Three-dimensional positron emission tomography/computed tomography analysis of 13NO3- uptake and 13N distribution in growing kohlrabi.

We report the application of three-dimensional positron emission tomography/computed tomography (PET/CT) for the analysis of (13)NO(3)(-) uptake and (13)N distribution in growing kohlrabi. The analytical procedures, equipment parameters, and image reconstruction mode for plant imaging were tested and selected. (13)N in growing kohlrabi plants was imaged versus time using both PET movies and PET/CT tomograms. The (13)NO(3)(-) transport velocity in kohlrabi from root to petiole was estimated to be 1.0 cm/min. The appearance of shell-shaped (13)NO(3)(-) transport pathways, corresponding to the kohlrabi corm, suggests the existence of special routes with higher efficiency for (13)NO(3)(-) transport, which tends to have the shortest distances to the leaves or buds. Standardized uptake values (SUVs), used as the representative figures for describing (13)N distribution, were quantified versus time at some putative sites of interest. For multiple analysis of the same-plant, (13)N distribution in kohlrabi under normal conditions, methionine sulfoximine (MSX) stress, and recovery from MSX stress was examined. The (13)N distribution variation studies were also done under the above three growth conditions. Our results suggest a significant downregulation of nitrate uptake in kohlrabi in the presence of MSX.

[The value of (18)F-FDG PET/CT in differential diagnosis of benign and malignant pulmonary lesions: a Meta-analysis.].

OBJECTIVE: Using Meta analysis to evaluate the value of (18)F-FDG PET/CT ((18)fluorine-fluorodeoxyglucose Positron emission tomography/computed tomography) in differentiating between benign and malignant pulmonary lesions. METHODS: Relevant documentations from PubMed and other 5 databases from 1980 to 2008 were searched, and the eligible literatures according to the inclusive criteria were selected. The statistical information and quality of science were assessed and classified. The data were analyzed using Meta-Disc1.4 software. The diagnostic value of PET/CT in distinguishing benign from malignant pulmonary lesions was evaluated by the pooled sensitivity, specificity, the likelihood ratio (LR) and summary receiver operating characteristic curve (SROC curve) statistical indicators. RESULTS: Seven literatures were collected including 5 in English and 2 in Chinese, and 795 cases were included in the study. Heterogeneity test showed that the homogeneity of the study was good. By using deterministic models to analyze the data, the value of the weighted sensitivity was 95% (93% - 97%), the specificity was 77% (71% - 82%), the positive likelihood ratio was 4.12, negative likelihood ratio was 0.08, and the SROC area under the curve (area under curve, AUC) was 94%. CONCLUSION: PET/CT is of high diagnostic value in differentiation between benign and malignant lung lesions, but large sized, multicenter, prospective studies are needed to assess its clinical value more accurately.