Noninvasive Imaging Approaches to Evaluate the Patient With Known or Suspected Aortic Disease

Abstract

Both chronic and acute aortic conditions are challenges for primary care physicians and cardiac specialists. Longitudinal progression of chronic aortic diseases and appropriate timing of open or endovascular surgery are usually derived from serial noninvasive imaging studies. Rapid imaging is necessary as not to delay the diagnosis of a potentially life-threatening diagnosis. Given the frequency of missed cases of dissection, atypical presentation, and time-dependent morbidity and mortality, imaging is paramount for diagnosis and treatment of any aortic disorder. An ideal imaging modality will precisely, safely, and rapidly confirm suspected acute or chronic aortic pathology with quantitative information on aneurysm formation and progression, as well as on tear location, extent, and type of dissection including evaluation for imminent complications. Today, invasive angiography has been replaced by noninvasive imaging strategies with multislice computed tomography (CT) and MRI for both chronic and acute pathologies; under emergency conditions, acute aortic syndromes can be imaged and confirmed at the bedside by transesophageal echocardiography (TEE), particularly to identify ascending aortic pathology such as type A aortic dissection. According to the International Registry of acute Aortic Dissection (IRAD), as early as 2002, CT was the diagnostic modality of choice for dissection in 63%, followed by TEE in 32%, and angiography and MRI in 4% and 1%, respectively.1 With excellent accuracy and similar sensitivity and specificity CT, MRI, and TEE have become diagnostic options2,3; however, hemodynamic instability of a given patient, and both availability and local expertise, determine the appropriateness of either modality. Whereas invasive angiography visualizes 2D luminograms, noninvasive multidetector CT (MD-CT) is the result of rapid image acquisition and 3D reconstruction in high resolution during brief opacification by intravenous contrast material.4 The technical leap with MD-CT was the creation of a cone-shaped x-ray beam generating image data over a volume, rather than …