TY - JOUR T1 - Validation of dynamic contrast enhanced CT (DCE-CT) using positron emission tomography (PET) and 15O-labeled water in healthy subjects JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1220 LP - 1220 VL - 50 IS - supplement 2 AU - Julie Louring-Andersen AU - Liselotte Hoejgaard AU - Ian Law Y1 - 2009/05/01 UR - http://jnm.snmjournals.org/content/50/supplement_2/1220.abstract N2 - 1220 Objectives PET with 15O-labeled water is a well-established method to quantify regional cerebral blood flow (rCBF). However, the 2 min half-life limits its use. An interesting and flexible alternative rCBF imaging method is based on DCE-CT scans that are used routinely in diagnosing stroke. This study aims to validate the rCBF values measured by DCE-CT against rCBF measured by H215O-PET in healthy subjects. We hypothesize that rCBF measured by DCE-CT will deviate less than 10% from rCBF measured by H215O-PET. Methods Three healthy volunteers (2 M, 1 F) were injected with 800 MBq H215O in two consecutive scans performed on a Siemens HRRT PET scanner, with simultaneous arterial blood sampling for kinetic modeling. On the same day, DCE-CT was performed using a Siemens Biograph 40 PET/CT scanner with a bolus of 40 ml hyperosmolic iodine contrast agent injected over 8 s followed by a 40 s cine scan (one frame/s) over the basal ganglia, covering 28 mm (four slices). Parametric rCBF images were fitted from PET with PXMOD after delay and dispersion correction of the arterial input curve, and from DCE-CT using commercially available software (Neuroperfusion, Siemens). Ten regions of interest were drawn over corresponding anatomical gray matter regions. Results The average (SD) rCBF DCE-CT (72.1 ± 19.9 ml/(100 g min)) was significantly larger (27%, p < 0.005, paired t-test) than the average rCBF PET (56.7 ± 14.9 ml/(100 g min)). Conclusions In a limited number of subjects we found that rCBF calculated using DCE-CT gave significantly larger values than when using H215O-PET as the gold standard. This overestimation was probably due to the rCBF DCE-CT images being dominated by the blood volume component. ER -