Objective To examine the interrelation between the cognitive deviation and loneli-ness levels of medical students and its influencing factors. Methods Totally 220 medical students in grade two of one medical school were selected by method of cluster random sampling. The data of the research were obtained through cognitive bias questionnaire (CBQ) and emotional-social loneliness questionnaire. Interrelation between the cognitive deviation type and condition of emotional-social lone-liness of medical students were analyzed by Pearson product-moment correlation two-tailed test. Multi-ple stepwise regression analysis was conducted by taking score of emotional-social loneliness as de-pendent variable and score of CBQ as independent variable. Differences in cognitive deviation and loneliness levels between rural and urban students as well as between students from single child family and students from non single child family were analyzed by independent-sample t test. Results Neg-ative cognitive deviation of depression-distortion type was positively correlated with medical students' emotional isolation (r=0.161, P=0.021),social isolation (r=0.266,P=0.000), emotional loneliness (r=0.340, P=0.000) and social loneliness (r=0.385, P=0.000). The regression equation was: score of emotional-social loneliness=27.165+1.908 (depression-distortion)+0.836 (depression-non distortion).Students from non single child family had higher scores than students from single child family in the perspectives of depression-distortion”(P=0.017), social isolation(P=0.001), emotional loneliness(P=0.016), social loneliness(P=0.000). Rural students had higher scores in the above four perspectives than urban students(P<0.05). Conclusions Negative cognitive deviation levels of medical students is positively correlated with emotion and social isolation conditions and loneliness experiences. Regres-sion analysis shows that unhealthy cognitive disposition and thinking mode probably are one of the im-portant reasons leading to medical students' stress disorder. Students from single child family and rural area may experience social loneliness more deeply and students from single child family have obvious cognitive deviation.

Objective To discusse the feasibility and application value of the computer-assisted liver cancer ablation planning based on the three dimensional ultrasound.Methods Forty three-dimensional ultrasound images of 39 patients with 40 tumors'maximum diameter between 21 to 70 mm were collected and then acquired image segmentation and visualzation.The computer-assisted liver cancer ablation planning based on three dimensional ultrasound was comparied with the artificial ablation planning based on two dimensional ultrasound to find out the differences in the success rate,damage rate,time-consuming and the number of insertions between these two methods.Results Compared with the artificial ablation planning based on two dimensional ultrasound,the computer-assisted liver cancer ablation planning had a higher success rate(92.31% vs 53.85%,P =0.000),lower damage rate(7.50% vs 25.00%,P =0.034),shorter time-consuming(44.0 s vs 263.0 s,P =0.000)and less insersion times(3 vs 4,P =0.009).Conclusions The computer-assisted liver cancer ablation planning based on three dimensional ultrasound is more efficient and safety than the traditional way.

Objective To compare the accuracy,convenience and repeatability of 3DUS-US and CT-US image fusion technology based on electromagnetic positioning.Methods A tissue-mimicking phantom was established and used to obtain ultrasound or CT volume images.Two different operators performed 3DUS-US and CT-US image fusion and repeated 10 times,respectively.The success rate,the registration error distance and fusion time of two techniques were recorded and compared between the different operators.Results The ultrasound and CT images of the phantom and its stability could meet the demands of this experiment.3DUS-US and CT-US image fusions were successful.The registration error distance of 3DUS-US image fusion was (1 .70 ± 0.42)mm and fusion time was (76.00 ± 9.99)s,they were obviously superior to CT-US (P = 0.014,P < 0.001 ).There were no significant differences between the two operators in the registration error distance and fusion time of 3DUS-US (P =0.508,P =0.5 1 7).But the registration error distance of CT-US image fusion in experienced operator was lower than the junior (P =0.009),and fusion time had not statistical difference between the two operators (P =0.234).Conclusions The technique of 3DUS-US automatic image fusion based on electromagnetic positioning has advantages of convenience and no experiential dependence comparing with CT-US in the phantom experiments,so it is worthy of being widely popularized in clinical application.

Objective To explore the value of contrast-enhanced ultrasound (CEUS) in improving the diagnosis ability for xanthogranulomatous cholecystitis ( XGC ) and wall-thickening gallbladder cancer ( GBC) . Methods Forth-three patients with XGCs and 31 patients with wall-thickening GBCs proved by pathology were enrolled in this study ,the features on conventional ultrasound and CEUS were recorded ,and the preliminary diagnosis before and after CEUS were given by doctors . Results Significant differences were found in continuous gallbladder inner wall and arterial blood supplement on conventional ultrasound , 58 .1％ (25/43) had continuous inner wall and 34 .9％ (15/43) had arterial blood flow in XGCs compared to 19 .4％ (6/31) and 100％ in GBCs . On CEUS ,72 .1％ (31/43) demonstrated continuous gallbladder inner wall and 48 .8％ (21/43) had hypoechoic nodules in the wall in XGCs compared to 16 .1％ (5/31) and 19 .4％ (6/31) in GBCs ,respectively ( P <0 .05) . No significant difference was found in intra-calcification , infiltration to adjacent organs ,gallbladder stones and fast-in and fast-out enhanced pattern( P >0 .05) . The area under ROC curve was improved from 0 .701 to 0 .899 after combining with CEUS ( P < 0 .05 ) . Conclusions Conventional ultrasound combining with CEUS could help acquiring more effective ultrasonic information and may improve the differential diagnosis ability of XGCs and GBCs .