多层螺旋CT冠状动脉成像质量与辐射剂量的相关性研究

发布时间：2018-04-05 07:01

  本文选题：256层螺旋CT　切入点：冠状动脉疾病　出处：《蚌埠医学院》2013年硕士论文

【摘要】：目的:通过优化多层螺旋CT（Multi-sliceSpiral Computed Tomography，MSCT）冠状动脉成像的扫描条件，探讨降低辐射剂量的不同扫描方法在无创性MSCT冠状动脉造影（Coronary CT Angiography，CCTA）中的临床应用价值及其局限性，旨在降低辐射剂量同时保证诊断图像质量，以减少对病人的危害。方法:设备采用256层螺旋CT(BrillianceiCT，Philips，荷兰)。按拟定的排除标准，共180例病人纳入本研究，共分为A、B、C三组，每组60例；A组:常规回顾性心电门控组（对照组）；B组:前瞻性心电门控组；C组:基于BMI优化管电流回顾性心电门控组。所有病人随机分组。三组扫描条件设定：管电压均设为120kV；管电流均基于病人体质量指数（Bodymassindex，BMI）选择。三组对比剂均选用非离子型碘对比剂碘普罗胺（Iopromide，370mgI/ml，拜耳医药）。记录每例病人的性别、年龄、体重、身高、BMI、平均心率及扫描长度；并测量原始轴位冠状动脉增强图像上的升主动脉根部（SI1）、右冠状动脉近段（SI2）、左主干（SI3）的CT值，然后计算三者强化的平均值（SI4），同时测量胸大肌的CT值（SI5）。图像噪声（Background noise,BN）用测量升主动脉根部CT值的标准差（Standard deviation,SD）表示。根据拟定的公式：SI4=(SI1+SI2+SI3)／3；SNR=SI4／BN；CNR=(SI4－SI5)／BN；计算出图像质量的客观评估指标，即信号噪声比（Signalnoiseratio,SNR）和对比度噪声比(Contrastnoiseratio,CNR)。根据美国心脏学会（American Heart Association,AHA）冠状动脉16节段分法,评估冠状动脉主支共10个节段的主观图像质量，即右冠状动脉（RCA）、左主干（LM）、前降支（LAD）及回旋支（LCX）；采用4分制半定量对冠状动脉节段进行评分：4分（优秀），3分（良好），2分（中等），1分（差），其中以≥2分能满足诊断要求的标准。同时记录检查时由计算机自动生成的容积CT剂量指数（CTDIVOL）和剂量长度乘积（DLP），并计算出有效辐射剂量（ED）。然后对三组病人的基本资料、客观与主观图像质量评估指标、CTDIVOL、DLP及ED进行统计学分析，并对三组之间结果两两比较，以P＜0.05为差异有统计学意义。 结果：①A、B、C三组病人基本资料，在性别、年龄、BMI、平均心率及扫描长度方面具有良好的一致性，差异无统计学意义（P＞0.05）。②A、B、C三组病人的图像BN分别为：30.48±5.60、30.95±4.57和32.08±3.56,三组之间差异无统计学意义(P＞0.05)，但C组BN较A组与B组有所增加。A、B、C三组病人的图像SNR分别为：15.42±3.73、15.09±3.08和14.47±2.72,三组之间差异无统计学意义(P＞0.05)，但C组图像SNR较A组与B组有所下降。A、B、C三组病人的图像CNR分别为：13.29±3.52、13.05±2.95和12.40±2.60,三组之间差异无统计学意义(P＞0.05)，但C组图像CNR较A组与B组有所下降。A、B、C三组病人的图像总评分分别为：3.63±0.41分、3.62±0.45分和3.58±0.44分，三组之间差异无统计学意义（P＞0.05），三组图像质量均可以满足诊断要求。③A、B、C三组病人的ED分别为：14.34±0.92mSv、3.56±0.36mSv和7.16±1.40mSv，三组之间差异有统计学意义(P＜0.05)，B组与A组和C组与A组相比ED均明显降低，分别降低约75.17%、50.07%，以B组降低更显著。 结论：①前瞻性心电门控技术与常规回顾性心电门控技术相比，可显著地降低辐射剂量，同时保证诊断图像质量。②基于BMI优化管电流回顾性心电门控方法与常规回顾性心电门控技术相比，可有效地降低辐射剂量，同时能满足诊断要求的图像质量。③前瞻性心电门控技术比基于BMI优化管电流回顾性心电门控方法降低辐射剂量更明显。
[Abstract]:Objective: through the optimization of multi-slice spiral CT (Multi-sliceSpiral Computed Tomography, MSCT) scanning conditions of coronary artery imaging, to explore the different scanning methods to reduce the radiation dose in noninvasive coronary angiography with MSCT (Coronary CT Angiography, CCTA) the clinical value and limitation of the diagnostic image quality and ensure to reduce the radiation dose to to reduce the harm to patients. Methods: a device using 256 slice spiral CT (BrillianceiCT, Philips, Holland). According to the exclusion criteria, the study included a total of 180 cases of patients, divided into A, B, C three groups, 60 cases in each group; A group: conventional retrospective ECG gated group (control group); group B: prospective ECG gated group; group C: optimization of BMI tube current retrospective ECG gated group. All patients were randomly divided into two groups based on the set. The three group of scanning conditions: tube voltage was set to 120kV; tube current were body mass index based on disease The number of (Bodymassindex, BMI). The three groups were chosen as contrast agent of non-ionic iodine contrast medium-omnipaque370 (Iopromide, 370mgI/ml, Bayer). Records of each patient's gender, age, weight, height, BMI, average heart rate and scanning length; and measuring the original axial coronary artery enhancement of ascending aorta the root of the image (SI1), the proximal segment of right coronary artery (SI2), left main (SI3) of the CT value, and then calculate the average value of the three enhancement (SI4), simultaneous measurement of the pectoralis major muscle CT value (SI5). The image noise (Background noise, BN) for the measurement of aortic root CT the value of the standard deviation (Standard deviation, SD). On the basis of the formula: SI4= (SI1+SI2+SI3) / 3; SNR=SI4 / BN; CNR= / BN; (SI4SI5) calculates the objective evaluation index of image quality, the signal to noise ratio (Signalnoiseratio, SNR) and contrast to noise ratio (Contrastnoiseratio, CNR). According to the American Heart Learn (American Heart Association, AHA) of 16 coronary artery segments, the subjective image quality assessment of the main coronary vessels were 10 segments, namely the right coronary artery (RCA), (LM), left anterior descending and circumflex (LAD) (LCX); using 4 point semi quantitative wasassessed segmental coronary artery: 4 (excellent), 3 points (good), 2 (medium), 1 points (difference), which is more than 2 points to meet the diagnostic requirements of the standard. The volume CT dose index recorded at the same time to check automatically by a computer generated (CTDIVOL) and dose length the product (DLP), and calculate the effective radiation dose (ED). Then the basic data of the three groups of patients, evaluation index, objective and subjective image quality of CTDIVOL, DLP and ED were analyzed, and 22 of the results of the comparison between the three groups, with P < 0.05, the difference was statistically significant.
缁撴灉锛氣憼A,B,C涓夌粍鐥呬汉鍩烘湰璧勬枡,鍦ㄦ，

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