Posterior tibial recurrent artery
Origin and course
Inconstant branch that arises before the anterior tibial reaches the extensor compartment
Ascends anterior to popliteus with the recurrent nerve to that muscle, anastomosing with the inferior genicular branches of the popliteal artery
Renal arterial cut-off sign, as the name suggests, is an abrupt termination of the contrast-opacified lumen of the renal artery. It may or may not be associated with contrast extravasation.
It is seen in a vascular injury, e.g. segmental or main renal artery thrombosis or occlusion.
The renal arterial resistive index (RI) is a sonographic index to assess for renal arterial disease.
It is measured as
RI = (peak systolic velocity - end diastolic velocity ) / peak systolic velocity
the normal value is ≈ 0.60
with 0.70 being around the upper limits of normal
Renal arteriovenous fistulae (AVFs) are anomalous direct communications between arteries and veins in the kidney, which may be confused with a renal arteriovenous malformation (AVM).
The incidence of renal AVF is variable, estimated at 0.3-19% in native kidneys and 6-8% in ren...
Renal arteriovenous malformations (renal AVMs) are an uncommon vascular anomaly, which may be confused with a renal arteriovenous fistula (renal AVF).
Like arteriovenous malformations elsewhere in the body, a renal AVM is formed by a connection between the arterial and venous structu...
The renal arteries originate from the abdominal aorta and enter the renal hila to supply the kidneys. Any variant in arterial supply is important to clinicians undertaking surgery or other interventional renal procedures.
They arise from the abdominal aorta at the L1-2 ...
Renal artery aneurysms (RAA) are considered the second most common visceral aneurysm (15-22%), most common being splenic artery aneurysm (60%). They are more common in females. Most of the lesions are saccular and tend to occur at the bifurcation of main renal artery.
RAAs occur i...
Renal artery dissection may occur as a result of the following processes 1:
aortic dissection extending to involve the renal artery
iatrogenic (e.g. catheterisation)
connective tissue disease (eg. Marfan syndrome)
Renal artery occlusion can happen acutely due to in-situ thrombus, embolism, or dissection. Unless immediately treated, it can lead to renal infarction 1.
The condition is more common in the elderly, however, it may be seen in a younger age group if they have risk factors (describ...
Renal artery pseudoaneurysms are uncommon vascular finding, with the majority occuring after a renal intervention.
A renal artery pseudoaneurysm differs from a renal artery true aneurysm (as might occur in fibromuscular dysplasia) in that it does not involve all three layers of the a...
Renal artery stenosis (RAS) refers to a narrowing of a renal artery. When the process occurs slowly, it leads to secondary hypertension. Acute renal artery stenosis does not lead to hypersecretion of renin.
When the stenosis occurs slowly, collateral vessels form and supply the kidne...
Renal infarction results from interruption of the normal blood supply to part of, or to the whole kidney. The main imaging differential diagnosis includes pyelonephritis and renal tumours.
The demographics of affected patients will depend on the underlying cause, although as most ...
Renal sympathetic denervation (RSDN), also known as renal denervation, is an interventional procedure that uses radiofrequency ablation to destroy the nerve endings in the wall of the renal arteries. Endovascular (trans-catheter) techniques are an alternative to surgical sympathectomy.
Renal vascular pedicle injury is a severe form of renal trauma, which if not recognised and treated expediently with lead to the loss of the kidney.
Contrast enhanced CT is the Imaging modality of choice. On CT it is recognised as a non-enhaning kidney. Perirenal ha...
The renal veins are asymmetric paired veins that drain the kidneys.
The renal vein is formed by the union of two-to-three renal parenchymal veins in the renal sinus. It emerges from the renal hilum anterior to the renal artery and drains into the inferior vena cava at th...
There are several variations in renal venous anatomy. Some of these are specific to the left renal vein.
Left renal vein anomalies are generally classified into four types 2:
the ventral pre-aortic limb of the left renal vein is obliterated, but the dorsal retro-aortic limb persists a...
Renal vein thrombosis can be either from "bland" thrombus or tumour thrombus (extension of tumor into the vein). There are numerous aetiologies for bland thrombus, but it most commonly occurs in the hypercoagulable nephrotic syndrome. Renal vein thrombus is commoner on the left side, presumably ...
Renal vein varices develop for various reasons and are usually asymptomatic.
Renal vein varices are usually asymptomatic. Some patients may present with flank pain and/or haematuria.
chronic renal vein thrombosis
Renovascular hypertension (RVH) is a type of secondary hypertension, where high blood pressure develops secondary to renal artery disease.
Approximately 2.5% (range 0.5-5%) of hypertensive patients will have RVH as a cause 2,3.
There are a number of condit...
When issuing an MRI or CT report on a patient with an aortic aneurysm, whether it be thoracic or abdominal, a number of features should be mentioned to aid the referring clinician in managing the patient. Reporting tips for aortic aneurysms include 1-2:
size and shape
sac dimensions (outer sur...
Retinal Vasculopathy with Cerebral Leukoencephalopathy and Systemic manifestations (RVCL-S) is an autosomal dominant microvasculopathy of the brain, retina, and other organ systems.
RVCL-S was described by Stam and colleagues in 2016 to encompass several previously described condit...
Retroaortic left renal vein (RLRV) is a normal anatomical variant where the left renal vein is located between the aorta and the vertebra, and drains into the inferior vena cava.
Its recognition is important in order to avoid complications during retroperitoneal surgery or interventional proced...
The retromandibular vein runs through the substance of the parotid gland.
Origin and course
The retromandibular vein is formed, usually within the parotid, by the confluence of the maxillary vein and the superficial temporal vein. It lies deep to the facial nerve and superficial...
Retroperitoneal fibrosis (RPF), is a condition that has previously been described as chronic periaortitis. It is an uncommon fibrotic reaction in the retroperitoneum that typically presents with ureteric obstruction.
The disease is part of a spectrum of entities that have a common pathogenic pr...
Retroperitoneal haemorrhage can be a source of significant yet occult blood loss.
The clinical features are varied depending on the amount of hemorrhage present, rate of onset and ability of the surrounding structures to contain the hemostatic system. The classical featur...
The reverse figure 3 sign (also known as the E sign) is seen on barium swallows in patients with a coarctation of the aorta and is the medial equivalent of the figure 3 sign seen on plain chest radiographs. It is formed by prestenotic dilatation of the ascending aorta, indentation of the coarcta...
Following months of preparation, experts in the field of vasculitis from 12 different countries proposed an update to the 1994 International Chapel Hill Consensus Conference nomenclature of vasculitides. This 2012 update at the time of writing (mid-2016) remains the most widely used system for d...
Rhupus syndrome is a term traditionally used to describe patients uncommonly having the coexistence of
systemic lupus erythematosus (SLE) and
rheumatoid arthritis (RA)
The right colic artery may arise directly from the superior mesenteric artery (SMA) but often arises from a common trunk with the ileocolic artery or middle colic artery.
It courses to the right to the ascending colon and divides into a descending branch that supplies the lower portion of the a...
The right coronary artery (RCA) is one of the two main coronary arteries that supply the heart with oxygenated blood.
It is a branch of the ascending aorta, with its normal origin in the right aortic sinus, just superior to the aortic valve
The RCA courses to th...
The right gastric artery is a branch of the common hepatic artery which supplies the lesser curvature of the stomach.
The right gastric artery branches off from the common hepatic artery as it turns into the lesser omentum. It runs along the lesser curvature of the stomac...
The right gastroepiploic artery (RGA) arises from the gastroduodenal artery as it divides into its two terminal branches, the right gastroepiploic artery and the superior pancreaticoduodenal artery.
The RGA passes between the first part of the duodenum and the pancreas, ...
The right hepatic artery (RHA) is formed when the proper hepatic artery (PHA) bifurcates. The hepatic arteries provide 25% of the blood supply and 50% of the oxygen supply to the liver.
The PHA bifurcates into the right and left hepatic arteries on reaching the porta hepatis. The...
The right pulmonary artery (RPA) is one of the branches of the pulmonary trunk, branching at the level of the transthoracic plane of Ludwig. It is longer than the left pulmonary artery and courses perpendicularly away from the pulmonary trunk and left pulmonary artery, between the superior vena ...
Right-sided aortic arch is a type of aortic arch variant characterised by the aortic arch coursing to the right of the trachea. Different configurations can be found based on the supra-aortic branching patterns, with the two most common patterns being the right-sided aortic arch with mirror imag...
Rim sign in renal vascular compromise is seen in major renal vascular compromise.
It can be seen in:
renal artery obstruction from embolism, thrombosis or dissection
renal vein thrombosis
acute tubular necrosis
At contrast-enhanced CT or MRI, a thin (1-3 mm) rim of su...
Rotational vertebral artery occlusion syndrome, also known as Bow Hunter's syndrome, is a rare form of vertebrobasilar insufficiency secondary to dynamic compression of the usually-dominant vertebral artery.
It has many predisposing aetiologies, but is most often due to large osteophytes, atla...
Saccular cerebral aneurysms, also known as berry aneurysms, are intracranial aneurysms with a characteristic rounded shape and account for the vast majority of intracranial aneurysms. They are also the most common cause of non-traumatic subarachnoid haemorrhage.
When larger than 25...
The Sano shunt is a palliative surgical technique sometimes used as a step in Norwood procedure for hypoplastic left heart syndrome.
The procedure involves placement of an extracardiac conduit between the right ventricle and main pulmonary artery stump. This technique prevents the reduced diast...
The pectoral girdle has a rich plexus of arterial vessels that anastomose around the scapula and its muscles known as the scapular anastomosis. It functions to allow blood to flow around the scapula and shoulder joint if there is injury or occlusion. Contributing branches arise from as proximal...
Scimitar sign traditionally referred to a catheter angiographic appearance, although it can also be seen on MRA and CTA. It denotes lateral displacement and stenosis of the popliteal artery in patients with cystic adventitial disease.
Scimitar syndrome, also known as hypogenetic lung syndrome, is characterised by a hypoplastic lung that is drained by an anomalous vein into the systemic venous system. It is a type of partial anomalous pulmonary venous return and is one of the several findings in congenital pulmonary venolobar ...
Secondary pulmonary arterial hypertension includes all cases of pulmonary arterial hypertension except for those for which no cause is identified with are then termed idiopathic pulmonary arterial hypertension.
The classification of pulmonary arterial hypertension into primary and secondary ha...
Segmental arterial mediolysis (SAM) is an increasingly recognised vascular disease of the middle-aged and elderly and a leading cause of spontanoeus intra-abdominal haemorrhage. It is characterised by fusiform aneurysms, stenoses, dissections and occlusions within splanchnic arterial branches. I...
The sentinel clot sign is a useful CT finding for the evaluation of probable anatomic sites of haemorrhage.
On CT, acute clotted haemorrhage typically has high attenuation (45 to 80 HU), whereas surrounding areas of acute non-clotted haemorrhage or more chronic haemorrhage have either lower att...
Septal cerebral veins originate at the lateral aspect of the anterior horns of the lateral ventricles then pass medially, inferior to the genu of the corpus callosum. They then turn backwards and traverse along the septum pellucidum and enter the internal cerebral vein behind the foramen of Monr...
Serpentine aneurysm is a rare subtype of intracranial aneurysm with a distinct appearance. It consists of a partially thrombosed giant intracranial aneurysm (≥ 25 mm) traversed by a patent serpiginous intra-aneurysmal vascular channel. This vascular channel has an entry and an exit point, differ...
Shmoo sign refers to the appearance of a prominent, rounded left ventricle and dilated aorta on a plain AP chest radiograph giving the appearance of Shmoo, a fictional cartoon character in the comic strip Li'l Abner, which first appeared in 1948. This sign is indicative of left ventricular enlar...
Shone syndrome, also known as Shone complex, is a rare syndrome characterised by left-sided, obstructive congenital heart defects.
Shone syndrome is thought to be very rare, accounting for less than 1% of all congenital heart disease 1.
Patients, usually ne...
The short gastric arteries are a group of short arteries arising from the terminal splenic artery and the left gastroepiploic artery which supply the fundus of the stomach along it's greater curvature.
The vessels are short in length, variable in number and course through the gastrosplenic liga...
Shrinking lung syndrome (SLS) refers to a rare complication of systemic lupus erythematosus (SLE), and is characterised by:
restrictive pattern on pulmonary function tests
As with SLE in general, it is thought to carry a increased fem...
Sickle cell disease (SCD) is a hereditary (autosomal recessive) condition resulting in the formation of abnormal haemoglobin (a haemoglobinopathy), which manifests as multisystem ischaemia and infarction, as well as haemolytic anaemia.
There is no recognised gender predilection. ...
Abdominal manifestations of sickle cell disease (SCD) are wide and can involve many organs.
For a general discussion, please refer to sickle cell disease.
may occur transiently with the sequestration syndrome, where rapid pooling of blood occurs in the spleen, resulting ...
The sigmoid arteries are branches, between two-to-four, of the inferior mesenteric artery (IMA) and supply the sigmoid colon.
origin: inferior mesenteric artery
course: after arising from IMA, these branches descend to the left in the sigmoid mesocolon
superiorly with ...
The sigmoid sinus is a paired structure and one of the dural venous sinuses. It is the continuation of the transverse sinus (which is similarly variable in size) and becomes the sigmoid sinus as the tentorium ends. It is here that the sinus receives the superior petrosal sinus.
It passes inferi...
The signal flare phenomenon is a useful sign to identify active bleeding in a liquefied haematoma with haematocrit effect on dynamic CT scan images.
When active arterial haemorrhage is present in a liquefied haematoma that has a haematocrit effect, a signal flare phenomenon may be seen as a lin...
In the past 15 years sildenafil citrate-induced penile Doppler has emerged as a technique for evaluating erectile dysfunction. It has greater patient acceptability than the usual papaverine-induced colour Doppler and is safer.
Sildenafil citrate is a popular vasodilator drug used in treatment o...
Single coronary arteries are rare (incidence 0.03-0.07%), with a higher incidence in patients with congenital heart disease (in particular truncus arteriosus and pulmonary atresia). They occur when there is a single ostia arising from the aorta with no ectopic ostia. There is a wide variety of c...
Single umbilical artery (SUA) results when there is a congenital absence of either the right or left umbilical artery. In the usual situation, there are paired umbilical arteries. For some unknown reason, the absence of the left umbilical artery is much more common (~70%).
The sinotubular junction is the region of the ascending aorta between the aortic sinuses (of Valsalva) and where the normal tubular configuration of the aorta is attained.
Sinus of Valsalva aneurysms are a cause of thoracic aortic dilatation. They can be either congenital or acquired (mycotic).
There is a male predilection (M:F ratio being around 3-4:1). They are relatively more common in eastern and Asian populations and can occur in any age group ...
Situs classification can be a daunting topic, but it falls into three main groups :
situs solitus: the normal configuration of thoracic and abdominal organs
situs inversus: mirror image of normal
situs ambiguus: an intermediate configuration with duplication (isomerism)
Situs is best thought...
Situs inversus, short form of the Latin “situs inversus viscerum”, is a term used to describe the inverted position of chest and abdominal organs. It is called situs inversus totalis when there is a total transposition of abdominal and thoracic viscera (mirror image of internal organs normal pos...
Situs solitus refers to the normal position of the thoracic and abdominal organs.
On plain radiograph, careful attention should be directed at the location of the aortic arch, gastric fundus, cardiac apex, pulmonary fissures and the branching pattern of ...
The small cardiac vein is a vein of the heart which accompanies the acute marginal artery from the RCA. It courses in the right posterior atrioventricular groove and drains into the coronary sinus close to it’s termination but may drain directly into the right atrium. It drains the right ventric...
The small saphenous vein (SSV) forms part of the superficial venous drainage of the lower limb.
Small saphenous vein is the preferred terminology over other terms such as short saphenous vein, external saphenous vein or lesser saphenous vein 5.
Origin and course
Soft-tissue sarcomas are a heterogeneous group of malignant tumours of mesenchymal origin (sarcoma) that originate from the soft tissues rather than bone. They are classified on the basis of tissue seen on histology. The commoner sarcomas in the adult and paediatric population are listed below.
Sonographic halo sign is used in a number of situations. They include:
hypoechoic halo sign (also known as target or bull's eye sign) in liver metastases: used in hepatobiliary imaging, is a concerning feature for malignant lesion if the lesion is a hyperechoic liver lesion 1,2
The Spetzler-Martin arteriovenous malformation (AVM) grading system allocates points for various features of intracranial arteriovenous malformations to give a grade between 1 and 5. Grade 6 is used to describe inoperable lesions. The score correlates with operative outcome.
size of ni...
The sphenopalatine artery, formerly known as the nasopalatine artery, is the terminal branch of the maxillary artery that is the main supply to the nasal cavity. It is colloquially know as the artery of epistaxis given its common involvement in cases of nose bleeds. It is a major contributor to ...
The sphenoparietal sinus is one of the dural venous sinuses and is located along the posteroinferior ridge of the lesser wing of the sphenoid bone. It consists of the sinus of the lesser sphenoid wing and of the parietal portion of the frontal ramus of the middle meningeal vein. It drains into t...
Spinal arteriovenous malformations (AVMs) are characterised by arteriovenous shunting with a true nidus. They represent ~25% of spinal vascular malformations.
Different types of spinal AVM (see below) have differing age of presentation, but overall 80% present between the age 20 ...
Spinal arteriovenous malformations can be classified in a number of ways:
extramedullary: 80% 1
Or into four types 2:
type I: single coiled vessel (dural AV fistula)
type II: intramedullary glomus AVM
type III: juvenile
type IV: intradural perimedullary (AV fistula)
The spinal cord blood supply is formed by many different vessels with an extensive collateral supply and drainage.
The spinal cord is supplied by three longitudinal arteries:
single anterior spinal artery: supplies the anterior two-thirds of the spinal cord
paired posterior s...
Spinal vascular malformations (SVM) are rare but knowledge of them is important as if undiagnosed and untreated they can lead to serious complications.
There are two main types of SVMs 1,2:
spinal arteriovenous fistula (AVF): 70% of SVMs
pial: small, large, or giant
dural AVF (DA...
Splenial artery or posterior pericallosal artery arises most commonly from the parieto-occipital branch of the PCA. It represents an important collateral supply from the posterior to anterior cerebral arteries as it anastomoses with the pericallosal artery.
the splenial artery ...
The splenic artery is one of three branches coeliac trunk and supplies the spleen as well as large parts of the stomach and pancreas.
Origin and course
The splenic artery is one of the terminal branches of the coeliac trunk, passing from the coeliac axis toward the splenic hilum...
Splenic artery aneuryms are the commonest visceral arterial aneurysm formation as well as the 3rd commonest abdominal aneurysm (after the aorta and iliac vessels). Aneurysms are usually saccular in configuration and they can either be in the form of a true aneurysm (much more common) or as a pse...
Splenic artery pseudoaneurysms are a rare type of pseudoaneurysm arising from any portion of the splenic artery and its branches.
Unlike splenic artery true aneurysms, splenic artery pseudoaneurysms will nearly always present with symptoms 2. Fewer than 200 cases of sple...
Splenic steal syndrome is a possible complication after liver transplantation. In this syndrome, blood flows preferentially from the celiac artery into the splenic artery and the hepatic artery is relatively hypoperfused as a result. This complication can threaten a liver transplant's survival.
The splenic vein drains the spleen, part of the pancreas, and part of the stomach.
Origin and course
The splenic vein is formed by splenic tributaries emerging at the splenic hilum in the splenorenal ligament at the tip of the tail of pancreas. It runs in the splenorenal ligame...
Spontaneous retroperitoneal haemorrhage (SRH) is a distinctive clinical pathology of retroperitoneal bleeding without a preceding history of trauma.
Clinical presentation may be vague and varied:
no inciting history
no evidence of cutaneous bruising
back, lower abdomin...
The stag's antler sign refers to upper lobe pulmonary venous diversion (cephalisation) in pulmonary venous hypertension or pulmonary oedema as seen on frontal chest radiograph.
The prominence of upper lobe pulmonary veins resemble a stag's antlers. It is the earliest sign of pulmonary venous hy...
Along with the DeBakey classification, the Stanford classification is used to separate aortic dissections into those that need surgical repair, and those that usually require only medical management. The Stanford classification divides dissections by the most proximal involvement:
type A: A aff...
Stewart-Treves syndrome refers to an angiosarcoma seen in the setting of lymphoedema 1.
It was classically attributed to lymphoedemas induced by radical mastectomy to treat breast cancer. Nowadays, we know that it can arise in any chronically lymphoedematous region due to any cause2.
The straight sinus is one of the main dural venous sinuses and is found at the junction between the falx cerebri and the tentorium cerebelli and is triangular in cross section.
It receives the inferior sagittal sinus, the vein of Galen at its anterior end and some superior cerebellar veins alo...
The string of beads sign is the description typically given to the appearance of the renal artery in fibromuscular dysplasia (FMD) but may also be used to describe the appearance of splanchnic arteries in segmental arterial mediolysis (SAM). It refers to the appearance arising from the stenoses ...
String of pearls sign can refer to:
string of pearls sign on an abdominal radiograph of fluid-filled dilated small bowel loops
string of pearls sign on ultrasound in polycystic ovarian syndrome
string of pearls sign for angiographic appearances in fibromuscular dysplasia
The angiographic string sign, also known as the carotid string sign, refers to the thin string of intravenous contrast material distal to a stenotic focus in the internal carotid artery (ICA).
A thin stripe of flow is caused by decreased pressure and flow distal to the stenosis, whi...
The string sign may refer to:
angiographic string sign
gastrointestinal string sign
string sign of parosteal osteosarcoma
Stroke is a clinical diagnosis that refers to a sudden onset focal neurological deficit of presumed vascular origin.
It is divided into two broad categories:
ischaemic stroke (80% 2)
haemorrhagic stroke (15%)
Haemorrhage may be due to hypertension or other secondary causes such as vascular ...
The subclavian arteries are asymmetric paired arteries that supply blood to the posterior cerebral circulation, cerebellum, posterior neck, upper limbs and the superior and anterior chest wall.
Right and left subclavian arteries classically have different origins:
Helpful mnemonics to remember the branches of the subclavian artery include:
Very Indignant Tired Individuals Sip Strong Coffee Served Double Daily
VIT C, D (as in vitamins C and D).
Very Indignant Tired Individuals Sip Strong Coffee Served Double Daily
V: vertebral artery