A new non-invasive graphical method for quantification of cerebral blood flow with[ 123 I ] IMP.

OBJECTIVE

[ 123 I ] N-isopropyl-p-iodoamphetamine ( 123 I -IMP) is an ideal perfusion tracer for single photon emission computed tomography, which shows good linearity between cerebral blood flow (CBF) and accumulation. However, quantification of CBF using 123 I -IMP without arterial blood sampling has been challenging, with previous methods requiring empirically obtained regression formulae to estimate CBF. Furthermore, the CBF value obtained via some of the previous methods would be affected by the clearance rate of 123 I -IMP from the lungs. This paper introduces a new non-invasive quantification method for CBF using 123 I -IMP and dynamic planar images.

METHODS

We have developed a theory based on Microsphere model. This method does not involve regression formulae for estimation and allows for direct measurement of CBF, considering the clearance rate of 123 I -IMP from the lungs. The study method is executed as easily as conventional Graph-Plot method. We compared the CBF values obtained by our study method and the established autoradiograph (ARG) method.

RESULTS

CBF values obtained using the new method demonstrated significant correlation with values determined using ARG method.

CONCLUSIONS

The novel method described presents a reliable and more simple way of determining CBF when compared to current methods.