RESUMEN
Purpose: The aim of this study was to assess the value of the FDOPA PET kinetic parameters extracted using full kinetic analysis for tumor grading with neuronavigation-guided biopsies as reference in patients with newly-diagnosed gliomas. Methods: Fourteen patients with untreated gliomas were investigated. Twenty minutes of dynamic positron-emission tomography (PET) imaging and a 20-min static image 10 min after injection were reconstructed from a 40-min list-mode acquisition immediately after FDOPA injection. Tumors volume-of-interest (VOI) were generated based on the MRI-guided brain biopsies. Static parameters (TBRmax and TBRmean) and kinetic parameters [K1 and k2 using full kinetic analysis with the reversible single-tissue compartment model with blood volume parameter and the time-to-peak (TTP)] were extracted. Performances of each parameter for differentiating low-grade gliomas (LGG) from high-grade gliomas (HGG) were evaluated by receiver-operating characteristic analyses (area under the curve; AUC). Results: Thirty-two tumoral VOI were analyzed. K1, k2, and TTP were significantly higher for HGG than for LGG (median K1-value = 0.124 vs. 0.074 ml/ccm/min, p = 0.025, median k2-value = 0.093 vs. 0.063 min-1, p = 0.025, and median TTP-value = 10.0 vs. 15.0 min, p = 0.025). No significant difference was observed for the static parameters. The AUC for the kinetic parameters was higher than the AUC for the static parameters (respectively, AUCK1 = 0.787, AUCk2 = 0.785, AUCTTP = 0.775, AUCTBRmax = 0.551, AUCTBRmean = 0.575), significantly compared to TBRmax (respectively, p = 0.001 for K1, p = 0.031 for k2, and p = 0.029 for TTP). Conclusion: The present study suggests an additive value of FDOPA PET/CT kinetic parameters for newly-diagnosed gliomas grading.
RESUMEN
The possible hemispheric specialization of the basal ganglia during emotional prosody (i.e., vocal emotion) processing has still to be elucidated. Coupled with affective measures and neuroimaging, Parkinson's disease offers a unique opportunity to study this question, on account of its characteristically asymmetric striatal dysfunction, which translates into predominantly contralateral motor symptoms. We investigated the cerebral metabolic bases of emotional prosody recognition in patients with Parkinson's disease with left- versus right-lateralized motor symptoms, postulating that patients with greater right hemispheric brain dysfunction have a specific impairment that correlates with the metabolic modification of a brain network known to be involved in emotional prosody. A total of 38 patients performed a validated emotional prosody recognition task and underwent a resting-state F-18 fluorodeoxyglucose PET scan, as well as clinical, motor, neuropsychological, and psychiatric assessments. Patients' performances were compared with those of 45 healthy controls. As expected, vocal emotion recognition was significantly poorer among patients with left-sided motor symptoms than among both right-sided patients and controls. There was no significant difference between right-sided patients and controls. This effect was observed for both the total score and the happiness subscore. Interestingly, regressions showed that the greater the emotional misattribution, the greater the patients' age and asymmetric motor symptom severity. Finally, at the metabolic level, positive correlations were found between the happiness recognition subscore and the metabolism of the right orbitofrontal cortex in patients with left-sided motor symptoms. A right orbitofrontal-basal ganglia coupling seems to be specifically involved in the vocal emotion recognition deficit observed in Parkinson's disease. The asymmetry of motor symptoms is thus an important clinical factor, in that it may influence the presence or severity of affective disorders in Parkinson's disease.
