[Dynamic vascular imaging with magnetic resonance imaging of the thoracic and abdominal region. Technique optimization].

Several Magnetic Resonance (MR) imaging techniques for the study of the main thoracic and abdominal vessels are analyzed. Such techniques based on the static representation of vessels, as MR angiography (MRA), are considered, together with dynamic techniques--i.e., cine MR--and those based on ultra-fast sequences with bolus contrast medium administration; the latter are considered also according to their use in the study of the early parenchymogram. Namely, the investigated techniques are: 3D/2D inflow imaging with and without presaturation, 3D inflow imaging with paramagnetic contrast medium administration, 2D/3D phase/dephase subtraction imaging, cine MR with heart gating, the sequential dynamic single-slice technique with bolus contrast medium, and the apnea multi-slice imaging. The main parameters are indicated for each technique and type of sequence. From our experience, rather precise indications emerge as to the use of the various techniques according to the investigated region and to the suspected disease. The best techniques for demonstrating sacciform aneurysms proved to be the 3D inflow ones, as well as the cine MR and the turbo-flash sequences with contrast medium; as for dissecting aneurysms, cine MR proved best. In portal flow conditions and in major veins thromboses, 2D inflow and phase/dephase subtraction sequences are suggested. In the study of renal stenoses, limitations and advantages of 2D versus 3D sequences are compared. Moreover, indications, limitations and specificity are analyzed of the early parenchymogram based on ultra-fast sequences with paramagnetic contrast medium. In the authors' experience, the different MR vascular imaging techniques must be considered only an integration to more specific investigations, but it is likely that, as it happened with MRA of the head and neck, the increase in resolution and the reduction in artifacts will--soon--turn this kind of imaging into the examination of choice in vascular studies.