Response to ‘Magnetic Resonance Imaging for Aortic Dissection’

Abstract

We would like to congratulate the authors on their review of imaging for thoracic aortic disease. 1 However, we would like to comment on the section regarding dissection. Multidetector contrast-enhanced computed tomography (CT) remains the most widely available modality for imaging patients with this disease, but has some limitations which may be misleading. The images acquired are a representation of one moment in the cardiac cycle and these static images may not illustrate the complex anatomical and functional changes occurring in aortic dissection. The dimensions of the true and false aortic lumens will vary with systole and diastole and this will have an effect on factors such as device sizing and determining dynamic from static obstruction. Magnetic resonance imaging (MRI) with ECG-gating is able to give static and dynamic high-resolution information in a single examination.False lumen thrombosis is accepted as an important factor in determining the prognosis of patients presenting with dissection, and is diagnosed on CT by the absence of contrast in the false lumen on first pass imaging. 2 A delayed second scan may detect late enhancing structures but the ideal timing for this will be related to both the cardiac output and local flow conditions.MRI is able to deliver anatomical and functional information in a single scan and compared with multidetector contrast-enhanced CT and has the added benefit of not using ionising radiation. The next generation of endoluminal devices will be more conformable to the aortic arch and MRI generated data will allow the use of shorter endoluminal devices in patients requiring intervention.