While Internet brings convenience to teenagers,there are some negative and bad things too.In the network,various sorts of information is mixed,the good and bad are intermingled,and much harmful information has become the pollution source to students' inner world,which will have great impact on the moral socialization and virtue.

Objective To evaluate the influence of the resolution of medical grayscale LCD over the detective efficiency of pulmonary nodule.Methods By reviewing PACS, 93 on-line chest DR images were collected.These radiographs included 23 normal images that had no nodule confirmed by CT, 32 doubtful images that also had no nodule confirmed by CT,and 38 positive images that had nodules confirmed by CT.These nodules didn't show obvious calcification and their diameters were from 0.30 to 1.90 cm. Nine patients had multi-nodules.Three residents or postgraduates, three attending physicians, and three associate professors or professors interpreted the 93 chest images by using three types of displays: Barco Z-2261, Barco Z-3620 and Barco Z-5620.All observers evaluated their confidence of the presence of pulmonary nodule with five-point level rating scale : ( 1 ) definitely positive, ( 2 ) probably positive, ( 3 ) uncertain, (4) probably negative, (5)definitely negative.SPSS 11.5 software was used to analyze the results ,including to draw the ROC curves and to perform Z test.Results The areas under the ROC curves of 2 M display, 3 M display and 5 M display were 0.774,0.784,0.816 for experienced radiologists; for instructors were 0.754,0.764,0.768 ;for teaching assistants were 0.695,0.754,0.774.However, for the detection of pulmonary nodules,there was no significant difference between observers with different ranks using the same modality of display,and no significant difference was found between the different modalities of displays used by observers with the same rank.Conclusion It's equivalent for detection performance with 2,3 and 5 M medical grayscale LCD display in detecting pulmonary nodule; Experienced radiologists can get more information using 5 M display;By reasonably matching displays, we could improve the cost-efficacy.

Post-traumatic stress disorder (PTSD) is a mental disorder causing great distress to individuals, families and even society, and there is not yet effective way of unified prevention and treatment up till now. Lots of neuroimaging techniques, however, such as the magnetic resonance imaging, are widely used to the study of the pathogenesis of PTSD with the development of medical imaging. Functional magnetic resonance imaging (fMRI) can be applied to detect the abnormalities not only of the brain morphology but also of the function of various cerebral areas and neural circuit, and plays an important role in studying the pathogenesis of psychiatric diseases. In this paper, we mainly review the task-related and resting-state functional magnetic resonance imaging studies of the PTSD, and finally suggest possible directions for future research.
Brain ; physiopathology ; Humans ; Magnetic Resonance Imaging ; Neuroimaging ; Stress Disorders, Post-Traumatic ; physiopathology

Objective To observe changes of the structure and function of microvessels during the formation and development of the rat cerebral glioma with steady-state susceptibility contrast-enhanced MR imaging. Methods A total of 30 bearing-tumor rats were divided into 3 groups (1-week group, 2-week group and 3-week group) and underwent MR examination. Blood volime (BV) and vessel size index (VSI_(MRI)) of peripheral tumor areas, central tumor areas and normal cerebral tissue in the opposite side were measured, and compared with histologic findings. Results With time of bearing-tumor increasing, BV of central tumor area present an up-and-down curve-like change, which related to the host blood vessel regression in tumor central area, the decreasing of blood vessel density and histopathologically obvious necrosis. BV of peripheral tumor areas increased because of active blood angiogenesis in this area, while VSI_(MRI) increased gradually, especially in the central tumor area. There was obviously correlation between the VSI_(MRI) and VSI _(histo) (P<0.01). Conclusion BV and VSI_(MRI) can exactly reflect the morphology and functional information of microcirculation of tumor during the growth and development of gliomas.

Objective To explore the of value steady-state susceptibility contrast-enhanced MRI (SSCE-MRI) in assessment of anti-angiogenesis therapy in rat C6 glioma. Methods Seventeen rats with the bearing-tumor were randomly divided into the therapy group (n=8) and the contrast group (n=9). Human-recombination endostatin (10 mg/kg) was injected to animals in therapy group, and saline of the same dose was injected to the contrast group for 7 days. Blood volume (BV) and vessel size index (VSI) were measured of tumors in peripheral, central and normal areas with MR pre- and post-therapy. Results After therapy of endostatin, the tumor volume was obviously different between therapy group and contrast group (t=5.26, P<0.05). BV and VSI_(MRI) of tumor decreased in both peripheral and central areas, particularly in the peripheral area (t=4.14, 3.66, all P<0.01). Conclusion Assessment of therapeutic effect of anti-angiogenesis in C6 glioma is feasible with SSCE-MRI, and it can reflect the changes of BV and VSI_(MRI) pre- and post-therapy.

Objective To assess the influence of medical monochrome liquid crystal displays (LCD) with different resolutions for the detection performance of micro-nodules (diameter <10 mm) on chest radiograms. Methods Eighty-seven DR chest images that were verified with CT were selected from PACS on-line, including 32 positive images, 32 suspected images and 23 normal images. The diameters of all nodules were lower than 10 mm. Three of high-, mid- and low-experienced radiologists who participated in the ROC study interpreted these 87 images using three types of LCDs with different resolutions, respectively. Regarding the presence of nodule, five-point confidence level rating scale was used, i.e. definitely absent, probably absent, possibly present, probably present and definitely present. All observers marked their confidence levels of every image according to the presence of pulmonary nodule on different displays. Software SPSS 13.0 was used for statistical analysis. Results AUC increased with the increasing resolutions and radiologists' experiences in 2MP, 3MP, 5MP displays. For the detection performance of pulmonary nodules (diameter <10 mm), there was no significant difference among different types of displays or different aptitudes of radiologists. Conclusion It's equivalent for the detection performance of pulmonary nodule (diameter <10 mm) on 2MP, 3MP and 5MP medical monochrome LCD when no restriction on the use of image post-processing tools. Highly-experienced radiologist can get the most information when using 5MP display. It is advisable to combine the diagnostic workstation system with high-, mid- and low-resolution monitors, and reasonable equipment scheme between different types of displays and different aptitudes of radiologists could result in better cost-efficacy.

Objective To investigate changes of striatal DAT following hypoxic ischemic (HI)brain injury in newborn piglets using 11C-N-2-carbomethoxy-3-(4-fluorophenyl)-tropane (CFT) PET/CT,and to evaluate the value of 11C-CFT PET/CT in brain injury.Methods Newborn piglets with HI brain injury (n =20) were taken as a model group,and five piglets were used as a control group.Radioligand 11CCFT (55.5-74.0 MBq) was injected through the jugular vein,and PET/CT imaging was performed to observe the changes of striatal DAT in newborn piglets.The ST/occipital lobe (OC) ratio was calculated.Model group was divided into 0-6 h,20-24 h,44-48 h and 68-72 h sub-groups after HI in accordance with the imaging time.The piglets were sacrificed immediately after 11C-CFT PET/CT scanning,and then the brains were removed for pathological analysis.Data analysis was performed with one-way analysis of variance and Pearson linear correlation analysis.Results After intravenous injection of 11C-CFT,the radioactivity accumulation in cortical,striatum,and cerebellum was shown clearly in the control and model groups.The radioactivity accumulation was lower in the white matter.The radioactivity in cortical and cerebellum exhibited decreased with time,while the striatum was still clear.After HI,the ST/OC activity ratio in the striatum was initially increased,and the ratio of 0-6 h group (1.34 ± 0.04) was statistically significant compared with that of thecontrol group (1.18 ± 0.06 ; F =4.658,P ＜ 0.05),followed by a gradual decrease.ST/OC ratios of other HI subgroups were 1.27 ±0.01,1.27 ±0.10 and 1.18 ±0.05,respectively.There was a positive correlation between the number of DAT positive neurons ((13 ± 3),(13 ± 4),(8 ±3) and (4 ±4)/high power field) and 11C-CFT ST/OC activity ratios (r =0.844,P ＜0.05).Conclusion 11C-CFT PET/CT study can accurately reflect the changes of DAT in the striatum,and the amount of DAT is related to the severity of the ischemic insult in a newborn piglet model of HI.

Objective To estimate reliability of magnetic resonance elastography (MRE) in measuring liver stiffness of volunteers and patients with chronic liver disease and to assess inter-rater consistency.Methods MRE was performed on a 3.0 T scanner in all subjects,including 24 volunteers (control group) and 64 patients with liver disease (chronic liver disease group).Liver stiffness was measured blindly by two raters.The pathological fibrosis score was applied as a standard reference for liver fibrosis in 22 patients.The intraclass correlation coefficient (ICC) was used to evaluate inter-rater reliability.The differences of liver stiffness between two groups were evaluated using non-parametric MannWhitney U test.Spearman analysis was used to analyze the correlation between fibrosis stages and liver stiffness.Results The intraclass correlation coefficient of liver stiffness was perfect (ICC =0.99,P ＜ 0.01)between two raters.There was significant difference of mean stiffness between control group and patient group (U =90.5,P ＜0.01) with(2.35 ±0.34) kPa and(4.17 ± 0.47) kPa,respectively.The correlation between fibrosis stage (3,3,5,5 and 6 patients in fibrosis stage S0,S1,S2,S3 and S4) and stiffness (2.13,3.25,3.82,5.45 and 7.35 kPa) was very strong (r =0.96,P ＜0.01).Conclusion MRE is a reliable and promising tool to measure liver stiffness and to assess liver fibrosis.

Objective To build the linear models for exploring relations between behavior data and functional magnetic resonance image(fMRI) signals of brain during cognitive task and to validate whether it is reasonable.Methods The linear models of behavior data and fMRI signals were built,and the functional regions of brain were detected by tests of corresponding parameters.Experimental data of Stroop tasks were used to study the effects of the models by comparing with the results of SPM.Results The results of Stroop data showed that dorsal lateral prefrontal cortex(Brodmann 9/46),and superior frontal median cortex(Brodmann 8/9) were associated with response time of Stroop tasks,and accorded with SPM results and other reports.Conclusion The models can quantitatively analyze the relations of response time and fMRI signals,providing a new way to explore functional images of cognition.

2 cm).Immunohistochemistrical stain slice of operative specimen showed a lots of vascular endothelial cells and small vessels,which correlated with the tumor angioimaging area on CT images.The sensitivity,specificity,and positive predictive valve of tumor angioimaging in the lung cancers were 47.2%,91.3%,and 95.5%,respectively.Conclusion The “tumor angioimaging” sign can be regarded as another specific feature in peripheral lung cancer with contrast CT.