TY - JOUR T1 - <strong>Extrastriatal I123-FP-CIT uptake in brain: is it constant?</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1645 LP - 1645 VL - 59 IS - supplement 1 AU - Mehmet Gencturk AU - Jerry Froelich AU - Ali Salavati AU - Manojeet Bhattacharya Y1 - 2018/05/01 UR - http://jnm.snmjournals.org/content/59/supplement_1/1645.abstract N2 - 1645Objectives: Background and Propose: Dopamine transporter (DaT) imaging is an adjunct diagnostic tool in parkinsonian disorders. Interpretation of DaT scans is based on visual reads. SBRquant is an automated semi-quantitative method that measures the striatal binding ratio (SBR) in DaT scans using the formula [(caudate nucleus or putamen binding−background binding)/background binding]. Different regions of the brain are used as reference background in different studies to calculate SBR, with occipital lobe being the most common. In this study, we aimed to evaluate the variability of extrastriatal I123-FP-CIT uptake in different regions of the brain, using the SBR. Methods: The study included 32 patients who underwent DaT-SPECT/CT for the clinical suspicion of Parkinsonism between December 2016 and May 2017. The images were obtained using Siemens Symbia Intevo SPECT/CT system with Low Penetration High Resolution Collimators. Slab view images were interpreted visually as; dopaminergic deficit is present, not present or equivocal. Quantitative analysis was carried out using the the Siemens Syngo. SPECT Striatal Analysis’ (SSSA; version VB10) software. SBR’s were measured using three different regions of the brain as reference background; occipital lobe (SBRoccipital), frontal lobe (SBRfrontal) and cerebellar hemisphere (SBRcerebellum). SBR values in these three different brain regions were compared against each other in pairwise fashion using paired t-test based method comparison. Results: On visual analysis; dopaminergic deficit was present in 13/32 (41%), not present in 16/32 and equivocal in 3/32 (9%) patients. On Quantitative analysis, using 2.5 as the cut-off for SBRoccipital; dopaminergic deficit was present in 17/32 (53%) and not present in 15/32 (47) patients. Of the 3 patients equivocal on visual analysis 2 were positive for dopaminergic deficit quantitatively and 1 was negative. Regarding the remainder 29 patients there was disagreement in between quantitative and visual analysis in 4 patients. SBRcerebellum values were higher than SBRoccipital and frontal SBRfrontal. Group comparisons demonstrated statistically significant difference between SBRcerebellum with SBRoccipital (p&lt;0.0001) and SBRcerebellumwith SBRfrontal (p=0.0002). There was no statistically significant difference between SBRoccipital with SBRfrontal (p=0.2255). Conclusions: This study demonstrated that extrastriatal background I123-FP-CIT uptake is not constant in brain and cerebellar uptake is less than the cerebral cortical uptake. ER -