目的:比较肺动脉CT血管造影(CTPA)成像中,双源CT的大螺距Flash模式、双能模式(DECT)、传统128层螺旋CT模式(128-CT)及64层CT(64-CT)扫描模式下,图像成像质量及辐射剂量的差异。资料与方法临床拟诊为肺动脉栓塞的167例患者中,先从Flash模式的患者中随机选出20例,计算体重指数和平均年龄,以此为标准,选出体重指数和年龄匹配的其他3组不同检查模式患者,每组20例。由2名医师对图像质量进行5级评分及信噪比(SNR)比较,并比较各组CT容积剂量指数(CTDIvol)、剂量长度乘积(DLP)及有效剂量(ED)。结果 Flash组CTDIvol、DLP和ED分别为(3.72±0.74)mGy、(137.5±28.7)mGy·cm、(2.34±0.41)mSv,DECT组分别为(5.31±1.21)mGy、(181.6±34.5)mGy·cm、(3.24±0.57) mSv,128-CT组分别为(5.66±1.47)mGy、(198.7±42.1)mGy·cm、(3.58±0.63) mSv,64-CT组分别为(6.75±1.68)mGy、(231.5±54.2)mGy ·cm、(4.21±0.89) mSv。4种方法对肺动脉不同部位图像质量主观评分和SNR比较,差异无统计学意义(P>0.05)。结论4种扫描方式得到的图像质量无明显差异,双源CT的大螺距Flash模式辐射剂量最小,DECT和128-CT模式辐射剂量无明显差别,64-CT模式辐射剂量最大。
Purpose To compare radiation dose and image quality of different scan modes for CT pulmonary angiography (CTPA) including high-pitch flash mode, dual energy CT (DECT) mode, 128-slice mode of dual source CT and 64-slice CT mode. Materials and Methods One hundred and sixty-seven patients with suspected pulmonary embolism were retrospectively studied. All the patients underwent CTPA. Twenty patients were selected randomly from the patients scanned by high-pitch flash mode. Patients who were scanned by the other three modes were selected with body mass index and age matched those in high-pitch flash mode, with 20 patients in each group. Two radiologists assessed signal-to-noise ratio (SNR) and image quality with 5-piont scale. Dose parameters of volume CT dose index (CTDIvol), dose length product (DLP), and effective dose (ED) were compared among the four groups. Results Mean CTDIvol, DLP and ED were (3.72±0.74) mGy, (137.5±28.7) mGy · cm, and (2.34±0.41) mSv for Flash mode;(5.31±1.21) mGy, (181.6±34.5) mGy· cm and (3.24±0.57) mSv for DECT mode;(5.66±1.47) mGy, (198.7±42.1) mGy·cm and (3.58±0.63) mSv for 128-CT mode;and (6.75±1.68) mGy, (231.5±54.2) mGy·cm and (4.21±0.89) mSv for 64-CT mode. There was no significant difference of SNR and image quality among the four modes (P>0.05). Conclusion There are no significant difference of image quality among the four groups. Flash mode allows for minimum radiation dose compared to other modes. DECT mode and 128-CT mode get higher radiation dose with no difference between them. 64-CT mode gets the highest radiation dose.