Direct correlation between cardiac and striatal F-18-DOPA uptake in de novo Parkinson's disease

Aim: Subtle cognitive impairment may be found in Parkinson\u2019s disease (PD) already at the time of diagnosis. The pathogenesis of this impairment is still matter of debate and could be heterogeneous, including changes in several neurotransmitter systems. The present study aims to unveil cognitive\u2010dopaminergic correlations in PD by assessing cognitive and dopaminergic functions at the time of diagnosis and cognitive function 1 and 3 years later, during chronic dopaminergic treatment. We report here the preliminary data concerning the correlation between dopaminergic and cognitive functions at baseline. Methods: Fifteen consecutive, drug\u2010na\uefve, de novo PD patients (mean age 69.0\ub15.0) underwent an extended neuropsychological test battery and brain 18F\u2010FluoroDOPA (Fluoro\u2010DOPA) PET/CT as a biomarker of dopaminergic activity. Sixteen neuropsychological variables were grouped into 5 factors by means of factor analysis, i.e., executive (NPS\u2010EX), visuo\u2010constructive (NPS\u2010VS), verbal memory (NPS\u2010VM), verbal fluency (NPS\u2010VF) and abstract reasoning (NPS\u2010AB) factors. PET images were flipped in order to have the less affected hemisphere (LAH), defined clinically, on the same side. A fully MRI\u2010based normalization was applied and images were smoothed (8 mm Gaussian filter). Normalized scans were then submitted to multiple regression analysis in SPM8 for voxel\u2010wise evaluation of the correlation between cognitive factors and dopaminergic activity (age and education as nuisance). p<0.005 at peak level and p<0.05 False Discovery Rate corrected at cluster level were accepted as significant. Results: NPS\u2010AB showed correlation with Fluoro\u2010DOPA uptake in the striatum, insula and inferior frontal gyrus (BA47) of the LAH while NPS\u2010EX correlated with Fluoro\u2010DOPA uptake in the striatum and insula of the more affected hemisphere (MAH). NPS\u2010VF and NPS\u2010VS correlated with Fluoro\u2010DOPA in bilateral striatum and BA47, in the insula of the LAH, and (NPS\u2010VS only) in the temporal lobe of the LAH. No correlation was found for NPS\u2010VM. Conclusion: The consistent correlation of almost all neuropsychological factors (but verbal memory) with striatal Fluoro\u2010DOPA uptake confirms that even at the earliest stages the cognitive function is correlated with the biological severity of the disease. Moreover, these results point to the insula and the inferior frontal gyrus (BA47) as key nodes in the dopaminergic extrastriatal pathways involved in cognitive function in early PD

18F-FDG PET/CT is a prognostic biomarker in patients affected by bone metastases from breast cancer in comparison with 18F-NaF PET/CT.

AIM: To compare 18F-FDG PET/CT and 18F-NaF PET/CT with respect to disease prognostication and outcome in patients affected by bone metastases from breast cancer (BC). PATIENTS, METHODS: We retrospectively investigated 32 women with BC and documented bone metastases. Semi-quantitative parameters were applied to 18F-FDG PET/CT and 18F-Na PET/CT in order to evaluate disease extent and tumour metabolism. We used time-to-event analyses (Kaplan Meier and COX proportional hazard methods) to estimate progression-free (PFS) and overall survival (OS) in order to assess the independent prognostic value of 18F-FDG PET/CT and 18F-Na PET/CT. RESULTS: The sensitivity of 18F-NaF PET/CT (100%) was higher (p &lt; 0.05) than that of 18F-FDG PET/CT (72% and 72%). None of the 18F-FDG PET/CT-negative patients showed disease progression at the end of follow-up. After adjustment for age, Ki-67 levels, presence of visceral metastases, hormone therapy, duration of bone disease and response to first-line therapy, only 18F-FDG SUV mean [HR 15.7, 95% confidence interval (CI) 1.15-214.5] and 18F-FDG whole-body bone metabolic burden (WB-B-MB) (HR 16.9; 95%CI 1.87-152.2) were independently and significantly associated with OS. None of the 18F-NaF PET/CT parameters were associated with OS. None of the conventional clinical prognostic parameters remained significantly associated with OS after the inclusion of PET/CT parameters in the model. CONCLUSION: 18F-FDG PET/CT is independently associated with OS in BC patients with bone metastases and its prognostic impact seems to be higher than conventional clinical and biological prognostic factors. Although 18F-NaF PET/CT has a higher diagnostic sensitivity than 18F-FDG PET/CT, it is not independently associated with OS