MyPACS.net: Radiology Teaching Files > Case 218823

never visited SUPERIOR MESENTERIC ARTERY (SMA) ANEURYSM
Contributed by: Safwan Halabi, Radiologist, Henry Ford Health System, Michigan, USA.
Patient: 41 year old male
History: This is a 41-year-old male with a history of multiple medical problems, including diabetes, hypertension, rheumatic fever status post mitral valve replacement during childhood, schizophrenia, and mild mental retardation. He presented to the emergency room with the chief complaint of syncopal episode x one. On physical examination, there was a palpable pulsatile mass in the abdomen. Upon further history, this patient had infective bacterial endocarditis approximately five months prior to presentation requiring mitral valve replacement.
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Fig. 7: 3D Reconstruction

Fig. 8: SMA Angiography (RAO)

Fig. 9: Intra-operative visualization of the aneurysm cavity s/p feeding vessel ligation

Fig. 10: Aneurysm contents
Findings:

CT Abdomen/Pelvis: There is an 8 x 6.5 cm aneurysm in the mid abdomen. This is adjacent to the superior mesenteric artery and either arises from the superior mesenteric artery or one of its branches. The superior mesenteric vein and the uncinate process of the pancreas are displaced by the pseudoaneurysm. The ileocolic vein is mildly dilated.

Visceral angiogram (SMA): There is a large aneurysm approximately 4 cm distal to the SMA origin.

Operative note: Evidence of superior mesenteric artery aneurysm, opened and ligated with aortic control, via right groin cutdown with 33-mm inflation balloon placed within the aorta for occlusion.

Diagnosis: Superior mesenteric artery aneurysm.
Discussion: Superior mesenteric artery aneurysm: a focal dilatation of the lumen of the superior mesenteric artery (SMA), related to the same conditions as those that cause aneurysm of the hepatic artery (see aneurysm hepatic artery). Diagnosis is suggested by cross-sectional methods such as ultrasound with Doppler and CT but magnetic resonance angiography or catheter angiography is needed for confirmation. focal dilatation of the lumen of the hepatic artery caused by vasculitis (polyarteritis nodosa, cystic medial necrosis, fibromuscular dysplasia), infection (mycosis, tuberculosis, syphilis), Osler Rendu Weber disease, atherosclerosis, or following liver transplantation at the site of the arterial anastomosis. Hepatic artery aneurysms may not uncommonly rupture spontaneously. Plain films may demonstrate curvilinear calcification. On cholangiography signs of external compression exerted by the aneurysm on the bile ducts may be visible. Likewise barium studies may show compression of the visceral organs. Direct evidence of the aneurysm will be provided by ultrasound and Doppler ultrasound that will demonstrate a pulsatile mass with arterial flow pattern. Larger aneurysms (more than 1 cm in diameter) are visible on CT as a round low attenuation area on precontrast images. This area will show intense contrast enhancement during the arterial phase following intravenous contrast medium administration. In some instances due to slow flow delayed abnormal contrast accumulation will remain visible during the portal venous and even during the parenchymatous phase. In addition segmental hypoperfusion of the liver parenchyma distal to the aneurysm may be noticed. Catheter angiography is indicated first to confirm the diagnosis and secondly for therapeutic management by transcatheter embolization. Magnetic resonance angiography MRA with gadolinium Gd chelates injected intravenously may visualize equally well the aneurysm but has no therapeutic potential.
References: http://www.amershamhealth.com/medcyclopaedia/Volume%20IV%201/ANEURYSM%20SUPERIOR%20MESENTERIC%20ARTERY.asp (Referenced Nov 11, 2003)
Comments:
great case!--Rex Jakobovits, 2004-07-06
Additional Details:

Case Number: 218823Last Updated: 11-05-2009
Anatomy: Vascular/Lymphatic   Pathology: Vascular
Modality: CT, Photograph, Angiography, PathologyAccess Level: Readable by all users
Keywords: superior mesenteric artery visceral aneurysm

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