Areas under the curve, expressed in SUV, of the peak area (first 5 minutes) and the rest of the arterial input function in the three populations of subjects.

<p>Areas under the curve, expressed in SUV, of the peak area (first 5 minutes) and the rest of the arterial input function in the three populations of subjects.</p

Retest variability for 2TCM, Logan with full input, and Logan with PBIF, respectively.

<p>In the present study, results with Logan and the PBIF (variability: 16%; ICC = 0.89) were nearly identical to those obtained with Logan and the full input function. <i>V</i>_T values obtained with 2TCM, Logan with full input and Logan with PBIF were strongly correlated (scatter plots are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060231#pone.0060231.s001" target="_blank">Figure S1</a>).</p

Comparison of Logan-<i>V</i>_T results in cortical and subcortical regions for healthy volunteers, alcoholic subjects and cannabis smokers, obtained with full input and the PBIF.

<p>Results at baseline in alcoholic subjects (A) and cannabis smokers (B), compared to healthy controls for both full input and PBIF. PBIF provided accurate Logan-<i>V</i>_T values in healthy subjects and alcoholic patients and closely replicated previous findings of widespread downregulation. In cannabis smokers, PBIF underestimated Logan-<i>V</i>_T (arrows); the results suggest the erroneous conclusion that downregulation also occurred in subcortical regions.</p

Results from the alcohol and cannabis studies using PBIF.

<p>Bold text underscores differences between PBIF and full sampling modeling.</p