Imaging Pearls ❯ Vascular ❯ SMA
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- “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 vasculitides 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 vasculitides, 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 vasculitides, 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 vasculitides 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. - “Systemic lupus erythematosus is an autoimmune disease caused by immune complex deposition that classically affects young women. The disease process often involves the joints, kidneys, gastrointestinal tract, and skin. Lupus may affect vasculature of the entire gastrointestinal tract, but the SMA distribution is involved most commonly. Polyarteritis nodosa is a medium-vessel fibrinoid necrotizing vasculitis that occurs in middle-aged to older adults. Classically, it causes microaneurysms and erosion of the arterial wall, most commonly affecting the kidneys, gastrointestinal tract, and liver.”
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 vasculitides, 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 vasculitides, although it classically results in alternating aneurysm and stenosis of the abdominal splanchnic arteries, without involvement of other vessels.
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. - “CT angiographic findings of vasculitis include circumferential arterial wall thickening, luminal narrowing, and microaneurysms. Long-segment smooth tapering without evidence of atherosclerotic disease usually is seen in vasculitis. A beaded appearance of the SMA may be seen with multiple aneurysms. The extent of the disease must be detailed, because focal disease can be managed with surgical or endovascular treatment, and diffuse disease is managed medically.”
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. - Colonic diverticulosis and angiodysplasia can be differentiated readily at multidetector CT, which is of prognostic importance, because bleeding recurs in up to 85% of untreated patients with angiodysplasia, while only 25% of untreated diverticular patients experience recurrent bleeding.
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.
- “Superior Mesenteric Artery Aneurysms (SMAAs) SMAAs account for 5.5% of all visceral artery aneurysms. They most commonly present with abdominal pain and GI bleeding. Aneurysms commonly affect the proximal 5 cm of the artery. SMAAs occur more commonly in men and have a rupture rate of 38% in that cohort. Pseudoaneurysms of the SMA are most often caused by arterial dissection while true aneurysms are most often caused by septic emboli.
Visceral Artery Aneurysms: Diagnosis, Surveillance, and Treatment
Fady Ibrahim et al.
Curr Treat Options Cardio Med (2018) 20: 97
- 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”)
- 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
- “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
- “However, given that atherosclerotic disease is widespread in the elderly population, the diagnosis of this entity requires not only correlation with appropriate clinical symptoms but also visualization of collateral pathways (eg, celiac-SMA collaterals via the pancreaticoduodenal arcade and SMA-IMA collaterals via the arc of Riolan and marginal artery of Drummond). Although these collateral pathways can compensate for significant stenoses over long periods of time, symptoms usually develop when blood flow via these collaterals is no longer sufficient to supply the bowel.”
Computed Tomography Angiography of the Small Bowel and Mesentery Raman SP, Fishman EK Radiol Clin N Am 54 (2016) 87–100 - “The classic phenotypic appearance of the aorta in patients with Marfan syndrome is annuloaortic ectasia, with dilatation of the aortic annulus and sinuses of Valsalva, and effacement of the sinotubular junction, resulting in a tulip-shaped configuration of the aortic root.”
Pre- and Postoperative Imaging of the Aortic Root Hanneman K et al. RadioGraphics 2016; 36:19-37
- “Fast scanning along with high resolution of multidetector computed tomography (MDCT) have expanded the role of non-invasive imaging of splanchnic arteries. Advancements in both MDCT scanner technology and three-dimensional (3D) imaging software provide a unique opportunity for non-invasive investigation of splanchnic arteries. Although standard axial computed tomography (CT) images allow identification of splanchnic arteries, visualization of small or distal branches is often limited. Similarly, a comprehensive assessment of the complex anatomy of splanchnic arteries is often beyond the reach of axial images.”
Three-dimensional MDCT angiography of splanchnic arteries: Pearls and pitfalls.
Dohan A et al.
Diagn Interv Imaging. 2014 Jun 30. pii: S2211-5684(14)00202-2. doi: 10.1016/j.diii.2014.06.011. [Epub ahead of print - “However, the submillimeter collimation that can be achieved with MDCT scanners now allows the acquisition of true isotropic data so that a high spatial resolution is now maintained in any imaging plane and in 3D mode. This ability to visualize the complex network of splanchnic arteries using 3D rendering and multiplanar reconstruction is of major importance for an optimal analysis in many situations.”
Three-dimensional MDCT angiography of splanchnic arteries: Pearls and pitfalls.
Dohan A et al.
Diagn Interv Imaging. 2014 Jun 30. pii: S2211-5684(14)00202-2. doi: 10.1016/j.diii.2014.06.011. [Epub ahead of print
- “ 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. - “ 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. - “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. - “Bowel wall hyperdensity reflects vasodilation, which is the first consequence of hypoxic damage. The absence of wall enhancement corresponds to the ensuing vasoconstriction; bowel-loop thickening and dilatation are related to the increased capillary permeability, pneumatosis and the presence of air within the mesenteric-portal system reflect the necrosis of the intestinal mucosa, whereas pneumoperitoneum/pneumoretroperitoneum corresponds to a transmural extension of the necrosis. Therefore, wall hyperdensity, the absence of enhancement and wall thickening are an early stage of the disease, in contrast to loop dilation, parietal and portomesenteric pneumatosis and pneumoperitoneum/pneumoretroperitoneum which reflect an advanced stage of disease and are characterized by high mortality rates.”
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. - “Bowel wall hyperdensity reflects vasodilation, which is the first consequence of hypoxic damage. The absence of wall enhancement corresponds to the ensuing vasoconstriction; bowel-loop thickening and dilatation are related to the increased capillary permeability, pneumatosis and the presence of air within the mesenteric-portal system reflect the necrosis of the intestinal mucosa, whereas pneumoperitoneum/pneumoretroperitoneum corresponds to a transmural extension of the necrosis.”
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. - “Bowel infarction is an uncommon but often underestimated cause of non traumatic acute abdomen and early diagnosis is crucial in order to avoid irreversible damage to the bowel wall. MDCT is a fundamental imaging technique that must be promptly performed in all patients with acute abdomen and suspected bowel ischemia. Thanks to the dedicated reconstruction program, its diagnostic potential is much improved compared to the past and currently is superior to that of any other noninvasive technique.”
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. - “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. - “Bowel wall hyperdensity reflects vasodilation, which is the first consequence of hypoxic damage. The absence of wall enhancement corresponds to the ensuing vasoconstriction; bowel-loop thickening and dilatation are related to the increased capillary permeability, pneumatosis and the presence of air within the mesenteric-portal system reflect the necrosis of the intestinal mucosa, whereas pneumoperitoneum/pneumoretroperitoneum corresponds to a transmural extension of the necrosis. Therefore, wall hyperdensity, the absence of enhancement and wall thickening are an early stage of the disease, in contrast to loop dilation, parietal and portomesenteric pneumatosis and pneumoperitoneum/pneumoretroperitoneum which reflect an advanced stage of disease and are characterized by high mortality rates.”
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. - “Bowel wall hyperdensity reflects vasodilation, which is the first consequence of hypoxic damage. The absence of wall enhancement corresponds to the ensuing vasoconstriction; bowel-loop thickening and dilatation are related to the increased capillary permeability, pneumatosis and the presence of air within the mesenteric-portal system reflect the necrosis of the intestinal mucosa, whereas pneumoperitoneum/pneumoretroperitoneum corresponds to a transmural extension of the necrosis.”
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. - “Bowel infarction is an uncommon but often underestimated cause of non traumatic acute abdomen and early diagnosis is crucial in order to avoid irreversible damage to the bowel wall. MDCT is a fundamental imaging technique that must be promptly performed in all patients with acute abdomen and suspected bowel ischemia. Thanks to the dedicated reconstruction program, its diagnostic potential is much improved compared to the past and currently is superior to that of any other noninvasive technique.”
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. - “Intravascular thrombosis and thromboembolism are critical diagnoses which are frequently made on contrast-enhanced computed tomography (CECT) or Doppler ultrasound. For a variety of reasons, some patients with acute intravascular pathology are imaged using CT without intravenous contrast. In the acute setting, the increased Hounsfield unit (HU) density of the thrombus compared to the blood pool allows the diagnosis to be made, or at least suggested, on non-enhanced computed tomography (NECT). The increased density of the clot is commonly referred to as the "hyperdense vessel sign." This is a well-known finding in the setting of stroke, but hyperdense vessels can also signal arterial or venous thrombosis in the chest, abdomen, pelvis, and extremities. Once a hyperdense vessel sign is noted on NECT, further exploration with CECT, angiography, or ultrasound may then be performed. Here, we present a pictorial review of the appearance of acute intravascular thrombosis as seen on non-enhanced computed tomography.”
Imaging findings of acute intravascular thrombus on non-enhanced computed tomography.
Whitesell RT, Steenburg SD.
Emerg Radiol. 2014 Jun;21(3):271-7 - “Intravascular thrombosis and thromboembolism are critical diagnoses which are frequently made on contrast-enhanced computed tomography (CECT) or Doppler ultrasound. For a variety of reasons, some patients with acute intravascular pathology are imaged using CT without intravenous contrast. In the acute setting, the increased Hounsfield unit (HU) density of the thrombus compared to the blood pool allows the diagnosis to be made, or at least suggested, on non-enhanced computed tomography (NECT). The increased density of the clot is commonly referred to as the "hyperdense vessel sign." This is a well-known finding in the setting of stroke, but hyperdense vessels can also signal arterial or venous thrombosis in the chest, abdomen, pelvis, and extremities. Once a hyperdense vessel sign is noted on NECT, further exploration with CECT, angiography, or ultrasound may then be performed.”
Imaging findings of acute intravascular thrombus on non-enhanced computed tomography.
Whitesell RT, Steenburg SD.
Emerg Radiol. 2014 Jun;21(3):271-7 - “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 - “ Percutaneous endovascular treatment using a covered stent may be a safe and feasible tool for SMA pseudoaneurysm.”
Endovascular Treatment of Superior Mesenteric Artery Pseudoaneurysm Using Covered Stents in Six Patients
Kim SW et al.
AJR 2014; 203:432-438 - “ Superior mesenteric artery (SMA) pseudoaneurysms are potentially life-threatening because of the risk of massive fatal hemorrhage and acute mesenteric ischemia. SMA pseudoaneurysms are rare with an incidence of only 0.01-2.6%, limiting our understanding of their pathophysiology and natural history.”
Endovascular Treatment of Superior Mesenteric Artery Pseudoaneurysm Using Covered Stents in Six Patients
Kim SW et al.
AJR 2014; 203:432-438 - “ In conclusion, our study shows that placement of covered stents for the treatment of SMA pseudoaneurysms can lead to technical success and clinical success with midterm stent patency. Therefore, percutaneous endovscular treatment using a covered stent may be a safe and feasible tool for the treatment of SMA pseudoaneurysms.”
Endovascular Treatment of Superior Mesenteric Artery Pseudoaneurysm Using Covered Stents in Six Patients
Kim SW et al.
AJR 2014; 203:432-438 - “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.
- “In conjunction with an appropriate clinical history, several CT findings can suggest the diagnosis of SMA syndrome. These findings include narrowing of the aortomesenteric angle and distance, distension of the stomach and duodenum, and dilatation of the left renal vein with left-sided venous collaterals.”
Superior mesenteric artery syndrome: spectrum of CT findings with multiplanar reconstructions and 3-D imaging
Raman SP, Neyman EG, Horton KM, Eckhauser FE, Fishman EK
Abdom Imaging 2012 Feb 12 (Epub ahead of print)
- Epidemiology of SMA syndrome:
- 0.013–0.78% incidence based on upper gastrointestinal barium studies
- Females are more commonly affected
- Two thirds of patients are between 10 and 39 years old, although it has been reported even
in octogenarians (Figure 12).
- Most commonly associated with severe, debilitating illnesses such as malignancy,
malabsorption syndromes, AIDS, trauma and burns; and with scoliosis surgery - Indirect Radiologic Signs Helpful on Axial Images
- If multiplanar or 3D reconstructions typically performed only after an analysis of the axial
images, these indirect signs are helpful in deciding on further evaluation:
- Dilated left renal vein prior to passing between aorta and SMA
- Dilated venous collaterals, such as lumbar or gonadal vein
- Disease processes in the region - SMA Syndrome Pathophysiology and Direct Radiologic Findings
- Mean angle formed by the superior mesenteric artery and the aorta varies between 38 and
56° with range of 20 to 70° reported
- In SMA syndrome it diminishes to 6-16°
- Mean aortomesenteric distance is 10–28 mm . In SMA syndrome it diminishes to 2-8 mm - Superior Mesenteric Artery (SMA) Syndrome
- SMA syndrome is an uncommon but well recognized clinical entity characterized by
compression of the third, or transverse, portion of the duodenum (D3) between the aorta
and the superior mesenteric artery. - “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 - “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 - SMA Thrombosis: Facts
-SMA occlusion results in acute intestinal ischemia and infarction
-May be a result of thrombus from cardiac thrombus (50%), atrial fibrillation (40%)
-When acute thrombus usually in more distal portion of the SMA than proximal - "Although splanchnic artery aneurysms are relatively rare, they are being diagnosed with increased frequency given the widespread availability of MDCT and 3D imaging capabilities."
MDCT and 3D CT Angiography of Splanchnic Artery Aneurysms
Horton KM, Smith C, Fishman EK
AJR 2007;189:641-647
- "Although splanchnic artery aneurysms are relatively rare, they are being diagnosed with increased frequency given the widespread availability of MDCT and 3D imaging capabilities. It is important that these aneurysms be diagnosed accurately because they can carry a high morbidity and mortality, even in asymptomatic patients."
MDCT and 3D CT Angiography of Splanchnic Artery Aneurysms
Horton KM, Smith C, Fishman EK
AJR 2007;189:641-647
- Splanchnic Artery Aneurysms: Facts
- Incidence of 0.01-0.2% in autopsy series
- Most common is splenic artery aneurysm (60%), with hepatic artery aneurysm being second most popular (20%)
- Aneurysm rupture is associated with high morbidity and mortality
- Splanchnic Artery Aneurysms: Facts
- Splenic artery (60%)
- Hepatic artery (20%)
- SMA (5.5%)
- Celiac artery (4%)
- Pancreatic arteries (2%)
- Gastroduodenal artery (GDA) 1.5%
- Splenic Artery Aneurysms: Facts
- 4x more common in woman than men
- In woman association with pregnancy and multiparity
- Although more common in woman more likely to rupture in men
- Risk of rupture (2-3%) increases with pregnancy, portal hypertension, and after liver tralntation
- Vasculitides that involve the GI Tract
- Takayasu arteritis
- Polyarteritis nodosa
- Wegener granulomatosis
- Churg-Strauss syndrome
- Microscopic polyangitis
- SLE
- Rheumatoid vasculitis
- "Unsuspected mesenteric arterial abnormality may elude diagnosis when axial MDCT sections are interpreted without 3D renderings."
Unsuspected Mesenteric Arterial Abnormality: Comparison of MDCT Axial Sections to Interactive 3D Rendering
Chen JK, Johnson PT, Horton KM, Fishman EK
AJR 2007;189:807-813
- "In the era of isotropic data, perhaps the new standard of care will be to review all MDCT data sets in 3D mode to exclude any unsuspected vascular abnormality."
Unsuspected Mesenteric Arterial Abnormality: Comparison of MDCT Axial Sections to Interactive 3D Rendering
Chen JK, Johnson PT, Horton KM, Fishman EK
AJR 2007;189:807-813
- "This ability to visualize the mesenteric vasculature in real-time using 3D rendering and multiplanar reconstruction is crucial for the comprehensive review of the complex mesenteric vessels."
Mesenteric CT Angiography: A Discussion of Techniques and Selected Applications
Smith Cl, Horton KM, Fishman EK
Tech Vasc Interventional Rad 9:150-155, 2006
- "As CT scanners and 3D imaging software continue to advance, it is very likely that in the near future 3D imaging of the abdomen and abdominal vasculature will become a routine method for review of all CT exams rather than a specialized separate process done in select cases."
Mesenteric CT Angiography: A Discussion of Techniques and Selected Applications
Smith Cl, Horton KM, Fishman EK
Tech Vasc Interventional Rad 9:150-155, 2006
- Superior Mesenteric Artery Aneurysms: Facts
- 3rd most common visceral artery aneurysm
- 5.5% of visceral artery aneurysms
- Usually located in the first 5 cm of the SMA
- Etiology ranges from pancreatitis and mass effect of pseudocyst to autodigestion of vessel wall by pancreatic enzymes to trauma
- Superior Mesenteric Artery Aneurysms: Etiology
- Pancreatitis
- Nonsurgical trauma
- Surgical trauma
- Arteriosclerosis
- Infection
- Collagen vascular disease
- Arteritis
- Dissection
- Superior Mesenteric Artery Aneurysms: Presentation
- Abdominal pain
- Back pain
- Bleeding
- Rupture
- Current therapy: resect all aneurysms or pseudoaneurysms greater than 2 cm
- "Multidetector CT may offer a distinct advantage over traditional single-detector CT in the evaluation of mesenteric vasculature.Narrower collimation coupled with shorter scanning times reduces motion artifact and permits scanning during peak IV Contrast enhancement, which improves both axial and reformatted images."
Bowel Obstruction Revealed by Multidetector CT
Khurana B et al.
AJR 2002;178:1139-1144
- Polyarteritis Nodosa: Facts
- Systemic necrotizing vasculitis that affects small and medium size arteries
- GI tract involvement is seen in up to 50% of patients
- Common sites of involvement; kidneys, heart, liver, CNS and skin
- Polyarteritis Nodosa: Angiographic Findings
- Aneurysms in the 1-5 mm range
- Vascular ectasia
- Stenosis or occlusion of vessels
- Intraparenchymal infarction
- Aneurysm rupture