title: Establishing test-retest reliability of an adapted [(18)F]fallypride imaging protocol in older people.
abstract: [(18)F]fallypride is a high-affinity dopamine D2/3 receptor tracer with the ability to reliably quantify D2/3 receptor sites in both striatal and corticolimbic regions. The translational potential of [(18)F]fallypride imaging is, however, limited by the lengthy scanning sessions (60-80 minutes duration over a total of 3-4 hours) required by current protocols. The aims of our study were to adapt [(18)F]fallypride imaging for use in clinical populations with neurological and neuropsychiatric disorders, by reducing the duration of individual scanning sessions; and to establish the reproducibility and reliability of our adapted protocol in healthy older people. Eight participants (five male and three female; mean age=75.87±4.39 years) were scanned twice, 4-6 weeks apart. [(18)F]fallypride binding potential was determined from image data collected during three sampling times: 0-30; 60-90; and 210-240 minutes post injection. High reproducibility and reliability (test-retest variability <8%; intraclass correlation coefficient >0.8) were observed in all but the prefrontal regions, and remained so when sampling times were reduced to 20 minutes (0-20; 70-90; 220-240 minutes). The adapted protocol is feasible for use across neuropsychiatric disorders in which dopamine has been implicated and is sufficiently sensitive to detect within-subject changes between 2.7% and 5.5% in striatal and limbic regions.
authors.affiliation: St Thomas' PET Imaging Centre, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK.
authors.forename: Joel T
authors.initials: JT
authors.lastname: Dunn
authors.forename: Chloe
authors.initials: C
authors.lastname: Clark-Papasavas
authors.forename: Paul
authors.initials: P
authors.lastname: Marsden
authors.forename: Stacey
authors.initials: S
authors.lastname: Baker
authors.forename: Marcel
authors.initials: M
authors.lastname: Cleij
authors.forename: Shitij
authors.initials: S
authors.lastname: Kapur
authors.forename: Robert
authors.initials: R
authors.lastname: Kessler
authors.forename: Robert
authors.initials: R
authors.lastname: Howard
authors.forename: Suzanne J
authors.initials: SJ
authors.lastname: Reeves
mesh_terms: D000368:Aged; D000375:Aging / Q000378:metabolism; D001549:Benzamides / Q000493:pharmacokinetics; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D001931:Brain Mapping / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D011485:Protein Binding; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D050637:Receptors, Dopamine D3 / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D001549:Benzamides; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D019788:Fluorodeoxyglucose F18; C574003:fallypride