应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.     

双能CT双期增强扫描结合虚拟平扫对肾脏透明细胞癌的诊断价值

目的 探讨双能CT双期增强结合虚拟平扫对肾脏透明细胞癌的诊断价值.方法 对60例临床怀疑肾脏透明细胞癌的患者进行前瞻性研究,进行双能CT的单能平扫及双能皮髓交界早期、实质期增强扫描,采用虚拟平扫后处理软件生成虚拟平扫图像,分别根据虚拟平扫结合双期增强及单纯双期增强图像进行诊断,以病理结果为标准,计算两者诊断肾脏透明细胞癌的准确率,并以x2检验比较;以Wilcoxon秩和检验比较常规平扫和虚拟平扫图像对肿瘤的显示;以配对样本t检验比较患者所接受的单期X线辐射剂量和总辐射剂量差异、常规平扫与虚拟平扫图像肿瘤的CT值差异.结果 虚拟平扫结合双能CT双期增强图像对透明细胞癌的诊断准确率高于单纯双期增强[分别为93.3％ (56/60)和78.3％ (47/60);x2=5.6,P＜0.05].常规平扫显示42例肾透明细胞癌病灶,对肿瘤显示优、良、一般和差的分别为22、12、4和4例,虚拟平扫分别为26、10、3和3例,差异无统计学意义(Z=0.00,P=1.00).虚拟平扫的单期CTDIvol(8.85±1.28) mGy、DLP剂量(196.45±21.12) mGy·cm和总的CTDIvol( 17.69±2.35) mGy、DLP剂量(392.90±42.25) mGy·cm均低于常规平扫[分别为(10.20±1.44)mGy、(218.29±29.60) mGy·cm、(30.61±3.27) mGy和(654.86±88.81)mGy·cm],t值分别为4.21、3.58、23.63、16.12,P值均＜0.05.常规平扫和虚拟平扫的CT值分别为(34.94±7.00)和(39.37±6.35)HU,差异有统计学意义(t=-14.39,P＜0.05).结论 双能CT皮髓交界早期及实质期双期增强结合虚拟平扫对肾脏透明细胞癌的诊断价值较大,对多数患者可以做出准确诊断,并明显降低辐射剂量.     

应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.     

应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.     

应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.     

应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.     

应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.     

应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.     

应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.     

双源CT低管电压技术在超重患者冠状动脉成像中的应用

目的 探讨在超重患者双源CT冠状动脉成像中低管电压技术的应用价值,评价其图像质量和辐射剂量.方法 将66例接受双源CT冠状动脉检查,体质量<85 kg、且体质量指数(BMI)为25.0～30.0 ks/m2的患者完全随机化分为A、B 2组.A组30例,管电压为120 kVp;B组36例,管电压为100 kVp.所有患者均采用回顾性心电门控螺旋扫描和四维智能在线剂量调控(CARE Dose 4D)技术,严格控制扫描范围.对2组的扫描数据分别进行多种图像后处理,由影像科副主任医师和副主任技师各1名采用双盲法评估图像质量.测量并计算信噪比(SNR)、对比信噪比(CNR).记录CT容积剂量指数(CTDIvol)和剂量长度乘积(DLP),计算有效辐射剂量(ED).应用两独立样本t检验比较2组患者图像ROI的CT值、噪声、SNR、CNR、辐射剂量及对比剂用量、图像质量评分等.应用X2检验比较两组患者冠状动脉图像质量分级显示段数.应用Kappa检验判断2名评价者评分的一致性.以P<0.05为差异有统计学意义.结果 图像ROI内CT值、噪声(以标准差SD计算)、SNR测量值:A组右冠状动脉(RCA)起始部分别为(429.3±77.4)HU,24.0±8.2、21.8±9.9,左冠状动脉主干(LMA)起始部分别为(436.7±79.0)HU、19.4±7.3、22.3±9.8;B组RCA分别为(503.5±95.4)HU、34.0±12.6、21.0±10.7,LMA分别为(491.7±96.2)HU、33.4±15.5、20.6±11.4;CNR测量值:A组为24.4±10.3,B组为21.9±8.2.2组患者冠状动脉血管腔内强化平均CT值、噪声比较,B组大于A组,差异有统汁学意义(P值均<0.05);2组间SNR、CNR筹异无统计学意义(P值均>0.05);2组CTDIvol比较,A组为(42.2±13.8)mGy,B组为(20.2±6.5)mGy,差异有统计学意义(P<0.05);A组ED为(9.5±3.6)roSy,B组为(4.8±1.7)mSv,差异有统汁学意义(P<0.05);A组图像质量评分为(4.5±1.0)分,B组为(4.7±0.5)分,筹异无统计学意义(P>0.05);A绀评价383段冠状动脉,图像优良者377段(98.4%)B组评价490段冠状动脉,图像优良者483段(98.6%).结论 对于BMI在25.0～30.0 kg/m2的患者,使用100 kVp管电压配合CARE Dose 4D技术进行双源CT冠状动脉检查,可以获得较好的图像质量,并且可以显著降低辐射剂量.

Abstract：

Objective To investigate the image quality and the radiation dose of dual-source computed tomography coronary angiography by using low kilovohage combination with low tube current in overweight patients.Methods Sixty-six patients with body mass inde,(BMI)25.(0-30.0 kg/m2 and a body weight<85 kg were randomized two groups(group A and group B).Thirty patients in group A were examined with 120 kVp,and 36 patients in group B with 100 kVp.ECG-pulsing and care dose 4D for radiation dose reduction were used in all patients.All images were transferred to Siemens workstation for post processing and analysis.Two observers blimted to clinical data independently assessed the image quality of each coronary segment by using a 5-point scoring scale(5:excellent,1:no diagnostic).and measured the different image parameters including image noise,signal-to-noise ratio(SNR)and contrast-to-noise ratio (CNR).The effective dose(ED)was calculated by using CT dose volume index(CTDIvol)and the doselength product (DLP). The mean intraluminal attenuation, image noise, SNR, CNR, radiation dose,volume of contrast medium, and mean image quality scores were compared between the two groups with t test. The grading quantity of coronary artery segment was compared with Chi-square test. The interobserver agreement was determined by Kappa statistics. Results The mean intraluminal attenuation, image noise,SNR in group A were (429. 3±77.4 ) HU, 24.0±8.2, 21.8±9. 9 in right coronary artery ( RCA), and (436. 7±79. 0) HU, 19.4±7.3, 22. 3±9. 8 in left main coronary artery (LMA ), and that in group B were (503.5±95.4) HU, 34.0±12.6, 21.0±10.7 in RCA, and (491.7±96.2) HU, 33.4±15.5,20.6±11.4 in LMA. The CNR were 24.4±10.3 in group A and 21.9±8.2 in group B. The mean intraluminal attenuation and image noise were significantly higher for group B compared with group A ( P <0. 05 ). There were no difference in SNR and CNR between the two groups ( P > 0. 05 ). Estimated ED in group B was significantly lower than that in group A [CTDIvol = (42. 2±13. 8) mGy, ED = (9. 5±3.6)mSv in group A vs. CTDIvol = ( 20. 2±6.5 ) mGy, ED = (4. 8±1.7 ) mSv in group B ; each P < 0. 05 ].Mean image quality scores were not significantly different between two groups ( 4. 5±1.0 in group A vs.4. 7±0. 5 in group B, P > 0. 05 ). A total of 383 coronary artery segments were evaluated in group A and 490 segments in group B. The difference of grading quantity of coronary artery segment was no statistical significant between two groups. Conclusions 100 kVp combination with ECC-pulsing and CARE Dose 4D of dual-source CTCA was valuable for patients with BMI ranging from 25 to 30 kg/m2 which have a better image quality and low radiatiun dose.     

Can virtual non-enhanced CT be used to replace true non-enhanced CT for the detection of palpable cervical lymph nodes? A preliminary study

Purpose

To investigate the potential of virtual non-contrast CT (VNCT) from dual-energy CT to replace true nonenhanced CT (TNCT) for the detection of enlarged cervical lymph nodes.

Materials and methods

Thirty-nine patients with 94 histopathologically proven cervical lymph nodes were imaged with the dual-energy CT technique. VNCT images from the arterial [VNCT-A] and venous phases [VNCT-V] were obtained with the liver VNC application. The mean CT number and signal-to-noise ratio (SNR) were compared. Image quality was evaluated with a score scale of 1–5. Effective dose (ED) was calculated and compared.

Results

Mean CT numbers of cervical lymph nodes were higher on VNCT than on TNCT (P = 0.034). There was no difference in the SNR among three sets of non-enhanced CT images, but the CNR of VNCT images was higher than that of TNCT images (P < 0.001). Image quality of VNCT from two phases was comparable to that of TNCT (P = 0.070). There was no difference in image quality of three sets of non-enhanced CT images (P > 0.05). ED from dual-phase dual-energy CT was lower than that from tri-phase CT scans (P < 0.001).

Conclusion

VNCT images from dual-energy CT of the neck had diagnostic image quality; they have the potential to replace TNCT, thus reducing the radiation dose.     

Liver virtual non-enhanced CT with dual-source, dual-energy CT: a preliminary study

Purpose

To compare virtual non-enhanced liver CT (VNCT) from dual-energy CT (DECT) with true non-enhanced liver CT (TNCT) in patients.

Methods

A total of 102 patients underwent multi-phase abdominal CT. Liver arterial VNCT (VNCT_A) and portovenous VNCT (VNCT_V) images were derived from the arterial and portovenous DECT data. The mean CT number, signal to noise ratio (SNR), image quality, contrast to noise (CNR) of liver lesions, lesion detectability and radiation dose were compared.

Results

There was no difference in mean CT numbers of all organs (all P?>?0.05). SNR on VNCT images was higher than that of TNCT (all P?<?0.001). Image quality of VNCT was diagnostic but lower than that of TNCT (P?<?0.001). VNCT_A images were superior to VNCT_V (P?<?0.001). VNCT_A and VNCT_V detected 78 (91%) and 70 (81%) of 86 hepatic focal lesions visualised on TNCT. There was no difference in the size, attenuation and CNR of focal hepatic lesions (all P?>?0.05), but SNR of the lesions on VNCT was higher than that on TNCT (P?<?0.001). Radiation dose of biphase DECT was lower than that of routine triphase CT (P?<?0.001).

Conclusion

VNCT_A may potentially replace TNCT as part of a multi-phase liver imaging protocol with consequent saving in radiation dose.     

多层螺旋CT低剂量扫描技术在甲状腺增强扫描中的临床应用

目的：探讨多层螺旋 CT 低剂量扫描技术在甲状腺增强扫描中的临床应用价值。方法80例患者随机分为4组(每组各20例),4组分别为：A 组,120 kV、180 mA;B 组,120 kV、100 mA;C 组,100 kV、180 mA;D 组,100 kV、100 mA。主观评价图像质量并评分,统计甲状腺 CT 值、图像背景噪声(N)、图像信噪比(SNR)、CT 剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效辐射剂量(ED)并进行对比分析。结果4组图像主观评分为3.90±0.31、3.75±0.44、3.70±0.47、3.60±0.60,SNR 为26.34±3.13、25.08±1.87、25.86±2.38、24.87±2.20,四者无统计学差异(P >0.05);甲状腺 CT 值为(168.55±13.39)HU、(170.70±11.34)HU、(185.20±22.35)HU、(190.55±21.38)HU,N 为(6.48±0.84)HU、(6.83±0.45)HU、(7.19±0.86)HU、(7.66±1.01)HU, CTDIvol 为(10.95±0.00)mGy、(6.08±0.00)mGy、(6.59±0.00)mGy、(3.66±0.00)mGy,DLP 为(145.67±8.79)mGy·cm、(84.58±4.94)mGy·cm、(89.86±3.26)mGy·cm、(50.20±1.89)mGy·cm,ED 为(0.73±0.04)mSv、(0.42±0.03)mSv、(0.45±0.03)mSv、(0.25±0.01)mSv,四者有统计学差异(P <0.05)。结论多层螺旋 CT 低剂量扫描技术既能保证图像质量又能有效降低甲状腺增强 CT 检查的辐射剂量。     

双源CT不同扫描方式在肺动脉成像临床应用

目的 比较第一代与Flash双源CT不同扫描方式在肺动脉成像时剂量与图像质量.方法 收集120例临床疑诊为PE患者,按扫描方式随机分为4组：A组行第一代双源CT双能量扫描（80/140kV）,B组行flash双源CT双能量扫描（80/sn140kV）,C组行flash双源CT双能量扫描（100/sn140kV）,D组行flash双源CT双能量扫描（140/80kV）.比较4组间的CT容积剂量指数（CT dose volume index,CTDIvol）、剂量长度乘积（dose length product,DLP）、背景噪声和肺动脉信噪比.结果 各组间患者一般情况没有明显统计学差异.B组的CTDIvol,DLP值明显低于A、C两组,图像质量明显好于D组.结论 flash双源CT（80/sn140kV）在获得满意的图像质量的同时可以减低辐射剂量.     

自动管电流调节技术对主动脉夹层术后的评价及其辐射剂量的研究

目的探讨64排螺旋CT(MSCT),采用固定噪声指数(NI)的Z轴自动管电流调节(ATCM)技术在主动脉夹层术后CT造影中对图像质量及辐射剂量的影响。资料与方法随机将本院主动脉夹层术后的患者100例分为2组,每组50例。A组采用固定管电流扫描技术,均采用280 mA。B组采用Z轴ATCM扫描技术,管电流为100～350 mA,根据体重指数(BMI)不同分为两组:BMI>25 kg/m2者,NI=10;BMI<25 kg/m2者,NI=12,其余扫描参数均一致。将所有图像均传输至ADW 4.3工作站,进行三维及二维后处理,同时记录机器自动生成的CT剂量指数(CTDlvol)、相应剂量长度乘积(DLP)。结果 B组在不影响诊断的情况下,辐射剂量较A组CTDlvol降低了28.3%、DLP降低了30.4%。A组CTDIvol均值为(19.13±1.94)mGy;DLP均值为(1205.59±197.12)mGy.cm,B组BMI>25 kg/m2者CTDIvol均值为(14.82±2.97)mGy;DLP均值为(887.6±177.51)mGy.cm,BMI<25kg/m2者CTDIvol均值为(12.61±2.17)mGy;DLP均值为(789.86±139.33)mGy.cm,所有图像均能满足诊断需要。结论 64排螺旋CT采用固定NI的ATCM技术在主动脉夹层CT造影中可获得较好图像质量,在满足诊断需求的同时降低了患者辐射剂量。     

二代双源CT对冠状动脉支架的显示及辐射剂量的研究

目的 对比分析二代双源CT前瞻性心电触发高螺距螺旋扫描模式(Flash模式)和回顾性心电门控螺旋扫描模式(常规模式)下冠状动脉支架的显示质量和辐射剂量.方法 常规模式和Flash模式下共计120例患者的155个冠状动脉植入支架纳入本研究,平均年龄(64.9±10.6)岁,所有患者的心率均控制在≤65次/min,且心律规则.所有患者分成两组,分别接受Flash模式和常规模式的冠状动脉成像.冠状动脉原始图像均进行Kernel B26和Kernel B46的数据重建,并由两位医师对支架的显示质量进行独立的4级评分.两种模式下的冠状动脉显示质量利用卡方检验进行统计分析,而不同冠状动脉扫描模式下的容积CT剂量指数值(CTDIvol)和剂量长度乘积值(DLP),利用t检验进行辐射剂量的对比研究.结果 2位医师对所有冠状动脉支架显示质量的评分具有较好的一致性(Kappa=0.764,P＜0.001),Flash模式和常规模式的平均评分分别为:1.61±0.77和1.65±0.82.两种冠状动脉扫描模式的图像质量差异无统计学意义(x2=0.865,P=0.834).Flash模式的CTDIvol(3.24±1.21)明显低于常规模式(31.26±10.79),差异有统计学意义(t=19.83,P<0.001);Flash模式的DLP(54.61±19.88)同样低于常规模式(468.30±174.88),差异有统计学意义(t=18.06,P＜0.001).结论 控制患者心率≤65次/min且心律规则,Flash模式在降低辐射剂量的前提下可获得与常规模式相同质量的冠状动脉支架图像.

Abstract：

Objective To compare a prospective ECG-gated high-pitch spiral technique (Flash) and conventional retrospective ECG-gated spiral technique for the image quality of coronary artery stent and radiation dose with a dual source CT.Methods One hundred and fifty five coronary stents in one hundred and twenty patients (mean age 64.9 ± 10.6 years,heart rates≤65 bpm) were examined using a dual source CT.All patients were divided in two groups,receiving either Flash or conventional coronary artery CT angiography separately.After images of coronary artery were reconstructed using both the smooth (B26) and sharp (B46) kernel,the coronary stent image quality and stent lumen were scored by two observers individually using four point scale (1 = excellent,4 = unvaluable) .The effective radiation dose of volume CT dose index (CTDIvol,mGy) and dose length product (DLP,mGy x cm) were also calculated for each patient.x2-test analysis of image quality and t-test analysis of radiation dose were used respectively for statistical difference between two groups.Results Interobserver agreement for stent image quality was good (Kappa =0.764,P＜0.001).The mean scores were 1.61 ±0.77 and 1.65 ±0.82 in Flash group and conventional group respectively.There was no significant difference in image quality between the two groups (x2 = 0.865,P = 0.834).The effective radiation dose in Flash group was significantly lower than that in conventional group.The mean values of CTDIvol were 3.24 ± 1.21 in Flash group and 31.26 ± 10.79 in conventional group (t = 19.83,P < 0.001) ,and the mean values of DLP in Flash group and conventional group were 54.61 ±19.88 and 468.30 ± 174.88,respectively (t = 18.06,P < 0.001).Conclusions Compared with the conventiaonal coronary artery CT angiography,the Flash coronary artery CT angiography technique has a similar coronary stent image quality,but at a lower radiation dose in patients with heart rates lower than 65 beats per minute.     

双源CT双能量心肌灌注成像的图像质量及辐射剂量研究

目的：探讨运用双源CT双能量技术行冠状动脉血管成像的图像质量和辐射剂量。方法：204例患者分为两组行双源CT冠状动脉血管造影检查,A组采用双能量扫描方案,B组采用传统单能量扫描方案,比较两组的图像质量及辐射剂量。结果：A、B两组冠状动脉图像质量评分分别为（4.70±0.72）分、（4.70±0.71）分,两组间差异无统计学意义（t=-1.000,P=0.318）。A、B两组图像左、右冠状动脉信噪比（SNR）分别为A组20.0±3.4和19.0±3.0、B组20.1±3.2和19.9±3.2,且两组间差异均无统计学意义（t=1.967,P=0.051;t=-0.233,P=0.816）。A、B两组的容积CT剂量指数（CTDIvol）、剂量长度乘积（DLP）、有效辐射剂量（ED）分别为（48.27±8.70）mGy、（54.10±8.77）mGy;（565.63±115.48）mGy.cm、（702.75±144.04）mGy.cm;（9.62±1.96）mSv、（11.95±2.45）mSv,A组的CTDIvol、DLP及ED明显低于B组,差异均有统计学意义（t=-4.764,P=0.000;t=-7.501,P=0.000;t=-7.501,P=0.000）。结论：双能量心肌灌注成像技术在不降低图像质量的情况下,能够显著降低患者的有效辐射剂量,有很高的临床应用价值。     

64层螺旋CT自动毫安技术对降低下肢动脉 血管成像辐射剂量的研究

目的 探讨64层螺旋CT自动毫安技术(ATCM)对降低下肢动脉血管成像辐射剂量的可行性。方法 通过预实验改变噪声指数(NI)调节管电流,得出NI值为10 HU时图像质量与辐射剂量匹配较佳。搜集52例疑有下肢动脉闭塞糖尿病及高血压病患者病例,随机分为实验组和对照组行自肾下腹主动脉至足底的CT容积扫描,每组病例26例。对照组采用常规固定300 mA(FM组),实验组采用NI为10 HU的自动毫安(ATCM组)技术。分别选择肾下腹主动脉、髋关节水平股动脉、 NFDB1 动脉及踝关节胫前动脉平面作为观察平面,对两种毫安技术的图像质量、图像噪声和辐射剂量均采用 t 检验方法进行统计学分析。结果 FM组的辐射剂量CTDI_vol为10.81 mGy,平均DLP为(1280.4±124.7)mGy·cm,ATCM组的平均CTDI_vol为(5.14±1.23)mGy,平均DLP为(582.86±150.41)mGy·cm,比FM组降低约54.4%,两组差异有统计学意义(CTDI_vol、DLP的 t 值分别为13.13、17.36, P 值均<0.05)。FM组的4个选取平面图像噪声分别为13.8±4.04、14.53±2.79、5.69±1.38、(4.75±1.38) HU。ATCM组分别为10.76±2.11、12.13±2.96、10.47±2.96、(6.17±1.53) HU,两组差异有统计学意义( t 值分别为2.911、3.038、7.287及3.186, P 值均<0.05),ATCM组肾下腹主动脉、髋关节水平股动脉层面的图像噪声较FM组的低,而 NFDB1 动脉、踝关节胫前动脉层面的图像噪声较FM组的高,ATCM组图像噪声变异度小,图像更加均匀。FM组图像质量评分平均为2.654±0.562,ATCM组图像评分平均为2.462±0.582,两组图像质量评分差异无统计学意义( t =1.21, P ＞0.05)。结论 使用噪声指数为10的下肢动脉ATCM技术,在保证图像质量的情况下可以降低辐射剂量约54.4%。     

应用心电脉冲技术降低64层螺旋CT冠状动脉成像的辐射剂量

目的 评价心电脉冲(ECG-pulsing)技术对降低CT冠状动脉成像射线剂量的价值及其对图像质量的影响.方法 2007年10月26日到2008年3月12日期间,配合良好,心率控制在80次/min以下,且心律齐的连续受检者59例,采用完全随机化分组方法分为2组,组1(29例)使用传统方法进行CT冠状动脉成像检查,组2(30例)使用ECG-pulsing技术,通过CT机自动得到平均容积CT剂量指数(CT dose index volume,CTDIvol)和剂量长度乘积(dose length product,DLP),计算出相应的有效剂量(effective dose,ED).获得的图像通过双盲法进行质量评分,对两组CTDIvol值、ED值及图像质量评分用t检验进行比较.结果 (1)组1和组2的CTDIvol值分别为(70.0±1.1)和(39.0±2.7)mGy,ED值分别为(16.8±2.0)和(9.5±1.7)msv,两者之间差异均有统计学意义(t值分别为57.675、15.346,P值均<0.01).(2)组1和组2冠状动脉各段图像质量平均评分分别为:组1(3.8±0.2)分,组2(3.8±0.1)分,差异无统计学意义(t=-0.222,P>0.05).结论 64层螺旋CT冠状动脉造影检查时合理运用ECG-pulsiag技术可大幅度降低辐射剂量且不影响图像质量.     

中国人仿真胸部体模检测多层螺旋CT扫描组织器官剂量的研究

目的 利用中国人仿真胸部模型来测量不同噪声指数下胸部各组织器官的吸收剂量,计算有效剂量(ED)并对MSCT胸部扫描进行剂量评估.方法 对CDP-1C型中国人仿真胸部体模在CT体层解剖和X线衰减两方面进行等效性论证;通过在体模内布放热释光剂量计(TLD)来测量不同噪声水平下各组织器官的吸收剂量,并记录相应的剂量长度乘积(DLP);将两者分别换算为ED后选择单因素t检验方法进行对比研究,分析自动管电流调制(ATCM)技术时不同噪声指数胸部CT扫描的剂量水平.结果 中国人仿真胸部体模与成人CT胸部图像的结构相似.体模主要器官平均CT值为肺-788.04 HU、心脏45.64 HU、肝脏65.84 HU、脊柱254.32 HU,与成人偏差程度分别为肺0.10%、心脏3.04%、肝脏4.49%、脊柱4.36%.肝脏的平均CT值差异有统计学意义(t=-8.705,P＜0.05);肺、心脏和脊柱平均CT值与人体差异无统计学意义(t值分别为-0.752、-1.219、-1.138,P＞0.05).当噪声指数从8.5逐渐增至22.5时,DLP从393.57 mGy·cm递减至78.75 mGy·cm,各器官吸收剂量呈下降趋势(以肺为例,平均吸收剂量从22.38 mGy递减至3.66 mGy).应用DLP所计算的ED较器官吸收剂量计算的ED偏低(以噪声指数为8.5为例,两种方法的ED分别为6.69和8.77 mSv).结论 应用中国人仿真体模来进行CT剂量评估更为准确;基于ATCM技术的胸部CT扫描噪声指数设定至少应大于8.5.

Abstract：

Objective Using the Chinese anthropomorphic chest phantom to measure the absorbed dose of various tissues and organs under different noise index, and to assess the radiation dose of MSCT chest scanning with the effective dose(ED). Methods The equivalence of the Chinese anthropomorphic chest phantom(CDP-1C) and the adult chest on CT sectional anatomy and X-ray attenuation was demonstrated. The absorbed doses of various tissues and organs under different noise index were measured by laying thermoluminescent dosimeters(TLD) inside the phantom, and the corresponding dose-length products(DLP) were recorded. Both of them were later converted into ED and comparison was conducted to analyze the dose levels of chest CT scanning with automatic tube current modulation (ATCM) under different noise index. Student t-test was applied using SPSS 12.0 statistical software. Results The Phantom was similar to the human body on CT sectional anatomy. The average CT value of phantom are -788.04 HU in lung,45.64 HU in heart,65.84 HU in liver,254.32 HU in spine and the deviations are 0.10%,3.04%, 4.49% and 4.36% respectively compared to humans. The difference of average CT value of liver was statistically significant(t=-8.705,P＜0.05),while the differences of average CT values of lung, heart and spine were not significant(t value were -0.752,-1.219,-1.138,respectively and P＞0.05).As the noise index increased from 8.5 to 22.5, the DLP decreased from 393.57 mGy·cm to 78.75 mGy·cm and the organs dose declined. For example, the average absorbed dose decreased from 22.38 mGy to 3.66 mGy in lung. Compared to ED calculating by absorbed dose, the ED calculating by DLP was lower. The ED values of the two methods were 6.69 mSv and 8.77 mSv when the noise index was set at 8.5. Conclusions Application of the Chinese anthropomorphic chest phantom to carry out CT dose assessment is more accurate. The noise index should be set more than 8.5 during the chest CT scanning based on ATCM technique.