The superior vena cava (SVC) is a large valveless venous channel formed by the union of the brachiocephalic veins. It receives blood from the upper half of the body (except the heart) and returns it to the right atrium.
The SVC begins behind the lower border of the first right co...
Superior vena cava (SVC) obstruction can occur from extrinsic compression, intrinsic stenosis or thrombosis. Malignancies are the main cause and are considered an oncologic emergency. Superior vena cava syndrome (SVCS) refers to the clinical syndrome with symptoms that results from this obstruct...
SVC obstruction can cause SVC syndrome which is the most common condition affecting this vessel. It can be secondary to an extrinsic compression or intraluminal thrombosis/stenosis. Collateral pathways, with the azygos vein being the most important collateral vessel, form in response to severe n...
Superior vena caval duplication is the most common form of a left sided SVC, where the normal right sided SVC remains. The right SVC however can be smaller in ~2/3rds of such cases 3.
Results from failure of the embryonic left anterior cardiac vein to regress. Drainage is variable an...
The superior vesical artery is a branch of the anterior division of the internal iliac artery. It supplies part of the bladder, ureter, seminal vesicle and ductus deferens.
origin: anterior division of internal iliac artery
supply: superior bladder, ureter, ductus de...
The supraorbital artery is a branch of the ophthalmic artery supplying part of the orbit and face.
The supraorbital artery originates from the ophthalmic artery, upon branching it lies medial to the optic nerve.
The supraorbital artery courses superiorly and med...
The suprascapular artery is 1 of the 4 branches of the thyrocervical trunk (off the first part of the subclavian artery).
It traverses inferiorly and laterally in the lower anterior neck superficial to the anterior scalene muscle and phrenic nerve before crossing the third part of the subclavia...
The supratrochlear artery, also known as the frontal artery, originates from the ophthalmic artery as one of its terminal branches.
After arising from the ophthalmic artery, it pierces the orbital septum and courses in the superior and medial aspect of the orbit, medial to the su...
The supreme intercostal arteries, or superior intercostal arteries, are formed as a direct result of the embryological development of the intersegmental arteries. These arteries are paired structures of the upper thorax which normally form to provide blood flow to the first and second intercosta...
The staging system for moyamoya disease first described by Suzuki and Takaku in their seminal 1969 article1 is still in use today. Formally, the staging refers to findings on conventional angiography, although there are efforts to apply similar systems to MR angiography.2
Suzuki stage appears t...
von Hippel-Lindau disease
Systemic hypertension is defined medically as a blood pressure greater than 140/90 mmHg.
essential hypertension: idiopathic (95%)
secondary hypertension: underlying cause identified (5%)
Causes of secondary hypertension:
chronic renal failure...
Systemic lupus erythematosus (SLE) is a complex autoimmune disease with multisystem involvement. It is also sometimes classified as a vasculitis.
There is an overall increased female predilection. In adults, women are affected 9-13 times more than males. In children, this ratio i...
Central nervous system manifestations of systemic lupus erythematosus (CNS lupus) describe a wide variety of neuropsychiatric manifestations that are secondary to systemic lupus erythematosus (SLE) in the central nervous system (CNS).
For a general discussion, and for links to other system spec...
Takayasu arteritis (TA), also known as idiopathic medial aortopathy or pulseless disease, is a granulomatous large vessel vasculitis that predominantly affects the aorta and its major branches. It may also affect the pulmonary arteries. The exact cause is not well known but the pathology is thou...
The Takeuchi procedure refers to a direct anastomosis of the anomalous left coronary artery from the pulmonary artery directly to the aorta was described in the 1970s and currently remains the procedure of choice.
An intrapulmonary aortocoronary tunnel or baffle was performed by Takeuchi prior ...
A tangential calcium sign is a sign seen with an aortic aneurysm rupture. The calcified intimal rim is discontinuous and is seen to tangentially point away from the aneurysmal lumen. This sign is seen at the point of breach. There is associated retroperitoneal leakage.
Tardus parvus refers to a particular pattern of Doppler ultrasound spectral waveform. It commonly occurs downstream from significant arterial stenosis, and in particular is useful in assessing for renal artery stenosis.
tardus: prolonged systolic acceleration (i.e. slow ...
Tear drop sign of the superior mesenteric vein (SMV) is one of the important signs in the staging of pancreatic adenocarcinoma. Its importance lies in its diagnosis as well as prognostic significance. This sign is used in assessing the resectability of pancreatic cancer.
The tela choroidea is the thin, highly vascularised, loose connective tissue portion of pia mater that gives rise to the choroid plexus. Thus, it is basically the lamina propria of the ependyma and lies directly adherent to it, without any tissue in between the two 6.
Being part ...
A telangiectasia commonly refers to a group of abnormally prominent capillaries that occur close a mucosal surface. Rarely they are also referred to denote vascular malformations at other non mucosal sites (e.g capillary telangiectasiae of the brain 1)
There are numerous condition...
Temporal tap manoeuvre consists in tapping over the ipsilateral temporal artery while assessing the carotid bifurcation on Doppler ultrasound aiming to produce a reflected flow in the external carotid artery (ECA) and thus helping to distinguish which vessel is being assessed: external vs. inter...
The temporopolar artery is usually a dorsolateral branch from the M1 segment of the middle cerebral artery (MCA) and supplies the polar and anterolateral portions of the temporal lobe.
This artery may arise as a branch from the anterior temporal artery 1.
The tentorial angle is measured between a line connecting the nasion with the tuberculum sellae and the the angle of the straight sinus. Normally it should measure between 27° and 52°.
Abnormalities of the posterior fossa / base of skull can alter this. For example this angle is elevated in ach...
Terson syndrome refers to vitreous haemorrhage associated with subarachnoid haemorrhage, however some authors include retinal haemorrhage as well. The syndrome is a poor prognostic marker in patients with subarachnoid haemorrhage.
Terson syndrome has been reported to occur in 13-5...
The testicular arteries (also known as the spermatic arteries) are the long, small-diameter gonadal arteries in the male that supply the testis alongside the cremasteric artery and the artery to the ductus deferens.
As paired structures they arise symmetrically, slightly...
Thalamostriate veins are formed by the joining of anterior caudate vein and the vein of stria terminalis. They join the septal veins and form internal cerebral veins.
The thalamostriate veins can be compressed in preterm neonates who have had germinal matrix haemorrhage. This...
The thoracic aorta is the most superior division of the aorta and is divided into three sections:
The thoracic aorta begins at the aortic valve, located obliquely just to the left of the midline at the level of the the third intercostal space. It ...
Thoracic aortic aneurysms are relatively uncommon compared to abdominal aortic aneurysms. There is a wide range of causes, and the ascending aorta is most commonly affected. CTA and MRA are the modalities of choice to image this condition.
The term aneurysm is used when the axial d...
There are a number of causes and mimics of thoracic aortic dilatation.
post-stenotic dilatation, e.g. bicuspid aortic valve
thoracic aortic aneurysm
atherosclerosis (usually descending thoracic aorta)
Thoracic aortic injury is the most common type of traumatic aortic injury and is a critical life-threatening, and often life ending event. It can result from either blunt or penetrating trauma:
blunt trauma (more common)
rapid deceleration (eg. motor vehicle accident, fall from great height)
The differential for thoracic aortic stenosis includes:
aortitis (especially Takayasu arteritis)
Williams syndrome: supravalvular aortic stenosis
congenital rubella syndrome: supravalvular aortic stenosis
The thoracic duct is the main lymphatic channel for the return of chyle to the venous system. It drains lymph from both lower limbs, abdomen (except the convex area of the liver), left hemithorax, left upper limb and left face and neck.
The thoracic duct is the superior continua...
Thoracic outlet syndrome (TOS) refers to a group of clinical syndromes caused by congenital or acquired compression of the brachial plexus or subclavian vessels as they pass through the superior thoracic aperture.
Clinical presentation will depend on the structure compre...
A handy mnemonic to remember the structures found at the level of the thoracic plane (also known as the plane of Ludwig) is:
C: cardiac plexus
L: ligamentum arteriosum
A: aortic arch (inner concavity)
P: pulmonary trunk
T: tracheal bifurcation (carin...
The thoracoacromial artery is a vessel arising from the axillary artery at the axilla.
origin: first branch of the second part of the axillary artery 1
supply: pectoralis major and minor, anterior part of the deltoid, and dermal sensation overlying the clavipectoral ...
A useful mnemonic to remember the branches of the thoracoacromial artery is:
The threads and streaks sign refers to an angiographic appearance of a vascularised tumour thrombus extending into the ipsilateral renal vein or the inferior vena cava from a renal cell carcinoma. This gives an appearance of linear, thread like or string like appearance of the involved vessel.
The thrombolysis in cerebral infarction (TICI) grading system was described in 2003 by Higashida et al 1 as a tool for determining the response of thrombolytic therapy for ischaemic stroke. In neurointerventional radiology it is commonly used for patients post endovascular revascularisation. Lik...
Thrombus fissuration is a sign of impending rupture of an aortic aneurysm. It reflects blood dissecting into the intramural thrombus. This sign is observed on contrast-enhanced CT as linear contrast infiltrations from the aneurysm lumen through the intramural thrombus. Thrombus fissurations exte...
The thyrocervical trunk is one of the 3 branches of the first part of the subclavian artery and gives of numerous branches to supply viscera of the neck, the brachial plexus, neck muscles and the scapular anastomosis.
The trunk arises lateral to the vertebral artery from the anterosuperior wall...
The thyroidea ima artery is an uncommon variant of the blood supply to the inferior aspect of the thyroid gland. It is reported in ~7.5% (range 1.5-12.2%) of individuals and can arise from:
right common carotid artery
internal thoracic artery
The thyroidea ...
The tibioperoneal or TP trunk, which occasionally referred to as the tibiofibular trunk is the direct continuation of the popliteal artery in the posterior upper leg after the anterior tibial artery origin. It is a short trunk that bifurcates into two terminal branches.
Time of flight angiography (TOF) is an MRI technique to visualize flow within vessels, without the need to administer contrast. It is based on the phenomenon of flow-related enhancement of spins entering into an imaging slice. As a result of being unsaturated, these spins give more signal that s...
TIPS evaluation is useful to ensure that the shunt is working properly and that no stenosis has occurred within the stent. Ultrasound is often used as a first-line modality.
The normal TIPS should show colour Doppler flow throughout its length. The in-stent ve...
Top of the basilar syndrome, also known as rostral brainstem infarction, occurs when there is thromboembolic occlusion of the top of the basilar artery. This results in bilateral thalamic ischaemia due to occlusion of perforator vessels.
Clinically, top of the basilar syn...
Transjugular intrahepatic portosystemic shunt (TIPS) is a treatment for portal hypertension in which direct communication is formed between a hepatic vein and a branch of the portal vein, thus allowing some proportion of portal flow to bypass the liver. The target portosystemic gradient after TI...
Transposition of inferior vena-cava (also known as left sided IVC) refers to a variant course of the inferior vena cava. It is the most common anomaly of IVC and occurs due to persistence of left supracardinal vein.
Diagnosis of left sided IVC is important for
planning of vascular procedures l...
Transposition of the great arteries (TGA) is the most common cyanotic congenital cardiac anomaly with cyanosis in the first 24 hours of life. It accounts for up to 7% of all congenital cardiac anomalies 1 and can be assessed with echocardiography, gated cardiac CT, or cardiac MRI.
The transverse cervical artery, also known as the cervicodorsal trunk, is 1 of the 4 branches of the thyrocervical trunk (off the first part of the subclavian artery).
It is a short artery that bifurcates into the superficial and deep branches, both which course superficially and laterally acro...
The transverse sinus is one of the dural venous sinuses and drains the superior sagittal sinus, the occipital sinus and the straight sinus, and empties into the sigmoid sinus which in turn reaches the jugular bulb.
The two transverse sinuses arise at the confluence of the three aforementioned s...
Traumatic aortic injury (TAI) is most often caused by blunt trauma (refered to as BTAI) and is best described in terms of injury location, type and and severity:
abdominal aortic injury
thoracic aortic injury
minimal aortic injury
See traumatic aortic injury in the exam.
Getting a film with traumatic aortic injury in the exam is one of the many exam set-pieces that can be prepared for.
This is one of the cases you should look and not speak for 10 seconds as there tends to be a lot of findings on the film of patients with traumatic aortic injury.
A useful mnemonic to remember the tributaries of the inferior vena cava is:
I Like To Rise So High
I: common iliac veins
L: lumbar veins
T: right testicular (gonadal) vein
R: renal veins
S: suprarenal veins
H: hepatic veins
Triple-rule-out CT (TRO CT) angiography may be ordered in the setting of acute chest pain to examine the thoracic aorta and the coronary and pulmonary arteries. The protocol helps exclude life-threatening causes of acute chest pain, especially if atypical, or if alternative causes to acute coron...
In a true aneurysm, the aneurysm is bound by all three layers of the vessel wall (intima, media and adventitia). The wall may be attenuated. The risk of rupture is proportional to the size of the aneurysm.
Tulip bulb sign refers to characteristic appearance due to dilatation of sinuses of Valsalva slightly extending into the ascending aorta as seen on CT scan of chest.
It is seen especially in Marfan's syndrome.
On CT angiography, aneurysm of the aortic root with effacement of sinotubular junct...
Tumour thrombus is defined as tumour demonstrated within a vessel, typically a vein. This phenomenon is classically associated renal cell carcinoma (RCC), where tumour may invade the renal vein and migrating proximally where it can reach the right atrium. Tumour thrombus is usually composed of ...
Blood vessel derived tumours may arise from:
cells supporting or surrounding blood vessels
glomus tumour of finger
Most arise in the soft tissues or viscera. Primary tumours of the large vessels (eg. aorta, IVC)...
A type II endoleak is a commonest form of endoleak are after an abdominal aortic repair.
They may occur in 10-44% of patients having reparis and can comprise around half of all endoleaks 1.
They may be simple of complex. Simple leak usually occur secondary to backflow...
The ulnar artery is a terminal branch of the brachial artery, arising at the proximal aspect of the forearm. Along with the radial artery, it is one of the main arteries of the forearm.
origin: terminal branch of the brachial artery
location: inferior aspect of the cubital fossa
The ulnar vein is one of the two major deep veins of the forearm, along with the radial vein. As is usual in the upper and lower limbs, there are often two veins (venae comitantes) that run on either side of the ulnar artery and anastomose freely with each other.
It forms in the hand from the d...
Ultrasound assessment of carotid arterial atherosclerotic disease has become the first choice for carotid artery stenosis screening, permitting the evaluation of both the macroscopic appearance of plaques as well as flow characteristics in the carotid artery.
This article focus on internal caro...
Ultrasound (US) guided peripheral intravenous cannulation (IVC) is the placement of a cannula into a peripherally located vein under the direct vision of ultrasound. This process allows the cannulation of veins that are unable to be visualised or palpated without ultrasound. In trained individua...
An umbilical arterial aneurysm (UAA) is an extremely rare but potentially lethal vascular anomaly which is usually detected in utero.
If tends to favour the placental end of the umbilical artery in the cord.
Concurrent associated anomalies are thought to be ...
Umbilical arterial catheters are used in neonatal care and need to be carefully assessed on all neonatal films.
The catheter should pass through the umbilicus, travel inferiorly through the umbilical artery, then in the anterior division of the internal iliac artery, into the common ...
The umbilical artery gives rise to both a nonfunctional remnant of the fetal circulation, and an active vessel giving supply to the bladder. In the adult the obliterated area of the vessel is identifiable as the medial umbilical ligament and the patent segment is the superior vesical artery.
Umbilical vein varix (UVV) refers to a focal dilatation of the umbilical vein.
It tends to favour the intra-abdominal portion of the cord (typically between the abdominal wall and the liver) which is then termed a fetal intra-abdominal umbilical vein varix (FIUVV) or the in...
Umbilical venous catheters are commonly used in the neonatal period for vascular access, and should be carefully assessed for position on all neonatal films.
An umbilical venous catheter generally passes directly superiorly and remains relatively anterior in the abdomen. It passes th...
The term unfolded aorta refers to the widened and 'opened up' appearance of the aortic arch on a frontal chest radiograph. It is one of the more common causes for apparent mediastinal widening and is seen with increasing age.
It occurs due to the discrepancy in the growth of the ascending aorta...
Unilateral pulmonary artery atresia (UPAA) or unilateral absence of the pulmonary artery (UAPA) is a variant of pulmonary artery atresia.
The estimated prevalence is around 1 in 200,000 young adults. The reported frequency on the right side is slightly greater for some reason 10....
Unilateral pulmonary vein atresia is a type of pulmonary vein atresia.
It results from failure of incorporation of the common pulmonary vein into the left atrium. There is no recognised right or left predilection.
The condition usually present in infancy or ch...
Upper gastrointestinal bleeding (UGIB) is defined as bleeding proximal to the ligament of Treitz.
The incidence of acute UGIB is ~100 per 100,000 adults per year. UGIB is twice as common in men as in women and increases in prevalence with age 5. The demographics of the affected in...
Upper limb anatomy encompasses the anatomy of the shoulder, arm, elbow, forearm, wrist and hand.
Uterine arteriovenous malformations (UAVM) result from formation of multiple arteriovenous fistulous communications within the uterus without an intervening capillary network.
Presentation can vary. UAVMs can cause life-threatening massive bleeding in young women. Bleedin...
The uterine artery is seen bilaterally and is a branch of the anterior division of the internal iliac artery.
It runs medially in the pelvis, within the base of the broad ligament, to the outer surface of the uterus. From lateral to medial it has a descending, transverse ...
Uterine artery embolisation (UAE) is an interventional radiological technique to occlude the arterial supply to the uterus and is performed for various reasons.
Uterine artery embolisation has been practised for more than 20 years for controlling haemorrhage following delivery / aborti...
Uterine artery embolisation (UAE) is used as an alternative to hysterectomy in selected patients and MRI assessment is key in allowing not only pre-procedure assessment but also assessing post-procedural outcome.
For a general discussion of the underlying condition refer to the article on ute...
Uterine artery flow notching refers to phenomenon observed in uterine arterial Doppler ultrasound assessment.
The presence of notching after 22 weeks is associated with several other conditions including adverse pregnancy outcomes. These include
pregnancy induced hyper...
Uterine artery pseudoaneurysm (UAP) is a rare cause of secondary postpartum haemorrhage.
UAP usually presents as delayed (secondary) postpartum haemorrhage, that is per vaginal bleeding which occurs more than 24 hours and up to 6 weeks postpartum. However, some reported ...
The vaginal artery is a branch of the anterior division of the internal iliac artery, and should not to be mistaken with the vaginal branch of the uterine artery. It is often considered to be a homolog of the inferior vesical artery, which is present only in males.
origin: anterior div...
Variant anatomy of the aortic arch occurs when there is failure of normal aortic development. It results in a number of heterogenous anomalies of the aorta and its branch vessels.
Normally, the aorta ascends in the superior mediastinum to the level of the sternal notch before arc...
Variation in hepatic arterial anatomy is seen in 40-45% of people. Classic branching of the common hepatic artery from the coeliac artery, and the proper hepatic artery into right and left hepatic arteries to supply the entire liver, is seen in 55-60% of the population.
In general, the common ...
Varicocoele is the dilatation of pampiniform plexus of veins, a network of many small veins found in the male spermatic cord. It is the most frequently encountered mass of the spermatic cord.
The estimated incidence is at ~15% of general male population and ~40% of subfertile and ...
Varicocoele embolisation is a minimally invasive method of treating varicoceles by embolising the testicular vein (internal spermatic veins).
failed surgical ligation
Relative contraindications include:
Varicose veins are dilated tortuous superficially located venous channels that accompany the superficial veins of the upper or lower limbs.
Varicose veins are more common in women than men and are more common in the lower limb than in the upper limb 5. Risk factors include:
SVC & IVC - variants
Intracranial arteries - variants
Vascular compression disorders are numerous and can be divided into those cases where a vascular structure is the "compress-er" or the "compress-ee" . Some conditions fall into both categories, where one vessel compresses another.
Compression of a vascular structure
Vascular Ehlers-Danlos syndrome (EDS) or type IV Ehlers-Danlos syndrome (EDS 4) is the most malignant form of Ehlers-Danlos syndrome. This form is often accompanied by neurovascular complications secondary to vessel dissections and/or aneurysms.
Vascular EDS represents about 4% of...
Vascular malformations and tumours are a heterogeneous group of lesions that may affect the arterial, capillary, venous or lymphatic system or any combination thereof. They encompass a bewildering range of lesions, syndromes, and masses ranging from the relatively common (e.g. infantile hemangi...
Venous pathology is common and includes:
disorders of vessel wall
Vascular rings and slings refer to the congenital vascular encirclement of the oesophagus and/or trachea by anomalous/aberrant vessels.
Vascular rings are rare, occurring in <1% of patients 1. No gender or ethnic predispositions have been identified 3.
The are numerous vascular syndromes that can occur in the body. There include
Syndromes principally involving the vascular system
coeliac artery compression syndrome
hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)
hypothenar hammer syndrome