Feasibility & Repeatability of ASL-Based PhMRI After a Single Dose Oral Challenge as a Tool for Assessing 5-HT Function

Anne Klomp¹, Matthan W. Caan¹, Aart J. Nederveen¹, Liesbeth Reneman¹

The purpose of this study was to verify feasibility and repeatability of ASL-based phMRI after an oral challenge in assessing cerebral serotonin function. Twelve subjects were scanned six times; twice before and after taking 16mg citalopram and once before and after taking placebo. Subjects were blinded to treatment and treatment order was (pseudo)randomized. Although within-session reproducibility of the ASL signal was good, effects of the citalopram challenge could not be repeated between sessions. We attribute these contradictory findings between the two citalopram sessions to the need for relatively large sample sizes due to variation in both ASL signal and serotonergic activity.