Imaging aortic aneurysmal disease

Imaging techniques play a crucial role in the diagnosis, follow-up and management of aortic aneurysms. Ultrasound, CT and MRI have strengths and limitations in the assessment of this disease depending on the aorta segment involved, reason for the study (screening, follow-up or surgical indication) and patient characteristics. Ultrasound, transthoracic or abdominal, is highly useful in the diagnosis and follow-up of proximal ascending aorta and abdominal aorta aneurysms, respectively. However, other imaging modalities may be required to confirm measurements and add information on adjacent structures or the involvement of aortic branches. Transoesophageal echocardiography is frequently limited to perioperative indications. CT plays a central role in the diagnosis, risk stratification and management of most aneurysms, particularly those located distal to the proximal ascending aorta. Advantages of CT over other imaging modalities include rapid image acquisition, its multiplanar capacity with submillimetric spatial resolution and wide availability. The main limitations of CT are the radiation exposure and need for nephotoxic contrast administration. MRI is less readily available but overcomes these limitations and adds functional and biomechanical information, and is mainly indicated in young individuals who require repetitive studies and long-term follow-up. Aortic diameters are the cornerstone of current clinical practice in aortic aneurysms, and some limitations in accuracy and reproducibility measurements may generate errors in clinical decision making. Better understanding of imaging modalities, beyond the simple clinical application of diameters, may improve the management of this disease. In addition, new biomechanical and metabolic information could potentially provide a more reliable prediction of the risk of aneurysm rupture.