CTA Abdomen and Pelvis CTA of the abdomen and pelvis presents many benefits over the other modalities. Relative to US, CTA is considered slightly more accurate at determining aneurysm diameter [27,30,31]. The use of iodinated contrast carries its own risks and contraindications that require consideration [35]. CT Abdomen and Pelvis The majority of evidence regarding AAA surveillance using CT is based on CTA data and is primarily related to contrast bolus timing. Contrast-enhanced CT is well established in the literature and is capable of identifying aortic aneurysms, with many papers discussing incidental AAA identification [9,11,13]. There is no specific literature regarding the use of noncontrast CT in the surveillance of AAA. One study reviewed the incidence of AAA incidentally found during CT colonography. This included patients who underwent CT imaging, some with and others without the use of intravenous (IV) contrast. This review did not distinguish the difference between those patients [11]. This technique could theoretically be of use in patients with chronic renal disease who have aneurysms less amenable to imaging by US. Noncontrast imaging can be employed in CTA protocols to evaluate for calcification, with spectral CT scanners offering virtual noncontrast reconstructions as an alternative. MRI Abdomen and Pelvis There is no relevant literature regarding the use of MRI for AAA surveillance in this setting; although, MRI may be useful in some cases. Similar to CT, there is excellent reproducibility in measurements between MRI examinations, a critical characteristic in monitoring for subtle changes in AAA size. Aortography Abdomen There is no relevant literature regarding the use of conventional angiography in the surveillance of AAA. Noninvasive techniques to monitor aneurysm characteristics make this invasive option less reasonable.
Abdominal Aortic Aneurysm Follow up Without Repair . CTA Abdomen and Pelvis CTA of the abdomen and pelvis presents many benefits over the other modalities. Relative to US, CTA is considered slightly more accurate at determining aneurysm diameter [27,30,31]. The use of iodinated contrast carries its own risks and contraindications that require consideration [35]. CT Abdomen and Pelvis The majority of evidence regarding AAA surveillance using CT is based on CTA data and is primarily related to contrast bolus timing. Contrast-enhanced CT is well established in the literature and is capable of identifying aortic aneurysms, with many papers discussing incidental AAA identification [9,11,13]. There is no specific literature regarding the use of noncontrast CT in the surveillance of AAA. One study reviewed the incidence of AAA incidentally found during CT colonography. This included patients who underwent CT imaging, some with and others without the use of intravenous (IV) contrast. This review did not distinguish the difference between those patients [11]. This technique could theoretically be of use in patients with chronic renal disease who have aneurysms less amenable to imaging by US. Noncontrast imaging can be employed in CTA protocols to evaluate for calcification, with spectral CT scanners offering virtual noncontrast reconstructions as an alternative. MRI Abdomen and Pelvis There is no relevant literature regarding the use of MRI for AAA surveillance in this setting; although, MRI may be useful in some cases. Similar to CT, there is excellent reproducibility in measurements between MRI examinations, a critical characteristic in monitoring for subtle changes in AAA size. Aortography Abdomen There is no relevant literature regarding the use of conventional angiography in the surveillance of AAA. Noninvasive techniques to monitor aneurysm characteristics make this invasive option less reasonable.