Reference region automatic extraction in dynamic [(11)C]PIB.
The positron emission tomography (PET) radiotracer [(11)C]Pittsburgh Compound B (PIB) is a marker of amyloid plaque deposition in brain, and binding potential is usually quantified using the cerebellum as a reference where the specific binding is negligible. The use of the cerebellum as a reference, however, has been questioned by the reported cerebellar [(11)C]PIB retention in familial Alzheimer's disease (AD) subjects. In this work, we developed a supervised clustering procedure for the automatic extraction of a reference region in [(11)C]PIB studies. Supervised clustering models each gray matter voxel as the linear combination of three predefined kinetic classes, normal and lesion gray matter, and blood pool, and extract reference voxels in which the contribution of the normal gray matter class is high. In the validation with idiopathic AD subjects, supervised clustering extracted reference voxels mostly in the cerebellum that indicated little specific [(11)C]PIB binding, and total distribution volumes of the extracted region were lower than those of the cerebellum. Next, the methodology was applied to the familial AD cohort where the cerebellar amyloid load had been demonstrated previously, resulting in higher binding potential compared with that obtained with the cerebellar reference. The supervised clustering method is a useful tool for the accurate quantification of [(11)C]PIB studies.
Biophysics Group, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Yoko
Y
Ikoma
Paul
P
Edison
Anil
A
Ramlackhansingh
David J
DJ
Brooks
Federico E
FE
Turkheimer
D000465:Algorithms; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D000814:Aniline Compounds; D052160:Benzothiazoles / Q000493:pharmacokinetics; D002250:Carbon Radioisotopes; D016022:Case-Control Studies; D002531:Cerebellum / Q000000981:diagnostic imaging*; D016000:Cluster Analysis; D006801:Humans; D058225:Plaque, Amyloid / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging*; D012016:Reference Values; D015203:Reproducibility of Results; D013844:Thiazoles; D014018:Tissue Distribution
C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D000814:Aniline Compounds; D052160:Benzothiazoles; D002250:Carbon Radioisotopes; D013844:Thiazoles