TY - JOUR T1 - Reference Tissue Models and Blood–Brain Barrier Disruption: Lessons from (<em>R</em>)-[<sup>11</sup>C]PK11195 in Traumatic Brain Injury JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1975 LP - 1979 DO - 10.2967/jnumed.109.067512 VL - 50 IS - 12 AU - Hedy Folkersma AU - Ronald Boellaard AU - W. Peter Vandertop AU - Reina W. Kloet AU - Mark Lubberink AU - Adriaan A. Lammertsma AU - Bart N.M. van Berckel Y1 - 2009/12/01 UR - http://jnm.snmjournals.org/content/50/12/1975.abstract N2 - (R)-[11C]PK11195 is a tracer for activated microglia. The purpose of this study was to assess the validity of the simplified reference tissue model for analyzing (R)-[11C]PK11195 studies in traumatic brain injury (TBI), where blood–brain barrier disruptions are likely. Methods: Dynamic (R)-[11C]PK11195 scans were acquired at 3 time points after TBI. Plasma input–derived binding potential (BPNDPI), volume of distribution (VT) and K1/k2, and simplified reference tissue model–derived binding potential (BPNDSRTM) were obtained. Simulations were performed to assess the effect of varying K1/k2. Results: Early after TBI, an increase in VT, but not in BPNDPI, was found. Early K1/k2 correlated with VT and BPNDSRTM but not with BPNDPI. One and 6 mo after TBI, BPNDSRTM correlated with BPNDPI. Conclusion: Early after TBI, (R)-[11C]PK11195 studies should be analyzed using plasma input models. ER -