CAJ | 학술논문

目的：探讨70 kV管电压在头颅CT血管成像中的可行性。方法：80例临床疑似脑血管疾病的患者随机分成2组，其中40例患者行新双源 CT 70kV 头颅 CT 血管成像（70kV 组），另40例患者行120 kV 头颅 CT 血管成像（120 kV组）。测量每例患者颈内动脉、大脑中动脉CT 值，计算信噪比（SNR）和对比噪声比（CNR）。两名放射医师对所有病例以4分法对图像质量进行评分。计算有效剂量（ED）。比较两组间的图像质量及辐射剂量。结果：70 kV组颈内动脉及大脑中动脉的平均CT值[（511．1±93．8）HU，（459．1±83．4）HU]高于120 kV 组的 CT 值[（289．1±46．6）HU，（260．9±43．4）HU，P＜0．001]。70 kV 组图像噪声[（18．3±2．1）HU]高于120 kV 组[（8．7±1．0）HU，P＜0．001]，70 kV组的SNR颈内动脉，CNR颈内动脉及SNR大脑中动脉，CNR 大脑中动脉（28．3±6．1，26．2±5．9及25．4±5．3，23．3±5．2）低于120 kV组（33．9±7．5，30．1±7．1及30．7±7．4，26．9±6．9，P＜0．05）。70 kV组的主观评分（3．5±0．7）与120 kV组（3．6±0．5，P＝0．22）无显著性差异；两组读者间一致性为中等（kappa值＝0．54，0．59，P＜0．001）。70 kV组与120 kV组ED分别为（0．2±0．0）、（1．2±0．1）mSv（P＜0．001），辐射量降低了80％。结论：70 kV管电压在头颅CT血管成像中是可行的，能在降低辐射量的同时保持足够的图像质量。
목적：탐토70 kV관전압재두로CT혈관성상중적가행성。방법：80례림상의사뇌혈관질병적환자수궤분성2조，기중40례환자행신쌍원 CT 70kV 두로 CT 혈관성상（70kV 조），령40례환자행120 kV 두로 CT 혈관성상（120 kV조）。측량매례환자경내동맥、대뇌중동맥CT 치，계산신조비（SNR）화대비조성비（CNR）。량명방사의사대소유병례이4분법대도상질량진행평분。계산유효제량（ED）。비교량조간적도상질량급복사제량。결과：70 kV조경내동맥급대뇌중동맥적평균CT치[（511．1±93．8）HU，（459．1±83．4）HU]고우120 kV 조적 CT 치[（289．1±46．6）HU，（260．9±43．4）HU，P＜0．001]。70 kV 조도상조성[（18．3±2．1）HU]고우120 kV 조[（8．7±1．0）HU，P＜0．001]，70 kV조적SNR경내동맥，CNR경내동맥급SNR대뇌중동맥，CNR 대뇌중동맥（28．3±6．1，26．2±5．9급25．4±5．3，23．3±5．2）저우120 kV조（33．9±7．5，30．1±7．1급30．7±7．4，26．9±6．9，P＜0．05）。70 kV조적주관평분（3．5±0．7）여120 kV조（3．6±0．5，P＝0．22）무현저성차이；량조독자간일치성위중등（kappa치＝0．54，0．59，P＜0．001）。70 kV조여120 kV조ED분별위（0．2±0．0）、（1．2±0．1）mSv（P＜0．001），복사량강저료80％。결론：70 kV관전압재두로CT혈관성상중시가행적，능재강저복사량적동시보지족구적도상질량。
Objective:To explore the radiation dose and image quality of cerebral CT angiography using 70kVp tube voltage.Methods:Eighty patients with clinically suspected cerebrovascular disease were divided into two groups.One group (40 patients)underwent cerebral CT angiography with 70kVp tube voltage,while the other group (40 patients)underwent conventionaltube voltage (120kVp)cerebral CT angiography.The CT values of the internal carotid artery (ICA)and the middle cerebral artery (MCA)in each patient were measured.Signal-to-noise ratio (SNR)and contrast-to-noise ratio (CNR)in each patient were also calculated.Two observers blindly evaluated the image quality using a 4-point scale.Effec-tive dose (ED)was calculated for each patient.Results:The 70kVp group showed higher CT values [(511.1±93.8)HU, (459.1±83.4)HU]than 120kVp group [(289.1±46.6)HU,(260.9±43.4)HU,P<0.001).Image noise of 70kVp group [(18.3±2.1)HU]was higher than 120kVp group [(8.7±1.0)HU,P<0.001],the SNRICA,CNRICA and SNRMCA, CNRMCA (28.3±6.1,26.2±5.9 vs 25.4±5.3,23.3±5.2)of 70kV group were lower than 120kV group (33.9±7.5, 30.1±7.1 vs 30.7±7.4,26.9±6.9;P<0.05).There were no significant differences between the 70kVp group (3.5± 0.7)and the 120kVp group (3.6±0.5,P= 0.22)regarding the mean score.Moderate interreader agreement was found for both groups (kappa values were 0.54 and 0.59,all the P value<0.001).ED were (0.2±0.0)mSv and (1.2±0.1)mSv for 70kVp and 120kVp groups (P<0.001)respectively,and the average effective dose was decreased by 80% in the 70kVp group.Conclusion:The application of 70kVp in cerebral CT angiography is feasible,it can reduce radiation dose without no-ticeable loss in diagnostic quality.