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Small Bowel: Vascular Pathology Including Aneurysms and Vasculitis Imaging Pearls - Educational Tools | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Small Bowel ❯ Vascular Pathology Including Aneurysms and Vasculitis

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  • “Medication-induced angioedema of the small bowel is a relatively uncommon and somewhat underdiagnosed condition associated with medications that inhibit the renin-angiotensin system. These most commonly include the angiotensin- converting enzyme (ACE) inhibitors , particularly lisinopril and enalapril, and to a lesser  extent the angiotensin II receptor blockers.”
    CT Findings of Acute Small-Bowel Entities  
    Sugi MD et al.
    RadioGraphics 2018; 38:1352–1369 
  • "The incidence of ACE inhibitor–induced angioedema is estimated at approximately 0.3% of patients receiving this common class of medications, with contributing risk factors includ- ing African descent, a history of drug rash or seasonal allergies, and age greater than 65 years. Other reports note that adult women who are overweight are at particular risk for this disorder, which can occur days to years after these medications are initially administered.”
    CT Findings of Acute Small-Bowel Entities  
    Sugi MD et al.
    RadioGraphics 2018; 38:1352–1369 
  • “CT findings of ACE inhibitor–induced angio- edema include circumferential wall thickening (most commonly involving the jejunum), mural stratification, straightening of bowel loops, interloop or mesenteric edema, and ascites . The laboratory findings are helpful, as there is usually a normal serum lactate level and a normal or only mildly elevated white blood cell count.”
    CT Findings of Acute Small-Bowel Entities  
    Sugi MD et al.
    RadioGraphics 2018; 38:1352–1369 
  • "Removing the inciting agent (the ACE inhibi- tor) usually leads to complete resolution of the angioedema. Certain patients may experience repetitive episodes if the medication is not recognized as the inciting agent or if the cause is hereditary, while others may develop other sites of angioedema in the body, including in the head and neck. Keeping this relationship in mind is important for the radiologist, who may have the opportunity to be the first to suggest the diagnosis.”
    CT Findings of Acute Small-Bowel Entities  
    Sugi MD et al.
    RadioGraphics 2018; 38:1352–1369 
  • “In the acute setting, CT findings of acute radiation enteritis may include mucosal hyperenhancement, wall thickening, and ulcer formation. Localized inflammatory changes including interloop edema, regional free fluid, and pneumatosis may also be seen. Chronic find- ings include submucosal thickening, stricturing, fistula formation, and luminal narrowing secondary to chronic intimal inflammation. The diagnosis of acute radiation enteritis primarily remains one of exclusion and depends largely on clinical history and the time course. However, recognition is helpful as these changes may be reversible, resolving with time following completion of therapy.”
    CT Findings of Acute Small-Bowel Entities  
    Sugi MD et al.
    RadioGraphics 2018; 38:1352–1369 
  • "Acute regional or diffuse spontaneous hemorrhage in the small bowel is relatively rare but has been described in patients undergoing anticoagulation therapy or with bleeding diatheses. The most common location of acute small-bowel bleeding is in the jejunum (69%). However, hemorrhage can be diffuse or even multifocal, uncommonly causing hematoma formation across multiple segments of small bowel. On CT images, hemorrhage may manifest as circumferential thickening of the bowel wall of varying length and is often most evident on CT images obtained without intravenous contrast material. A potential secondary consequence  is bowel obstruction owing to mass effect, although most of these patients are managed conservatively.”
    CT Findings of Acute Small-Bowel Entities  
    Sugi MD et al.
    RadioGraphics 2018; 38:1352–1369 
  • • On intravenous contrast-enhanced CT images of the abdo- men and pelvis, the “target” or “double halo” sign represents mural stratification caused by hyperenhancement of both the inner mucosa and the outer muscularis propria/serosa, with a middle layer of low-attenuating submucosal edema.  
    • Dilated loops of small bowel (>3 cm in diameter) with pa- per-thin walls should raise strong suspicion for acute vascular compromise owing to thromboembolic disease.  
    • Mechanical obstruction of two points along a short segment of small bowel in a single location can lead to a twisted C- or U-shaped configuration, the typical appearance seen in closed-loop small-bowel obstruction at CT.  
    CT Findings of Acute Small-Bowel Entities  
    Sugi MD et al.
    RadioGraphics 2018; 38:1352–1369 
  • • Vasculitis should be considered under certain circumstances, namely in young patients, when the affected segments of small bowel are atypical in distribution (eg, in the duodenum or a patchy distribution across multiple vascular territories) and when there is associated systemic involvement by a similar process.  
    • CT findings of ACE inhibitor–induced angioedema include circumferential wall thickening (most commonly involving the jejunum), mural stratification, straightening of bowel loops, interloop or mesenteric edema, and ascites.  
    CT Findings of Acute Small-Bowel Entities  
    Sugi MD et al.
    RadioGraphics 2018; 38:1352–1369 
  • “Celiac disease is chronic intolerance of gluten that induces intestinal mucosal lesions in genetically predisposed patients. Although in most cases the symptoms and histologic abnormalities completely resolve with use of a strict gluten-free diet, com plications occur in some patients. The complications include small-bowel intussusception, ulcerative jejunoileitis, lymphoma, adenocarcinoma, hyposplenism, cavitating lymphadenopathy syndrome, and pneumatosis intestinalis.”
    Celiac Disease in Adults: Evaluation with MDCT Enteroclysis
    Philippe Soyer et al.
    AJR 2008 191:5, 1483-1492
  • “Celiac disease is now recognized as a common disease, occurring in about 1 in every 200 Americans. However, less than 10% of cases are currently diagnosed, with a diagnostic delay of more than 10 years from onset of symptoms. Celiac disease is a chronic autoimmune disorder induced in genetically susceptible individuals after ingestion of gluten proteins, which are found in wheat, rye, barley, and certain other grains. The small bowel mucosa is primarily affected, resulting in progressive degrees of villus inflammation and destruction with resulting induction of crypt hyperplasia. The destruction begins in the duodenum and over time progresses distally to the ileum. Loss of villi, which absorb fluid, and hypertrophy of crypts, which produce fluid, result in chronic fluid excess in the small bowel lumen.”
    CT Findings in Adult Celiac Disease
    Scholz FJ et al.
    RadioGraphics 2011; 31:977–992
  • “Chronic excess fluid and its effects on bowel wall structure and tone create the small bowel malabsorption pattern (MABP), which was described long ago in barium studies of patients with celiac disease. Features of the celiac disease MABP include duodenitis , dilution, dilatation, slow transit, flocculation , moulage, reversal of the jejunalileal fold pattern, and transient small bowel intussusception.”
    CT Findings in Adult Celiac Disease
    Scholz FJ et al.
    RadioGraphics 2011; 31:977–992

  • CT Findings in Adult Celiac Disease
    Scholz FJ et al.
    RadioGraphics 2011; 31:977–992
  • “Small bowel loops are often dilated and fluidfilled as a result of the chronic inflammatory process. This leads to progressive dilution of enteric contrast material. Small hyperattenuating flecks of barium may be seen precipitating in the dilated small bowel loops, a phenomenon termed flocculation. The small bowel lumen contains both intrinsic physiologic fluid and administered enteric contrast material. Peristaltic waves sweeping periodically through the bowel result in variable laminar flow of these different fluid components within the flaccid bowel lumen in a recognizable pattern.”
    CT Findings in Adult Celiac Disease
    Scholz FJ et al.
    RadioGraphics 2011; 31:977–992
  • “Prominence of upper mesenteric lymph nodes is a feature of celiac disease. Autoimmune stimulation in celiac disease provokes regional lymphocytic proliferation. The duodenum and proximal jejunum are the initial organs targeted for autoimmune destruction, and nodal prominence is most marked in the upper small bowel mesentery. Mesenteric lymph node enlargement, low-attenuation lymph nodes, and cavitating lymph nodes are well-described features of celiac disease. However, cavitating or low-attenuation lymph nodes are infrequent and are found in patients with advanced symptomatic disease.”
    CT Findings in Adult Celiac Disease
    Scholz FJ et al.
    RadioGraphics 2011; 31:977–992
  • “The superior mesenteric artery (SMA) provides vital blood supply to the midgut, and an acute abnormality can rapidly precipitate bowel ischemia and infarction and lead to morbidity and mortality. Vascular diseases that acutely compromise the SMA threaten its tributaries and include occlusion, dissection, aneurysm rupture, pseudoaneurysm, vasculitis, and SMA branch hemorrhage into the bowel.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vascular diseases that acutely compromise the SMA and threaten its tributaries include occlusion, dissection, aneurysm rupture, pseudoaneurysm, vasculitis, and SMA branch hemorrhage into the bowel. Clinical evaluation and imaging are both essential to determine whether a patient should be treated conservatively or requires a surgical or interventional procedure."
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • Within the mesenteric root, the SMA branches into approximately four to six jejunal and nine to 13 ileal arteries arising on the left side. The right-sided branches include the middle colic, right colic, and ileocolic arteries . The branching pattern of the colonic arteries often varies, although the middle colic artery commonly arises from the proximal SMA, and the ileocolic artery represents the terminal branch. The SMA provides blood supply from the ampullary region of the second portion of the duodenum to the distal transverse colon near the splenic flexure."
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “An acute arterial embolus is the main cause (40%–50%) followed by arterial thrombosis (15%–30%) , mesenteric venous thrombosis (20%), and nonocclusive mesenteric ischemia (10%–20%). Embolic material originating from the heart is usually lodged in the SMA a few centimeters distal to the origin, near the location of the middle colic artery origin. Smaller emboli can travel farther and occlude more distal branches. In comparison, thrombosis secondary to rupture of an unstable atherosclerotic plaque often occurs in the proximal 2 cm of the SMA. Nonocclusive ischemia occurs in patients with hypotension, such as those with cardiogenic shock and hypoperfusion, which result in severe mesenteric vasoconstriction. “
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Visualization of a proximal segment with arterial wall thickening and calcification is diagnostic of a preexisting atherosclerotic plaque that likely ruptured to cause complete occlusion. A distal occlusion near the origin of the middle colic artery likely represents a dislodged clot from the heart, commonly in a patient with atrial fibrillation. Diffuse narrowing of the SMA and branches without focal occlusion is suggestive of nonocclusive mesenteric ischemia.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT. "
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “In the emergency setting, it is critical to identify the radiologic findings that represent severe ischemia, which is associated with higher morbidity, and for which surgical treatment with exploratory laparotomy and resection of the bowel is likely necessary. The presence of pneumatosis, or gas in the bowel wall, is a concerning finding that raises the possibility of transmural infarction. Locules of gas may track into mesenteric veins and the portal vein (1). A frank pneumoperitoneum indicates a bowel perforation secondary to transmural wall necrosis. Severe ischemia with transmural infarction also can be seen as mesenteric fat stranding and ascites.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ”In a hemodynamically stable patient who presents early with favorable vascular and bowel CT findings, endovascular treatment may be the best option. In a meta-analysis, Salsano et al evaluated and compared the outcomes of seven studies and showed that endovascular therapy had better outcomes, with significantly lower mortality and bowel resection.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ” Certain multidetector CT findings must be considered in planning an intervention and should be detailed in the CT interpretation. Placing a stent for proximal SMA stenosis most commonly due to calcified atherosclerotic disease is best achieved with a noncovered balloon-expandable stent as opposed to a self- expandable nitinol stent. In this scenario, the rigidity and hoop-strength of the balloon-expandable stent make it better at preventing elastic recoil from the atherosclerotic plaque. However, self-expandable stents are often placed in distal stenosis of SMA branches, because they are generally more flexible and more likely to accommodate greater vessel tortuosity.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ” Diagnosis.—SMA dissection can be divided into two groups: spontaneous isolated and combined. Spontaneous isolated SMA dissection (SISMAD) is SMA dissection that occurs without aortic dissection . Combined SMA dissection is more common and is due to an aortic dissection flap extending into the proximal vessel. SISMAD is a rare disease, although it is being identified more often with the use of CT angiography. An increased incidence of SISMAD has been described in men and patients aged 50–70 years old. Dissection is the result of blood entering the media of an artery through an intimal defect and creating a true lumen in continuity with the unaffected aorta and a false lumen.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “SMA aneurysms account for 5.5% of all visceral artery aneurysms and are the third most common type. They occur predominantly in men and in the 5th decade of life. SMA aneurysms are associated with substantial morbidity, because they put the patient at risk for rupture and hemorrhage. Approximately 38%–50% of patients present with rupture, and mortality rates range from 40% to 60%. The majority of aneurysms occur in the proximal 5 cm of the SMA.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “There are several causes of aneurysms including atherosclerosis, trauma, surgery, inflammation and/or vasculitis, infection, and collagen vascular disorders. Most commonly, SMA aneurysms are asymptomatic and are found incidentally at imaging. Patients may present with colicky abdominal pain or rarely a pulsatile mass. Patients who present with a rupture have signs of hemodynamic compromise. SMA aneurysms must be identified and characterized by the radiologist to give the emergency medicine physician and vascular interventional radiologist the opportunity to treat appropriately.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vasculitis refers to inflammation of the blood vessel walls and includes a diverse group of conditions. Some of the vasculitis's may involve the SMA. Up to 50% of cases of vasculitis involve the mesenteric arteries, but only 16% manifest as isolated mesenteric disease. The pathogenesis of vasculitis varies with each type and can include cell-mediated, immune complex–mediated, and antineutrophil cytoplasmic antibody–mediated inflammation.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Segmental arterial mediolysis is a nonatherosclerotic and noninflammatory arteriopathy characterized by lysis of the smooth muscle of the outer media that results in dissecting aneurysms and intramural hematomas. Unlike those of most vasculitis's, inflammatory or immune markers are most often normal. Middle-aged and elderly patients are affected most commonly and can present with abdominal pain, distention, decreased hemoglobin level, bowel ischemia, or shock. Imaging findings of segmental arterial mediolysis are similar to those of other vasculitis's, although it classically results in alternating aneurysm and stenosis of the abdominal splanchnic arteries, without involvement of other vessel.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vasculitis refers to inflammation of the blood vessel walls and includes a diverse group of conditions. Some of the vasculitis's may involve the SMA. Up to 50% of cases of vasculitis involve the mesenteric arteries, but only 16% manifest as isolated mesenteric disease. The pathogenesis of vasculitis varies with each type and can include cell-mediated, immune complex–mediated, and antineutrophil cytoplasmic antibody–mediated inflammation.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • SMA Thrombosis: Causes
    • Embolic
    • Progression of atherosclerosis
    • Trauma
    • Infection
    • Spontaneous
  • SMA Occlusion
    Embolism (57%) > thrombosis
    • half of patients with SMA embolus have cardiac thrombus
    • 40% have atrial fibrillation
    • occlusion more likely to be distally located in the SMA
    • synchronous emboli in other locations in 68%
    Thrombotic occlusion
    • more extensive intestinal infarction
  • Mesenteric Artery Stenosis
    • Atherosclerosis in older patients
    • Median arcuate ligament syndrome
       - younger patients
    • Other causes
       - tumor encasement (pancreatic cancer)
       - pancreatitis
       - vasculitis
  • Mesenteric Ischemia
    • Chronic mesenteric ischemia is caused by occlusive disease of mesenteric vessels
    • Most often due to atheroma
    • Women > men
    • Patients >60 years
    • Severe stenosis (often multivessel) manifests with abdominal pain or other nonspecific symptoms
  • Chronic Mesenteric Ischemia
    • Takayasu disease
    • fibromuscular dysplasia
    • thromboangiitis obliterans
    • periarteritis nodosum
    • radiation therapy
    • median arcuate ligament syndrome
  • Median Arcuate Ligament Syndrome
    • Median arcuate ligament runs obliquely between the diaphragmatic crura
    • Low lying ligament can compress celiac artery
    • Various degrees of narrowing and obstruction
    • Median Arcuate Ligament “Syndrome” if patient symptomatic
  • Visceral Arterial Aneurysms
    • splenic artery in 60%–80% of cases
    • hepatic artery in 20%
    • SMA in 5.5%
    • celiac artery in 4%
    • gastric and gastroepiploic artery in 4%,
    • GDA, pancreatic branches in 6%
    • jejunal and ileocolic arteries in 3%
    • IMA in less than 1%
  • Splenic Artery Aneurysms
    • Small and asymptomatic- serial imaging
    • Surgical intervention at 2 cm
    • More aggressive management may be warranted in high risk clinical settings
       - women of childbearing age
       - cirrhotics
  • Celiac Artery Aneurysms
    • Post-stenotic dilatation w/proximal stenosis
    • Atherosclerosis
    • Focal dissection
    • Medial degeneration
    • Genetic syndrome: Ehlers Danlos
  • Celiac Artery Aneurysms
    Rupture or impending rupture are made apparent by signs and symptoms
    • pain
    • gastrointestinal bleeding
    Size threshold for surgical repair of celiac artery aneurysms 2 cm in surgical candidates
  • Visceral Arterial Aneurysms
    • Treatment options include surgical vs endovascular approaches based on location
    • For many cases, ligation or coil embolization is the treatment of choice
    • Stents are used primarily in cases of aneurysms of major branches, where preservation of arterial flow is required
  • Pseudoaneurysms
    • Nearly always present with symptoms
    • Only 2.5% of cases presented incidentally
    • Untreated mortality rate approaches 90%
    • Small and large aneurysms can rupture
    • Emergent coil embolization
  • Mesenteric Artery Dissection
    • Isolated celiac or SMA dissection
    • Exclusive of aortic dissection
    • 10% of patients celiac and SMA involved
    • May present acutely w/ abdominal pain
    • Often incidentally identified on CT
    • typically stable without complication
  • Mesenteric Artery Dissection
    • atherosclerosis
    • vasculitis
    • connective tissue disorder
    • Type IV Ehlers-Danlos
    • Trauma
    • fibromuscular dysplasia
    • cystic medial necrosis
    • Hypertension
    • Systemic arterial mediolysis
  • Segmental Arterial Mediolysis
    • Rare noninflammatory vasculopathy
    • Medial layer disrupted
    • Dissection, hemorrhage, ischemia
    • Visceral and mesenteric arteries most common
    • Abdominal pain, GI bleeding
  • Segmental Arterial Mediolysis: CT
    • String of beads
    • Stenoses
    • Aneurysms
    • Dissection
    • Thrombosis
  • SAM: Differential Dx
    • FMD
    • PAN
    • ANCA assoc vaculitis
    • Giant cell arteritis
    • Takayasus
    • Bechets
    • Type IV EDS
  • Superior Mesenteric Artery Syndrome
    • Obstruction of the third portion of the duodenum between the SMA and aorta
    • Cast syndrome, Wilke syndrome
    • Arteriomesenteric duodenal compression syndrome
  • SMAS: CT Criteria
    • Aortomesenteric angle
       - Normally 28 to 65 degrees
       - Reduced to < 22 degrees in SMAS
    • Aortomesenteric distance
       - Normally 10-34 mm
       - Less than 8 mm in SMAS
    • Dilated duodenum and stomach proximal
    • Obstructed left renal vein (“nutcracker”)
  • “Originally described by Rokitansky in 1861, superior mesenteric artery syndrome (SMAS) is a relatively rare condition caused by obstruction of the third portion of the duodenum between the SMA and aorta. The condition has also been called cast syndrome, Wilke syndrome, or arteriomesenteric duodenal compression syndrome. Because of its relative infrequency, the incidence of the disorder is not well known. However, estimated incidence rates based on gastrointestinal barium series are from 0.01% to 0.33%.”


    Multidetector Row CT of Superior Mesenteric Artery Syndrome 
Gautam A. Agrawal, Pamela T. Johnson, Elliot K. Fishman 
J Clin Gastroenterol 2007;41:62–65

  • “As opposed to traditional imaging modalities like upper gastrointestinal and mesenteric arteriography, which depict either the bowel or vasculature respectively, CT enables direct visualization of obstructed bowel owing to duodenal compression by the SMA. Multiplanar MDCT with 3-dimen- sional rendering provides sagittal reconstructions that can be used to confirm the CT criteria of decreased aortomesenteric angle and distance in SMAS.”


    Multidetector Row CT of Superior Mesenteric Artery Syndrome 
Gautam A. Agrawal, Pamela T. Johnson, Elliot K. Fishman 
J Clin Gastroenterol 2007;41:62–65

  • “When conservative management fails, surgical treatment is employed. Surgical management includes duodenojejunostomy, gastrojejunostomy, or lysis of the ligament of Treitz with derotation of the bowel (Strong’s operation). After unsuccessful conservative management, surgical correction was required in 2/3 of patients in 1 small series.”

    
Multidetector Row CT of Superior Mesenteric Artery Syndrome 
Gautam A. Agrawal, Pamela T. Johnson, Elliot K. Fishman 
J Clin Gastroenterol 2007;41:62–65

  • An entity first described almost 150 years ago, ‘‘superior mesenteric artery (SMA) syndrome’’ represents a unique set of clinical symptoms caused by compression of the duodenum between the aorta and SMA. Classically described in young women, patients experience early post-prandial satiety, abdominal pain, nausea, and vomiting, often resulting in chronic anorexia and weight loss.


    Superior mesenteric artery syndrome: spectrum of CT findings with multiplanar reconstructions and 3-D imaging 
Siva P. Raman, Edward G. Neyman, Karen M. Horton, Frederic E. Eckhauser, Elliot K. Fishman 
 Abdom Imaging (2012) 37:1079–1088 

  • “SMA syndrome is thought to result from an abnormally short distance between the aorta and SMA, which results in compression of the duodenum. Patients with SMA syndrome usually present with nonspecific symptoms, making diagnosis extremely difficult. Typically seen in young women, their chronic anorexia, nausea, vomiting, and post- prandial abdominal pain are often blamed on non-anatomic, psychosocial causes, resulting in a delayed diagnosis. Nevertheless, when carefully questioned, these patients often have a characteristic history, with their symptoms relieved by changes in posture, such as turning to their left side, bringing their knees up to their chest, or the prone position.”


    Superior mesenteric artery syndrome: spectrum of CT findings with multiplanar reconstructions and 3-D imaging 
Siva P. Raman, Edward G. Neyman, Karen M. Horton, Frederic E. Eckhauser, Elliot K. Fishman 
 Abdom Imaging (2012) 37:1079–1088 

  • “In a normal patient, the distance between the aorta and SMA (‘‘aortomesenteric distance’’) should range from 10 to 34 mm, and the normal angle between the aorta and SMA (‘‘aortomesenteric angle’’) should be between 28° to 65°. Angiographic studies have shown that patients with SMA syndrome clearly have an abnormal aortomesenteric angle (6°–22°), and a shortened aorto-mesenteric distance (2–8 mm) compared to normal patients.”


    Superior mesenteric artery syndrome: spectrum of CT findings with multiplanar reconstructions and 3-D imaging 
Siva P. Raman, Edward G. Neyman, Karen M. Horton, Frederic E. Eckhauser, Elliot K. Fishman 
 Abdom Imaging (2012) 37:1079–1088
  • “Superior mesenteric artery syndrome (SMA syndrome) is an uncommon pathology that is caused by compression of the third part of the duodenum between the SMA and aorta. It is also known as Wilkie syndrome. Clinical manifestations related to proximal duodenal obstruction include epigastric pain, weight loss, nausea, and vomiting. Pain relief may be achieved by lying in the prone or left lateral decubitus position . Predisposing factors include rapid weight loss that causes loss of retroperitoneal fat, scoliosis, and body cast – all of which alter the angle between SMA and aorta.”


    Imaging Spectrum of Non-neoplastic Duodenal Diseases
 Sitthipong S et al.
Clinical Imaging (in press)
  • “Aortoduodenal fistula can be classified as being either primary or secondary. Primary ADF is defined as direct communication between distal duodenum and native aorta. The fixed retroperitoneal third portion of the duodenum makes it the most common location for fistula formation with aorta. The most common cause of primary ADF is atherosclerotic aortic aneurysm. Less common causes of primary ADF include tuberculosis, mycotic infection, Takayasu disease, and collagen vascular disease. Periaortic inflammatory process and adhesion between duodenum and aorta may be possible mechanisms for fistula formation.”


    Imaging Spectrum of Non-neoplastic Duodenal Diseases
 Sitthipong S et al.
Clinical Imaging (in press)
  • “Vasculitis that involves the gastrointestinal tract is usually part of a systemic disease, such as systemic lupus erythematosus (SLE), polyarteritis nodosa (PAN), and Wegener's granulomatosis. Clinical course depends on the size and location of the affected vessel. Manifestations of vasculitis with large vessel involvement may be indistinguishable from those of mesenteric ischemia. With medium-size vessel involvement, segmental inflammation and erosion may lead to aneurysmal formation, which commonly occurs in PAN. Gastrointestinal hemorrhage caused by aneurysmal rupture is the associated complication.”

    
Imaging Spectrum of Non-neoplastic Duodenal Diseases Sitthipong S et al.
Clinical Imaging (in press)
  • Segmental Arterial Mediolysis: Facts
    - Middle aged to elderly patient (age 50-80)
    - Leading cause of spontaneous intra-abdominal hemorrhage
    - May present with abdominal pain, distension, dropping hematocrit or shock
    - Mortality as high as 50%
  • Segmental Arterial Mediolysis: CT Findings
    - Fusiform aneurysms
    - Arterial stenosis
    - Vessel dissections
    - Vessel occlusions
    - Spontaneous hemorrhage may be seen
  • Segmental Arterial Mediolysis: Differential Diagnosis
    - Polyarteritis nodosa, Wegener’s granulomatosis
    - Mycotic aneurysms
    - Cystic medial necrosis
    - Fibromuscular dysplasia
  • “ Acute thromboembolic occlusion in the superior mesenteric artery (SMA) is a condition with high mortality and morbidity. Multi-detector computerised tomography with intravenous contrast enhancement (MDCTiv) may improve diagnostic accuracy and survival.”
    Impact of MDCT with intravenous contrast on the survival in patients with acute superior mesenteric artery occlusion
    Wadman M et al.
    Emerg Radiol. 2010 May;17(3):171-8
  • “Examination with MDCTiv in patients with acute SMA occlusion was associated with survival benefit. Hence, MDCTiv seems to be the method of choice in the workup phase. Radiologists should routinely describe the mesenteric vessels in patients with acute abdomen even when the diagnosis is not asked for. Patients with high creatinine levels are at risk to be examined without intravenous contrast, and survival in these patients is poor.”
    Impact of MDCT with intravenous contrast on the survival in patients with acute superior mesenteric artery occlusion
    Wadman M et al.
    Emerg Radiol. 2010 May;17(3):171-8
  • “ Radiologists should routinely describe the mesenteric vessels in patients with acute abdomen even when the diagnosis is not asked for. Patients with high creatinine levels are at risk to be examined without intravenous contrast, and survival in these patients is poor.”
    Impact of MDCT with intravenous contrast on the survival in patients with acute superior mesenteric artery occlusion
    Wadman M et al.
    Emerg Radiol. 2010 May;17(3):171-8
  • SMA Occlusion: Causes
    - Superior Mesenteric Artery Embolism (50%)
    - Cardiac thrombus source is most common
    - Asoociated with other emboli (20%)
    - Malignancy
    - Coagulation disorder
    - Associated with underlying cardiovascular disease
    - Cardiac Arrhythmia
    - Myocardial Infarction
    - Valvular Disease
    - Superior Mesenteric Artery Thrombosis (15-25%)
    - Underlying Chronic Mesenteric Ischemia
    - Associated conditions
    - Abdominal Trauma
    - Acute infection
  •  “Acute intestinal ischemia is an abdominal emergency occurring in nearly 1% of patients presenting with acute abdomen. The causes can be occlusive or non occlusive. Early diagnosis is important to improve survival rates. In most cases of late or missed diagnosis, the mortality rate from intestinal infarction is very high, with a reported value ranging from 60% to 90%. Multi-detector computed tomography (MDCT) is a fundamental imaging technique that must be promptly performed in all patients with suspected bowel ischemia.”
    Multi-detector CT features of acute intestinal ischemia and their prognostic correlations.
    Moschetta M et al.
    World J Radiol. 2014 May 28;6(5):130-8.
  •  “Acute intestinal ischemia is an abdominal emergency occurring in nearly 1% of patients presenting with acute abdomen. The causes can be occlusive or non occlusive. Early diagnosis is important to improve survival rates. In most cases of late or missed diagnosis, the mortality rate from intestinal infarction is very high, with a reported value ranging from 60% to 90%.”
    Multi-detector CT features of acute intestinal ischemia and their prognostic correlations.
    Moschetta M et al.
    World J Radiol. 2014 May 28;6(5):130-8.
  •  “The increased spatial and temporal resolution, high-quality multi-planar reconstructions, maximum intensity projections, vessel probe, surface-shaded volume rending and tissue transition projections make MDCT the gold standard for the diagnosis of intestinal ischemia, with reported sensitivity, specificity, positive and negative predictive values of 64%-93%, 92%-100%, 90%-100% and 94%-98%, respectively. MDCT contributes to appropriate treatment planning and provides important prognostic information thanks to its ability to define the nature and extent of the disease.”
    Multi-detector CT features of acute intestinal ischemia and their prognostic correlations.
    Moschetta M et al.
    World J Radiol. 2014 May 28;6(5):130-8.
  • “Intimal flap, thrombosed false lumen, and aneurysmal dilatation are the most common CT findings of spontaneous splanchnic artery dissection. In splanchnic artery dissection, conservative management without anticoagulation had good outcome except in patients with bowel ischemia, aneurysmal dilatation three times larger than a normal segment, or progression of dissection.”
    Spontaneous dissection of the splanchnic arteries: CT findings, treatment, and outcome
    Jung SC et al.
    AJR Am J Roentgenol. 2013 Jan;200(1):219-25
  • “Some investigators have suggested several risk factors, including cystic medial necrosis, fibromuscular dysplasia, segmental mediolytic arteriopathy, atherosclerosis, hypertension, pregnancy, and connective tissue disorders. In most reports and in our study, significant cor- relations with risk factors have been unclear.”
    Spontaneous dissection of the splanchnic arteries: CT findings, treatment, and outcome
    Jung SC et al.
    AJR Am J Roentgenol. 2013 Jan;200(1):219-25
  • “Intimal flap, thrombosed false lumen, and aneurysmal dilatation are the most common
    CT findings of spontaneous dissection of the splanchnic arteries. Bowel ischemia, aneurysmal dilatation three times the normal arterial diameter, and progression of dissection
    were the most important CT findings to indicate the need for endovascular stent insertion or surgery.”
    Spontaneous dissection of the splanchnic arteries: CT findings, treatment, and outcome
    Jung SC et al.
    AJR Am J Roentgenol. 2013 Jan;200(1):219-25
  • “ Twenty-four celiac and 18 SMA dissections were detected in 38 patients. One third of the dissections diagnosed with interactive multiplanar reconstruction/maximum intensity projection (MIP)/3-dimensional (3D) rendering were missed on standard imaging planes. No patients had bowel ischemia or died. Eighty-four percent of the patients were observed, 2 patients received anticoagulation, 2 patients received surgical repair, and 3 patients received stenting. Twenty-three of 25 cases treated with observation exhibited no change or improvement/resolution (2/25) with 20.9-month mean follow-up.”
    Isolated celiac and superior mesenteric artery dissection identified with MDCT: imaging findings and clinical course.
    Verde F, Bleich KB, Oshmyansky A, Black JH, Fishman EK, Johnson PT.
    J Comput Assist Tomogr. 2012 Sep-Oct;36(5):539-45.
  • “ Twenty-four celiac and 18 SMA dissections were detected in 38 patients. One third of the dissections diagnosed with interactive multiplanar reconstruction/maximum intensity projection (MIP)/3-dimensional (3D) rendering were missed on standard imaging planes.”
    Isolated celiac and superior mesenteric artery dissection identified with MDCT: imaging findings and clinical course.
    Verde F, Bleich KB, Oshmyansky A, Black JH, Fishman EK, Johnson PT.
    J Comput Assist Tomogr. 2012 Sep-Oct;36(5):539-45.
  • “Most isolated celiac and SMA dissections were asymptomatic/incidental, supporting observation and surveillance with intervention reserved for vascular compromise. Interactive multiplanar reconstruction/maximum intensity projection/3D rendering can increase diagnostic sensitivity.”
    Isolated celiac and superior mesenteric artery dissection identified with MDCT: imaging findings and clinical course.
    Verde F, Bleich KB, Oshmyansky A, Black JH, Fishman EK, Johnson PT.
    J Comput Assist Tomogr. 2012 Sep-Oct;36(5):539-45.
  • “Segmental arterial mediolysis (SAM) is a rare vasculopathy of unknown etiology characterized by disruption of the arterial medial layer, with resultant susceptibility to vessel dissection, hemorrhage, and ischemia.”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660.
  • “ Although the abdominal visceral arteries are most frequently affected in SAM , any vessel may be involved, including the retroperitoneal , intracranial , and coronary arteries. The histopathologic changes begin with vacuolar degeneration of smooth muscle cells in the arterial media, followed by fibrin deposition at the medial–adventitial junction . This in turn predisposes to dissecting aneurysms.”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660.
  • “ The angiographic appearance of SAM is variable, ranging from arterial dilation to aneurysm formation (single or multiple) to stenoses or occlusion, frequently with dissection . Correspondingly, symptoms arise both from stenoses and occlusions (e.g., postprandial pain from intestinal ischemia) and from dissections and aneurysms (e.g., sudden and catastrophic intraperitoneal bleeding).”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660.
  • “The differential diagnosis of SAM includes atherosclerosis, fibromuscular dysplasia (FMD), infection (e.g., mycotic aneurysm and endocarditis), connective tissue diseases (e.g., Behçet's disease and polyarteritis nodosa [PAN]), neurofibromatosis, and inherited defects in vessel wall structural proteins (e.g., type IV Ehlers-Danlos syndrome and Marfan's syndrome). ”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660.
  • “In summary, SAM is a rare but important cause of unexplained vascular lesions in patients in whom other inflammatory, infectious, or heritable diseases have been ruled out. The diagnosis should be considered when a patient presents with unexplained acute-onset abdominal pain with or without intraabdominal bleeding. SAM should also be kept in mind when aneurysms, stenoses, and occlusions are identified in medium-sized and large vessels, especially when these lesions are limited to a single anatomic location.”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660.
  • “ The discrimination of SAM from systemic inflammatory vasculitides is particularly important, since corticosteroids and immunosuppressive agents, which are crucial in the treatment of the inflammatory vasculitides, have no proven benefit in SAM. Without any evidence of an inflammatory etiology, the use of immunosuppressive regimens in SAM exposes the patient to undue risks, including infection and poor wound healing, and could possibly worsen the prognosis. Treatment of SAM involves embolization, surgical bypass, or resection of the injured arteries.”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660.
  • “Perforation of the mesenteric small bowel is an uncommon cause of an acute abdomen and can be due to various etiologies. In underdeveloped countries, infection is probably the most common cause, while in industrialized nations, perforation may be due to Crohn disease, diverticulitis, foreign body, trauma, tumor, mechanical obstruction, primary ischemic event, or iatrogenic causes. CT is usually the initial imaging examination in patients with an acute abdomen and is sensitive in diagnosing small bowel perforation. CT findings in the setting of small bowel perforation are often subtle, but when present, may help the radiologist determine a specific cause of perforation.”
    Perforation of the mesenteric small bowel: etiologies and CT findings.
    Hines J et al
    Emerg Radiol 2013 April 20(2):155-161
  • “Segmental arterial mediolysis (SAM) is a rare vasculopathy of unknown etiology characterized by disruptioSegmental arterial mediolysis (SAM) is a rare vasculopathy of unknown etiology characterized by disruption of the arterial medial layer, with resultant susceptibility to vessel dissection, hemorrhage, and ischemia. n of the arterial medial layer, with resultant susceptibility to vessel dissection, hemorrhage, and ischemia.”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660.
  • “ Although the abdominal visceral arteries are most frequently affected in SAM , any vessel may be involved, including the retroperitoneal , intracranial , and coronary arteries. The histopathologic changes begin with vacuolar degeneration of smooth muscle cells in the arterial media, followed by fibrin deposition at the medial–adventitial junction . This in turn predisposes to dissecting aneurysms.”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660. 
  • “ The angiographic appearance of SAM is variable, ranging from arterial dilation to aneurysm formation (single or multiple) to stenoses or occlusion, frequently with dissection . Correspondingly, symptoms arise both from stenoses and occlusions (e.g., postprandial pain from intestinal ischemia) and from dissections and aneurysms (e.g., sudden and catastrophic intraperitoneal bleeding).”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660. 
  • “The differential diagnosis of SAM includes atherosclerosis, fibromuscular dysplasia (FMD), infection (e.g., mycotic aneurysm and endocarditis), connective tissue diseases (e.g., Behçet's disease and polyarteritis nodosa [PAN]), neurofibromatosis, and inherited defects in vessel wall structural proteins (e.g., type IV Ehlers-Danlos syndrome and Marfan's syndrome). ”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660. 
  • “In summary, SAM is a rare but important cause of unexplained vascular lesions in patients in whom other inflammatory, infectious, or heritable diseases have been ruled out. The diagnosis should be considered when a patient presents with unexplained acute-onset abdominal pain with or without intraabdominal bleeding. SAM should also be kept in mind when aneurysms, stenoses, and occlusions are identified in medium-sized and large vessels, especially when these lesions are limited to a single anatomic location.”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660. 
  • “ The discrimination of SAM from systemic inflammatory vasculitides is particularly important, since corticosteroids and immunosuppressive agents, which are crucial in the treatment of the inflammatory vasculitides, have no proven benefit in SAM. Without any evidence of an inflammatory etiology, the use of immunosuppressive regimens in SAM exposes the patient to undue risks, including infection and poor wound healing, and could possibly worsen the prognosis. Treatment of SAM involves embolization, surgical bypass, or resection of the injured arteries.”
    Clinical diagnosis of segmental arterial mediolysis: Differentiation from vasculitis and other mimics
    Baker-LePain JC et al
    Arthritis Care Res 2010, 62: 1655–1660.
  •   “In each patient, MDCT demonstrated gastric and proximal duodenal dilatation with abrupt narrowing of the third portion of the duodenum between the aorta and SMA. Sagittal maximum intensity projection images reliably demonstrated the decreased aortomesenteric angle (mean in subjects 13.5 degrees, normal range 28 to 65 degrees) and distance (mean in subjects 4.4 mm, normal range 10 to 34 mm) in all 4 patients.”
    Multidetector row CT of superior mesenteric artery syndrome
    Agrawal GA, Johnson PT, Fishman EK
    J Clin Gastroenterol 2007 Jan;41(1):62-65
  • “ As opposed to traditional imaging modalities like upper gastrointestinal and mesenteric arteriography, which depict either the bowel or vasculature respectively, CT enables direct visualization of obstructed bowel owing to duodenal compression by the SMA. Multiplanar MDCT with 3-dimensional rendering provides sagittal reconstructions that can be used to confirm the CT criteria of decreased aortomesenteric angle and distance in SMAS.”
    Multidetector row CT of superior mesenteric artery syndrome
    Agrawal GA, Johnson PT, Fishman EK
    J Clin Gastroenterol 2007 Jan;41(1):62-65
  • SMA Syndrome:Facts
    -SMA angle to aorta normally 45 degrees (range 38-56 degrees) while in SMA syndrome has SMA angle of 6-25 degrees
    -SMA to aorta distance normally 10-20 mm while in SMA syndrome is 2-8 mm
  • SMA Syndrome:Facts
    Seen with
    -Marked weight loss
    -Anorexia nervosa
    -Total body casting
  • SMA Syndrome:aka
    -Arteriomesenteric duodenal compression
    -Chronic duodenal ileus
    -The cast syndrome
    -Wilkie’s syndrome
  • “The median arcuate ligament syndrome (or celiac artery compression syndrome) was first described in 1963 by Harjola (3). The definition of the syndrome relies on a combination of both clinical and radiographic features. It typically occurs in young patients (20–40 years of age) and is more common in thin women, who may present with epigastric pain and weight loss (4). The abdominal pain may be associated with eating, but not always (5). At physical examination, an abdominal bruit that varies with respiration may be audible in the midepigastric region. Symptoms are thought to arise from the compression of the celiac axis, resulting in a compromise in blood flow.”
  • “ The median arcuate ligament is a fibrous arch that unites the diaphragmatic crura on either side of the aortic hiatus. The ligament usually passes superior to the origin of the celiac axis. However, in some people, the ligament inserts low and thus crosses the proximal portion of the celiac axis, causing compression and sometimes resulting in abdominal pain. The diagnosis of clinically significant celiac axis compression, referred to as median arcuate ligament syndrome, is traditionally made with conventional angiography; however, the condition can now be diagnosed with three-dimensional computed tomographic (CT) angiography. In patients with median arcuate ligament syndrome, CT angiograms demonstrate a characteristic focal narrowing in the proximal celiac axis. The focal narrowing has a characteristic hooked appearance, which can help distinguish this condition from other causes of celiac artery narrowing, such as atherosclerotic disease.”
  • “ Once the disorder has been diagnosed, surgery can be performed to relieve the compression. In some patients, the ligamentous constriction of the celiac axis causes vascular damage, which may require vascular reconstruction. CT angiography can play a role in the diagnosis of median arcuate ligament syndrome by demonstrating the characteristic focal narrowing of the celiac artery in patients presenting with the appropriate clinical symptoms.”
    Median Arcuate Ligament Syndrome: Evaluation with CT Angiography
    Horton KM, Talamini MA, Fishman EK
    RadioGrapgics 25.1177-1182
  • Differential Diagnosis
    - SLE
    - Churg Strauss Syndrome
    - Vasculitis from drug abuse
    - Microscopic polyangitis
  • CTA Findings in PAN
    - Multiple aneurysms of varying sizes
    - Smooth narrowing of vessels; stenosis and occlusions of larger vessels
    - Thickening of wall of medium sized vessels
    - Aneurysms may be associated with hemorrhage
    - Bowel wall thickening often with associated strictures or perforation
  • Polyarteritis Nodosa: Facts
    - Most common in 5th-7th decade of life
    - More common in males (2-1)
    - Survival at 5 yrs less than 15% in fulminant disease
    - 50% of patients with abdominal involvement develop acute surgical abdomen with mortality of 12.5%

    Diagnostic Imaging: Cardiovascular
    Abbaro S
    AMIRSYS 2009
  • Polyarteritis Nodosa: Clinical Presentation

    Subacute presentation with weight loss, FUO, malaise

    Acute presentation could include;
    - Renal insufficiency or hemorrhage
    - Abdominal pain including ischemia, infarction, or perforation
    - Palpable purpura or ulcerations
  • Polyarteritis Nodosa (PAN): Facts
    - Systemic vasculitis causing necrotizing inflammation of small and medium sized vessels, resulting in microaneurysms, occlusions and strictures
    - Kidney is most commonly involved (70-80% of cases)
    - GI tract involved in up to 50% of cases
    - Muscle, skin and CNS are often involved
  • Which entities give you multiple mesenteric artery aneurysms?
    - Polyarteritis nodosa
    - Rheumatoid arthritis
    - Systemic lupus erthematosos (SLE)
    - Churg Strauss syndrome

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