artery.
gastroduodenal artery (GDA)
branch of the common hepatic artery and anastomoses with branches of the inferior pancreatic duodenal artery
dorsal pancreatic artery (DPA)
usually a bra...
Comet tail sign (in urological imaging) is helpful in distinguishing a ureteric calculus from a phlebolith and strongly favours the latter.
The sign refers to a tail of soft tissue extending from a calcification, representing the collapsed/scarred/thrombosed parent vein. When well seen it is s...
The common carotid artery is a paired structure that supplies blood to the head and neck.
left: branch of the aortic arch
right: branch of the brachiocephalic trunk
course: posterior to sternoclavicular joint, lateral to thyroid and trachea
supply: head and neck
The common facial vein is formed by the joining of the facial vein and anterior branch of the retromandibular vein. It is part of the venous drainage system of the face.
origin and termination: the facial vein (along with the facial artery) pierces the deep investing fascia of the neck...
The common femoral artery is the continuation of the external iliac artery at the level of the inguinal ligament. As well as supplying oxygenated blood to the leg, it gives off smaller branches to the anterior abdominal wall. The artery lies medial to the midpoint of the inguinal ligament, halfw...
The common hepatic artery (CHA) is a terminal branch of the coeliac artery.
Origin and course
The CHA is a terminal branch of the coeliac artery, it passes to the right in the lesser sac, and enters the lesser omentum to pass slightly upwards towards the porta hepatis. It gives ...
The common iliac arteries (CIA) are the large paired terminal branches of the abdominal aorta.
The abdominal aorta bifurcates anterolateral (to the left side) of the L4 vertebra, into the right and left common iliac arteries.
The common iliac arteries enter the ...
The common iliac vein, corresponding with the common iliac artery, drains venous blood from the pelvis, lower limbs and their associated structures.
location: pelvis, anterior to the sacroiliac joint
origin and termination: union of internal and external iliac veins; into the inferior...
The common interosseous artery is a branch of the proximal part of the ulnar artery at the level of the pronator teres in the distal part of the cubital fossa. It is a short vessel that dives laterally and deeply before bifurcating into anterior and posterior interosseous arteries.
The concentric ring sign is a pathognomonic sign for a subacute haematoma on MRI.
A subacute haematoma may show 3 characteristic layers of signal intensity:
a thin peripheral rim of low signal intensity on all pulse sequences corresponding to haemosiderin.
an inner peripheral high-signal inte...
The confluence of sinuses, also known as the torcula or torcular herophili is the site of the confluence of:
superior sagittal sinus
The anatomy is highly variable and three types can be distinguished:
type 1: superior sagittal sinus drains...
Congenital absence of the internal carotid artery (ICA) is a rare anomaly that occurs in less than 0.01% of the population. It encompasses agenesis, aplasia, and hypoplasia 1.
The most common type of collateral flow is through the circle of Willis, through the anterior communicating artery (ACO...
Congenital coronary artery anomalies (CCAAs) are not common, found only in ~1% (range 0.1-2%) of patients 1,3.The most important finding to look for is the "malignant" course of anomalous coronary artery, i.e. does the artery run between big pulsating objects - right ventricular outflow tract / ...
This congenital extrahepatic portosystemic shunt classification was proposed by Morgan and Superina in 1994 1:
type 1: complete diversion of portal blood into the Inferior vena cava with congenital absence of the portal vein
1a: superior mesenteric vein and splenic vein do not join to form a c...
Congenital haemangiomas are benign vascular tumours of childhood that are present at birth. They are mostly indistinguishable from infantile haemangioma on imaging but have distinct histological and clinical features.
While the majority are cutaneous or subcutaneous in nature, the can occur ext...
This congenital intrahepatic portosystemic shunt classification was proposed by Park et al. in 1990 1:
type 1: single large vessel of constant diameter connecting the right portal vein to the Inferior vena cava
type 2: localised, peripheral shunt with one or more communications in a single hep...
Congenitally corrected transposition of the great arteries, also known as levo- or L-loop transposition (L-TGA), is a rare cardiovascular anomaly with inversion of the ventricles and great arteries.
This anomaly comprises less than 1% of all congenital heart diseases 1,2,7.
Congenital portosystemic shunts are rare anatomical abnormalities linked to abnormal embryological venous development. They can be extrahepatic or intrahepatic. In either case, the underlying abnormality is shunting of blood from the portal venous system to the systemic venous system thus avoid...
Congenital vascular anomalies may be:
congenital cardiac abnormalities
Constrictive pericarditis (or perhaps better termed pericardial constriction) is a type of pericarditis which leads to diastolic dysfunction and potentially symptoms of right heart failure.
No single demographic is affected as there are numerous causes of constrictive pericarditi...
Contrast enhanced MR angiography (MRA) is a technique involving 3D spoiled gradient-echo (GE) sequences, with administration of gadolinium-based contrast agents (GBCA). It can be used to assess vascular structures of almost any part of the body. Its key features are:
T1 weighted spoiled gradien...
Contrast-induced nephropathy (CIN) is the third most common cause of all hospital-acquired acute renal failure and accounts for ~10% of all cases. There is still an ongoing debate regarding its occurrence after intravenous contrast medium administration because most of the cases occur after intr...
Contrast media extravasation (CMEV) refers to the leakage of contrast media from the normal intravascular compartment into surrounding soft tissues; It is a well-known complication of contrast-enhanced CT scanning. It can also occur in MRI studies, but the complications are rare given the low vo...
The conus artery is a small early branch off the right coronary artery (RCA) circulation.
The artery has a variable distribution, but usually supplies a region of the anterior interventricular septum and the conus of the main pulmonary artery (hence its name).
Coral reef aorta (CRA) is a rare disease, described as hard calcifications involving the arterial wall which protrude into the lumen. It predominantly involves the posterior thoracic and abdominal aorta. CRA luminal lesions can cause significant aortic stenosis.
Patients usually p...
Corona mortis, Latin for "crown of death", is a common variant vascular anastomosis between the external iliac artery or deep inferior epigastric artery with the obturator artery. It is reported to be present in a third of patients on routine multi-detector CT examination 1, 4.
Knowledge of th...
The coronary arteries arise from the coronary sinuses immediately distal (superior) to the aortic valve and supply the myocardium with oxygenated blood. They branch and encircle the heart to cover its surface with a lacy network resembling perhaps a slightly crooked crown.
Coronary artery aneurysms are an uncommon, predominantly incidental finding.
Coronary artery aneurysms are most common in men 3, likely reflecting the increased rates of atherosclerosis in men compared to women. Prevalence varies in the literature between 0.1-5% 4.
A coronary artery bypass graft (CABG or CAG) is placed during a surgical procedure to increase blood flow to the myocardium due to coronary stenoses, usually caused by coronary artery disease. Arteries or veins can be grafted during this procedure.
Long term outcome of coronary artery bypass gr...
Coronary artery disease (CAD) is the leading cause of mortality globally.
CAD is asymptomatic in most of the population. When severe enough it can cause angina, or an acute coronary syndrome including myocardial infarction. CAD may also present with heart failure or sudd...
Coronary Artery Disease - Reporting and Data System (CAD-RADSTM) classification is proposed by the Society for Cardiovascular Computed Tomography (SCCT), the American College of Radiology (ACR), and the North American Society for Cardiovascular Imaging (NASCI), last updated in 2016.
Coronary artery dissection (also known as spontaneous coronary artery dissection or SCAD) is a rare cause of acute coronary syndrome especially in young patients who are otherwise healthy.
Coronary artery dissection occurs mainly in young, otherwise health patients especially in f...
Microvascular obstruction (MVO), also known as no reflow phenomenon, is an established complication encountered in coronary angioplasty for prolonged acute myocardial infarction.
The phenomenon results from obstruction of the myocardial microcirculation, which is composed of vessel...
The coronary sinus is the major coronary vein. It returns the majority of the left ventricular blood flow to the right atrium.
The coronary sinus courses along the posterior wall of the left atrium into the left atrioventricular groove. It normally drains into the right atrium. T...
The coronary veins return deoxygenated blood from the myocardium back to the right atrium. Most venous blood returns via the coronary sinus. Coronary venous anatomy is highly variable, but is generally comprised of 3 groups of veins:
cardiac veins which drain into the coronary sinus:
Cortical vein thrombosis, also known as superficial cerebral vein thrombosis, is a subset of cerebral venous thrombosis involving the superficial cerebral veins besides the dural sinus, often coexisting with deep cerebral vein thrombosis or dural venous sinus thrombosis. It has different clinica...
The costocervical trunk is one of the branches of the second part of the subclavian artery. It arises from the posterior wall of the subclavian artery, posterior or medial to the anterior scalene muscle and courses posterosuperiorly across the suprapleural membrane where it divides into 2 branc...
The costoclavicular space is the anterior portion of the superior thoracic aperture, between the clavicle and first rib. The subclavian vessels and brachial plexus pass though the space related to the scalene muscles. Proximally, the plexus passes through the interscalene space, and distally thr...
Coup de poignard of Michon refers to spinal subarachnoid haemorrhage, usually as a result of a spinal AVM.
Presentation is with sudden excruciating back pain, akin to being stabbed with a dagger (poignard = french for dagger). It is the corollary of the thunderclap headache.
The cremasteric artery is a small branch of the inferior epigastric artery that enters the deep inguinal ring of the inguinal canal and supplies the layers of the spermatic cord and also the skin of the scrotum, including the cremaster muscle.
History and etymology
The word "cremaster" derives...
The crescent sign refers to the high signal crescent seen in the wall of a vessel when dissected. This may be seen both on T1 or T2 sequences depending on the age of the blood (see ageing blood on MRI). It is classically referred to in internal carotid artery dissection.
It should not be confus...
Cryoglobulinaemic vasculitis (CV) is a form of immune mediated primary vasculitis involving small to medium sized vessels. It may involve multiple organs and can have a range of clinical presentations.
There are three main types of cryoglobulinaemia which are grouped, as per the Br...
This is a basic article for medical students and other non-radiologists
CT abdomen is an increasingly common investigation that is used to help make diagnoses of a broad range of pathologies. A CT abdomen in its simplest form is a CT from diaphragm to symphysis pubis performed 60 seconds after ...
Multi-slice CT angiography of the splanchnic vessels is a powerful minimally invasive technique for evaluation of the splanchnic vascular system.
The actual procedure will vary depending on institutional protocol/guidelines but below is a typical description 2, 4:
CT cerebral venography is a rapid technique which provides an accurate detailed depiction of the cerebral venous system.
Rapid diagnosis of cerebral venous thrombosis.
general CT contraindications such as pregnancy, claustrophobia, etc.
iodinated contrast contr...
CT perfusion in ischaemic stroke has become established in most centres with stroke services as an important adjunct, along with CT angiography (CTA), to conventional unenhanced CT brain imaging.
It enables differentiation of salvageable ischaemic brain tissue (the penumbra) from irrevocably d...
The cubital fossa is a triangular space which forms the transition between the arm and the forearm. It is located anterior to the elbow joint.
superior: the line joining the medial and lateral humeral epicondyles
lateral: medial border of brachioradialis
Cutaneous leukocytoclastic angiitis is a form of vasculitis that affect the skin. This is considered the most common of vasculitis affecting the skin and usually results from deposition of immune complexes at the vessel wall. Patients usually have a palpable purpura.
Cystic adventitial disease (CAD) is an uncommon vascular pathology predominantly affecting peripheral vessels. The vast majority of cases occur in arteries, with venous involvement being an extremely rare occurrence 8.
It typically affects young to middle-aged individuals without ...
The cystic artery represents the main blood supply to the gallbladder. It most commonly arises from the right hepatic artery within Calots triangle 1.
The cystic artery passes posterior to the cystic duct to reach the neck of the gallbladder. At this point, it gives off two-to-fo...
Cystic hygroma, also known as cystic or nuchal lymphangioma, refers to the cystic variety of congenital lymphangioma which, most commonly, occur in the cervicofacial regions, particularly at the posterior cervical triangle.
They usually occur in the fetal/infantile and paediatri...
Along with the Stanford classification, the DeBakey classification is used to separate aortic dissections into those that need surgical repair, and those that usually require only medical management.
The DeBakey classification divides dissections into 1-5:
type I: involves asce...
A mnemonic used to remember the DeBakey classification 1 is:
B: both ascending and descending aorta (type I)
A: ascending aorta(type II)
D: descending aorta (type III)