多排螺旋CT非螺旋低剂量扫描筛查肺结节

目的探讨4排螺旋CT非螺旋低剂量扫描方式在肺结节诊断中的价值。方法对30例胸片可疑肺结节患者分别行螺旋低剂量和非螺旋低剂量扫描。采用Toshiba 4排多层螺旋CT（Asteion 4）扫描机。螺旋扫描采用预设35.5 mAs,床进20 mm/圈（即螺距1）,0.75 s/圈,非螺旋扫描预设24 mAs,床进20 mm/圈（层厚=层距）,0.48 s/圈,其他扫描参数相同：120 kV,准直0.5×4,DFOV 300 mm,重建层厚5mm。根据出现伪影程度及是否分辨出肺结节来评价CT图像质量,对肺结节进行简单计数。比较两者发现肺结节的差异及有效放射剂量的差异。结果两种扫描方式检查30例患者均为阳性,发现各种肺结节都是108个。非螺旋扫描的有效放射剂量低于螺旋扫描方式（P〈0.001）。结论非螺旋方式扫描与螺旋方式扫描在胸部低剂量检查中对于肺内病灶的发现及诊断无统计学差异,扫描剂量相对更低的非螺旋方式扫描应用于胸部疾病的诊断及筛查是可行的。

Non-spiral low-dose CT scan for screening of pulmonary nodules

Objective To explore the value of non-spiral mode of low-dose chest scan in diagnosis of pulmonary nodules. Methods Thirty patients with chest X-ray suspected pulmonary nodules underwent spiral low-dose and non-spiral low-dose CT scan under Toshiba 4 row multi-slice spiral CT (Asteion 4). The parameters were defaulted as 35.5 mAs, 20 mm/round (pitch=1), 0.75 s/rot in spiral scan, while in non-spiral scan wree defaulted as 24 mAs, 20 mm/round (thickness=layer distance), 0.48 s/rot. Other parameters including 120 kV, collimator 0.5×4, DFOV 300 mm, reconstruction slice thickness 5 mm were chosen in both scans. CT imaging quality was evaluated according to the degreex of image artifacts and the distinguishment of nodule, and the pulmonary nodules were counted, then the differences of finding the pulmonary nodules and effective radiation dose of both mode were analyzed. Results The images were good in one patient in both scanning mode, and excellent in 29 patients in spiral scanning mode, 28 patients in non-spiral scanning mode. A total of 108 nodules were found with two modes. The effective radiation dose in non-spiral scan was lower than that in spiral scan. No significant difference was found between non-spiral mode scanning and spiral scanning mode in the low-dose chest examination in the discovery and diagnosis of pulmonary nodules. Conclusion Lower dose of non-spiral scanning mode is feasible in diagnosis of pulmonary nodules.