Patent ID: 6271665
Filing Date: 2001-08-07
Classification: G01R

Abstract:
A spin labeling magnetic resonance method for measuring perfusion of fluid into an area without the use of ionizing radiation or exogenous tracer and wherein the fluid outside the area is tagged prior to perfusion into said area, said method comprising the steps of:(a) choosing an arbitrary area of interest to image;(b) magnetically tagging nuclei in said fluid outside said imagining area using a nonselective radio frequency (RF) inversion pulse followed immediately by a selective RF pulse-magnetic field gradient combination coincident with the imaging plane which re-inverts spins in the imaging plane and leaves the spins outside the plane inverted (tagged);(c) allowing time for the tagged nuclei to perfuse into said imaging area;(d) collecting tag image information in a rapid manner and generating an image where the intensity is decreased by the tagged nuclei that have traveled into the imaging plane;(e) collecting a control image in a manner exactly the same as that of the tagged images except that two non-selective RF pulses are used which leaves the spins outside the imaging plane untagged but imparts the same amount of signal loss due to magnetization transfer (MT);(f) processing said images to create a perfusion weighted image by calculating on a pixel by pixel basis the difference between the tag and control image, for which the intensity is a function of the perfusion rates; or(g) processing said images to determine the quantity of said fluid per quantity of said mass of image volume per unit time which has perfused into said imaging area as a function of spatial location.