Infected (Mycotic) Aneurysms: Spectrum of Imaging Appearances and Management

Abstract

Infected aneurysms are uncommon. The aorta, peripheral arteries, cerebral arteries, and visceral arteries are involved in descending order of frequency. Staphylococcus and Streptococcus species are the most common causative pathogens. Early clinical diagnosis of infected aneurysms is challenging owing to their protean manifestations. Clinically apparent infected aneurysms are often at an advanced stage of development or are associated with complications, such as rupture. Nontreatment or delayed treatment of infected aneurysms often has a poor outcome, with high morbidity and mortality from fulminant sepsis or hemorrhage. Current state-of-the-art imaging modalities, such as multidetector computed tomography and magnetic resonance imaging, have replaced conventional angiography as minimally invasive techniques for detection of infected aneurysms in clinically suspected cases, as well as characterization of infected aneurysms and vascular mapping for treatment planning in confirmed cases. Doppler ultrasonography allows noninvasive assessment for infected aneurysms in the peripheral arteries. Imaging features of infected aneurysms include a lobulated vascular mass, an indistinct irregular arterial wall, perianeurysmal edema, and a perianeurysmal soft-tissue mass. Perianeurysmal gas, aneurysmal thrombosis, aneurysmal wall calcification, and disrupted arterial calcification at the site of the infected aneurysm are uncommon findings. Imaging-guided endovascular stent-graft repair and embolotherapy can be performed in select cases instead of open surgery. Familiarity with the imaging appearances of infected aneurysms should alert the radiologist to the diagnosis and permit timely treatment, which may include endovascular techniques.

Aortic Mycotic Aneurysm - A Rare Cause, A Common Clinical Presentation

“…Mycotic aneurysm, Aorta, Bacteremia, Staphylococcus prevalence is unknown, but it is a rare entity, corresponding to 1-4% of all aneurysms [1,2].…”

“…Streptococcus and Staphylococcus species are the microorganisms with most affinity for the vascular wall and are responsible for 28-71% of all MA [4]. When identified, gram-negative microorganisms may be involved in up to 50% of all cases, with Salmonella species being the most common microorganism of this group [1,3].…”

“…In fact, the initial diagnosis is often a challenge because of the non-specific character of most of these symptoms, which may delay the final diagnosis, and worsen the outcome [1,2,4].…”

“…Infected/mycotic aneurysms (MA) correspond to an infection of the arterial wall with formation of saccular structures adjacent to the arterial lumen [1,2]. Its true down to the origin of the superior mesenteric artery.…”

Mycotic aneurysm of the tibioperoneal trunk: a first manifestation of an infected endocarditis

“…In decreasing frequency, the aorta, peripheral arteries, cerebral arteries and visceral arteries are the most affected sites 7 .…”