Using morphometry and impregnation technique of lanthanum nitrate,acomparative investigation on the epidermis structure of high and low electricresistance skin points was carried out in mice and rabbits at both light and electronmicroscope level,with special emphasis on the structure of gap junctions in epidermis.It was observed that the frequency of gap junctions in low resistance points wassignificantly higher,and their diameter was larger than that in high resistancepoints,while no difference was found in other structure parameters examinedbetween the two types of skin points.It is assumed that the gap junctions may bethe structure basis for the difference in skin electric resistance.

Objective To investigate the effect of gravity and lung volume on MR perfusion imaging of human lung using an arterial spin labeling sequence called flow sensitive alternating inversion recovery(FAIR).MethodsMagnetic resonance imaging of lung perfusion was performed in supine position in ten healthy volunteers on a 1.5 T whole body scanner(GE medical system).Five sequentially coronal slices with the gap of 3cm from dorsal to ventral(labeled as P3,P6,P9,P12,P15,respeectivly)were obtained on end respiration and the relative pulmonary blood flow(rPBF)was measured.Another coronal perfusion-weighted image of P3 slice was obtained on end inspiration.Tagging efficiency of pulmonary parenchyma with IR(⊿SI%),the rPBF and area of the P3 slice were analyzed.respectively.Paired Student's t test was used for statistical analysis.Results(1)In the direction of gravity,an increase in rPBF of the gravity-dependent lung was found.rPBF of right lung from dorsal to ventral were 100.57±18.22,79.57±12.36,61.65±11.15,48.92±9.96,41.20±9.88,respectively；and that of left lung were 106.61±26.99,78.89±11.98,64.00±13.64,51.27±8.95,43.04±12.18.No statistical differences between P12 and P15,there were significant statistic differences of any other two coronal planes.But along an isogravitational plane,no statistical difference was observed.Regression coefficients of right and left lung were -4.98 and -5.16,respectively.This means the rPBF of right lung falls by 4.98 for each centimeter above the dorsal and that of left lung falls by 5.16.(2)For(⊿)SI%,rPBF and area,there were significant statistic differences at different respiratory phases(P＜0.05).(⊿)SI%,rPBF,area at expiration phase vs.inspiration phase were 1.12±0.31 vs 0.71±0.18,90.78±17.35 vs 52.85±8.75,(12.59±3.23)×103mm2 vs (17.77±4.24)×103mm2 for right lung;and 1.01±0.24 vs 0.70±0.11,91.08±18.68 vs 54.58±10.70,(12.34±3.08)×103mm2 vs(17.34±4.98)×103mm2 for left lung.Greater (⊿)SI%and increased perfusion were observed on end expiration than on end inspiration.The area was larger on end inspiration than on end expiration.ConclusionsThe FAIR is sensitive to perfusion changes in the gravity-dependent lung.Pulmonary blood flow is less in a state of high lung inflation than in a low state(inspiration vs.expiration).Positioning the patient so that the area of interest is down-gravity and breath-hold on end expiration may improve visibility of perfusion defects.

Objective To evaluate multi-detector computed tomography(MDCT)features of lung cancer associated with cystic airspace,and to improve diagnostic accuracy.Methods 21 pathologically or clinically confirmed lung cancer associated with cystic airspace were retrospectively analyzed with regard to clinical data,pathological types and TNM stage,SUMmax and MDCT features.For dynamic follow-up CT scans,the lesion dynamic change was evaluated.Results There were 21 cases (1 1 adenocarcinoma,6 squamous carcinoma)in total. The lesion was predominant cysts in 2 cases(9.52%),cysts with GGO mixed lesions in 3 cases(14.29%),cysts with solid mixed lesions in 14 cases(66.67%),cysts with GGO and solid mixed lesions in 2 cases(9.52%).Four morphological patterns,20 cases had solid nodules,solid nodule protruding externally from the cyst wall was in 5 cases (23.81%),solid nodule protruding internally from the cyst wall was in 1 case (4.76%),solid tissue intermixed within clusters of cysts was in 14 cases(66.67%),the lesion presenting as circumferential thickening of the cyst wall was in 1 case (4.76%).The frequency of following features accounted for more than 60% of all MDCT signs,including round shape (66.67%),lobulation (80.95%),blood vessel passing through the cyst (76.1 9%),pleural indentation (80.95%);while the frequency of multiple cysts,irregular inner wall and septum in cyst in 19 lesions(90.48%)was more than 90%.With respect to the relationship between lesion and bronchus,bronchus passing through the cyst was the most common sign,accounting for 38.10%(8/21).Average CT enhancement value was 28.27 HU±7.27 HU(range 14.2-40 HU).Average SUVmax was 6.05(range 4.5-9.8),indicating marked FDG uptake.Two lesions manifested as progressive wall thickening and increased size of the cyst,and one lesion showed decreased size of the cyst and enlarged nodules in follow up CT.Conclusion The irregular inner wall,septum in cyst and blood vessel passing through the cyst are the most three important signs for the diagnosis of malignant lesions.

Objective To evaluate the diagnostic value of CT target scanning combining with changing position for pulmonary nodules in special location .Methods CT target scanning combining with changing position was performed in 22 patients with pulmo‐nary nodules adjacent to heart or in posterior costophrenic angle ,which were found with routine spiral CT scanning .For objective analysis , the signal‐noise‐ratio (SNR) and contrast‐noise‐ratio (CNR) of lung were calculated .In terms of subjective assessment ,the image quality was rated on a 3‐point scale (0-2) for pulmonary inflation ,gravity‐dependent pulmonary perfusion and severity of artifacts , respectively .The CT features of pulmonary nodules were compared between different scanning techniques .Moreover ,the diagnostic confidence for pulmonary nodules was evaluated .The paired t test ,Wilcoxon signed‐rank test and Kappa test were used for statisti‐cal analysis .Results In comparison with conventional spiral CT scanning ,CT target scanning combining with changing position im‐proved the subjective image quality scores (P<0 .01) ,increased the signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) , showed more detailed CT features (P<0 .05) ,and improved the confidence of diagnosis (P<0 .01) .Conclusion CT target scanning combining with changing position technique can show detailed features ,which should be recommended as the optimal scanning tech‐nique for pulmonary nodules adjacent to heart or in posterior costophrenic angle .

Objective:To investigate the influence of lung inflation on MR perfusion imaging of human lung using an arterial spin labeling sequence called flow sensitive alternating inversion recovery(FAIR).Methods:Coronal perfusion-weighted images were obtained at different respiratory phases from 10 healthy volunteers on a 1.5T whole body scanner(GE medical system)using FAIR sequence.The changes of tagging efficiency of pulmonary parenchyma(?SI %),pulmonary blood flow and area of the scanning slice of different respiratory phases were analyzed.Results:(1)Significant difference was found in ?SI% between different respiratory phases(right lung P=0.021 5,left lung P=0.008 4),with that at end expiration greater than that at end inspiration.(2)Significant difference was also found in pulmonary blood flow at different respiratory phases(right lung P=8.92?10-5,left lung P=0.000 2),with that at end expiration higher than that at end inspiration.(3)The areas of the scanning slice were also significantly different at different respiratory phases(right lung P=2.94?10-5,left lung P=0.000 5),with that at end inspiration larger than that at end expiration.Conclusion:Pulmonary blood flow during expiration is higher than that during inspiration,which might be due to the decreased lung volume and increased vascular density during expiration.

0.05), there were significant statistic differences of any other two TI values (P0.05), there were significant statistic differences of any other two TI values (P0.05 ) , there were significant statistic differences of any other two TI values (P

Objective To evaluate the effect of CT temporal subtraction(TS) for detection of lung nodules.Methods 80 cases of CT images (current and previous CT images) and corresponding CT TS images were presented, which included 30 cases with nodules(75 nodules) and 50 controls.4 observers, including 2 radiologists and 2 residents, indicated their confidence level regarding the presence of a new emerging or larger or solid component than before,which first used standard CT images, then with the addition of CT TS images.Receiver operating characteristic(ROC) curve analysis was used to evaluate the observers'' performance.Results The mean value of the area under the ROC curve (AUC) were 0.860 and 0.925 for four observers without and with TS images,respectively(P<0.01).Average sensitivity for detection of lung nodules was improved from 77.3%(58/75) to 89.3%(67/75) by using CT TS images.Conclusion The use of CT TS images can significantly improve radiologists'' performance for detection of lung nodules,especially when a small size solid or subsolid nodule presents near the pulmonary hilum.CT TS is more helpful for residents.

Objective To analyze the morphological features of smokers' lung on MDCT scan,measure the CT volumetric parameters,and explore the correlation with pulmonary functional test(PFT) indexes.Methods 59 smokers were enrolled,in which 14 were chronic obstructive pulmonary disease(COPD) patients,and 39 non-smokers were chosen as control group.All subjects underwent inspiratory and expiratory phase MDCT scan and PFT.Eleven pulmonary CT features caused by smoking among three groups were analyzed and compared.The emphysema index (EI 95) and mean lung density (MLD) were measured.The correlation between above mentioned parameters and PFT indexes were analyzed.Results ①Among three groups,significant differences were found for the score and incidence of entrilobular emphysema,paraseptal emphysema and brochiectasis or bronchial wall thickness(P＜0.01).②In COPD patients,paraseptal emphysema and DLCO/VA,brochiectasis or bronchial wall thickness and DLCO SB(％P),DLCO/VA(％P),as well as EI and MEF25％ (％P),DLCO SB(％P),DLCO/VA (％P)were negatively related.In smokers without COPD,there were negative correlation between centrilobular emphysema and FEV1/FVC,MEF25％ (％ P),MEF5％ (％ P),DLCO SB (％ P),DLCO/VA (％ P),paraseptal emphysema and DLCO SB(％P),DLCO/VA(％P),brochiectasis or bronchial wall thickness and DLCO/VA(％P),as well as EI and FEV1/FVC,MEF5％ (％P),and MLD and FEV1 (％ P),MEF25％ (％ P)were positively related.Conclusion MDCT can be used to analyze smokers' pulmonary morphology,and the morphological features and volumetric parameters are good predictions for pulmonary function.

Objective To evaluate multi-slice CT (MSCT) features and pathological basis of lung cancer containing thin-walled airspace. Methods Thirty?five cases of pathologically confirmed lung cancer containing thin-walled airspace were retrospectively analysed with regard to clinical data, pathological types and MSCT features between 2012 and 2015.There were 35 cases(25 adenocarcinoma, 9 squamous carcinoma, 1 spindle cell tumor) in total. MSCT features were compared between the lesions with or without solid component .Fisher exact test was used for the statistical analysis. For dynamic follow-up CT scans, the lesion dynamic change was evaluated .Correlations between the pathological section and CT images of the 11 cases were analysed. Results These features accounted for more than 60% of all MSCT signs in 35 cases, including round shape in 28 cases(80.0%),lobulation in 32 cases(91.4%),multiple cysts in 27 cases(77.1%), irregular inner wall in 33 cases(94.3%)and septum in airspace in 31 cases(88.6%). Shape, spiculation, bronchus cut-off, blood vessel and bronchus passing through the airspace, and ground-glass opacity were significantly different between the lesions with or without solid component(P<0.05).The frequency of spiculation(11 cases) and bronchus cut-off(12 cases) in mixed solid lesions was higher than that in lesions without solid component(1 case, respectively).The frequency of irregular shape(6 cases),blood vessel passing through the airspace(12 cases),ground-glass opacity(13 cases)and bronchus passing through the airspace(7 cases) in lesions without solid were higher than that in solid mixed lesions(1, 1, 5, 3 cases respectively).The pathological basis of the formation of thin-walled airspace was obvious central necrosis in solid lesions and emphysematous change due to the tumor cells diffused along the inner airspace wall and the alveolar wall destruction.Five lesions were with progressive wall thickening and increased size of the airspace,and two lesions were with decreased size of the airspace and enlarged nodules in followed CT.One case of lung cancer with thin-walled airspace evolved from ground glass nodule. Conclusions The CT manifestation of lung cancer containing thin-walled airspace was characteristic.The pathological basis of the thin-walled airspace was various.

Objective To investigate the predictive value of whole nodule size and solid component size of pulmonary subsolid nodules (SSNs)with different window setting on preoperative HRCT for pathologic grade in lung adenocarcinoma.Methods We retrospectively evaluated preoperative chest HRCT and pathological data of 125 patients with 127 surgically resected lung adenocarcinoma manifesting as SSNs.All specimens were divided into two groups:a total of 69 SSNs in group A,including 22 adenocarcinomas in situ (AIS) and 47 minimally invasive adenocarcinoma (MIA);a total of 58 SSNs in group B,including invasive adenocarcinoma (IAC).Observer 1 used computer aided diagnosis software to measure the volume of whole nodule with lung window setting (WNLW),volume of solid component with lung window setting (SCLW),volume of solid component with mediastinal window setting (SCMW) and volume of solid component with threshold of-300 HU(SCT) of all SSNs.Observer 2 randomly selected 50 SSNs and repeated all the measurements.The interobserver agreement regarding quantitative measurements were evaluated by using intraclass correlation coefficient(ICC).The differences of all quantitative features between two groups were evaluated by Mann-Whitney U test.All the quantitative features were evaluated by using univariate logistic regression analysis,significant quantitative features identified by univariate logistic regression analysis were included in the multivariate logistic regression and independent predictors of pathological grade were obtained.Receiver operating characteristic analysis was conducted for the independent predictive factors that exhibited statistically significant differences in the multivariate logistic regression.Results The interobserver agreement regarding quantitative features were excellent (ICC＞ 0.75).The WNLW,SCLW,SCMW and SCT of group B were significantly larger than those of group A (P＜ 0.001).The univariate logistic regression analysis indicated that WNLW,SCLW,SCMW and SCT were significant (P＜0.001),the multivariate logistic regression analysis indicated that SCT was the independent predictive factor (OR=1.013,95％CI:1.006—1.020,P＜0.001).When SCT larger than 139.00 mm3,SSN was significantly associated with IACs (AUC=0.887,sensitivity=81％,specificity=93％).Conclusion SCT of SSNs on preoperative HRCT can be used to distinguish between AIS-MIA and IAC,which may provide information for choice of operation.