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 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 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 .

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 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 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.

Objective To evaluate the correlation between thin-section CT morphologic features and pathological vascular invasion in the clinical stage ⅠA peripheral lung adenocarcinoma.Methods The preoperative thin-section CT images,clinical and pathological characteristics of 102 nodules in 98 patients were retrospectively analyzed and divided into two groups according to pathological vascular invasion.Variables including the diameter of tumor(T) and consolidation part (C) in the mix ground glass nodule (mGGN),C/T ratio,morphology and pathological classification were analyzed by two-independent samples Mann-Whitney U test or t test and x2 test or Fisher exact probability test.Variables with significant difference in the univariate analyses were entered into multivariate analysis to explore predictors for vascular invasion.The correlation between these measurements and vascular invasion was evaluated by a ROC analysis.Results All of 102 nodules,36 had pathological vascular invasion and 66 without.The numbers of two groups with speculation,air bronchogram,abnormal vein,vascular convergence,pleural indentation were 30,30;26,26;35,3;35,39;32,39 and the mediandiameter of tumors were 2.1(1.0-3.0),1.2(0.5-3.0) cm respectively.By univariateanalysis,spiculation,air bronchogram,abnormal vein,vascular convergence,pleural indentation,and diameter of tumor were significantly associated with pathological vascularinvasion (P＜0.01).By multivariate logistic analysis,the statistically significant difference were found in speculation and abnormal vein (OR=33.867,8 161.063,P＜0.05).The ROC analysis showed the area under curve,cut-off value,sensitivity and specificity ofthe diameter of tumor and consolidation part of mGGN and C/T ratio were 0.784,2.05 cm,66.7％,78.8％;0.886,1.08 cm,82.4％,90.0％ and 0.861,0.65,79.4％,85.0％ respectively in differentiating tumors with pathological vascular invasion.Conclusion The spiculation sign and abnormal vein are independent predictors for vascular invasion in stage ⅠA peripheral lung adenocarcinoma.

Objective To prospectively compare MR pulmonary perfusion imaging with quantitative HRCT for the detection of mild chronic obstructive pulmonary disease (COPD) and classification of COPD.Methods Sixty-two consecutive patients with COPD and 17 healthy volunteers underwent pulmonary function test (PFT),HRCT and MR perfusion imaging on the same day.According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD),all COPD patients were classified into 4 stages:stage Ⅰ (n =19),stage Ⅱ (n =17),stage Ⅲ (n =14),stage Ⅳ (n =12).The signal intensity of perfusion defects (SIPD),signal intensity of normal lung perfusion (SInormal) on 3D MR perfusion were obtained through postprocessing and the signal intensity ratio (RSI) was calculated.The total lung volume (TLV) was calculated automatically on HRCT and the total emphysema volume (TEV) was obtained by applying -950 HU thresholds.The TEV/TLV was deduced as emphysema index (EI).Several comparisons were made between the volunteers and COPD patients by one-way ANOVA and Kruskal-Wallis test.Results The RSI,SIPD,PEI,MSI,MSD values of MRI perfusion in volunteers (43.9 ± 7.2,48.2 ± 19.7,31.4,55.7,44.1) were significantly different from those in patients with COPD (18.1 ± 8.1,47.4 ± 20.0,8.6,30.2,22.7) (P ＜ 0.01).The RSI showed a significant difference between stage Ⅰ (24.4 ± 9.8) and stage Ⅲ (15.9 ± 5.3) or Ⅳ (9.2 ± 2.7) and between stage Ⅱ (19.9 ± 3.1) and stage Ⅳ (t =4.05-6.64,P ＜0.01).However,all MRI perfusion parameters between stage Ⅰ and stage Ⅱ,stage Ⅱ and stage Ⅲ,stage Ⅲ and stage Ⅳ were no differences (t =2.00-4.46,P ＞ 0.05).The median of EI in volunteers and stage Ⅰ-Ⅳ COPD patients were 1.2,3.8,8.0,13.7,18.3,and the quartile range were 3.7,7.1,9.2,10.5,7.7,respectively.The EI in volunteers showed significant differences with that of stage Ⅱ-Ⅳ COPD and the EI of stage Ⅳ was different from that of stage Ⅱ or Ⅰ (t =-7.32--1.85,P ＜ 0.01),but there was no significant difference between volunteers and stage Ⅰ COPD (t =-1.99,P ＞ 0.05).Conclusions The RSI of MRI is more sensitive than that of HRCT for assessing mild COPD.The severity of COPD could be reflected by MRI perfusion and HRCT.

Objective To compare the MSCT findings of malignant focal pulmonary ground-glass opacity nodules (fGGO) and solid nodules of 3 cm or less, and try to find specific signs in fGGO. Methods Clinical data (sex ratio, age), size of lesion and MSCT findings (shape, margin, interface, internal characteristics, adjacent structure) of 105 cases pathologically confirmed to have solid lung cancers and 48 cases with fGGO less than 3 cm were retrospectively analyzed. Differences were analyzed by using the Fisher exact test or Mann-Whitney U test. Results The male and female ratio of solid lung cancer(60:45) were higher than that of fGGO (18:30, X~2 value 5.09, P<0.05). But no differences were found in age and size of lesion (P value 0.200,0.673). For solid lung cancer, the incidence of round shape (n=101), irregular (n=4), speculation (n=60), vacuole sign (n=12) and air bronchograms (n=0) were significantly different from those of fGGO (38, 10, 19,25 and 7, respectively), and the corresponding (X~2 values were 11.48,4.07,29.70 and 22.38 respectively, P<0.05). No differences were found in lobulation, cusp angle, spine-like process, well-defined, coarse, ill-defined interface, honey-combing, pleural indentation sign and blood vessel cluster sign (there are 85,0,33,5,100,0,0,59,35 cases for solid cancer, and 42,1,15,3,45,0,2,32,16 for fGGO (X~2 values 1.00,2.20, 0.00,0.15, 4.43,1.50, 0.00, P>0.05). Conclusions Malignant fGGO and solid lung cancer manifest mostly similar MSCT features. The frequency of irregular shape, vacuole sign and air bronchograms was higher in fGGO than in solid lung cancer to some degree, but speculation is more infrequent in fGGO, which may be attribute to thepathological type and basis of tumor.

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.