双源CT在先天性心脏病低剂量检查中的应用

发布时间：2018-04-20 22:35

本文选题：先天性心脏病 + 辐射剂量　；参考：《泰山医学院》2012年硕士论文

【摘要】：目的探索先天性心脏病双源CT（Dual-source computed tomography DSCT）扫描的最佳方案，降低双源CT在先天性心脏病检查中的辐射剂量，减少射线对受检者潜在的危害，遵照循证医学的理念，寻求能满足诊断前提下的低剂量检查模式，为临床提供一种更为安全、可靠的检查方法。材料与方法对60例超声检查诊断为先天性心脏病的患者行双源CT扫描，将60例患者随机连续分成A、B两组，每组30例：A组采用传统的回顾性心电门控螺旋扫描，B组采用新模式的前瞻性心电门控大螺距扫描（即Flash模式）。使用德国SIEMENS公司的SOMATOM Definition Flash双源CT扫描仪，A组扫描参数：两个球管管电压均为80～120Kv，管电流实时调控，球管旋转时间0.28s，螺距（Pitch，P值）值随心率变化自动调节：0.2～0.5，层厚0.6mm。造影剂使用剂量、方法及注射速度根据患儿实际情况进行个体化计算，扫描范围从胸廓入口至左侧膈肌下5cm。B组扫描参数：两个球管管电压均为80～120kv，管电流实时调控，球管旋转时间0.28s，螺距固定为3.4，层厚0.6mm，造影剂使用剂量、方法、注射速度及扫描范围同A组标准。扫描完成采集后，将原始数据传至相应工作站进行任意方位和层厚的图像重建，多平面重组（MPR）、最大密度投影（MIP）、容积再现（VR）等后处理技术，用以显示复杂的三维解剖关系。制定图像质量评价标准，由具有丰富心血管影像诊断经验的两名高年资医师分别阅片并做出诊断，诊断不一致者共同回顾协调得出统一结论。同时评价其图像质量，记录并比较两组辐射剂量，评价心内外畸形数目，以手术或者造影结果对照。对两组病例的辐射剂量比较做两独立样本均数t检验，两组图像诊断准确率的比较做四格表资料的卡方检验。结果 1.年龄最小的患者仅为4个月，所有患者均安全、顺利完成检查，无造影剂过敏反应发生，检查前后临床表现无差异。 2. A、B两组各30例图像平均得分分别为4.3±0.7、4.1±0.8，两组图像均能满足诊断需求。 3. A组病例中心率范围为72～143bmp，平均扫描长度为18.6cm，平均辐射剂量为2.03±0.95mSv；B组心率范围为55～133bmp，平均扫描长度为17.8cm，平均辐射剂量为0.82±0.33mSv。两组辐射剂量做两独立样本均数t检验，结果：t=3.425，p＜0.05，两样本均数差别有统计学意义，B组所用辐射剂量低于A组。 4.两组病例经手术或者造影证实共计48例，其中45例为复杂先天性心脏病。经证实的病例中含单纯先天性心脏病，包括房、室间隔缺损、动脉导管未闭，复杂先天性心脏病包括法洛氏四联症、肺动脉闭锁、大血管-心室连接异常、右室双出口等。统计所有病例的心血管畸形数目（包括心内畸形、心脏-大血管连接部分、大血管部分、心脏位以及心外并发畸形），A组有26例经手术证实，CT诊断心内畸形133处，手术结果证实为136处，畸形诊断准确率为97.8%，其中漏诊卵圆孔未闭3例。B组22例经手术证实，CT诊断畸形101处，手术结果证实为106处，畸形诊断准确率为95.3%，其中漏诊卵圆孔未闭2例、二尖瓣大瓣裂1例、小的膜周部室间隔缺损2例。A、B两组心血管畸形诊断准确率做四格表资料的卡方检验，结果：x~2=1.175，p＞0.05，差别无统计学意义，两组图像在诊断准确率方面差别无统计学意义。结论前瞻性大螺距扫描模式所用辐射剂量远低于回顾性心电门控螺旋扫描模式所用辐射剂量，而其在图像质量与诊断准确率方面无统计学差异，，对先天性心脏病患者而言，是一种更为安全的扫描模式，为降低射线在受检者的潜在危险方面具有重大意义。
[Abstract]:objective
To explore the best way to scan the dual source CT (Dual-source computed tomography DSCT) of congenital heart disease, reduce the radiation dose of double source CT in the examination of congenital heart disease, reduce the potential harm of radiation to the subjects, follow the concept of evidence-based medicine, seek the low dose examination model which can meet the diagnosis premise, and provide a more clinical case. A safe, reliable inspection method.
Materials and methods
A double source CT scan was performed in 60 patients with congenital heart disease diagnosed by ultrasound. 60 patients were randomly divided into A, B two, 30 cases in each group. The A group adopted traditional retrospective ECG gated spiral scan, and the B group adopted a new mode of prospective ECG gated large pitch scan (i.e. Flash mode). The SOMATOM Defin of German SIEMENS company was used. Ition Flash dual source CT scanner, A group scanning parameters: two ball tube voltage is 80 to 120Kv, tube current real-time control, tube rotation time 0.28s, pitch (Pitch, P value) value changes automatically with the change of heart rate: 0.2 ~ 0.5, layer thickness 0.6mm. contrast agent use dose, method and injection speed according to the actual situation of children to carry out individual calculation, sweep The scanning range from the chest entrance to the left diaphragm 5cm.B group scanning parameters: two ball tube voltage is 80 ~ 120kv, the tube current is real-time control, the tube rotation time 0.28s, the pitch fixed 3.4, the thickness of 0.6mm, the use dose of contrast agent, the method, the injection speed and the scanning range are the same as the A group standard. After the scan completes the collection, the original data passes the corresponding data to corresponding On the workstation, the image reconstruction of any direction and thickness, the MPR, the maximum density projection (MIP), the volume reproduction (VR) and other post-processing techniques were used to display the complex three-dimensional anatomical relationship. The image quality evaluation standard was set up, and the two senior doctors with rich cardiovascular imaging diagnosis experience were read and diagnosed respectively. The patients with inconsistent diagnosis were reviewed and coordinated to draw a unified conclusion. At the same time, the image quality was evaluated, two groups of radiation doses were recorded and compared, and the number of internal and external malformations was evaluated by operation or contrast results. The radiation dose comparison of the two groups was compared with two independent samples t test, and the comparison of the accuracy rate of the two groups in the image diagnosis was four. The card inspection of the material.
Result
1. the youngest patients were only 4 months. All patients were safe and completed the examination without any allergic reaction. There was no difference in the clinical performance before and after the examination.
2. A, B two groups of 30 cases, the average image scores were 4.3 + 0.7,4.1 + 0.8, two groups of images can meet the diagnostic needs.
The case center rate of the 3. A group was 72 ~ 143bmp, the average scanning length was 18.6cm, the average radiation dose was 2.03 + 0.95mSv, the heart rate range of B group was 55 ~ 133bmp, the average scanning length was 17.8cm, the average radiation dose was 0.82 + 0.33mSv. two, and two independent samples were tested with t test. The results were t=3.425, P < 0.05, two samples were the difference. The radiation dose in group B was lower than that in group A.
4. a total of two cases were confirmed by surgery or angiography, of which 45 were complicated congenital heart disease. The confirmed cases included simple congenital heart disease, including atrial, ventricular septal defect, patent ductus arteriosus, complex congenital heart disease including tetralogy of Fallot, pulmonary artery atresia, large vascular ventricular connection abnormality, right ventricular double exit, and so on. The number of cardiovascular deformities in all cases (including intracardiac malformation, heart - large vascular connection part, large vessel part, heart position, and cardiac concurrency malformation), in group A, 26 cases were confirmed by surgery, and 133 were diagnosed by CT, 136 of the surgical results were confirmed, and the accuracy rate of malformation was 97.8%. 3 cases in group.B with missed diagnosis of oval foramen were 22 cases. It was confirmed by the operation that 101 malformations were diagnosed by CT, 106 were confirmed by operation, and the accuracy rate of malformation was 95.3%, including 2 cases of missed oval foramen, 1 cases of mitral valve cleft, 2 case of small circumference septal defect, and 2 diagnosis accuracy of B two for four cases of cardiovascular malformation, and the results were x~2=1.175, P > 0.05, the difference was not statistically significant. There was no significant difference in diagnostic accuracy between the two groups of images.
conclusion
The radiation dose used in the prospective large pitch scan mode is far lower than the radiation dose used in the retrospective ECG gated spiral scan mode, and there is no statistical difference in the image quality and diagnostic accuracy. For the patients with congenital heart disease, it is a safer scanning mode to reduce the potential risk of radiation in the subjects. It is of great significance.

【学位授予单位】：泰山医学院
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R816.92;R725.4

【参考文献】