双螺旋CT门静脉血管造影最佳扫描层厚和螺距的研究

评价双螺旋ＣＴ血管造影不同扫描层厚和螺距对门静脉成像质量的影响。方法将４个猪肝制成血管模型，分别以５种不同的螺距，层厚的组合形成式扫描。Ａ组螺距为１．０，层厚２．５ｍｍ；Ｂ组螺距１．５，层厚２．５ｍｍ；Ｃ组螺距２．０，层厚２．５ｍｍ；Ｄ组螺距１．０，层厚５．０ｍｍ；Ｅ组螺距１．５，层厚５．０ｍｍ。所有原始图像均采用最大信号强度投影（ＭａｘＩＰ）法处理。分析模型血管分支的显示与层厚和螺距的关系。结果

Experimertal collimation and pitch for imaging portal venous system using double spiral computed tomographic angiography

Objective To optimize parameters with double spiral computed tomographic angiography(SCTA) for visualization of portal veins. Methods 4 pig livers were scanned with five different parameters A, B, C, D, E, the pitchcollimation(mm) were 1.02.5, 1.52.5, 2.02.5, 1.05.0, and 1.55.0 respectively. All images were reconstructed with maximum intensity projection(MaxIP). The relationship of visualization of the model vessele branches with the collimation and pitch were analysed. Results (1) In regard to resolution of the constructed SCTA images, both A and B parameter combinations were good and superior to C, D and E. The images quality of E was the worst. (2) The reconstructed vessels were found to be somewhat amplified. Conclusions (1) The optimized collimation is 2.5 mm and pitch is 1.5 for portal vein imaging using SCTA with MaxIP algorithm. (2) The effect of collimation is greater than that of pitch on image quality of SCTA. (3) The main defect of SCTA is overestimation or underestimation of vessel stenosis.