Table 1—Role of Noninvasive Imaging Modalities in Patients With Coarctation

obtain optimal velocity profile across the coarctation to calculate the pressure gradient. Transesophageal echocardiography (TEE) has an important role in patients with native and repaired coarctation. The entire thoracic aorta can be image, except for a small segment of the ascending aorta, which is obscured by the trachea or right bronchus. It is our experience that endovascular stent can be adequately visualized by TEE, although optimal velocity profile at the site of coarctation cannot be obtained. We frequently used TEE in addition to CT in the follow-up of patients who have endovascular stent for coarctation. While MRI and CT are not suitable for intraoperative applications, TEE is ideal for this setting to monitor endovascular coarctation repair by angioplasty or stenting and to assess for procedural complications including dissection and stent dislodgement. 9,10 High-resolution images of the entire aorta including the coarctation segment can be obtained by MRI, which provides detailed anatomic information for the planning of invasive intervention such as surgery or percutaneous angioplasty. By virtue of its ability to provide multiple oblique-sagittal planes of the aorta, MRI is particularly suited in the follow-up of patients who have undergone surgical repair for coarctation, since the aortic arch and proximal descending aorta in these patients tend to be tortuous and difficult to image in the proper long axis view. 11 However, there are situations where MRI is not the imaging modality of choice. One obvious situation is in patients who cannot undergo MRI because they have metallic prostheses such as pacemakers. Optimal images cannot be obtained in patients who have had treatment with endovascular stents since the stent artifact generally obscures the aortic segment that has been stented. In these patients the location and morphology of the stent can best be assessed by using both CT and TEE. CT is less affected by the stent artifact and can provide high-resolution images in the transverse plane. Compared to MRI, the aortic arch is not as well seen by CT because it is imaged obliquely and reconstructed CT sagittal views have limited resolution.