The REICA method for quantification of cerebral blood flow is less affected by lung washout of [123I] IMP than the graph-plot method.

OBJECTIVE: The [Formula: see text]-Ray Evaluation with Iodoamphetamine for Cerebral blood flow Assessment (REICA) method is a new method for cerebral blood flow (CBF) quantification with SPECT and [123I] IMP, which does not require invasive arterial blood sampling, or the use of a regression formula. Moreover, it takes into consideration tracer retention, while the Graph-Plot (GP) method does not. This study aims to confirm the reliability of the REICA method in calculating CBF by accounting for pulmonary tracer retention artefact. METHODS: Data of 100 patients were retrospectively analyzed. Washout rate (WR) was defined as 1- (max count /min count) in the lungs. The bias due to WR was analyzed by dividing the data into high/low WR groups and a multiple regression analysis was also performed. RESULTS: The REICA method did not show significant bias according to the [Formula: see text] test ([Formula: see text]), while the GP method showed significant bias ([Formula: see text]). Both the REICA and GP methods showed significant correlation with autoradiography (ARG) method ([Formula: see text], [Formula: see text]) and WR ([Formula: see text], [Formula: see text]) when analyzed via multiple regression analysis with covariates of age and sex. CONCLUSIONS: The REICA method is a reliable method for CBF quantification, which is unaffected by tracer washout through the lungs unlike the GP method.