title: Robust fitting of [11C]-WAY-100635 PET data.
abstract: Fitting of a positron emission tomography (PET) time-activity curve is typically accomplished according to the least squares (LS) criterion, which is optimal for data having Gaussian distributed errors, but not robust in the presence of outliers. Conversely, quantile regression (QR) provides robust estimates not heavily influenced by outliers, sacrificing a little efficiency relative to LS when no outliers are present. Given these considerations, we hypothesized that QR would improve parameter estimate accuracy as measured by reduced intersubject variance in distribution volume (V(T)) compared with LS in PET modeling. We compare V(T) values after applying QR with those using LS on 49 controls studied with [(11)C]-WAY-100635. QR decreases the standard deviation of the V(T) estimates (relative improvement range: 0.08% to 3.24%), while keeping the within-group average V(T) values almost unchanged. QR variance reduction results in fewer subjects required to maintain the same statistical power in group analysis without additional hardware and/or image registration to correct head motion.
authors.affiliation: Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, USA. francesca.zanderigo@gmail.com
authors.forename: Francesca
authors.initials: F
authors.lastname: Zanderigo
authors.forename: Robert Todd
authors.initials: RT
authors.lastname: Ogden
authors.forename: Chung
authors.initials: C
authors.lastname: Chang
authors.forename: Stephen
authors.initials: S
authors.lastname: Choy
authors.forename: Andrew
authors.initials: A
authors.lastname: Wong
authors.forename: Ramin Vaziri
authors.initials: RV
authors.lastname: Parsey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D016011:Normal Distribution; D010879:Piperazines / Q000737:chemistry / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods*; D011725:Pyridines / Q000737:chemistry / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000737:chemistry / Q000378:metabolism; D012702:Serotonin Antagonists / Q000737:chemistry / Q000378:metabolism*; D055815:Young Adult
chemical_list: D002250:Carbon Radioisotopes; D010879:Piperazines; D011725:Pyridines; D019275:Radiopharmaceuticals; D012702:Serotonin Antagonists; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide