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 pattern of Doppler ultrasound spectral waveform resulting from arterial stenosis. The phenomenon is observed downstream to the site of stenosis, and is due to reduced magnitude of blood flow through the narrowed vessel during ventricular systole 7.
This characteristic ...
Tc-99m labeled RBC is one of the technetium radiopharmaceuticals used in the assessment of GI bleeding.
photon energy: 140 KeV
physical half life: 6 hours
biological half life:
normal distribution: heart, vessels, spleen
threshold for detection is 0.0...
The teardrop sign of the superior mesenteric vein is one of the important signs in the local staging of pancreatic adenocarcinoma. Its importance lies in its diagnostic, as well as prognostic, significance. This sign is used in assessing the resectability of pancreatic cancer.
The tela choroidea is the thin, highly vascularized, 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 to a mucosal surface. Rarely they are also referred to denote vascular malformations at other non-mucosal sites (e.g capillary telangiectasias of the brain 1)
There are numerous condit...
Temporal tap maneuver consists in tapping over the ipsilateral superficial 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: externa...
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 angle of the straight sinus. Normally it should measure between 27° and 52°.
Abnormalities of the posterior fossa or base of skull can alter this. For example, this angle is elevated in achon...
Terson syndrome refers to vitreous hemorrhage associated with subarachnoid hemorrhage, however, some authors include retinal hemorrhage as well. The syndrome is a poor prognostic marker in patients with subarachnoid hemorrhage.
Terson syndrome has been reported to occur in 13-50% ...
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 hemorrhage. This ...
Third inflow refers to anatomical variants leading to an additional venous inflow to the liver apart from the usual dual blood supply (portal vein and hepatic artery). They tend to be associated with parenchymal pseudolesions (focal hyperenhancement on post-contrast imaging, focal fat infiltrati...
Thoracic anatomy encompasses the anatomy of all structures of the thorax.
This anatomy section promotes the use of the Terminologia Anatomica, the international standard of anatomical nomenclature.
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 third intercostal space. It term...
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 normal aortic diameter varies based on...
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.
Approximately 80% of patients with thoracic aortic injury die at the scene of the trauma. In those who make it to hospital, clinical...
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 vessel for the return of chyle/lymph to the systemic 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 supe...
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 vascularized tumor 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 ischemic stroke. In neurointerventional radiology it is commonly used for patients post endovascular revascularization. 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 a linear contrast infiltration from the aneurysm lumen through the intramural thrombus. Thrombus fissurations ext...
The thyrocervical trunk is one of the 3 branches of the first part of the subclavian artery and gives off 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 wal...
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:
brachiocephalic trunk (most common: 1.9-6.0%)
right common carotid artery
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 color Doppler flow throughout its length. The in-stent vel...
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 ischemia due to occlusion of perforator vessels.
Clinically, top of the basilar synd...
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 ...
Transposition of the great arteries (TGA) (also known as transposition of the great vessels (TGV)) is the most common cyanotic congenital cardiac anomaly presenting during the newborn period, with cyanosis in the first 24 hours of life. It accounts for up to 7% of all congenital cardiac anomalie...
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 pancreatic artery, also known as the inferior pancreatic artery, is a branch of the splenic artery that supplies the pancreatic tail and body.
It arises from the proximal splenic artery and descends a short distance to run to the left along the posterior margin of the pancreas ne...
The paired left and right transverse sinuses are major dural venous sinuses and arise from the confluence of the superior sagittal, occipital and straight sinuses at the torcular herophili (confluence of sinuses).
On each side, the transverse sinus then runs in the lateral border of the tentori...
Traumatic aortic injury (TAI) is most often caused by blunt trauma (referred to as BTAI) and is best described in terms of injury location, type 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 a 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
The trident appearance (or sign) can refer to a variety of entities:
trident sign (osmotic demyelination)
trident sign (persistent trigeminal artery)
History and etymology
The trident is a three-pronged lance employed for spearing fish, and in Classical myth...
The trident sign of a persistent primitive trigeminal artery refers to the appearance of the intracranial circulation on lateral projection. The internal carotid artery, the abnormal vessel and superior portion of the basilar artery resemble the Greek letter tau (thus tau sign). This configurati...
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.
Tuberculous aortitis is a rare cause of aortitis in the context of wide-spread tuberculosis. It usually is a result of direct seeding from a contiguous lymph node or via hematogenous or lymphatic spread of distant infection. Fatal outcomes of tuberculous aortitis are commonly reported despite ag...
Tulip bulb sign refers to the characteristic appearance of annuloaortic ectasia as seen on CT angiography.
There is symmetric dilatation of the three sinuses of Valsalva, with extension into the ascending aorta and effacement of the sinotubular junction.
It is seen especially in Marfan syndro...
Tumor necrosis factor receptor-associated periodic syndrome (or sometimes abbreviated as TRAPS) is a condition characterized by recurrent (periodic) episodes of fever as well as spectrum of dermatologic findings, including migratory patches, edematous plaques, periorbital edema, and/or conjuncti...
Blood vessel derived tumors may arise from:
cells supporting or surrounding blood vessels
glomus tumor of finger
Most arise in the soft tissues or viscera. Primary tumors of the large vessels (eg. aorta, IVC) are ...
Tumor thrombus is defined as tumor extending into a vessel, typically a vein. It occurs in a wide variety of malignancies. It is vital to distinguish tumor thrombus from "bland" thrombus (free of neoplastic cells) in the setting of neoplasia, as this often impacts staging and treatment approach....
Tunica is a word used in anatomy to refer to a type of covering.
tunica adventitia (also known as tunica externa)
tunica albuginea (clitoris)
tunica albuginea (ovary)
tunica albuginea (penis)
tunica albuginea (testis)
Type I endoleaks are a sub group of endoleaks which occur at graft ends, often due to inadequate seal.
They occur as a result of poor apposition between one of the attachment sites of a stent-graft and the native aortic or iliac artery wall. Blood can leak can occur through this def...
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 or complex. Simple leak usually occur secondary to backflow...
A type III endoleak is a type of endoleak which usually occurs through a defect in the graft. It may be divided into two components.
IIIa: junctional separation of the modular components
IIIb: fractures or holes involving the endograft
It is relatively uncommon and only occurs ...
Type IV endoleaks are a type of endoleak which usually occurs secondary to graft porosity and are typically seen in the immediate post operative angiogram following an endovascular aneurysm repair.
Type IV endoleaks are extremely rare and studies report a prevalence of 0.3%. This ...
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...
Peripheral intravenous cannulation under ultrasound guidance 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 visualized or palpated without ultrasound. In trained individuals ...
An umbilical arterial aneurysm (UAA) is an extremely rare but potentially lethal vascular anomaly which is usually detected in utero.
It tends to favor the placental end of the umbilical artery in the cord.
Concurrently associated anomalies are thought to be...
Umbilical arterial catheters (UACs) are used in neonatal care for arterial sampling 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 i...
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.
The umbilical cord is a fetal organ that connects the placenta to the developing fetus and is a vital passage for nutrients, oxygen and waste products to and from the fetus.
The umbilical cord inserts into the center of the placental bulk and into the fetus at the umbilicus. Variations in inse...
The umbilical vein is the conduit for blood returning from the placenta to the fetus until it involutes soon after birth.
The umbilical vein arises from multiple tributaries within the placenta and enters the umbilical cord, along with the (usually) paired umbilical arteries. Once it enters the...
Umbilical vein varix (UVV) refers to a focal dilatation of the umbilical vein.
UVVs were initially thought to have a high association with other anomalies which include:
chromosomal anomalies: 5-12% with FIUVV 2,3
underlying congenital cardiovascul...
Umbilical venous catheters (UVCs) are commonly used in neonates 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 through...
The umbilicus is the fibrous remnant of the foetal attachment of the umbilical cord after birth. All layers of the anterior abdominal wall fuse at the umbilical ring, a small round defect in the linea alba located just inferior to the midpoint between the xiphoid process of the sternum and the p...
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), also known as unilateral absence of the pulmonary artery (UAPA) or proximal interruption of the pulmonary artery, is a variant of pulmonary artery atresia.
The term interruption is preferred by some to absence or atresia because the anom...
Unilateral pulmonary vein atresia is a type of pulmonary vein atresia.
The condition usually present in infancy or childhood with recurrent episodes of pneumonia and/or hemoptysis. Presentation in adulthood does occur but is uncommon.
It results from failure o...
Upper gastrointestinal bleeding (UGIB) is defined as bleeding proximal to the ligament of Treitz.
The incidence of acute upper GI bleeding is ~100 per 100,000 adults per year. Upper GI bleeding is twice as common in men as in women and increases in prevalence with age 5. The demog...
An upper gastrointestinal bleed usually refers to bleeding proximal to the ligament of Treitz.
Upper limb anatomy encompasses the anatomy of the shoulder, arm, elbow, forearm, wrist and hand.
This anatomy section promotes the use of the Terminologia Anatomica, the international standard of anatomical nomenclature.
Uterine arteriovenous malformations (UAVM) result from the formation of multiple arteriovenous fistulous communications within the uterus without an intervening capillary network.
The presentation can vary. UAVMs can cause life-threatening massive bleeding in young women....
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 embolization (UAE) is an interventional radiological technique to occlude the arterial supply to the uterus and is performed for various reasons.
Uterine artery embolization has been practised for more than 20 years for controlling hemorrhage following delivery/abortion,...
Uterine artery embolization (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 a 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 hyp...
Uterine artery pseudoaneurysm (UAP) is a rare cause of secondary postpartum hemorrhage.
UAP usually presents as delayed (secondary) postpartum hemorrhage, that is per vaginal bleeding which occurs more than 24 hours and up to 6 weeks postpartum. However, some reported ca...
The uterine venous plexus is a network of veins surrounding the uterus and has extensive anastomoses with the vaginal venous plexus inferiorly and ovarian venous plexuses laterally.
The uterine venous plexus lies along the lateral aspects and superior angles of the uterus within ...
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...
The Valsalva maneuver is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling.
It is commonly us...
The valveless veins are veins that lack venous valves. Most veins contain valves (known as the valvula venosa in the TA) to prevent backflow, i.e. ensuring that blood flow is always towards the heart 1.
Recent evidence shows that veins that were previously thought to be valveless, are now known...
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 celiac 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.
Varicocele is the dilatation of the 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 the general male population and ~40% of subferti...
Varicocele embolization is a minimally invasive method of treating varicoceles by embolizing the testicular vein (internal spermatic veins).
failed surgical ligation
Relative contraindications include:
Varicocele grading on color Doppler can be done variably. The most elaborate and widely-accepted grading was given by Sarteschi, as below.
For a general discussion of this condition refer to the article: varicocele.
baseline greyscale study in supine position and measure the diame...
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: