 Introduction/Background Abdominal aortic aneurysm (AAA) is defined as an aneurysmal dilation of the abdominal aorta of at least 3 cm in diameter. This entity has a high degree of morbidity and mortality in the event of rupture [1,2]. To mitigate this risk, screening programs have been widely instituted to identify small, developing aneurysms. Such screening reduces morbidity and health care costs related to this disease [3-8]. An increasing number of aneurysms are identified incidentally on ultrasound (US) and cross-sectional imaging, creating a growing cohort of patients with known AAA [9-12]. The reported prevalence of AAA in persons >65 years of age ranges from 1.7% to 4.5% for men and 0.5% to 1.3% for women [11,13,14]. Special Imaging Considerations For the purposes of distinguishing between CT and CT angiography (CTA), ACR Appropriateness Criteria topics use the definition in the Practice Parameter for the Performance and Interpretation of Body Computed Tomography Angiography (CTA) [25]. All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and recons/reformats. Only in CTA, however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. aResearch Author, UT Southwestern Medical Center, Dallas, Texas. bUT Southwestern Medical Center, Dallas, Texas. cPanel Chair, UT Southwestern Medical Center, Dallas, Texas. dPanel Vice-chair, University of Michigan Health System, Ann Arbor, Michigan. eMayo Clinic, Rochester, Minnesota. fTufts University School of Medicine, Boston, Massachusetts; Society for Vascular Surgery. gUniversity of Wisconsin, Madison, Wisconsin. hMassachusetts General Hospital, Boston, Massachusetts. iUniversity of Alabama at Birmingham, Birmingham, Alabama. jMayo Clinic, Rochester, Minnesota. kUniversity of Michigan Health System, Ann Arbor, Michigan.
Abdominal Aortic Aneurysm Follow up Without Repair .  Introduction/Background Abdominal aortic aneurysm (AAA) is defined as an aneurysmal dilation of the abdominal aorta of at least 3 cm in diameter. This entity has a high degree of morbidity and mortality in the event of rupture [1,2]. To mitigate this risk, screening programs have been widely instituted to identify small, developing aneurysms. Such screening reduces morbidity and health care costs related to this disease [3-8]. An increasing number of aneurysms are identified incidentally on ultrasound (US) and cross-sectional imaging, creating a growing cohort of patients with known AAA [9-12]. The reported prevalence of AAA in persons >65 years of age ranges from 1.7% to 4.5% for men and 0.5% to 1.3% for women [11,13,14]. Special Imaging Considerations For the purposes of distinguishing between CT and CT angiography (CTA), ACR Appropriateness Criteria topics use the definition in the Practice Parameter for the Performance and Interpretation of Body Computed Tomography Angiography (CTA) [25]. All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and recons/reformats. Only in CTA, however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. aResearch Author, UT Southwestern Medical Center, Dallas, Texas. bUT Southwestern Medical Center, Dallas, Texas. cPanel Chair, UT Southwestern Medical Center, Dallas, Texas. dPanel Vice-chair, University of Michigan Health System, Ann Arbor, Michigan. eMayo Clinic, Rochester, Minnesota. fTufts University School of Medicine, Boston, Massachusetts; Society for Vascular Surgery. gUniversity of Wisconsin, Madison, Wisconsin. hMassachusetts General Hospital, Boston, Massachusetts. iUniversity of Alabama at Birmingham, Birmingham, Alabama. jMayo Clinic, Rochester, Minnesota. kUniversity of Michigan Health System, Ann Arbor, Michigan.