胸部%体层摄影术,X线计算机%诊断技术和方法%辐射剂量
胸部%體層攝影術,X線計算機%診斷技術和方法%輻射劑量
흉부%체층섭영술,X선계산궤%진단기술화방법%복사제량
Thorax%Tomography,X-ray computed%Diagnostic techniques and procedures%Radiation dosage
目的 比较自动曝光控制技术(AEC)与管电流恒定技术(CCC)2种不同低剂量MSCT扫描方案对胸部CT图像质量的影响,探讨更加合理的肺低剂量扫描参数方案.方法 采用前瞻性多中心研究方法,研究对象为7所医院就诊的280例行胸部低剂量MSCT检查的受检者,设定管电流(mA)为研究变量,方法一为AEC技术,下设噪声标准差值(SD)为25(A1)及30(A2)各1组,并设定管电流上限为80 mA,下限为10 mA;方法二为CCC技术,下设40 mA(C1)及50 mA(C2)各1组;共4组,采用同一机型64层MSCT行胸部低剂量扪描.2名放射科医师应用双肓法阅片,比较2种不同扫描技术的曝光剂量、SD值,横断面、MPR的图像质量以及体质量指数(BMI)对图像质量的影响.曝光剂量及SD比较行方差分析及t检验;图像质量比较行Mann-Whitney检验;医师对图像诊断一致性检验行Kappa分析.结果 剂量长度乘积(DLP)AEC组较CCC组明显降低[(82.62±40.31)和(110.81±18.21)mGy·cm,F=56.88,P＜0.01].AEC技术中A2组DLP较A1组低[(72.77±36.68)和(92.46±41.61)mGy·cm],差异无统计学意义(t=0.82,P＞0.05).前者SD值在肺窗[(41.50±9.58)和(40.86±7.03)HU]及纵隔窗[(41.19±7.83)和(40.92±9.89)HU]均略高于后者,差异无统计学意义(F肺窗=0.835、1.910,P值均＞0.05).横断面图像质量AEC组肺窗得分除右下肺静脉水平[(4.92±0.25)和(4.93±0.17)分]、[左膈顶上缘水平(4.91±0.27)和(4.93±0.22)分]较CCC组略低外,AEC组得分均较CCC组略高[头臂静脉上缘(4.49±0.56)和(4.38±0.64)分;主动脉弓上缘(4.86±0.23)和(4.81±0.32)分;右肺上叶支气管开口(4.87±0.27)和(4.84±0.22)分;右肺中叶支气管开口(4.90±0.25)和(4.88±0.21)分],差异无统计学意义(F=0.076～1.748,P值均＞0.05);纵隔窗得分除头臂静脉上缘水平AEC组较CCC组高[(2.57±0.77)和(2.46±0.59)分],且差异有统计学意义(F=8.459,P=0.047)外,余各层面AEC组得分均较CCC组略低[(主动脉弓上缘(3.36±0.63)和(3.45±0.60)分;右肺上叶支气管开口(3.94±0.56)和(3.95±0.51)分;右肺中叶支气管开口(3.80±0.58)和(3.87±0.50)分;右下肺静脉(3.72±0.56)和(3.78±0.53)分;左膈顶上方(3.58±0.63)和(3.68 ±0.56)分],但差异均无统计学意义(F=0.083～3.380,P值均＞0.05).MPR图像质量肺窗及纵隔窗观察均略好于CCC组(Z肺窗=-2.358,Z纵隔窗=-1.330,P值均＞0.05).偏瘦、正常或偏重人群组,A1组肺窗及纵隔窗图像质量均优于A2组,差异无统计学意义(偏瘦:Z肺窗=0.000、Z纵隔窗=0.000;正常:Z肺窗=-0.062、Z纵隔窗=-0.746;偏重:Z肺窗=-1.177、Z纵隔窗=-1.715;P值均＞0.05),但在偏重人群纵隔窗图像质量A1组更好于A2组(Z=-1.715,P=0.144).结论 AEC组总曝光剂量明显低于CCC组,而AEC组的图像质量及SD值无论在肺窗或纵隔窗均与CCC组无明显差异,故建议在胸部低剂量筛查方案选择中应用AEC技术,对偏胖者宜采用SD=25方案,对正常及偏瘦者宜采用SD=30方案.
目的 比較自動曝光控製技術(AEC)與管電流恆定技術(CCC)2種不同低劑量MSCT掃描方案對胸部CT圖像質量的影響,探討更加閤理的肺低劑量掃描參數方案.方法 採用前瞻性多中心研究方法,研究對象為7所醫院就診的280例行胸部低劑量MSCT檢查的受檢者,設定管電流(mA)為研究變量,方法一為AEC技術,下設譟聲標準差值(SD)為25(A1)及30(A2)各1組,併設定管電流上限為80 mA,下限為10 mA;方法二為CCC技術,下設40 mA(C1)及50 mA(C2)各1組;共4組,採用同一機型64層MSCT行胸部低劑量捫描.2名放射科醫師應用雙肓法閱片,比較2種不同掃描技術的曝光劑量、SD值,橫斷麵、MPR的圖像質量以及體質量指數(BMI)對圖像質量的影響.曝光劑量及SD比較行方差分析及t檢驗;圖像質量比較行Mann-Whitney檢驗;醫師對圖像診斷一緻性檢驗行Kappa分析.結果 劑量長度乘積(DLP)AEC組較CCC組明顯降低[(82.62±40.31)和(110.81±18.21)mGy·cm,F=56.88,P＜0.01].AEC技術中A2組DLP較A1組低[(72.77±36.68)和(92.46±41.61)mGy·cm],差異無統計學意義(t=0.82,P＞0.05).前者SD值在肺窗[(41.50±9.58)和(40.86±7.03)HU]及縱隔窗[(41.19±7.83)和(40.92±9.89)HU]均略高于後者,差異無統計學意義(F肺窗=0.835、1.910,P值均＞0.05).橫斷麵圖像質量AEC組肺窗得分除右下肺靜脈水平[(4.92±0.25)和(4.93±0.17)分]、[左膈頂上緣水平(4.91±0.27)和(4.93±0.22)分]較CCC組略低外,AEC組得分均較CCC組略高[頭臂靜脈上緣(4.49±0.56)和(4.38±0.64)分;主動脈弓上緣(4.86±0.23)和(4.81±0.32)分;右肺上葉支氣管開口(4.87±0.27)和(4.84±0.22)分;右肺中葉支氣管開口(4.90±0.25)和(4.88±0.21)分],差異無統計學意義(F=0.076～1.748,P值均＞0.05);縱隔窗得分除頭臂靜脈上緣水平AEC組較CCC組高[(2.57±0.77)和(2.46±0.59)分],且差異有統計學意義(F=8.459,P=0.047)外,餘各層麵AEC組得分均較CCC組略低[(主動脈弓上緣(3.36±0.63)和(3.45±0.60)分;右肺上葉支氣管開口(3.94±0.56)和(3.95±0.51)分;右肺中葉支氣管開口(3.80±0.58)和(3.87±0.50)分;右下肺靜脈(3.72±0.56)和(3.78±0.53)分;左膈頂上方(3.58±0.63)和(3.68 ±0.56)分],但差異均無統計學意義(F=0.083～3.380,P值均＞0.05).MPR圖像質量肺窗及縱隔窗觀察均略好于CCC組(Z肺窗=-2.358,Z縱隔窗=-1.330,P值均＞0.05).偏瘦、正常或偏重人群組,A1組肺窗及縱隔窗圖像質量均優于A2組,差異無統計學意義(偏瘦:Z肺窗=0.000、Z縱隔窗=0.000;正常:Z肺窗=-0.062、Z縱隔窗=-0.746;偏重:Z肺窗=-1.177、Z縱隔窗=-1.715;P值均＞0.05),但在偏重人群縱隔窗圖像質量A1組更好于A2組(Z=-1.715,P=0.144).結論 AEC組總曝光劑量明顯低于CCC組,而AEC組的圖像質量及SD值無論在肺窗或縱隔窗均與CCC組無明顯差異,故建議在胸部低劑量篩查方案選擇中應用AEC技術,對偏胖者宜採用SD=25方案,對正常及偏瘦者宜採用SD=30方案.
목적 비교자동폭광공제기술(AEC)여관전류항정기술(CCC)2충불동저제량MSCT소묘방안대흉부CT도상질량적영향,탐토경가합리적폐저제량소묘삼수방안.방법 채용전첨성다중심연구방법,연구대상위7소의원취진적280례행흉부저제량MSCT검사적수검자,설정관전류(mA)위연구변량,방법일위AEC기술,하설조성표준차치(SD)위25(A1)급30(A2)각1조,병설정관전류상한위80 mA,하한위10 mA;방법이위CCC기술,하설40 mA(C1)급50 mA(C2)각1조;공4조,채용동일궤형64층MSCT행흉부저제량문묘.2명방사과의사응용쌍황법열편,비교2충불동소묘기술적폭광제량、SD치,횡단면、MPR적도상질량이급체질량지수(BMI)대도상질량적영향.폭광제량급SD비교행방차분석급t검험;도상질량비교행Mann-Whitney검험;의사대도상진단일치성검험행Kappa분석.결과 제량장도승적(DLP)AEC조교CCC조명현강저[(82.62±40.31)화(110.81±18.21)mGy·cm,F=56.88,P＜0.01].AEC기술중A2조DLP교A1조저[(72.77±36.68)화(92.46±41.61)mGy·cm],차이무통계학의의(t=0.82,P＞0.05).전자SD치재폐창[(41.50±9.58)화(40.86±7.03)HU]급종격창[(41.19±7.83)화(40.92±9.89)HU]균략고우후자,차이무통계학의의(F폐창=0.835、1.910,P치균＞0.05).횡단면도상질량AEC조폐창득분제우하폐정맥수평[(4.92±0.25)화(4.93±0.17)분]、[좌격정상연수평(4.91±0.27)화(4.93±0.22)분]교CCC조략저외,AEC조득분균교CCC조략고[두비정맥상연(4.49±0.56)화(4.38±0.64)분;주동맥궁상연(4.86±0.23)화(4.81±0.32)분;우폐상협지기관개구(4.87±0.27)화(4.84±0.22)분;우폐중협지기관개구(4.90±0.25)화(4.88±0.21)분],차이무통계학의의(F=0.076～1.748,P치균＞0.05);종격창득분제두비정맥상연수평AEC조교CCC조고[(2.57±0.77)화(2.46±0.59)분],차차이유통계학의의(F=8.459,P=0.047)외,여각층면AEC조득분균교CCC조략저[(주동맥궁상연(3.36±0.63)화(3.45±0.60)분;우폐상협지기관개구(3.94±0.56)화(3.95±0.51)분;우폐중협지기관개구(3.80±0.58)화(3.87±0.50)분;우하폐정맥(3.72±0.56)화(3.78±0.53)분;좌격정상방(3.58±0.63)화(3.68 ±0.56)분],단차이균무통계학의의(F=0.083～3.380,P치균＞0.05).MPR도상질량폐창급종격창관찰균략호우CCC조(Z폐창=-2.358,Z종격창=-1.330,P치균＞0.05).편수、정상혹편중인군조,A1조폐창급종격창도상질량균우우A2조,차이무통계학의의(편수:Z폐창=0.000、Z종격창=0.000;정상:Z폐창=-0.062、Z종격창=-0.746;편중:Z폐창=-1.177、Z종격창=-1.715;P치균＞0.05),단재편중인군종격창도상질량A1조경호우A2조(Z=-1.715,P=0.144).결론 AEC조총폭광제량명현저우CCC조,이AEC조적도상질량급SD치무론재폐창혹종격창균여CCC조무명현차이,고건의재흉부저제량사사방안선택중응용AEC기술,대편반자의채용SD=25방안,대정상급편수자의채용SD=30방안.
Objective To compare the image quality of chest low dose CT (LDCT) using automatic exposure control (AEC) and constant current control (CCC) and explore a more reasonable scanning protocol. Methods Two hundred and eighty participants were examined with 64 CT scanner at 7 centers in China. All were divided into 4 groups. Two groups underwent LDCT using AEC with standard deviation set at 25 (A1) and 30 (A2) respectively and the tube current ranged from 10 mA to 80 mA. The other two groups underwent LDCT using CCC with tube current set at 40 mA (C1) and 50 mA (C2) respectively. The axial and MPR images were evaluated by two radiologists who were blinded to the scanning protocols.The radiation dose, noise and the image quality of the 4 groups were compared and analyzed statistically.Differences of radiation dose and noise among groups were determined with variance analysis and t test,image quality with Mann-Whitney test and the consistency of diagnosis with Kappa test. Results There was a significant lower DLP in AEC group than in CCC group [(82.62±40.31)vs ( 110.81±18.21) mGy·cm (F =56. 88 ,P ＜ 0. 01 )], whereas no significant difference was observed between group A2 and group A1 0. 05]. The noisy of AEC group was higher than that of CCC group both on lung window(41.50±9.58 vs 40.86±7.03) and mediastinum window (41.19±7.83 vs 40.92±9.89), but there was no significant difference( Flung =0.835, P=0.476, Fmediastinum =1.910, P=0.128).The quality score of axial image in AEC group was higher than that in CCC group (superior margin of the brachiocephalic vein level: 4.49±0.56 vs4.38±0.64,superior margin of the aortic arch: 4.86±0.23 vs 4.81±0.32,the right superior lobar bronchus Level:4.87±0.27 vs 4. 84 ± 0. 22, the right middle lobar bronchus Level: 4.90±0.25 vs 4.88±0.21) except on the right inferior pulmonary vein level(4. 92 ±0. 25 vs 4. 93 ±0. 17) and superior margin of the left diaphragmatic dome level (4. 91±0.27 vs 4.93±0.22) on lung window, but no significant differences (F=0.076-1.748, P＞0.05) were observed. A significant higher score in AEC group was observed on mediastinum window compared with CCC group on superior margin of brachiocephalic vein level (2.57±0.77 vs 2. 46 ± 0. 59, F = 8. 459, P ＜ 0. 05 ), however, the score of AEC group was lower than that of CCC group on other levels without significant differences (superior margin of the aortic arch:3.36 ±0. 63 vs 3.45 ±0. 60,the right superior lobar bronchus level: 3.94 ±0. 56 vs 3. 95 ±0. 51 ,the right middle lobar bronchus Level: 3.80 ±0. 58 vs 3. 87 ±0. 50,the right inferior pulmonary vein level: 3.72 ±0. 56 vs 3.78 ±0. 53, superior margin of the left diaphragmatic dome level: 3.58 ± 0.63 vs 3.68±0.56,F=0.083-3.380,P ＞ 0.05 ). The MPR image quality of AEC group was better than that of CCC group both on lung window and mediastinum window (Zlung =-2.258, Zmedlastinum=-1.330, P＞0.05). For all participants including the underweighted group, the normal group and the overweighted group, the image quality of A1 group was better than that of A2 group without significant differences (the underweighted group: Zlung=0.000, P=1.000, Zmedastinum= 0.000, P=1.000;the normal group: Zlung =-0.062, P=0.950, Zmediastinum =-0.746, P = 0.456; the overweighted group: Zlung = - 1.177, P = 0.239,Zmediastinum =-1.715, P=0.144) both on lung and mediastinum windows, and for the higher BMI participants, a better image quality was obtained in A1 group than in A2 group on the mediastinum window (Z = -1. 715, P = 0. 144). Conclusions The total radiation exposure dose of AEC group is significantly lower than that of CCC group, but no statistical significant differences are observed between both groups in image quality and noise level. The AEC technique is highly recommended in thoracic LDCT scan for screening program, and the SD25 ( SD value = 25) scan protocol is suggested for higher BMI population while the SD30 (SD value = 30) scan protocol for lower BMI population.
