1.A comparative study of MRI and ultrasonic cardiography in morphology and blood flow of cavopulmonary anastomosis for patients with bidirectional Glenn shunt
Rongpin WANG ; Changhong LIANG ; Meiping HUANG ; Hui LIU ; Qiping DENG ; Mingfang YANG
Chinese Journal of Radiology 2011;45(11):999-1003
Objective To investigate the difference of morphology and blood flow of cavopulmonary anastomosis by MRI and that by ultrasonic cardiography (UCG) in patients with bidirectional Glenn shunt (BGS).Methods Phase-contrast MRI (PC-MRI) and contrast enhanced MRI (CE-MRI) were performed for superior vena cava ( SVC ) and inferior vena cava (IVC) in 22 patients with BGS on 3.0 T MR scanner.PC-MRI was used for measuring blood flow and CE-MRI for illustrating morphology.The width,peak flow velocity and gradient pressure of cavopulmonary anastomosis were calculated by using Report Card software.The similar data of UCG was collected.The parameters by MRI and that by UCG were compared statistically by t test and Pearson correlation.Results Based on the MRI data,the blood flow of SVC [ ( 1.002 ±0.208) L/min ] was significantly lower than that of IVC [ ( 1.794 ± 0.392 ) L/min ] ( t =- 15.148,P <0.01 ),while the regurgitation fraction of SVC [ (26.54 ± 12.82)% ] was significantly higher than that ofIVC [ ( 17.44 ± 10.17)% ] (t =11.060,P <0.01 ).The morphology displayed with MRI angiography couldnot be detected with UCG.The width of cavopulmonary anastomosis measured by MRI [ (12.46 ±3.43 ) mm ] was significantly higher than that of UCG[ ( 11.04 ± 2.63 ) mm] ( t =4.048,P < 0.01 ),while the peak flow velocity of cavopulmonary anastomosis measured by MRI [ (47.77 ± 10.44) cm/s] was significantly lower than that of UCG [ (52.19 + 9.63) cm/s] ( t =- 2.237,P < 0.05 ).No significant difference was found in gradient pressure of cavopulmonary anastomosis between the values by MRI [(0.95+0.42) mm Hg(1 mm Hg =0.133 kPa)] and that by UCG [(1.12+0.38)mm Hg] (t=2.010,P > 0.05).The width,peak flow velocity and gradient pressure of cavopulmonary anastomosis by MRI were closely correlated with those by UCG (r =0.858,0.489,0.427,all P< 0.05 ).Conclusions A good correlation is found in the width,peak flow velocity,and gradient pressure of the cavopulmonary anastomosis obtained by 3.0 T MRI and UCG.MRI is more useful tool to display the width and abnormal morphology of cavopulmonary anastomosis than UCG.
2.Metallic stent implantation in the treatment of malignant tracheal stenosis under general anaesthesia
Xuming BAI ; Yong JIN ; Hong XIE ; Long CHENG ; Xingshi GU ; Liuhui CHANG
Chinese Journal of Radiology 2012;46(4):354-358
ObjectiveTo evaluate the safety and feasibility of the tracheal stent implantation for treatment of malignant tracheal stenosis under general anaesthesia. Methods Eighteen patients with malignant tracheal stenosis underwent preoperative 64-slice spiral CT scan and airway reconstruction. The stenotic sites were located in main tracheal trunk(5 patients),in right main bronchus( 1 patient),in trachea and left main bronchus (4 patients),in trachea and right main bronchus (3 patients),in main tracheal trunk and bilateral main bronchus(5 patients).The degree of stenosis was rated 51% to 70% in 7 cases,71% to 90% in 11 cases.All patients,17 patients of ASA grade 1V and 1 patient of grade Ⅲ,presented with severe dyspnea. Under general anaesthesia,implantation of metallic stent was performed through the sputum aspiration hole of the connecting tubing with DSA guidance.The NBP,ECG,RR,SaO2 of the patients were recorded and compared with t test during the entire procedure. At the end of the procedure,relief of dyspnea,complications related to anesthesia and operation were recorded. Results The success rate of stent placement was 18/18,and dyspnea was significantly relived in all patients. Slightly bloody sputum occurred in 7 cases.The stent was obstructed by sputum in 1case,and the patient was treated with medication.There were no severe complications.The operative course were rated 11 to 9 in 17 cases,and 6 to 8 in 1 case.All 18 patients were cooperative during the procedure.Sixteen patients rated the procedure as very comfortable and 2 rated the procedure as comfortable.Respiratory rate (RR) and heart rate (HR) decreased in all patients after the operation [ ( 37.1 ± 2.8 )/min and ( 106.5 ± 14.2 ) bpm before the operation respectively,( 18.6 ± 1.4)/min and ( 73.2 ± 7.6) bpm after the operation respectively ],t =17.81 and 3.80,P < 0.01.Pulse oxygen saturation ( SaO2 ) during the operation [ ( 91.2 ± 1.8 ) % ]increased [ (76.3 ± 8.6 )% before the operation ] and increased further after the operation [ (94.5 ±4.3 ) % ],t =2.06 and 2.26,P < 0.01.Blood pressure (BP) showed no changes throughout the operation (P > 0.05 ).The conprehensive assessment of operation were favorable in all patients. Conclusion With careful preoperative evaluation and planning, tracheal stent implantation under general anaesthesia in patients with malignant tracheal stenosis is feasible and safe.
3.Comparative study of sclerotherapy of venous malformation in children using absolute ethanol and pingyangmycin
Jing ZHANG ; Haibo LI ; Shaoyi ZHOU ; Kunshan CHEN ; Chuanqiang NIU ; Xiaoyun TAN ; Yizhou JIANG ; Queqing LIN
Chinese Journal of Radiology 2012;46(4):350-353
ObjectiveTo evaluate and compare the curative effect and the safety of sclerotherapy of venous malformation in children using absolute ethanol and pingyangmycin.MethodsEighty children with venous malformation were treated by sclerotherapy with absolute ethanol or pingyangmycin under general anesthesia during February of 2009 to May of 2011. Diagnostic criteria included the presence of a bluecolored lesion at birth,with gradual increase in its size associated with a positive postural test.MRI showed characteristic imaging features.Eighty patients were divided into two groups by randomization.Forty patients were treated with absolute ethanol,and the remaining 40 patients with pingyangmycin. The therapeutic effects and side effects were observed and recorded during a follow-up period of 6 to 24 months ( average 15 months).Treatment results weredividedinto four categories: cure, basiccure, effective, and ineffective,and the former three categories were considered effective in treatment.Chi-square test was used to compare the rate of effective treatment and rate of complications in these two groups.ResultsThe effective patients treated with absolute ethanol was 38 (95.0%,38/40),and the effective patients with pingyangmycin was 26(65.0%,26/40),x2 test ( x2 =11.25,P < 0.01 ) difference was statistically significant.Eight patients developed skin necrosis; 4 patients serious local swelling,2 patients muscle fibrosis,1 patient cerebral embolism in the absolute alcohol group.Two patients developed postoperative fever and vomiting and 2 skin necrosis in the pingyangmycin group,the difference was statistically significant (x2 =12.29,P <0.01 ). ConclusionsSclerotherapyiseffectiveforthetreatmentofvenousmalformationsin children.Absolute ethanol is more effective,but associated with more complications,such as skin necrosis or as serious as cerebral embolism,than pingyangmycin.
4.The value of multi-slice spiral CT liver perfusion imaging to evaluate the chronic hepatic fibrosis and cirrhosis
Liling LONG ; Zhongkui HUANG ; Ke DING ; Jinyuan LIAO ; Jianning JLANG
Chinese Journal of Radiology 2012;46(4):317-321
ObjectiveTo investigate the value of the MSCT liver perfusion imaging parameters inthe evaluation of the chronic hepatic fibrosis and cirrhosis. Methods Liver CT perfusion ( CTP ) was performed in 107 participants,including 31 patients with mild hepatic fibrosis( S1,S2),34 patients with severe hepatic fibrosis ( S3,S4 ) and early stage of hepatic cirrhosis which conformed by liver pathologic biopsy,42 patients with hepatic cirrhosis who had typical clinical and image signs,and 30 healthy subjects as control group.The data of CTP ( HAP,PVP,LTP,HPI and TTP) at different stages were obtained with Body perfect CT-syngo CT2007A and control study with histopathologic stage.Compared the study index by the one-way ANOVA analysis. Used Spearman rank correlation to analysis the relationship between liver perfusion imaging parameters and the degrees of the chronic hepatic fibrosis. Used Logistic regression to analysis the maximum.regression coefficient among the liver perfusion imaging paraneters,which affected the histopathologic stage mostly.ResultsIn the subgroups of the chronic hepatic fibrosis S1,S2,S3,S4 to the hepatic cirrhosis,HAP values was (28.9 ±8.6),(24.6 ±2.4),(29.2 ±2.3) and (38.9 ± 7.0) ml · 100 ml -1 · min-1,respectively.HAP decreased firstly,then increased.Statistic analysis showed the difference of HAP between later-stage cirrhosis and other groups( F =40.26,P < 0.01 ).PVP values of above subgroups was (111.3 ± 18.1),(92.9 ±5.3),(73.0 ±9.0) and (54.1 ± 13.8) ml · 100 ml-1 ·min -1,respectively.TLP values of above subgroups was ( 140.2 ± 25.9 ),( 117.1 ± 4.5 ),( 102.3 ± 8.7 )and (93.0 ± 11.8) ml · 100 ml-1.min-1,respectively.The difference of PVP,TL.P among each subgroup was significant ( F =136.79,67.40,respectively,P < 0.01 ).HPI values of above subgroups was (20.4 ± 2.6)%,(21.0 ±2.1)%,(28.5 ±3.1)% and (42.6± 11.1)%,respectively.TTP values of above subgroups was (123.7±22.2),(137.1 ±27.1),(145.0 ±28.6) and (166.5 ±25.1)s,respectively.The difference of HPI,TTP among each subgroup was significant( F =93.05,17.37,respectively; P <0.01 ).PVP,TLP was significant negative correlation with the degree of the hepatic fibrosis( r =-0.920,-0.846,respectively; P <0.01 ).HAP,HPI and TTP was significant positive correlation with the degree of the hepatic fibrosis( r =0.611,0.882 and 0.545,respectively; P < 0.01 ).Logistic regression analysis showed the regression coefficient of PVP( - 8.798) was maximum.With an area under the receiver operating characteristic curve of PVP =84.76 ml · 100 ml- 1 · min- 1 as a diagnose critical point.The sensitivity was 0.890,the specificity was 0.950,and the accuracy was 0.931 in the prediction of the chronic hepatic fibrosis.Conclusions MSCT liver perfusion imaging parameters can reflect the hemodynamic changes of chronic hepatic fibrosis and cirrhosis.CTP may be helpful for differentiation the severe hepatic fibrosis and early stage of hepatic cirrhosis and later-stage cirrhosis.
5.Application of low-dose prospective electrocardiography-triggering dual-source CT angiography in infants and children with congenital heart disease
Yanhua DUAN ; Lebin WU ; Zhaoping CHENG ; Dawei WU ; Pei NIE ; Xiaopeng JI ; Ximing WANG
Chinese Journal of Radiology 2012;46(4):312-316
Objective To explore the application of low-dose prospective ECG-triggering dualsource CT (DSCT) angiography in infants and children with Kawasaki disease (KD).MethodsNineteen children diagnosed of Kawasaki disease underwent low-dose prospective ECG- triggering DSCT angiography (DSCTA) with free breathing and transthoracic echocardiogram (TTE).The overall imaging quality was graded on a five-point scale. Interobserver agreement in subjective image quality grading was assessed by Kappa statistics.The location,number and size of the aneurysms and dilations were recorded and compared with those of TTE.Pearson correlation analysis was used to evaluate the agreement on measurements between DSCTA and TTE.The average effective dose of DSCTA in all 19 children was calculated.ResultsDSCTA was performed successfully in all 19 children.A total of 91.5 % (226/247) segments permitted visualization with diagnostic image quality. Fifteen patients were diagnosed with coronary artery lesions. A total of 28 aneurysms and 15 arterial aneurysmal dilations were detected by DSCTA,while 19 aneurysms and 13 arterial aneurysmal dilations were found by TTE.TTE failed to detect 9 aneurysms (2 in the distal right coronary artery,2 in the posterior descending artery,1 in the middle of left anterior descending artery,1 in the middle of left circumflex artery,2 in the distal of LCX and 1 in the obtuse marginal branch)and 2 arterial aneurysmal dilations (1 at the diagonal branch and 1 at obtuse marginal branch). The concordance of DSCTA and TTE in measurement of diameter and length of these aneurysms and aneurysmal dilatations are good (0.63 ± 0.20) and (0.58 ± 0.20) cm vs ( 1.49 ± 0.83 ) and ( 1.22 ± 0.66) cm ( r =0.989 and 0.965,P < 0.05 ).There was a good agreement on overall image quality ( Kappa =0.87 ). The mean effective dose was(0.24 ± 0.08) mSv.ConclusionProspective ECG-triggering DSCTA with very low effective radiation dose is safe,reliable and more sensitive than TTE on diagnosing of coronary artery lesions,especially in the distal lesions,in infants and children with KD.
6.Preliminary study of lateral cerebral angiography with reverse rotation in the digital image registration and subtraction
Zhenglin SHEN ; Dongyang LIU ; Zhenghai SHEN ; Shuping LI ; Ziyan ZHANG ; Yongjuan WU ; Peijun LIU
Chinese Journal of Radiology 2012;46(4):367-370
ObjectiveInvestigate the value and feasibility of image registration with reverse rotation in lateral cerebral DSA.Methods ( 1 ) Experimental study:the target images were subtracted directly,and subtracted again after reverse rotation.Software of registration and subtraction with reverse rotation edited by the author utilizing Visual Basic.The function of the automatic angle detection by the software were evaluated to see whether it detected the angle of line.The subtraction function of DSA by the software was evaluated.(2) Clinical retrospective study:the untreated mask and target inages of 15 patients with motion along vertical axis during lateral cerebral DSA were uploaded to the software.The target images were processed with and without the software to get two sets of images.( 3 ) Evaluation:four experienced radiologists read and compared the two sets of the images,and graded their findings.Results ( 1 ) The automatic detection by the software suggested that the target images should be rotated counterclockwise 1.3°. The subtraction result of the software was satisfactory.(2)In the 15 sets of images,there were only three sets of images deemed optimal after traditional subtraction.After reverse rotation,artifacts were significantly reduced and the image sharper. There were ten cases with significant artifacts after traditional subtraction,and those images were sharper and showed more peripheral vessels after reverse rotation. The traditional subtraction images of two sets could not be interpreted,the reverse rotation registration images reached the diagnostic quality.(3)Subjective evaluation: there were more information and less noise and distortion in the registration images with reverse rotation than in the traditional subtraction. But the image resolution decreased slightly after reverse rotation registration.ConclusionThe registration of digital angiography with reverse rotation can improve the image quality in lateral cerebral DSA.
7.Whole body diffusion weighted imaging pattern of normal bone marrow
Fengzhen CUI ; Jianling CUI ; Shilei WANG ; Chuanguo DU ; Jicun LIU ; Yingcai SUN
Chinese Journal of Radiology 2012;46(4):340-344
Objective To analyze the pattern of normal bone marrow on whole body diffusionweighted imaging (WB-DWI) and its influence factors.MethodsA total of 98 healthy volunteers (male 47 and female 51). All volunteers underwent WB-DWI at 1.5 T MR scan. The ADC value,the signal intensity on DWI obtained with a b value of 800 s/mm2 ( SIDWI ),and the signal intensity on short time inversion recovery images ( SISTIR ) of thoracic vertebrae,lumber vertebrae,bilateral head of femur,bilateral neck of femur,bilateral superior segment of femur,bilateral inferior segment of femur,bilateral ilium,bilateral head of humerus,bilateral scapula were measured and compared with ANOVA test and StudentNewmar-Keuls test.The normal appearance of bone marrow on WB-DW[ was assessed. The relationship between the SIDwI and the ADC,and the SIDWI and the SISTIR of bone marrow were analyzed.The ADC of bone marrow between male and femaIe were compared. Spearman correlation analysis was performed for different age groups.Results( 1 ) Bone marrow signal intensity was different among 98 healthy volunteers.Bone marrow in 69 healthy volunteers (female 24,male 45 ) showed low to intermediate signal intensity,whereas in the remaining 29 healthy volunteers (female 27,male 2) showed high signal intensity.(2) The SIDWI of thoracic vertebrae ( median 44.54),lumber vertebrae ( median 35.01 ),head of femur ( median 13.61 ),neck of femur ( median 16.00),superior segment of femur ( median 21.45 ),ilium ( median 25.77),head of humerus (median 18.35),scapula (median 36.12) was positively correlated with the ADC [ (0.55 ±0.08) × l0-3,(0.53 ±0.08) × 10-3,(0.30 ± 0.10) × 10-3,(0.42 ± 0.16) × 10-3,(0.74±0.14) ×l0- 3,(0.49±0.10) ×10-3,(0.36±0.13) ×10-3,(0.49±0.11) × 10-3mm2/s]and the SISTIR ( median 61.81,64.99,53.27,69.08,73.10,66.35,73.16,79.81 ),r =0.513 and 0.695,0.741 and 0.764,0.443 and 0.489,0.641 and 0.656,0.510 and 0.648,0.475 and 0.715,0.366 and 0.446,0.437 and 0.739 ;P < 0.01. (3) There was significant difference of the ADC of bone marrow in different bone,F =138.69,P < 0.01. Student-Newman-Keuls test revealed that no significant difference was found in the ADC between thoracic vertebrae and lumbar vertebrae,ilium and scapula,head of humerus and inferior segment of femur ( P > 0.05 ),and significant difference was found in the ADC values between the remaining two groups ( P < 0.05 ). The bones associated with decreasing ADC values were superior segment of femur,thoracic vertebrae and lumber vertebrae,ilium and scapula,neck of femur,head of humerus,head of femur and inferior segment of femur. ( 4 ) The ADC values of bone marrow of female subjects in thoracic vertebrae [ (0.59 ±0.07) × 10-3 mm2/s],lumber vertebrae [ (0.58 ±0.06) × 10 -3 mm2/s],head of femur ( median 0.33 × 10 -3 mm2/s),neck of femur ( median 0.53 × 10 -3 mm2/s),superior segment of femur ( median 0.81 × 10-3 mm2/s),inferior segment of femur ( median 0.32 ×10-3 mm2/s),ilium [ (0.52 ± 0.09 ) × 10-3 mm2/s ],head of humerus (median 0.42 × 10-3 mm2/s),scapula [ (0.53 ± 0.09) × 10-3 mm2/s] were significantly higher than those of male subjects [ (0.51 ±0.07) × 10-3,(0.48 ±0.07) × 10-3,median 0.23 × 10-3,median 0.31 × 10-3,median 0.66 × 10-3,median 0.23 × 10-3,(0.46 ±0.10) × 10-3,median 0.27 × 10-3,(0.45 ±0.11 ) × 10 3mm2/s].(5)There was significant negative correlation between the ADC values of bone marrow and age in thoracic vertebrae,lumber vertebrae,head of femur,neck of femur,superior segment of femur,ilium,head of humerus for female subjects,r =-0.549, -0.629, -0.329, -0.524, -0.338, -0.548 and -0.416,respectively,P < 0.05.There was no significant correlation between ADC values and age in inferior segment of femur and scapula for female subjects and all the regions for male subjects ( P > 0.05 ).Conclusions The ADC and the SIsTIR of bone marrow correlates with the SIDW1.The ADC values of bone marrow is affected by age and sex,and is different for different bones.
8.MRI assessment of mid-urethral ligament changes in female stress urinary incontinence
Mei BAI ; Hongyi LIU ; Yue HAN ; Guoping XU ; Ping FANG ; Yang ZHAO ; Jingjin LI
Chinese Journal of Radiology 2012;46(4):336-339
Objective To evaluate the MRI value in changes of mid-urethral ligament injury offemale stress urinary incontinence (SUI).MethodsComparison of MRI changes of mid-urethral ligament on 30 healthy female volunteers and 20 female SUI patients.Chi-square test was used to compare the form of SUI patient's mid-urethral support ligaments Results The female nid-urethral support ligaments were composed of 4 groups of ligaments,including the periurethral ligament and pubourethral ligaments (1 pair),and at both sides of the urethra's paraurethral ligaments (1 pair) and suburethral ligament lying dorsal urethra,connecting the urethra and pelvic arcus tendinous fasciae.In normal MRI,ligament was a thin strip and showed low signal on both T1WI and T2WI,T2WI sagittal and cross-section scan was the best combination to show the middle urethral support ligaments changes,with tension;6 patients (20%) in the 30 patients normal control group could be seen tortuously and slack like around the urethra ligaments.Twenty SUI patients mid-urethral support ligaments were performance laxity or rupture,rates were 39% (47/120) and 42% (50/120) (x2 =43.191,P < 0.05 ).On T2WI,the ligamentous laxity was floating,and losstension,also could performance one side extension and thinner than the other side.The ligament rupture was performance of the signal interruption,ligament contracture and one end of liganent attachment points separation.ConclusionMRIcanobjectiveeffectiveevaluatethemid-urethralsupportligaments' pathological changes in stress urinary incontinence patients.
9.Multi-slice spiral CT multiplanar reconstruction findings of localized fat collection adjaction to the subdiaphragmatic inferior vena cava
Hetao CAO ; Jian LU ; Jinli ZHAO ; Tingting LIU ; Jufeng QIN ; Wen XU ; Jiangchun QIN ; Junkang JIANG
Chinese Journal of Radiology 2012;46(4):332-335
ObjectiveTo discusses the MSCT multiplanar reconstruction manifestation (MPR) of localized fat collection adjaction to subdiaphragmatic inferior vena cava (IVCfat).MethodsThe thoracic and abdominal MSCT scan data of 8246 patients were browsed,45 patients with presumed IVCfat on axial CT scans were further studied prospectively with MSCT MPR.The predisposing position of IVCfat and its relationship with IVC were observed.It was divided into two kinds of intraluminal type and extraluminal type according to the angle of IVCfat with respect of the wall of IVC.The other 50 patients without IVCfat were randomly selected as the control group.The sagittal inclination angle (SIA) and diameter ratio (DR) between supra- and sub-diaphragmatic IVC between the two groups were compared by using t test.Results The detection rate was 0.55% (45/8246).Of which hepatic vein lacuna 8 patients,subdiaphragmatic gap medial to IVC 28 patients and IVC groove 9 patients.The shape of IVCfat showed mainly for the round,oval and crescents on axial CT scans,of 15 patients intraluminal type,4 showed target signs .The shape of IVCfat showed mainly for half-moon at MPR.The SIA and DR at IVCfat group were 21.62° ± 8.42°and 2.01 ±0.84 respectively,at control group were 16.75° ±7.82°(t =1.594,P >0.05) and 1.31 ±0.28(t =2.341,P < 0.05 ) respectively.ConclusionThe round,oval or half of limited fat density shadow adjaction to subdiaphragmatic inferior vena cava which similar to in the lumen is the characteristic performance of IVCfat,it may be an anatomical variation.
10.An experimental study of comparing digital tomosynthesis and multi-slice CT scanning for the detection of pulmonary nodules using the anthropomorphic chest phantom
Feng ZHAO ; Yongming ZENG ; Shengkun PENG ; Gang PENG ; Renqiang YU ; Huan TAN ; Wenjing CAI
Chinese Journal of Radiology 2012;46(4):363-366
ObjectiveTo compare detection rate of pulmonary nodules and the radiation doses of digital tomosynthesis (DTS) and MSCT chest scanning by using the anthropomorphic chest phantom which containsthermoluminescent dosimeters( TLD ) and simulated pulmonary nodules.Methods The radiation doses of DTS and MSCT scanning were measured by using the anthropomorphic chest phantom which contains 45 TLD and simulated pulmonary nodules.The radiation doses of najor organs were converted into effective dose ( ED ). Three radiologists of different clinical experiences independently reviewed and recorded the density,diameter and position of pulmonary nodules.The sensitivity of nodule detection by DTS and MSCT were compared by Fisher exact test and Chi-square test. The paired t test was conducted to analyze the dose levels of DTS and MSCT.ResultsThe sensitivity of detection nodule by DTS and MSCT were 66.7% (30/45) and 91.1% (41/45) respectively.Statistically significant difference between the two examinations existed ( x2 =8.073,P < 0.05).The sensitivity of detection - 650 HU ground glass opacity pulmonary nodule by MSCT and DTS were 93.3% (14/15) and 73.3% (11/15) respectively.There was no significant difference between DTS and MSCT ( P > 0.05 ).The sensitivity of detection - 800 HU ground glass opacity nodule and ground glass opacity nodule (d < 8 mm) by DTS were 33.3% (5/15) and 16.7% (2/12) respectively,which were lower than those by CT[80.0% (12/15) and 66.7% (8/12)].The radiation doses of DTS for various organs in the chest were lower than those of CT. Statistical significant difference between DTS and MSCT existed ( lung t =19.69,thoracic vertebral t =30.01,heart t =16.33,liver t =5.06,breast t =9.43,thyroid gland t =8.05 ;P < 0.05).The effective doses of the DTS and MSCT were 0.65 and 7.71 mSv respectively.ConclusionsThere is no difference between the DTS and MSCT in the detection rate of -650 HU ground glass opacity nodule.For detecting the ground glass opacity nodule ( - 800 HU) and ground glass opacity nodule (d < 8 mm),MSCT is superior to DTS. However,the radiation dosage of DTS is 8.41% of the MSCT scanning.