Evaluation of clinicopathologic findings affecting 18F-FDOPA uptake of intracranial glioma

Purpose: While 18F-FDOPA PET is clinically useful in the evaluation of brain tumors, tumor uptake of 18F-FDOPA are known to vary. We investigated clinical, genetic, pathologic findings and MR findings that could affect 18F-FDOPA uptake of intracranial gliomas to improve the interpretation of 18F-FDOPA PET and the determination of therapeutic plans based on it. Methods: We retrospectively reviewed 21 consecutive patients (M/F=13/8; median age 50 years; age range 21-72 years) with pathologically confirmed intracranial glioma and 9 patients (M/F=4/5; median age 49 years, age range 31-62 years) with non-tumorous lesions, who underwent both 18F-FDOPA brain PET/CT and brain MR imaging for preoperative evaluation from July 2015 to June 2018. 18F-FDOPA PET images were acquired during 30min immediately after injection. We calculated SUV ratio (SUVR) of lesion to reference (contralateral striatum or contralateral normal white matter) on 10-30 min summed image and the washout ratio of SUVR. In glioma patients, we evaluated the association between FDOPA uptake and clinicopathologic findings including the histology, tumor grade, IDH mutations and conventional MR findings (tumor size, location, laterality, gadolinium enhancement, proportion of non-contrast enhancing tumor, proportion of necrosis, and proportion of edema), and perfusion MR parameters (leakage-correlated rCBV/rCBF, vascular permeability). Results: 18F-FDOPA uptake of gliomas in terms of SUVRstriatum and SUVRwhite matte was significantly higher than no-tumorous lesions (p<0.001). SUVRstriatum was associated with tumor grade, IDH mutation, histology, proportion of necrosis on MRI (p<0.05). Only proportion of non-enhancement on MRI is associated with SUVRwhite matter (p=0.005). There were no clinicopathologic findings associated with the washout of 18F-FDOPA uptake in gliomas (p>0.05). There was no significant correlation between SUVR and perfusion MR parameters in gliomas (p>0.05), although there was a positive correlation between the degree of gadolinium enhancement on MRI and SUVRStriatum (Spearman’s rho=0.881, p=0.002) or SUVRWhite matter (Spearman’s rho=0.991, p=0.001) in non-tumorous lesions. Conclusion: 18F-FDOPA uptake of glioma was tumor specific with minimal effect of BBB breakage and associated with IDH mutation and histology. Further studies with a larger number of cases and molecular features such as LAT1 is needed to better understand the related mechanism of these clinicopathologic features and 18F-FDOPA uptake in glioma.Maste

Statin/ezetimibe combination therapy vs statin monotherapy for carotid atherosclerotic plaque inflammation

It remains uncertain whether statin/ezetimibe combination therapy serves as a useful and equivalent alternative to statin monotherapy for reducing atherosclerotic plaque inflammation. The aim of the present study was to compare the effects of statin/ezetimibe combination therapy and statin monotherapy on carotid atherosclerotic plaque inflammation using F-18-fluorodeoxyglucose ((18)FDG) positron emission tomography (PET)/computed tomography (CT) imaging. Data were pooled from 2 clinical trials that used serial (18)FDG PET/CT examination to investigate the effects of cholesterol-lowering therapy on carotid atherosclerotic plaque inflammation. The primary outcome was the percent change in the target-to-background ratio (TBR) of the index vessel in the most diseased segment (MDS) at 6-month follow-up. Baseline characteristics were largely similar between the 2 groups. At the 6-month follow-up, the MDS TBR of the index vessel significantly decreased in both groups. The percent change in the MDS TBR of the index vessel (primary outcome) did not differ significantly between the 2 groups (-8.41 +/- 15.9% vs -8.08 +/- 17.0%, respectively, P = .936). Likewise, the percent change in the whole vessel TBR of the index vessel did not differ significantly between the 2 groups. There were significant decreases in total and LDL cholesterol levels in both groups at follow-up (P < .001). There were no significant correlations between the percent changes in MDS TBR of the index vessel, changes in the lipid, and high-sensitive C-reactive protein levels. The reduction in carotid atherosclerotic plaque inflammation by statin/ezetimibe combination therapy was equivalent to that by the statin monotherapy