Method for coordinating mr angiography scan with arrival of bolus at imaging site

Abstract

An MRI method is provided for determining the arrival of selected contrast material at a target artery or other fluid-carrying vessel after injection of contrast material at a remote vascular site. By precisely knowing the arrival time, an additional MR angiography scan of the artery may be readily coordinated with the onset of artery enhancement. Initiation of this MR angiography scan may be immediate. Alternatively, determination of the arrival time of a test bolus of contrast to the imaging site can be used to calculate the transit time of a test bolus from the injection site to the imaging site. This information may then be used as an estimate of a subsequent MR angiography scan using a full bolus of contrast. The method for determining contrast arrival includes injecting the contrast material at an injection site, and simultaneously commencing acquisition of a succession of MR images of a section taken through the target vessel, proximate to the imaging site. A succession of RF excitation pulses are applied to first and second zones to selectively saturate MR signals passing therethrough, the first and second saturation zones being positioned on opposing sides of the imaging section and respectively extending away therefrom, in opposite directions, along the vessel. Each MR image can be monitored, upon being acquired, to determine the arrival of the contrast material at the imaging site.