The ITI wall measurement method was recommended because of its high conformity to the LTL measurements used in echocardiography, which is a consideration more relevant to the thoracic aorta [25,37]. The Society for Cardiovascular Magnetic Resonance and others advocate measurement of the outer aortic wall contour for aneurysms [38,39]. MRI Abdomen and Pelvis For the initial imaging evaluation of suspected AAA, the considerations for MRI of the abdomen and pelvis without dedicated MRA sequences are similar to that of MRA [8,10,25]. As with CT, a routine MRI abdomen and pelvis with IV contrast or MRI abdomen and pelvis without and with IV contrast can be used to measure abdominal aortic diameter if the aortic contour is well depicted. Either procedure may also characterize possible nonaortic causes of a pulsatile abdominal mass. AAAs can also be incidentally detected on MRI of the abdomen and pelvis performed for other reasons [5]. Accurate and reproducible aortic diameter measurements, comparable to CTA measurements, can be obtained from MRI without IV contrast by using black-blood sequences acquired with spin-echo techniques [40]. With advanced imaging methods, MRI can also provide functional and hemodynamic data, such as quantification of aortic wall stiffness and blood flow [25]. Radiography Abdomen and Pelvis There is no relevant literature supporting the use of radiography for the initial imaging evaluation of a pulsatile abdominal mass suspected to be an AAA. Radiography is not recommended for initial imaging for suspected AAA because of its low sensitivity for AAA detection [3,7]. AAA can be incidentally discovered on abdominal radiographs obtained for other purposes if aortic wall calcifications are visible and allow for assessment of aortic diameter; however, AAA morphology and extent may not be accurately or fully evaluated [3]. Pulsatile Abdominal Mass
Pulsatile Abdominal Mass Suspected Abdominal Aortic Aneurysm. The ITI wall measurement method was recommended because of its high conformity to the LTL measurements used in echocardiography, which is a consideration more relevant to the thoracic aorta [25,37]. The Society for Cardiovascular Magnetic Resonance and others advocate measurement of the outer aortic wall contour for aneurysms [38,39]. MRI Abdomen and Pelvis For the initial imaging evaluation of suspected AAA, the considerations for MRI of the abdomen and pelvis without dedicated MRA sequences are similar to that of MRA [8,10,25]. As with CT, a routine MRI abdomen and pelvis with IV contrast or MRI abdomen and pelvis without and with IV contrast can be used to measure abdominal aortic diameter if the aortic contour is well depicted. Either procedure may also characterize possible nonaortic causes of a pulsatile abdominal mass. AAAs can also be incidentally detected on MRI of the abdomen and pelvis performed for other reasons [5]. Accurate and reproducible aortic diameter measurements, comparable to CTA measurements, can be obtained from MRI without IV contrast by using black-blood sequences acquired with spin-echo techniques [40]. With advanced imaging methods, MRI can also provide functional and hemodynamic data, such as quantification of aortic wall stiffness and blood flow [25]. Radiography Abdomen and Pelvis There is no relevant literature supporting the use of radiography for the initial imaging evaluation of a pulsatile abdominal mass suspected to be an AAA. Radiography is not recommended for initial imaging for suspected AAA because of its low sensitivity for AAA detection [3,7]. AAA can be incidentally discovered on abdominal radiographs obtained for other purposes if aortic wall calcifications are visible and allow for assessment of aortic diameter; however, AAA morphology and extent may not be accurately or fully evaluated [3]. Pulsatile Abdominal Mass