Modern diagnostic imaging of aortic dissection and occlusion

For the diagnostic work-up of the aorta, noninvasive cross-sectional imagin g techniques have almost replaced invasive catheter angiography. CT- and MR -angiography are supplemented by sonography which is used predominantly for the assessment of abdominal aortic aneurysm and dissections of the thoraci c aorta. This review deals with the diagnostic approach to two disease enti ties involving the aorta: aortic dissection and aortic occlusion. Transoesophageal echocardiography (TEE),CT- and MR-angiography (MRA) are us ed in the assessment of aortic dissection. Published sensitivity and specif city values regarding the detection and classification of dissections into Stanford A and Stanford B range between 96-100% for all three modalities. R esults for multislice CTA have not yet been reported, but can be expected t o be at least as good. The ability to delineate additional information rega rding the precise morphology of true and false lumen, entry and reentry-sit es, the development of thrombus or paraaortic hematomas,as well as the asse ssment of aortic regurgitation or involvement of coronary arteries depend o n the chosen technique. Reflecting the ability to collect functional imagin g data, both TEE and MRA are superior to CTA in the assessment of aortic va lve involvement, while TEE is the modality of choice for evaluation of coro nary arteries. Sonography is of limited use in the assessment of abdominal dissections. For the evaluation of patients with suspected aortic occlusion both CTA and MRA represent the imaging modalities of choice. Both provide for a compreh ensive and precise depiction of the underlying aortic morphology, the exten t of collateral flow as well as delineation of distal run-off vessels. MRA should be employed in patients with impaired renal function as paramagnetic contrast agents are not nephrotoxic.