title: Imaging essential tremor.
abstract: To investigate over time changes in striatal dopamine transporter (DAT), we performed two sequential N-omega-fluoropropyl-2beta-carbomethoxy-3beta-(4-iodophenyl) tropane single photon computed tomography (SPECT) scans in 20 subjects with essential tremor (ET), in 13 with Parkinson disease (PD) and in 23 healthy controls (HC, one scan only). We also performed an [(99m)Tc]ethyl cysteinate dimer bicisate SPECT exam for regional brain network analysis in 9 ET, in a second group of 18 PD (9 with tremor, tPD and 9 akinetic-rigid dominant, arPD) and in 8 HC. PD subjects had a reduced DAT binding in comparison to ET and HC with an annual decline rate of 7.3% in the contralateral putamen. There were no mean uptake differences between ET and HC at baseline and no uptake loss over time in ET. A discriminant analysis grouped 30% (first scan) and 5% (second scan) of ET as PD and a partition analysis showed overlap between ET and PD for caudate nucleus uptake. Spatial covariance analysis revealed that the expression of the PD-related regional pattern separated both tPD and arPD from ET and HC. In conclusion, PD and ET do not share a common pattern of dopaminergic loss over time. However, mild impairment of dopamine transporter in the caudate nucleus may contribute to tremor onset in ET.
authors.affiliation: Department of Human Physiology, University of Milano, Milano, Italy. iuisaias@yahoo.it
authors.forename: Ioannis U
authors.initials: IU
authors.lastname: Isaias
authors.forename: Giorgio
authors.initials: G
authors.lastname: Marotta
authors.forename: Shigeki
authors.initials: S
authors.lastname: Hirano
authors.forename: Margherita
authors.initials: M
authors.lastname: Canesi
authors.forename: Riccardo
authors.initials: R
authors.lastname: Benti
authors.forename: Andrea
authors.initials: A
authors.lastname: Righini
authors.forename: Chengke
authors.initials: C
authors.lastname: Tang
authors.forename: Roberto
authors.initials: R
authors.lastname: Cilia
authors.forename: Gianni
authors.initials: G
authors.lastname: Pezzoli
authors.forename: David
authors.initials: D
authors.lastname: Eidelberg
authors.forename: Angelo
authors.initials: A
authors.lastname: Antonini
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D016002:Discriminant Analysis; D020329:Essential Tremor / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D007456:Iodine Isotopes; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000473:pathology; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014326:Tropanes
chemical_list: D007456:Iodine Isotopes; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane