颅脑低剂量CT扫描的优化研究

发布时间：2018-03-07 06:21

本文选题：CT扫描　切入点：颅脑　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：目的对比研究常规颅脑CT扫描和低剂量颅脑CT扫描的有效辐射剂量和图像质量差异,以确定优化后的颅脑CT扫描方案(低剂量)在临床的应用价值,使“颅脑病变低度可能”患者,接受最优化的低辐射剂量CT扫描,在不影响图像诊断的前提下,降低这一特殊群体患者所接受的有效辐射剂量。方法放射技师与神经科医师共同依据患者自诉体征及临床查体情况,赋分、筛选出“颅脑病变低度可能”患者183例。其中,男性患者98例、女性患者85例;年龄最小的患者16岁,年龄最大的患者75岁,平均年龄为(58±11.3)岁。按就诊顺序,随机分成三组,分别为常规颅脑CT扫描方案(120k V,280effm As)对照组和优化后低剂量颅脑CT扫描方案(100k V,200effm As)研究组(1)及优化后低剂量颅脑CT扫描方案(100k V,150effm As)研究组(2),使用SIEMENS 64层双源螺旋CT分别进行扫描。扫描完成后,设备自动计算生成出扫描容积CT剂量指数CTDIvol(volume CT dose index)和剂量长度乘积DLP(dose length product)值,计算每次扫描的有效辐射剂量ED(effective dose)。ED等于DLP值×转换系数,单位是m Sv,根据相关文献资料,CT颅脑成像的有效辐射剂量计算转换系数设置为0.0023。分别由两位高年资影像诊断医师和神经科临床医师,共同采用盲法评价三组扫描方案获得的图像质量,统计与比较、分析影像诊断医师和临床主治医师对CT图像的满意度、影像诊断与最终临床的诊断符合率。结果常规扫描方案对照组颅脑CT扫描患者接受的平均有效剂量为(1.43±0.35)m Sv,优化后低剂量扫描方案研究组(1)患者接受的平均有效剂量为(0.68±0.17)m Sv,优化后低剂量扫描方案研究组(2)患者接受的平均有效剂量为(0.53±0.12)m Sv,前者明显高于后两者,差异具有明显统计学意义(t=18.75,P0.05);低剂量扫描方案研究组(1)图像的诊断满意度、伪影水平、图像噪声及空间分辨力评分与常规扫描方案组扫描获取的颅脑CT图像评分均小于标准值1.972,差异无统计学意义(t=1.64,t=0.439,t=0.490,t=0.481;P0.05),能够满足放射诊断医师的诊断要求,能够对“颅脑病变低度可能”患者做出正确的诊断,为临床医师的精准治疗提供影像学依据。低剂量扫描方案研究组(2)图像的诊断满意度、伪影水平、图像噪声及空间分辨力评分与常规扫描方案组扫描获取的颅脑CT图像评分均大于标准值1.972,差异有统计学意义。结论颅脑低剂量CT扫描方案(2)(100k V,150effm As),所接受的有效辐射剂量比常规扫描方案(120k V,280effm As)大幅下降,但是图像质量下降明显,诊断信心受到较大影响,临床医生满意度降低,不适于应用推广。优化后的颅脑CT扫描方案(1)(100 k V,200effm As)有效降低了“颅脑病变低度可能”患者CT检查的有效辐射剂量,同时图像质量能够达到诊断要求,并且方案通俗易懂,技师操作简单易行,具备可行的临床应用价值,值得临床推广应用。
[Abstract]:Objective to compare the difference of effective radiation dose and image quality between conventional and low-dose craniocerebral CT scans in order to determine the clinical application value of optimized low-dose craniocerebral CT scans. Make the patients with "low degree of craniocerebral lesion possible" receive optimal low radiation dose CT scan without affecting the image diagnosis, Methods Radiographers and neurologists were assigned a score according to the patients' private complaint signs and clinical physical examination, and selected 183 cases of patients with "low possibility of craniocerebral lesions". There were 98 males and 85 females, the youngest patients were 16 years old, the oldest patients were 75 years old, the average age was 58 卤11.3 years. The study group was divided into two groups: the routine brain CT scan regimen (120kV) 280effm As) control group, the optimized low-dose craniocerebral CT scan scheme (100kV / 200effm As)) and the optimized low-dose brain CT scan regimen (100kV 150effm As). The study group was treated with SIEMENS 64-slice dual-source spiral CT. Scan separately. After the scan is complete, The scanning volume CT dose index (CTDIvol(volume CT dose index) and the dose length product (DLP(dose length product) were automatically calculated by the device. The effective radiation dose ED(effective dose).ED for each scan was calculated to be equal to DLP value 脳 conversion coefficient. The conversion coefficient was set to 0.0023 according to the effective radiation dose of CT craniocerebral imaging. The blind method was used to evaluate the image quality, statistics and comparison of the three groups of scanning schemes, and the satisfaction of imaging diagnostics and clinical attending physicians to CT images was analyzed. Results the average effective dose of craniocerebral CT scan patients in the control group was 1.43 卤0.35mSv.After the optimization of the low-dose scanning regimen, the average effective dose of the patients was 1.43 卤0.35mSv. The average effective dose was 0.53 卤0.12mSv. the former was significantly higher than that of the latter, and the average effective dose was 0.53 卤0.12mSv. The difference was statistically significant (P 0.05). The diagnostic satisfaction and artifact level of the low dose scan group were significantly higher than that of the control group (P < 0. 05). The scores of image noise and spatial resolution were less than the standard value of 1.972, and the difference was not statistically significant. The difference was not statistically significant. It could meet the diagnostic requirements of radiologists. Can make the correct diagnosis for the patients with "low degree of craniocerebral lesions", and provide the imaging basis for the accurate treatment of clinicians. The scores of image noise and spatial resolution were higher than that of the standard value of 1.972in the conventional scan group, and the difference was statistically significant. Conclusion the low dose CT scan scheme is 100k V + 150effm Asn, and the effective radiation is obtained. The radiation dose was significantly lower than that of the conventional scanning scheme (120kV / 280effm / s). However, the image quality has declined significantly, the confidence in diagnosis has been greatly affected, and the clinicians' satisfaction has been reduced. It is not suitable for application popularization. The optimized CT scan scheme of 100kV / 200effm As) can effectively reduce the effective radiation dose of the patients with "low degree of craniocerebral lesions", and the image quality can meet the diagnostic requirements, and the scheme is easy to understand. The technician is simple and easy to operate, has the feasible clinical application value, is worth the clinical popularizing application.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R816.1

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