Magnetic Resonance Imaging Findings in a Positron Emission Tomography-Positive Thoracic Aortic Aneurysm.

Diffusion-weighted MRI (DW-MRI) and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) findings are described in a patient with a thoracic aortic aneurysm. Both examinations have the ability to noninvasively assess biological processes associated with aneurysm instability and therefore to potentially impact clinical decision-making regardless of the vessel size. Despite similarities between images on both techniques, FDG-PET evaluates glycolysis, while DW-MRI evaluates cell density, edema, and perfusion. Longitudinal studies including larger patient numbers are needed to investigate the temporal continuum and clinical significance of these findings.