【作者】 李剑；

【导师】 王锡明； 李春卫；

【作者基本信息】 山东大学 ， 医学影像医学与核医学， 2010， 硕士

【摘要】 目的探讨双源CT(DSCT)在主动脉夹层诊断中的临床应用,并比较非心电门控、回顾性心电门控与前瞻性心电门控3种扫描技术的图像质量和辐射剂量。方法收集2008年8月-2009年11月间在本院疑诊主动脉夹层的115例患者[年龄36-77岁,平均(45.2±6.4)岁,心率49-107次／分(beat per minute, bpm),平均(83.3±6.5)bpm,所有患者心律齐,心率波动范围≤10 bpm,身体质量指数(body mass index, BMI)<30 kg/m2],随机将其分成3组(A组35例,B组41例,C组39例),3组分别采用西门子双源CT扫描机(Siemens Somatom Definition,2008G)行非心电门控、回顾性心电门控(RGH)及前瞻性心电门控(PGT)主动脉血管成像扫描,所有患者均经手术或传统主动脉造影介入治疗证实。分别由2名医师在双盲的情况下对主动脉及冠状动脉进行靶重组,结合薄层MIP、MPR、VRT及横断面图像,独立评价所有患者的图像质量。1.通过比较强化后主动脉CT值评价主动脉图像质量。主动脉CT值测量方法：测量并记录增强后升主动脉根部、同层面胸主动脉及主动脉末端分叉上方层面夹层真腔的CT值,计算三者平均值即为强化后主动脉的CT值,以主动脉强化后CT值≥200 Hu作为满足临床诊断要求的指标。2.记录3组患者满足临床诊断的可评价冠状动脉节段比例；3.记录所有患者的图像噪声(IN)、容积CT剂量指数(CTDIvol)和剂量长度乘积(DLP)。采用kappa检验,评价2名医师对主动脉图像质量评分的一致性,采用卡方检验比较冠状动脉图像质量,应用q检验(SNK检验)及秩和检验分析比较3组患者的图像质量和辐射剂量,以P＜0.05认为差异有统计学意义。结果115例患者均成功完成了DSCTA检查,3组患者主动脉强化后CT值均≥200 HU,可得到满足诊断要求的图像；2名医师对3组患者主动脉图像质量评价结果得到了较高的一致性的(Kappa值=0.76)；3组主动脉强化后CT值分别为(428.5±27.9)Hu, (337.6±39.4)Hu, (334.9±65.2)Hu, A、B及A、C两组间差异均有统计学意义(p<0.05),B、C两组间差异无明显统计学意义(p>0.05)；可满足临床诊断的可评价冠状动脉节段A组占58.40%(306／524),B组占98.70%(610／618),C组占97.76%(568／581),A、B及A、C两组间差异均有统计学意义(p<0.05),B、C组间差异无明显统计学意义(P=0.2976)；A、B、C三组图像噪声(IN)分别为(23.31±4.25)Hu,(14.39±3.52)Hu,(15.63±4.18)Hu, A、B及A、C两组间差异均有统计学意义(p<0.05),B、C两组间差异无统计学意义(p>0.05)。容积CT剂量指数(CTDIvol)分别为(10.15±1.07)mGy, (48.36±7.12)mGy, (18.78±1.17)mGy,每两组间差异均有统计学意义(p<0.05)；剂量长度乘积(DLP)分别为(459.02±44.18) mGyxcm, (2182.69±285.99) mGyxcm, (849.37±106.53) mGyxcm,每两组间差异均有统计学意义(p<0.05)。结论综合比较3种检查方法的辐射剂量和图像质量,得出DSCT前瞻性心电门控主动脉血管成像是主动脉夹层诊断的一种微创、安全、可靠的检查方法。更多还原

【Abstract】 ObjectiveTo explore the clinical application of dual-source computed tomography (DSCT) in aortic dissection(AD), and compare the image quality and radiation dosage among non ECG-gated scan, retrospectively ECG-gated spiral scan and prospectively ECG-gated traverse scan. Methods115 patients [age 36-77 years, mean age (45.2±6.4) years, HR 49-107 beats per minute (bpm), mean HR (83.3±6.5) bpm, with a stable HR, variability of HR≤10 bpm, body mass index (BMI):< 30 kg/m2] with suspected aortic dissection underwent CT angiography using dual-source computed tomography (DSCT, Siemens Somatom Definition,2008G). Grouping them into 3 groups, randomly. Group A (35 patients) was scanned with non ECG-gated scan, group B (41 patients) was scanned with retrospectively ECG-gated helical scan (RGH) and group C (39 patients) was scanned with prospectively ECG-gated traverse scan (PGT). All patients were confirmed by operation or conventional aortic angiography. All images were transferred to an external workstation (Leonardo; Siemens Medical Solutions) for further analysis. In addition to the CT axial slices,3D reconstructions (MPR, MIP, CPR and VRT were included) were used to reformat the aorta and coronary artery. Two experienced reviewers assessed the image quality double-blindly. 1.After enhancement scanning, average CT value were used to assess aortic images quality, which were calculated from average CT value of the root of ascending aorta,thoracic aorta at the same level and extremity of aorta. The study considered image quality to be diagnosable if CT value of aorta was≥200Hu.2. All coronary artery segments which met the need of clinical diagnosis in patients were recorded.3. All patients’ image noise (IN), CT dose index (CTDIvol) and dose length product (DLP) were recorded. The degree of inter-observer agreement in image quality of aorta was determined by Kappa test, and qualitative image quality of coronary artery was compared with chi-square test. Quantitative image noise and radiation dose were evaluated with q test (SNK) and the rank sun test. Statistical analyses were performed with SPSS version 13.0. A p-value<0.05 was considered to indicate a significant difference.ResultsDSCT aortic angiography in 115 patients was successful. The CT value of all patients were≥200Hu. There was a good agreement (Kappa value=0.76) between 2 readers in aortic image quality. The CT value of group A, B and C were (428.5±27.9) Hu, (337.6±39.4) Hu and (334.9±65.2) Hu, respectively, and there were significant differences between group A and B, group A and C (p<0.05) and there was no significant difference between group B and C (p>0.05). Diagnostic coronary artery segments were 58.40% (306/524),98.70% (610/618), and 97.76% (568/581) respectively, and there were significant differences between group A and B, group A and C (p<0.05) and there was no significant difference between group B and C p=0.2976). Image noise(IN) were (23.31±4.25) Hu, (14.39±3.52) Hu and (15.63±4.18) Hu, respectively, and there were significant differences between group A and B, group A and C (p<0.05) and there was no significant difference between group B and C (p>0.05). The CT dose index (CTDIvol) were (10.15±1.07) mGy, (48.36±7.12) mGy and (18.78±1.17) mGy, and there were significant differences between every two groups (p<0.05). The DLP were (459.02±44.18) mGyxcm, (2182.69±285.99) mGyxcm and (849.37±106.53) mGyxcm, and there were significant differences between every two groups (p<0.05)ConclusionComparing radiation dosage and image quality among the three scanning technique, dual-source CT (DSCT) prospectively ECG-gated traverse scan is a noninvasive, safe and reliable examination in AD diagnosis.更多还原