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Congenital hyperinsulinism of infancy (CHI) is character-

The aim of this study was to evaluate 2-(2-nitro-1 H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide (EF5) labeled with 18 F-fluorine to image hypoxia in patients with squamous cell carcinoma of the head and neck (HNSCC). Methods: Fifteen patients with HNSCC were studied. Measurement of tumor blood flow was followed by an 18 F-EF5 PET/CT scan. On a separate day, 18 F-FDG PET/CT was performed to determine the metabolically active tumor volume. In 6 patients, dynamic 18 F-EF5 images of the head and neck area were acquired, followed by static images acquired at 1, 2, and 3 h after injection. In the remaining 9 patients, only static images were obtained. 18 F-EF5 uptake in tumors was compared with that in neck muscle, and the 18 F-EF5 findings were correlated with the 18 F-FDG PET/CT studies. Results: A total of 13 primary tumors and 5 lymph node metastases were evaluated for their uptake of 18 F-EF5. The median tumor-to-muscle 18 F-EF5 uptake ratio (T/M) increased over time and was 1.38 (range, 1.1-3.2) 3 h after tracer injection. The median blood flow in tumors was 36.7 mL/100 g/min (range, 23.3-78.6 mL/100 g/min). Voxel-by-voxel analysis of coregistered blood flow and 18 F-EF5 images revealed a distinct pattern, resulting in a T/M of 1.5 at 3 h to be chosen as a cutoff for clinically significant hypoxia. Fourteen of 18 tumors (78%) had subvolumes within the metabolically active tumor volumes with T/M greater than or equal to 1.5. Conclusion: On the basis of these data, the potential of 18 F-EF5 to detect hypoxia in HNSCC is encouraging. Further development of 18 F-EF5 for eventual targeting of antihypoxia therapies is warranted.

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Previous imaging studies in Parkinson's disease have focused mainly on the striatum, a region with very high dopaminergic activity. Using modern high-sensitivity 3D [(18)F]fluorodopa (Fdopa)-PET, mesocortical monoamine projections can be studied. To study the frontal monoaminergic system in unmedicated early Parkinson's disease in vivo, we examined 20 early Parkinson's disease patients (10 women, 10 men) and 16 healthy subjects (nine women, seven men) with 3D Fdopa-PET, using standard region-of-interest-based analysis with MRI co-registration. Women with Parkinson's disease had 87% higher Fdopa uptake in the right dorsolateral prefrontal cortex (area 46) compared with men with Parkinson's disease, whereas there was no sex difference in the control group (sex x disease interaction, P = 0.03). The uptake in the right dorsolateral prefrontal cortex was 82% higher in men with Parkinson's disease and 219% higher in women with Parkinson's disease compared with control groups (effect of disease, P < 0.0001). Also in the left dorsolateral prefrontal cortex and in the medial frontal cortex, early Parkinson's disease patients had significantly (18-94%) higher Fdopa uptake compared with healthy controls. In the putamen, both men and women with Parkinson's disease had a significantly lower (27-46%) uptake compared with healthy controls. These results indicate that frontal monoaminergic activity is increased and that there is a sex difference in the prefrontal monoaminergic system in early Parkinson's disease. The reported sex difference may be linked to clinical sex differences in the symptoms and treatment response in Parkinson's disease.

Animal studies suggest that the dopaminergic system plays a role in central pain modulation. We have previously demonstrated with positron emission tomography (PET) that striatal dopaminergic hypofunction may be involved in the burning mouth syndrome. The aim of the present study was to evaluate the nigrostriatal dopaminergic system in patients with atypical facial pain using PET. In seven patients with atypical facial pain, striatal presynaptic dopaminergic function was assessed with [18F]FDOPA and dopamine D1 and D2 receptor availabilities with [11C]NNC 756 and [11C]raclopride, respectively. The results were compared with those of healthy controls. A quantitative region-of-interest analysis showed that the uptakes of [18F]FDOPA and [11C]NNC 756 did not differ between patients and controls. There was a tendency of increased D2 receptor availability in the left putamen (P=0.056), and the D1/D2 ratio in the putamen was decreased bilaterally by 7.7% (P=0.002) in patients when compared to controls. In a voxel-based analysis, the uptake of [11C]raclopride was increased in the left putamen (P=0.025). In conclusion, the increase in D2 receptor availability in the left putamen and the decrease in D1/D2 ratio imply that alterations in the striatal dopaminergic system as evaluated by PET may be involved in chronic orofacial pain conditions.

Both 1H MRS-derived temperature and FF are promising methods to study BAT activity noninvasively. The association between the lipid-burning capacity of BAT and whole-body insulin sensitivity emphasizes the role of BAT in glucose handling. Furthermore, the relation of FF to high-density lipoprotein and low-density lipoprotein cholesterol suggests that BAT has a role in lipid clearance, thus protecting tissues from excess lipid load.