Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

1,159 results found
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Pulmonary vein stenosis

Pulmonary vein stenosis refers to a spectrum of conditions characterized by narrowing of the pulmonary veins. It can be congenital or acquired. primary pulmonary vein stenosis - occurs in children secondary pulmonary vein stenosis - occurs in adults and usually associated with some identifiabl...
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Pulmonary vein thrombosis

Pulmonary vein thrombosis is a rare but potentially serious condition with a number of underlying possible etiologies. Clinical presentation Often the signs and symptoms are non-specific and can range from acute (pulmonary infarction) to more insidious (progressive or recurrent pulmonary edema...
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Pulsatile portal venous flow

A pulsatile portal venous flow pattern can result from both physiological and pathological causes. In well subjects mild pulsatility, or in rare situations, even marked pulsatility has been described, particularly in thin subjects, with a venous pulsatility index of >0.5 with an inverse correla...
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Pulsatile tinnitus

Pulsatile tinnitus is a specific type of tinnitus and refers to the perception of rhythmic noise, usually in time with the patient's heartbeat, in the absence of an external source, which is most commonly but not exclusively due to underlying vascular pathology. Clinical presentation Patients ...
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Pulsatility index (ultrasound)

The pulsatility index is a calculated flow parameter in ultrasound, derived from the maximum, minimum, and mean Doppler frequency shifts during a defined cardiac cycle. Along with the resistivity index (RI), it is typically used to assess the resistance in a vascular system. Terminology Pulsat...
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Pulsus bisferiens

Pulsus bisferiens or double pulse refers to a wave pattern where there is the presence of two systolic peaks that can be seen in pressure tracings of the the ascending aorta, the aortic arch, and the carotid artery. It can occur in patients with aortic valve pathology: aortic regurgitation wit...
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Radial artery

The radial artery is a terminal branch of the brachial artery and arises at the cubital fossa of the forearm. It is one of the two main arteries of the forearm, along with the ulnar artery. Summary origin: terminal branch of the brachial artery location: inferior aspect of the cubital fossa ...
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Radial collateral artery

The radial collateral artery is one of the two terminal branches of the deep brachial artery. As it descends in the distal part of the posterior compartment of the arm, it pierces the lateral intermuscular septum and contributes to the arterial anastomosis of the elbow specifically the radial re...
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Radialis indicis artery

The radialis indicis artery is a branch of the radial artery in the hand that supplies the radial aspect of the index finger (2nd digit). It arises from the radial artery in the plam just after the origin of the princeps pollicis artery. The artery courses distally along the radial (lateral) pal...
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Radial recurrent artery

The radial recurrent artery is the largest lateral branch of the radial artery in the forearm, arising just after its origin. It courses proximally on supinator from its origin to form an arterial arcade with the anterior branch (radial collateral artery) of the profunda brachii (deep brachial) ...
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Radial vein

The radial vein is one of the two major deep veins of the forearm, along with the ulnar vein. As is usual in the upper and lower limbs, there are often two veins (venae comitantes) that run on either side of the radial artery and anastomose freely with each other. It forms in the hand from the ...
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Radiation-induced cerebral vasculopathy

Radiation-induced cerebral vasculopathy encompasses a complex and broad range of effects on the intra- and extracranial vessels resulting from injury from radiation exposure. Manifestations can include hemorrhages and ischemic strokes, cavernoma and capillary telangiectasias, and large vessel st...
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Ramus intermedius artery

The ramus intermedius is a variant coronary artery resulting from trifurcation of the left main coronary artery 1. It is present in ~20% (range 15-30%) 2-3 of the population. It can have a course similar to the obtuse marginal branches of the left circumflex artery or the diagonal branches of t...
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Rapid ultrasound in shock

The rapid ultrasound in shock (RUSH) protocol is a structured point-of-care ultrasound (POCUS) examination performed at the time of presentation of a shocked patient. It is a more detailed and longer exam than the FAST scan, with the aim to differentiate between hypovolemic, cardiogenic, obstruc...
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Rasmussen aneurysm

Rasmussen aneurysm (not to be confused with Rasmussen encephalitis) is an uncommon complication of pulmonary tuberculosis and represents a pulmonary artery aneurysm adjacent or within a tuberculous cavity.  Epidemiology It can be present in up to 5% of patients with chronic cavitary tuberculos...
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Rastelli procedure

The Rastelli procedure is a surgical procedure to correct certain combinations of cardiovascular defects in patients with cyanotic congenital heart disease. Rationale The operation is based on a redirection of ventricular outflows using an intracardiac baffle that tunnels the left ventricle to...
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Raymond–Roy occlusion classification of intracranial aneurysms

The Raymond–Roy occlusion classification (RROC) is an angiographic classification scheme for grading the occlusion of endovascularly treated intracranial aneurysms 1. It is also known as the Raymond class, Montreal scale or the Raymond Montreal scale. class I: complete obliteration class II: r...
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Raynaud phenomenon

Raynaud phenomenon (also known as Raynaud syndrome) describes a localized vasculopathy whereby there is an exaggerated vascular response to cold temperature or emotional stresses. Terminology Raynaud phenomenon is classified as being either 'primary' or idiopathic, or 'secondary' to another un...
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Rectus sheath hematoma

Rectus sheath hematomas, as the term implies, occur when a hematoma forms in the rectus abdominis muscle/rectus sheath. It is most common in its lower segment and is generally self-limiting. Epidemiology Rectus sheath hematomas are more common in women with a 3:1 F:M ratio. Clinical presentat...
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Recurrent artery of Heubner

Recurrent artery of Heubner, also known as the medial striate artery or long central artery, is the largest perforating branch from the proximal anterior cerebral artery (ACA) and is the only one routinely seen on angiography. Gross anatomy Origin and course Its origin is near the A1-ACOM-A2 ...
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Recurrent tibial arteries

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 Suppl...
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Renal arterial cut-off sign

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.
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Renal arterial resistive index

The renal arterial resistive index (RI) is a sonographic index of intrarenal arteries defined as (peak systolic velocity - end diastolic velocity ) / peak systolic velocity. The normal range is 0.50-0.70. Elevated values are associated with poorer prognosis in various renal disorders and renal t...
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Renal arteriovenous fistula

Renal arteriovenous fistulae (AVFs) are anomalous direct communications between arteries and veins in the kidney, which may be confused with a renal arteriovenous malformation (rAVM). Epidemiology The incidence of renal AVF is variable, estimated at 0.3-19% in native kidneys and 6-8% in re...
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Renal arteriovenous malformation

Renal arteriovenous malformations (renal AVMs) are an uncommon vascular anomaly, which may be confused with a renal arteriovenous fistula (renal AVF). Pathology Like arteriovenous malformations elsewhere in the body, a renal AVM is formed by a connection between the arterial and venous structu...
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Renal artery

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. Gross anatomy Origin They arise from the abdominal aorta at the L1-2 ...
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Renal artery aneurysm

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. Epidemiology RAAs occur i...
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Renal artery dissection

Renal artery dissection may occur as a result of the following processes 1: aortic dissection extending to involve the renal artery iatrogenic (e.g. catheterization) trauma atherosclerosis fibromuscular dysplasia connective tissue disease (eg. Marfan syndrome) idiopathic
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Renal artery occlusion (acute)

Renal artery occlusion can happen acutely due to in-situ thrombus, embolism, or dissection. Unless immediately treated, it can lead to renal infarction 1. Epidemiology The condition is more common in the elderly, however, it may be seen in a younger age group if they have risk factors (describ...
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Renal artery pseudoaneurysm

Renal artery pseudoaneurysms are uncommon vascular finding, with the majority occuring after a renal intervention. Pathology 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...
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Renal artery stenosis

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. Pathology When the stenosis occurs slowly, collateral vessels form and supply the kidne...
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Renal infarction

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 tumors. Epidemiology The demographics of affected patients will depend on the underlying cause, although as most c...
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Renal sympathetic denervation

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.  Indicat...
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Renal vascular pedicle injury

Renal vascular pedicle injury  is a severe form of renal trauma, which if not recognized and treated expediently with lead to the loss of the kidney.  Radiographic features CT Contrast enhanced CT is the Imaging modality of choice. On CT it is recognized as a non-enhaning kidney. Perirenal he...
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Renal vein

The renal veins are asymmetric paired veins that drain the kidneys.  Gross anatomy Course 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...
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Renal vein anomalies

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: type I  the ventral pre-aortic limb of the left renal vein is obliterated, but the dorsal retro-aortic limb persists a...
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Renal vein thrombosis

Renal vein thrombosis can be either from "bland" thrombus or tumor thrombus (extension of tumor into the vein). There are numerous etiologies for bland thrombus, but it most commonly occurs in the hypercoagulable nephrotic syndrome. Renal vein thrombus is commoner on the left side, presumably du...
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Renal vein varices

Renal vein varices develop for various reasons and are usually asymptomatic. Clinical presentation Renal vein varices are usually asymptomatic. Some patients may present with flank pain and/or hematuria. Pathology Etiology chronic renal vein thrombosis nutcracker syndrome retroaortic le...
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Renovascular hypertension

Renovascular hypertension (RVH) is a type of secondary hypertension, where high blood pressure develops secondary to renal artery disease.  Epidemiology Approximately 2.5% (range 0.5-5%) of hypertensive patients will have RVH as a cause 2,3.  Pathology Etiology There are a number of conditi...
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Reporting tips for aortic aneurysms

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...
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Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is an autosomal dominant microvasculopathy of the brain, retina, and other organ systems. Terminology RVCL-S encompasses several previously described conditions 1,2, including cerebroretinal vasculopath...
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Retro-aortic left brachiocephalic vein

The retro-aortic left brachiocephalic vein is a rare vascular variant where the left brachiocephalic vein passes more inferiorly through the superior mediastinum, coursing inferior to the aortic arch and posterior to the ascending aorta to join the right brachiocepahilc vein forming the superior...
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Retroaortic left renal vein

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 procedu...
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Retromandibular vein

The retromandibular vein runs through the substance of the parotid gland. Gross anatomy 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...
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Retroperitoneal fibrosis

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...
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Retroperitoneal hemorrhage

Retroperitoneal hemorrhage can be a source of significant yet occult blood loss. Clinical presentation 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 feature...
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Retroperitoneal lymphangioma

Retroperitoneal lymphangiomas are rare benign cystic lesions of vascular origin that show lymphatic differentiation.  For a broader discussion, please refer to the parental article on lymphangioma.  Epidemiology Only about 1% of all lymphangiomas occur in the retroperitoneal space. Abdominal ...
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Reverse figure 3 sign (esophagus)

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...
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Reversible cerebral vasoconstriction syndrome

Reversible cerebral vasoconstriction syndrome (RCVS) is a group of conditions with a common clinical and radiologic presentation. It is characterized by thunderclap headache and reversible vasoconstriction of the cerebral arteries. Terminology Numerous and varied terms have been used to descri...
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Revised International Chapel Hill Consensus Conference nomenclature of vasculitides

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...
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Rhupus syndrome

Rhupus syndrome is a term traditionally used to describe patients uncommonly having the coexistence of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA)
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Right colic artery

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...
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Right coronary artery

The right coronary artery (RCA) is one of the two main coronary arteries that supply the heart with oxygenated blood. Gross anatomy Origin It is a branch of the ascending aorta, with its normal origin in the right aortic sinus, just superior to the aortic valve Course The RCA courses to th...
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Right gastric artery

The right gastric artery is a branch of the common hepatic artery which supplies the lesser curvature of the stomach. Gross Anatomy Course 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...
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Right gastroepiploic artery

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. Gross Anatomy Course The RGA passes between the first part of the duodenum and the pancreas, ...
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Right hepatic artery

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. Gross anatomy The proper hepatic artery bifurcates into the right and left hepatic arteries at or before rea...
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Right marginal artery

The right marginal artery, also known as the right intermediate atrial branch, supplies the surrounding right atrial tissues 1,2 and, in 10-15% of cases, provides the main arterial supply to the sinus node 3,4. Terminology It also sometimes known as a the acute marginal artery or margo acutus ...
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Right pulmonary artery

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 ...
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Right sided aortic arch

Right-sided aortic arch is a type of aortic arch variant characterized 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...
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Right-to-left shunt (mnemonic)

A useful mnemonic to remember the differential diagnoses associated with right-to-left cardiovascular shunts is: 1-5 Mnemonic 1: a combination vessel; truncus arteriosus 2: number of arteries involved; transposition of the great arteries 3: "tri-" means 3, the number of leaflets involved; t...
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Rotational vertebral artery occlusion syndrome

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.  Pathology It has many predisposing etiologies, but is most often due to large osteoph...
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Round belly sign (abdominal compartment syndrome)

Round belly sign is a sign of increased abdominal pressure in abdominal compartment syndrome where the abdomen has a rounded appearance of transverse section on CT, rather than its typical oval shape. The sign is positive when the AP to transverse diameter of the abdomen (abdominal ratio) is > ...
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Ruptured berry aneurysm

Rupture of a berry aneurysm, also known as a saccular aneurysm, usually results in a subarachnoid hemorrhage (SAH) but can, depending on the location of the rupture and presence of adhesions to the aneurysm, also result in cerebral hematoma, subdural hematoma and/or intraventricular hemorrhage. ...
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Saccular cerebral aneurysm

Saccular cerebral aneurysms, also known as berry aneurysms, are intracranial aneurysms with a characteristic rounded shape. They account for the vast majority of intracranial aneurysms and are the most common cause of non-traumatic subarachnoid hemorrhage. Terminology Those larger than 25 mm i...
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Sano shunt

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...
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Scapular anastomosis

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...
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Scimitar (disambiguation)

The term scimitar, referring to the characteristic shape of the Middle Eastern sword, may refer to the following: scimitar syndrome (lungs) scimitar sign (cystic adventitial disease) scimitar sacrum (bones)
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Scimitar sign (cystic adventitial disease)

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. 
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Scimitar syndrome (lungs)

Scimitar syndrome, also known as hypogenetic lung syndrome, is characterized by a hypoplastic lung that is drained by an anomalous pulmonary 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 ...
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Secondary pulmonary arterial hypertension

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...
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Segmental arterial mediolysis

Segmental arterial mediolysis (SAM) is an increasingly recognized vascular disease of the middle-aged and elderly and a leading cause of spontanoeus intra-abdominal hemorrhage. It is characterized by fusiform aneurysms, stenoses, dissections and occlusions within splanchnic arterial branches. Im...
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Sentinel clot sign

The sentinel clot sign is a useful CT finding for the evaluation of probable anatomic sites of hemorrhage. On CT, acute clotted hemorrhage typically has high attenuation (45 to 80 HU), whereas surrounding areas of acute non-clotted hemorrhage or more chronic hemorrhage have either lower attenua...
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Septal cerebral veins

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...
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Serpentine aneurysm

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...
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Shmoo sign

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...
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Shone syndrome

Shone syndrome, also known as Shone complex, is a rare syndrome characterized by left-sided, obstructive congenital heart defects. Epidemiology Shone syndrome is thought to be very rare, accounting for less than 1% of all congenital heart disease 1. Clinical presentation Patients, usually ne...
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Short gastric arteries

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...
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Shrinking lung syndrome

Shrinking lung syndrome (SLS) refers to a rare complication of systemic lupus erythematosus (SLE), and is characterized by: unexplained dyspnea restrictive pattern on pulmonary function tests elevated hemidiaphragm Epidemiology As with SLE in general, it is thought to carry a increased fema...
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Sickle cell disease

Sickle cell disease (SCD) (historically known as drepanocytosis) is a hereditary (autosomal recessive) condition resulting in the formation of abnormal hemoglobin (a hemoglobinopathy), which manifests as multisystem ischemia and infarction, as well as hemolytic anemia.  Hemoglobin SC (HbSC) dis...
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Sickle cell disease (abdominal manifestations)

Abdominal manifestations of sickle cell disease (SCD) are wide and can involve many organs. For a general discussion, please refer to sickle cell disease. Splenic splenomegaly may occur transiently with the sequestration syndrome, where rapid pooling of blood occurs in the spleen, resulting ...
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Sigmoid arteries

The sigmoid arteries are branches, between two-to-four, of the inferior mesenteric artery (IMA) and supply the sigmoid colon.  Summary origin: inferior mesenteric artery course: after arising from IMA, these branches descend to the left in the sigmoid mesocolon anastomosis: superiorly with ...
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Sigmoid sinus

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...
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Signal flare phenomenon

The signal flare phenomenon is a useful sign to identify active bleeding in a liquefied hematoma with hematocrit effect on dynamic CT scan images. When active arterial hemorrhage is present in a liquefied hematoma that has a hematocrit effect, a signal flare phenomenon may be seen as a linear, ...
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Sildenafil citrate-induced penile Doppler

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 color Doppler and is safer. Sildenafil citrate is a popular vasodilator drug used in treatment of...
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Single coronary artery

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...
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Single umbilical artery

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 unknown reasons, the absence of the left umbilical artery is much more common (~70%). Epidemiology The estimat...
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Sinistral portal hypertension

Sinistral portal hypertension (also known as left-sided portal hypertension or segmental portal hypertension) is an uncommon form of portal hypertension. Clinical presentation Sinistral portal hypertension is most commonly found incidentally in asymptomatic patients. In symptomatic patients, t...
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Sinotubular junction

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.
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Sinus of Valsalva aneurysm

Sinus of Valsalva aneurysms are a cause of thoracic aortic dilatation, arising from one of the aortic sinuses. They can be either congenital or acquired (mycotic). Epidemiology There is a male predilection (M:F ratio being around 3-4:1). They are relatively more common in eastern and Asian pop...
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Situs classification

Situs classification (plural: sitūs) 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 the normal configuration situs ambiguus (heterotaxy): an intermediate configuration with ...
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Situs inversus

Situs inversus, (rare plural: sitūs inversi) 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 ...
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Situs solitus

Situs solitus (rare plural: sitūs soliti) refers to the normal position of the thoracic and abdominal organs. Radiographic features Plain radiograph On plain radiograph, careful attention should be directed at the location of the aortic arch, gastric fundus, cardiac apex, pulmonary fissures a...
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Small cardiac vein

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...

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