TY - JOUR T1 - Longitudinal Amyloid Imaging Using <sup>11</sup>C-PiB: Methodologic Considerations JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1570 LP - 1576 DO - 10.2967/jnumed.112.113654 VL - 54 IS - 9 AU - Bart N.M. van Berckel AU - Rik Ossenkoppele AU - Nelleke Tolboom AU - Maqsood Yaqub AU - Jessica C. Foster-Dingley AU - Albert D. Windhorst AU - Philip Scheltens AU - Adriaan A. Lammertsma AU - Ronald Boellaard Y1 - 2013/09/01 UR - http://jnm.snmjournals.org/content/54/9/1570.abstract N2 - Several methods are in use for analyzing 11C-Pittsburgh compound-B (11C-PiB) data. The objective of this study was to identify the method of choice for measuring longitudinal changes in specific 11C-PiB binding. Methods: Dynamic 90-min 11C-PiB baseline and follow-up scans (interval, 30 ± 5 mo) were obtained for 7 Alzheimer disease (AD) patients, 11 patients with mild cognitive impairment (MCI), and 11 healthy controls. Parametric images were generated using reference parametric mapping (RPM2), reference Logan values, and standardized uptake value volume ratios (SUVr), the latter for intervals between 60 and 90 (SUVr60–90) and 40 and 60 (SUVr40–60) minutes after injection. In all analyses, cerebellar gray matter was used as a reference region. A global cortical volume of interest was defined using a probability map–based template. Percentage change between baseline and follow-up was derived for all analytic methods. Results: SUVr60–90 and SUVr40–60 overestimated binding with 13% and 10%, respectively, compared with RPM2. Reference Logan values were on average 6% lower than RPM2. Both SUVr measures showed high intersubject variability. Over time, R1, the delivery of tracer to the cortex relative to that to the cerebellum, decreased in AD patients (P &lt; 0.05) but not in MCI patients and controls. Simulations showed that SUVr, but not RPM2 and reference Logan values, was highly dependent on uptake period and that changes in SUVr over time were sensitive to changes in flow. Conclusion: To reliably assess amyloid binding over time—for example, in drug intervention studies—it is essential to use fully quantitative methods for data acquisition and analysis. ER -