Ultrasonic visualization of the posterior thoracic aorta in long axis: diagnosis of a saccular mycotic aneurysm

Infected Aortic Aneurysms: Imaging Findings

PURPOSE

To determine the imaging characteristics of infected aortic aneurysms.

MATERIALS AND METHODS

Review of records of patients with surgical and/or microbiologic proof of infected aortic aneurysm obtained over a 25-year period revealed 31 aneurysms in 29 patients. This study included 21 men and eight women (mean age, 70 years). One radiologist reviewed 28 computed tomographic (CT) studies (22 patients underwent CT once and three patients underwent CT twice), 12 arteriograms (12 patients underwent arteriography once), eight nuclear medicine studies (six patients underwent nuclear medicine imaging once and one patient underwent nuclear medicine imaging twice), and three magnetic resonance (MR) studies (three patients underwent MR imaging once). Features evaluated included aneurysm size, shape, and location; branch involvement; aortic wall calcification; gas; radiotracer uptake on nuclear medicine studies; and periaortic and associated findings. The location of infected aortic aneurysms was compared with that of arteriosclerotic aneurysms.

RESULTS

Aneurysms were located in the ascending aorta (n = 2, 6%), descending thoracic aorta (n = 7, 23%), thoracoabdominal aorta (n = 6, 19%), paravisceral aorta (n = 2, 6%), juxtarenal aorta (n = 3, 10%), infrarenal aorta (n = 10, 32%), and renal artery (n = 1, 3%). Two patients had two infected aortic aneurysms. CT revealed 25 saccular (93%) and two fusiform (7%) aneurysms with a mean diameter at initial discovery of 5.4 cm (range, 1-11 cm). Paraaortic soft-tissue mass, stranding, and/or fluid was present in 13 (48%) of 27 aneurysms, and early periaortic edema with rapid aneurysm progression and development was present in three (100%) patients with sequential studies. Other findings included adjacent vertebral body destruction with psoas muscle abscess (n = 1, 4%), kidney infarct (n = 1, 4%), absence of calcification in the aortic wall (n = 2, 7%), and periaortic gas (n = 2, 7%). Angiography showed 13 saccular aneurysms with lobulated contour in 10 (77%). Nuclear medicine imaging showed increased activity consistent with infection in six (86%) of seven aneurysms. MR imaging showed three saccular aneurysms. Adjacent abnormal vertebral body marrow signal intensity was seen in one (33%) of three patients.

CONCLUSION

Saccular aneurysms (especially those with lobulated contour) with rapid expansion or development and adjacent mass, stranding, and/or fluid in an unusual location are highly suspicious for an infected aneurysm.

Mycotic aneurysm of the descending thoracic aorta: the role of transesophageal echocardiography

Mycotic aneurysms of the aorta are prone to rupture. Thus rapid and accurate diagnosis is essential so that surgical repair can be undertaken. We report a case of mycotic aortic aneurysm caused by mitral valve endocarditis. The aneurysm situated at the junction of the thoracoabdominal aorta was readily detected by transesophageal echocardiography. Computed tomography and aortography were complementary to transesophageal echocardiography in establishing the diagnosis. The patient underwent successful repair and acute inflammation of the aneurysm was present at histologic examination.

Diagnostic imaging of Salmonella-related mycotic aneurysm of aorta by CT

The purpose of this study was to review the computed tomography (CT) appearance of mycotic aneurysm of the aorta caused by Salmonella infection. Eight patients were suggested to have mycotic aneurysm of the aorta by clinical presentation of fever, abdominal or back pain, leukocytosis, and pulsatile abdominal mass in addition to positive blood or tissue culture of salmonella. All underwent plain radiography, abdominal sonography, and CT for confirmation. Five patients died during hospitalization despite medical or surgical treatment. CT features of mycotic aneurysm of aorta included (a) hazy aortic wall with rupture; (b) gas-forming inflammation around the aneurysm; (c) retroperitoneal paraaortic fluid collection and vertebral erosion; and (d) thrombus formation within a false lumen after aneurysmal rupture. Because of its availability and noninvasiveness, CT is the major diagnostic modality to use for Salmonella-related mycotic aneurysm.

Infected aortic aneurysm. Case report and imaging evaluation

An infected aortic aneurysm is evaluated by computed tomography (CT) following presentation on plain film in the emergency room. The importance of CT in delineating the location and cause of the aneurysm is noted. Other modes of evaluation of infected aortic aneurysms are reviewed and discussed. The advantages of CT evaluation are noted. A literature review notes plain film presentation of only one other infected aortic aneurysm. Pathological correlation with the CT imaging is presented.

Mycotic pseudoaneurysm of the descending thoracic aorta associated with vertebral osteomyelitis

A patient with osteomyelitis of the lower thoracic spine is reported in whom computed tomography (CT) revealed a large false aneurysm of the descending aorta. Useful radiological signs of the diagnosis are described, namely a thin aneurysm wall, a multilobulated margin and deformity of the aneurysm by adjacent vascular and osseous structures. Mycotic aneurysms of the aorta have a high mortality and the CT demonstration of a pseudoaneurysm has a vital role in management.

Surgical treatment of a tuberculous thoracoabdominal aneurysm

We report a case of tuberculous thoracoabdominal aneurysm successfully treated by surgery. Computerized tomography was diagnostic for location and etiology. The therapeutic plan included antituberculosis drug therapy started before surgery, direct PTFE prosthetic replacement and omentoplasty. A survey of other reports dealing with tuberculous abdominal or thoracic aorta involvement shows that their frequency, as that of tuberculosis in general, is diminishing.

Improved cross-sectional echocardiographic technique for visualization of the retrocardiac descending aorta in its long axis. Normal findings and abnormalities in saccular and/or dissecting aneurysms

The feasibility of using an improved ultrasonic technique for visualization of the retrocardiac descending thoracic aorta was studied in 50 consecutive patients. Both anterior and posterior aortic walls were well delineated in long as well as short axis in 92%. The mean length of the visualized portion of the retrocardiac aorta was 8.4 cm (range 4.5 to 13) and exceeded 6 cm in 40 of 46 patients. The mean diameter was 2.0 cm (range 1.3 to 2.7). Five patients with saccular (1 patient) and/or dissecting (all 5 patients) aneurysms involving the retrocardiac aorta were also examined. Abnormalities essentially identical to those seen with computerized tomography and aortography were noted. Intimal flaps were visualized by ultrasound in all 5 patients and were seen to oscillate reproducibly with the cardiac cycle, suggesting differential rates of filling of false and true lumens. This and other previous cross-sectional echocardiographic studies of the ascending aorta suggest that ultrasound may be useful in the initial evaluation of patients presenting with symptoms or signs suggestive of acute or chronic aortic disease.