Since there is a need for a widely applicable non-invasive test to assess gastric emptying in diabetic patients, we evaluated the sensitivity, specificity, and reproducibility of the [13C]octanoic acid breath test as compared with scintigraphy. Moreover, we examined the relationship between the breath test indices and gastric symptoms, cardiovascular autonomic function, and metabolic parameters. Forty healthy control subjects and 34 diabetic patients were studied. Three indices of gastric emptying, assessed by the breath test, were computed: half-emptying time (t1/2breath), gastric emptying coefficient (GEC), and lag phase. Furthermore, the half-emptying time, measured by scintigraphy (t1/2scint), was calculated and gastric symptoms and cardiovascular autonomic neuropathy (CAN) were scored. The coefficients of variation of day-to-day reproducibility in 10 healthy subjects were 29.6% for t1/2breath, 7.4% for GEC, and 46.5% for lag phase. An abnormal delay for t1/2scint (> 100 min) or t1/2breath (> 200 min) was noted in 12 patients. Based on the results for t1/2scint, the sensitivity of t1/2breath and GEC was 75% and the specificity was 86%. Both t1/2breath (rs = 0.523; p < 0.05) and GEC (r2 = -0.594; p < 0.05) were significantly associated with the gastric symptom score. A significant relationship to the CAN score was demonstrated for t1/2breath (rs = 0.448; p < 0.05), GEC (rs = -0.467; p < 0.05), and t1/2scint (rs = 0.602; p < 0.05). There were no significant associations of the breath test indices with the blood glucose levels during the test, HbA1c, age, and duration of diabetes. In patients with abnormal t1/2scint (n = 12) not only was t1/2breath significantly prolonged and GEC reduced, but also the scores of CAN and gastric symptoms were significantly increased as compared with those who had a normal t1/2scint (n = 22). We conclude that the [13C]octanoic acid breath test represents a suitable measure of delayed gastric emptying in diabetic patients which is associated with the severity of gastric symptoms and CAN but not affected by the blood glucose level.

No abstract

No abstract

No abstract

No abstract

The aim of this retrospective study was to investigate the value of positron emission tomography (PET) with 2-18fluor-2-deoxy-glucose (FDG) in the follow-up of Hürthle cell thyroid cancer (HTC), a rare variant of thyroid malignancies. FDG-PET studies were performed in 17 patients with HTC. In subgroup A (n = 13) PET was initiated because of an elevated thyroglobulin (Tg) level whereas in subgroup B (n = 4) the study was performed to evaluate suspect findings of morphologic imaging while Tg remained undetectable. Pathologically increased FDG uptake was found in all patients of subgroup A. In 10 studies, PET results were proven as true-positive either by surgery or by morphologic imaging. One study was false-positive. Final evaluation was not possible in two cases. In subgroup B, PET was true-negative in three and false-positive in one patient. For the detection of recurrent HTC by means of FDG-PET a meta-analysis including data of a multicenter study revealed an overall sensitivity of 92%, a specificity of 80%, a positive predictive value of 92%, and a negative predictive value of 80% while the accuracy was 89%. This study supports the efficiency of FDG-PET in the follow-up of HTC.

Unilateral destruction of the substantia nigra by local application of 6-hydroxydopamine (6-OHDA) serves as an animal model for Parkinson's disease. In this study, the changes in neostriatal dopamine D(2) receptor density were investigated with a small animal positron emission tomograph (PET) before and after 6-OHDA lesion. PET scans were performed in 14 rats after injection of the D(2) receptor radioligand [(18)F] N-methylbenperidol. After the first scan (day 0), nigrostriatal pathways were lesioned by unilateral injections of 6-OHDA. Further PET scans were performed on days 2 and 14 post-lesion. For both striata, B(max) values were determined from saturation binding curves with non-linear regression analysis. In the striatum ipsilateral to the lesion, B(max) initially amounted to 19.3+/-1. 9 fmol/mg (mean+/-SD) and increased to 19.7+/-2.2 and 29.9+/-5.7 fmol/mg on days 2 and 14 post-lesion, respectively. Contralateral B(max) values increased from 19.2+/-2 fmol/mg prior to the lesion to 21.2+/-2.9 and 28.6+/-5.7 fmol/mg on days 2 and 14, respectively. On day 14, the ipsilateral saturation binding curve differed from the ipsilateral pre-lesion curve (P=0.04; F test). When the contralateral pre-lesion saturation binding curve was compared with the contralateral post-lesion curve on day 14, a P value of 0.08 was obtained. This first serial in vivo imaging study of 6-OHDA-lesioned rats showed a time-dependent increase in striatal D(2) receptor density on both sides, the increase being more pronounced ipsilateral to the lesion. This result implies that compensatory mechanisms in the intact hemisphere contribute to regenerative processes following nigrostriatal dopaminergic denervation. Overall, our findings show the feasibility of repetitive in vivo studies of striatal receptor density with a small animal tomograph. Moreover, the applied in vivo saturation binding technique provides a versatile method for the quantification of time-dependent changes in the concentration of receptor binding sites.

Antimyosin scintigraphy often shows myocyte injury in patients with clinically suspected myocarditis. Histologic analysis of the endomyocardial biopsy alone is often negative, but additional immunohistologic analysis of the endomyocardial biopsy frequently provides evidence of myocardial inflammation in these patients. With immunohistologic analysis as the reference method, antimyosin scintigraphy has a high specificity but a lower sensitivity for the detection of myocarditis.