Comparison of imaging using11C-ITMM and18F-FDG for the detection of cerebellar ataxia.
Objective Newly developed methods for imaging type 1 metabotropic glutamate receptor (mGluR1) have the potential use for estimating cerebellar function. We aimed to compare mGluR1 imaging using N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-11C-methoxy-N-methylbenzamide (11C-ITMM) with the existing marker, fluorine-18-labeled fluorodeoxyglucose (18F-FDG) imaging, in the cerebellum.


METHODS
Fourteen subjects consisting of 12 patients with cerebellar ataxia and two healthy subjects underwent11C-ITMM and18F-FDG positron emission tomography. The degree of ataxia was scored with the Scale for the Assessment and Rating of Ataxia (SARA). Volumes-of-interest were placed on the anterior and posterior lobes and vermis. The binding potential (BPND) was calculated to estimate mGluR1 availability using the white matter as a reference region.18F-FDG uptake was normalized using the white matter (FUwm).


RESULTS
There were significant positive correlations between the BPNDand FUwmvalues in the anterior lobe (r=0.83, P<0.001), posterior lobe (r=0.69, P=0.009), and vermis (r=0.58, P=0.042). Regarding the relationship of SARA scores with the BPNDand FUwmvalues, a significant negative correlation was found only in the anterior lobe between the SARA scores and BPNDvalues (r=-0.64, P=0.029).


CONCLUSIONS
This study showed that mGluR1 imaging was comparable to18F-FDG imaging in the cerebellum. However, mGluR1 imaging was more strongly associated with the SARA scores than18F-FDG imaging was, suggesting that mGluR1 imaging can be a more specific technique than18F-FDG imaging for evaluating cerebellar ataxia.
Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan; Department of Neurology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komago2me Hospital, Tokyo, Japan. Electronic address: ishibashi@pet.tmig.or.jp.
Kenji
K
Ishibashi
Department of Neurology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komago2me Hospital, Tokyo, Japan. Electronic address: ymiura@cick.jp.
Yoshiharu
Y
Miura
Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan. Electronic address: toyohara@pet.tmig.or.jp.
Jun
J
Toyohara
Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan. Electronic address: ishii@pet.tmig.or.jp.
Kenji
K
Ishii
Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan; Institute of Cyclotron and Drug Discovery Research, Southern Tohoku Research Institute for Neuroscience, Koriyama, Japan; Department of Biofunctional Imaging, Fukushima Medical University, Fukushima, Japan. Electronic address: ishiwata@pet.tmig.or.jp.
Kiichi
K
Ishiwata
D000368:Aged; D000369:Aged, 80 and over; D001549:Benzamides / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D002524:Cerebellar Ataxia / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000378:metabolism; D012720:Severity of Illness Index
D001549:Benzamides; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C038530:N-methylbenzamide
(11)C-ITMM; (18)F-FDG; Cerebellar ataxia; PET; Type 1 metabotropic glutamate receptor