Abdominal Aortic Aneurysm - Diagnosis

Diagnosis

An abdominal aortic aneurysm is usually diagnosed by physical exam, ultrasound, or CT. Plain abdominal radiographs may show the outline of an aneurysm when its walls are calcified. However, this is the case in less than half of all aneurysms. Ultrasonography is used to screen for aneurysms and to determine the size of any present. Additionally, free peritoneal fluid can be detected. It is noninvasive and sensitive, but the presence of bowel gas or obesity may limit its usefulness. CT scan has a nearly 100% sensitivity for aneurysm and is also useful in preoperative planning, detailing the anatomy and possibility for endovascular repair. In the case of suspected rupture, it can also reliably detect retroperitoneal fluid. Alternative less often used methods for visualization of the aneurysm include MRI and angiography.

An aneurysm ruptures if the mechanical stress (tension per area) exceeds the local wall strength; consequently, peak wall stress (PWS) and peak wall rupture risk (PWRR) have been found to be more reliable parameters than diameter to assess AAA rupture risk. Medical software allows computing these rupture risk indices from standard clinical CT data and provides a patient-specific AAA rupture risk diagnosis.

• A ruptured AAA with an open arrow marking the aneurysm and the closed arrow marking the free blood in the abdomen

• Sagittal CT image of an AAA.

• Biomechanical AAA Rupture risk prediction.

• An axial contrast enhanced CT scan demonstrating an abdominal aortic aneurysm of 4.8 by 3.8 cm

• Ultrasound image of a normal abdominal aorta measuring 1.9 cm in diameter.

• The faint outline of the calcified wall of a AAA as seen on plain X-ray

• CT image of an AAA 40,8 mm.

• Abdominal aortic aneurysms (3,4 cm)