Magnetic Resonance angiography of epiaortic vessels in the thorax

Introduction. Magnetic Resonance angiography (MRA) is an accurate and non-invasive diagnostic method to evaluate vascular disease. On the basis of its technological advancements, this technique has gained an important role in the diagnostic protocol of cerebral and cervical vascular diseases. Nonetheless, MRA efficacy changes in different anatomic districts as a consequence of the specific anatomy and flow features. Cardiac and respiratory artifact and different coil sensitivity also affect MRA results. For these reasons, intrathoracic epiaortic vessels are a difficult applications for MRA. Material and methods. We examined 20 patients affected with epiaortic atherosclerosis with MRA, carried out with an 0.5 T MR unit (Vectra, GE). Examinations consisted of Phase Contrast (PC) 3D sequences (TR/TE/FA/Venc=30/13/45/30-50), with 3 axes of flow encode, matrix 128x256, 2 mm partition thickness, and axial and/or coronal acquisition volume. The MRA was repeated after Gd-DTPA intravenous perfusion and a qualitative and quantitative evaluation of pre- and post-contrast results was performed. Specific parameters of evaluation were: angiographic contrast, contrast to noise ratio, saturation effect of longitudinal magnetization, contrast between arteries and veins. All patients were examined with Doppler US and angiography. MRA data were compared to angiography in order to establish MRA sensitivity and specificity. Results and conclusions. PC sequences showed high accuracy in the examination of the proximal tract of epiaortic vessels; Gd-DTPA administration substantially improved MRA results. The perspectives of technological improvement will probably candidate PC MRA to be a valid alternative to US-Doppler and, perhaps, to angiographic study.