双排螺旋CT胸部非对称扫描方式的临床应用价值

Clinical Applications of Dual Slice SCT ASM in Chest

目的 :评价双排螺旋CT肺部非对称扫描方式的临床应用价值。材料和方法 :5 6例志愿者用螺旋CT行肺部扫描 ,分别采用非对称扫描方式 (ASM ,1mm/ 10mm层厚图像分别采用高分辨算法 <AS HRCT >/肺算法 <AS 10mm >)、标准螺旋水平扫描方式 (SCT)、常规高分辨 (HRCT)扫描方式 3种方法进行扫描。将 4组图像分别对照研究。结果 :AS 10mm图像噪声、边缘锐利度明显大于SCT图像 ;AS HRCT图像噪声小于HRCT图像 ,两者对图像边缘的显示无显著差异。非对称扫描方式较患者按常规获得 2组图像的方法能明显减少体表辐射剂量 ,平均每层可减少辐射剂量 2 0 %。 4组图像对于小病灶、肺内各种不同病灶的显示能力是相似的。结论 :非对称扫描方法在图像质量未下降的同时 ,可以较常规的 2种检查方法减少患者的受照剂量。

Purpose:To evaluate the clinical applications of the asymmetric scan mode using dual-slice spiral CT. Materials and Methods:56 volunteers with lung disease underwent the CT examination of the chest using dual-slice spiral CT. Three scan modes were selected in all patients,including the asymmetric scan mode (ASM) in 1mm thickness high resolution algorithm (AS-HRCT) combined with 10mm thickness chest algorithm (AS-10mm),the routine spiral CT scan mode (SCT) in 10mm thickness chest algorithm and the high-resolution CT scan mode (HRCT). AS-10mm and AS-HRCT image data were compared with the SCT and HRCT image data respectively. The sharpness of the image,the size of pulmonary nodule and the characteristics of lung lesions were also assessed in this study. Results:The noise of AS-10mm image was higher than that of SCT,and the noise of AS-HRCT image was lower than that of HRCT. The spatial resolution of AS-10mm image was higher than that of SCT image. The spatial resolution between AS-HRCT image and HRCT image was not different. The X-ray dose of ASM was less than the total dose of the SCT and HRCT mode and was reduced by 20%. AS-10mm image was more sharp than that of SCT. There were no difference of the sharpness between AS-HRCT image and those of HRCT. They had the same ability to find the small lesion,and to show remarkable findings. Conclusion:Dual-slice spiral CT ASM is a facilitative and lower-dose mode,which have the same image quality with other two modes.