Advances in Imaging Aortic Disease

Effective therapeutic intervention, be it through open repair or endovascular means, necessitates accurate characterization of the anatomic extent of aortic abnormalities, involvement of the aortic root and aortic branches, and associated impact on end organ perfusion. Imaging using transesophageal echocardiography, magnetic resonance, and computed tomography (CT) have been key tools in aortic disease characterization. While all three modalities continue to advance and evolve, CT has undergone the most rapid evolution in recent years with the introduction of faster gantry rotation times and greater numbers of detector rows that together improve the temporal resolution of the technique and make high spatial resolution cardiac gated acquisitions of the aorta possible. This advance has been most important in the assessment of the aortic root. Gated CT angiography provides and effective means of assessing the coronary arteries, the aortic annulus and the valve leaflets. The volumetric acquisition with isotropic spatial resolution allows characterization of the complex and non-planar anatomic relationships that are prevalent when the aortic root is involved with aortic aneurysm or dissection.

While clinical imaging has focused primarily on anatomic and morphologic characterization of aortic diseases, including their impact on aortic flow, techniques are emerging that promise to provide important insights into aortic wall physiology and biology. Techniques permitting in vivo sensing of inflammation, apoptosis, cell trafficking, and gene expression are currently under investigation in animal models. Although the field of molecular imaging is in its earliest stages and practical in vivo human imaging techniques may be years away, the development of these techniques in appropriate animal models should substantially advance our understanding of aortic disease pathogenesis and progression. This presentation will aim to balance current and near-term clinical advances in CT with an introduction to the nascent field of molecular aortic imaging.