[Quantitation of cerebral blood flow and partition coefficient using 123I-IMP dynamic SPECT with single arterial blood sampling].

A method base on the two-compartment model was developed to measure quantitative cerebral blood flow (CBF) and partition coefficient (lambda) of IMP from dynamic SPECT and single arterial blood sampling. In this method, the linear differential equation of two-compartment model, Yokoi proposed, was employed and quantitative CBF and lambda values were measured with the standard input function calibrated by single arterial sampling. The input function was derived from the standard input function scaled by a factor determined by the single arterial blood sample. This new technique was applied to 5 normal volunteers (Ages ranged from 25 to 29 yr., average 26 yr.). The optimal time to calibrate the standard input function in the individual study and optimal the period of the upper limit time to which input function is integrated from IMP administration for analysis of the equation were determined to minimize the difference between integration of the calibrated standard input function and of the individual input function. Minimization of the difference yields an optimal calibration time (4 to 10 min after IMP administration) and the period of the upper limit time (8 to 60 min after acquisition start). Comparison of CBF and lambda values obtained by the graphical method using the calibrated standard data and individual input function were performed. It should be noted that CBF values were in good agreement between the two methods, respectively (r = 0.92, P<0.01; r = 0.72, p = 0.01). This method is easy to estimate CBF and lambda by only single arterial blood sampling and IMP dynamic SPECT, and useful for routine studies.