Purpose or Case Report: This case-based, pictorial, educational exhibit will:
1. Examine the predisposing conditions of thoracic aortic aneurysm (TAA) in children
2. Illustrate the histopathologic and imaging features of these conditions
3. Demonstrate proper technique for measuring and reporting aortic dimensions in children
4. Review treatment options for TAA and how treatment depnds on the underlying disease and imaging findings
Methods & Materials: There are several inherited disorders and congenital defects that predispose to progressive dilation of the thoracic aorta in childhood. Well known disorders like Marfan syndrome and bicuspid aortic valve have long served as clinical models but many, seemingly disparate, disorders result in similar abnormalities of the aorta. As knowledge about the genetic and histopathologic underpinnings of TAA grows, management will be guided by multidisciplinary teams. In order to maintain value in these teams, the pediatric radiologist must understand the varied causes of TAA, the underlying histopathology, and the treatment implications. This exhibit will introduce these predisposing conditions, review the similarities and differences, and review treatment options.
Results: The following conditions that predispose to aortic aneurysm will be reviewed:

I. Extracellular Matrix Proteins
1. Marfan Syndrome
2. Ehlers-Danlos Syndrome
3. Alport Syndrome
4. Cutix Laxa
5. MFAP5 Gene Mutation

II. TGF-ß Signaling Pathway
1. Loeys-Dietz Syndrome
2. Osteoarthritis-Aneurysm Syndrome
3. Sphrintzen-Goldberg Syndrome
4. Arterial Tortuosity Syndrome
5. SMAD2 and SMAD4 Gene Mutations

III. Nonsyndromic Familial Thoracic Aortic Aneusysms and Dissections Gene Mutations
1. ACTA2
2. MYH11
3. MLK
4. PRKG1
5. FLNA
6. MAT2A

IV. Congenital Heart Disease
1. Bicuspid Aortopathy
2. Aortic Coaractation
3. Tetralogy of Fallot
4. Truncus Arteriosus
5. Hypoplastic Left Heart Syndrome
6. Ross Procedure
7. Arterial Switch Procedures
Conclusions: Seemingly disparate conditions converge to cause similar aortopathies, resulting in TAA. As knowledge about aortopathy expands, pediatric radiologists must maintain knowledge about the defects and disorders linked to TAA, understand expected patterns of aortic dilation in the different conditions, and provide meaningful information to colleagues in cardiology and surgery. In doing so, radiologists will maintain value in the multidisciplinary approach these conditions warrant.