Optimization of Supervised Cluster Analysis for Extracting Reference Tissue Input Curves in (R)-[11C]PK11195 Brain PET Studies

• Published in: Journal of cerebral blood flow and metabolism Vol. 32; no. 8; pp. 1600 - 1608
• Main Authors: Yaqub, Maqsood, van Berckel, Bart NM, Schuitemaker, Alie, Hinz, Rainer, Turkheimer, Federico E, Tomasi, Giampaolo, Lammertsma, Adriaan A, Boellaard, Ronald
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.08.2012; Nature Publishing Group; Sage Publications Ltd
• Subjects: Adult; Aged; Aged, 80 and over; Algorithms; Alzheimer Disease - diagnostic imaging; Alzheimer Disease - physiopathology; Alzheimer's disease; Biological and medical sciences; Blood Volume - physiology; Blood. Blood coagulation. Reticuloendothelial system; Brain; Carbon Radioisotopes; Cerebellum; Cerebellum - blood supply; Cerebellum - diagnostic imaging; Cerebral blood flow; Cluster Analysis; Cognitive ability; Cognitive Dysfunction - diagnostic imaging; Cognitive Dysfunction - physiopathology; Computer Simulation; Data processing; Humans; Image Interpretation, Computer-Assisted; Isoquinolines - pharmacokinetics; Kinetics; Medical sciences; Middle Aged; Models, Neurological; Neurodegenerative diseases; Neurology; Original; Pharmacology. Drug treatments; Positron emission tomography; Positron-Emission Tomography - methods; Protein Binding; Protein transport; Reference Values; Reproducibility of Results; Thalamus - blood supply; Thalamus - diagnostic imaging; Tissue Distribution; Vascular diseases and vascular malformations of the nervous system; Young Adult; parametric analysis; clustering; (R)-[11C]PK11195; reference tissue; Cluster analysis; Nervous system diseases; Optimization; Cerebral disorder; Encephalon; C]PK11195; Central nervous system disease; Positron emission tomography; (R)-; Cerebrovascular disease; Emission tomography
• DOI: 10.1038/jcbfm.2012.59
• ISSN: 0271-678X

Performance of two supervised cluster analysis (SVCA) algorithms for extracting reference tissue curves was evaluated to improve quantification of dynamic (R)-[11C]PK11195 brain positron emission tomography (PET) studies. Reference tissues were extracted from images using both a manually defined cerebellum and SVCA algorithms based on either four (SVCA4) or six (SVCA6) kinetic classes. Data from controls, mild cognitive impairment patients, and patients with Alzheimer's disease were analyzed using various kinetic models including plasma input, the simplified reference tissue model (RPM) and RPM with vascular correction (RPMVb). In all subject groups, SVCA-based reference tissue curves showed lower blood volume fractions (Vb) and volume of distributions than those based on cerebellum time-activity curve. Probably resulting from the presence of specific signal from the vessel walls that contains in normal condition a significant concentration of the 18 kDa translocation protein. Best contrast between subject groups was seen using SVCA4-based reference tissues as the result of a lower number of kinetic classes and the prior removal of extracerebral tissues. In addition, incorporation of Vb in RPM improved both parametric images and binding potential contrast between groups. Incorporation of Vb within RPM, together with SVCA4, appears to be the method of choice for analyzing cerebral (R)-[11C]PK11195 neurodegeneration studies.