MR-ANGIOGRAPHY OF THE THORACIC VESSELS

Through the introduction of newly invented high-performance gradient s ystems to MRI, which enable for echoplanar imaging (EPI), also magneti c resonance angiography (MRA) has gained an entirely new field of appl ications and techniques. Ultrafast imaging techniques in MRA allow the investigation of larger Vascular areas within a single breath-hold-pe riod. Artifacts like motion induced signal misregistrations, dephasing or saturation of the vascular signal are minimized by extremely short echo times. The technique thus requires the intravenous application o f a contrast media bolus, usually a gadolinium compound, which is in s tandard clinical use. Coordination of the bolus injection and the timi ng of the data acquisition is crucial for optimal results. The first p ass evaluation of the contrast media resembles CTA to a certain extend . Due to the fast measurement and the high contrast in contrast-enhanc ed MRA (CE-MRA) new applications and indications are developed like MR A of the pulmonary vessels. The paper offers considerations and trials for optimization of thoracical CE-MRA. Besides parameter constellatio n also bolus-optimization is described with respect to the dedicated a natomical premises. investigations on volunteers and on patients build a basis for suggestions on optimized CE-MRA procedures. To date, a fi nal estimation of the clinical value of the new technique cannot be gi ven since ongoing improvements change the optimal protocol frequently and the potential of further developments is high.