胸部能谱成像与常规CT扫描的辐射剂量与图像质量对比研究

发布时间：2018-06-23 09:22

本文选题：能谱成像 + 常规CT　；参考：《东南大学》2016年硕士论文

【摘要】：目的：通过自身对比胸部能谱成像与常规胸部CT扫描的辐射剂量及图像质量,探究能谱成像胸部临床普及性应用的可能性。方法：前瞻性对33例因病情需要行胸部CT平扫与增强扫描的患者进行自身对照研究,每一患者预先设置胸部平扫及增强动、静脉期能谱成像序列,扫描范围及FOV均一致。能谱动脉期扫描根据患者常规平扫所采用的mAs选择相应的能谱模式进行增强动脉期扫描,能谱静脉期按GSI Assist模式NI值设定12.15,自动调节mAs能谱模式扫描,动脉期及静脉期能谱成像均经ASIR40%重建获得层厚5mm、层距5mm的70Kev单能量图像。分别通过体模获取每一系列辐射剂量参数,并通过GSI2.0后处理AW461工作站取剂图像质量参数,以胸部平扫(层厚5mm、层距5mm)作为自身对照组,将增强动脉期、静脉期的辐射剂量参数及不同平面图像质量参数通过t检验进行对比分析,观察它们之间有无差异。结果：33例患者的常规胸部CT平扫与能谱成像模式中的动脉期辐射剂量指数分别为(11.1±3.9)和(10.3±0.0)mGy,剂量长度乘积分别为(380.6±136.0)和(357.6±48.7)mGy·am,差异均无统计学意义(P0.05)。在常规CT平扫与能谱成像动脉期的图像质量参数的对比中,所取得三个不同平面对应的9个兴趣区所得SD值差异均无统计学意义(P0.05)；在能谱静脉期成像中,所得剂量指数与剂量长度乘积分别为(15.8±5.7)mGy和(532.9±198.8)mGy.am,二者差值有统计学意义(P0.05,即常规CT平扫的剂量指数及剂量长度乘积低于能谱静脉期成像),而在两者的图像质量参数的对比中,所取三个不同平面对应9个兴趣区所得SD中,有7组差值具有统计学意义(P0.05,即能谱静脉期成像SD值即噪声指数小于常规CT平扫),2组差值无统计学意义(P0.05)。结论：通过选择合适的参数,胸部CT能谱扫描与常规扫描的射线剂量相当；70 keV单能量图像的噪声低于常规扫描的FBP重建图像,可在临床中常规应用。
[Abstract]:Objective: to explore the possibility of clinical popularization of energy dispersive chest imaging (EDS) by comparing the radiation dose and image quality between conventional chest CT and energy dispersive chest imaging (EDS). Methods: a prospective self-control study was carried out in 33 patients who underwent plain and enhanced chest CT scan because of their condition. Each patient was given chest plain scan and enhanced arteriography in advance, and the scanning range and FOV were the same in the phase of venous phase energy dispersive imaging. The arterial phase scan was performed with enhanced arterial phase scan according to the mAs mode of conventional plain scan. The venous phase was set at 12.15 according to the NI value of GSI Assist mode, and the scanning mode of mAs energy spectrum was automatically adjusted. Spectral imaging of arterial phase and venous phase were reconstructed by ASIR 40% to obtain 5 mm slice thickness and 70 Kev single energy images from 5mm. Each series of radiation dose parameters were obtained by phantom, and the image quality parameters were obtained by GSI 2.0 post-processing AW461 workstation. The chest plain scan (5mm thickness, interval 5mm) was used as the control group to enhance the arterial phase. The radiation dose parameters and the quality parameters of different plane images in venous period were compared and analyzed by t test to see if there were any differences between them. Results the arterial phase radiation dose indices in conventional chest CT plain scan and energy dispersive imaging were (11.1 卤3.9) and (10.3 卤0.0) mGy, respectively. The dose length product was (380.6 卤136.0) mGy and (357.6 卤48.7) mGy, respectively. There was no significant difference (P0.05). In comparison of image quality parameters of arterial phase between conventional CT plain scan and energy dispersive imaging, there was no significant difference in SD values obtained from 9 regions of interest corresponding to three different planes (P0.05). The product of dose index and dose length were (15.8 卤5.7mGy) and (532.9 卤198.8) mGy.am. the difference between them was statistically significant (P0.05, that is, the dose index and dose length product of conventional CT scan were lower than those of EDS venous phase imaging). Of the SD obtained from 9 regions of interest corresponding to three different planes, there was no significant difference between the two groups (P0.05, i.e., the SD value of energy dispersive venous phase imaging, that is, the noise index was lower than that of conventional CT scan). Conclusion: by selecting the appropriate parameters, the noise of the single energy image of 70 Kev is lower than that of the FBP reconstruction image of conventional scan, and it can be used in clinic.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R816.4

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