MR-Based Correction of Brain PET Measurements for Heterogeneous Gray Matter Radioactivity Distribution

• Published in: Journal of cerebral blood flow and metabolism Vol. 16; no. 4; pp. 650 - 658
• Main Authors: Meltzer, Carolyn Cidis, Zubieta, Jon Kar, Links, Jonathan M., Brakeman, Paul, Stumpf, Martin J., Frost, J. James
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.07.1996; Lippincott Williams & Wilkins
• Subjects: Aged; Algorithms; Biological and medical sciences; Brain - diagnostic imaging; Brain - pathology; Computer Simulation; Deoxyglucose - analogs & derivatives; Deoxyglucose - pharmacokinetics; Fentanyl - analogs & derivatives; Fentanyl - pharmacokinetics; Fluorine Radioisotopes; Fluorodeoxyglucose F18; Humans; Investigative techniques, diagnostic techniques (general aspects); Magnetic Resonance Imaging; Male; Medical sciences; Models, Neurological; Nervous system; Periaqueductal Gray - diagnostic imaging; Periaqueductal Gray - metabolism; Periaqueductal Gray - pathology; Phantoms, Imaging; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Reference Values; Sepharose; Tomography, Emission-Computed; Opiate receptors; Magnetic resonance imaging; Alzheimer disease; Emission computed tomography; Radionuclide study; Human; Grey matter; Central nervous system; Exploration; Method; Algorithm; Nuclear magnetic resonance imaging; Partial; Volume; Brain (vertebrata); Positron; Emission tomography
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1097/00004647-199607000-00016

Partial volume and mixed tissue sampling errors can cause significant inaccuracy in quantitative positron emission tomographic (PET) measurements. We previously described a method of correcting PET data for the effects of partial volume averaging on gray matter (GM) quantitation; however, this method may incompletely correct GM structures when local tissue concentrations are highly heterogeneous. We have extended this three-compartment algorithm to include a fourth compartment: a GM volume of interest (VOI) that can be delineated on magnetic resonance (MR) imaging. Computer simulations of PET images created from human MR data demonstrated errors of up to 120% in assigned activity values in small brain structures in uncorrected data. Four-compartment correction achieved full recovery of a wide range of coded activity in GM VOIs such as the amygdala, caudate, and thalamus. Further validation was performed in an agarose brain phantom in actual PET acquisitions. Implementation of this partial volume correction approach in [18F]fluorodeoxyglucose and [11C]-carfentanil PET data acquired in a healthy elderly human subject was also performed. This newly developed MR-based partial volume correction algorithm permits the accurate determination of the true radioactivity concentration in specific structures that can be defined by MR by accounting for the influence of heterogeneity of GM radioactivity.