头颈部软组织肿块的CT灌注采样方法研究

Studies on Sampling Methods of CT Perfusion for Soft Tissue Neoplasms of Head and Neck

目的研究不同CT灌注采样方法对头颈部软组织肿块性病变评价的影响.方法 CT灌注检查74例(78侧)头颈部软组织肿块, 根据增强扫描后病变密度的变化选择不同CT灌注的采样方法.方法Ⅰ:对所有病变进行整体采样(采样面积为各肿块面积的90% ～ 100%);方法Ⅱ:对不均匀增强病变(15侧)的强化区(增强前后CT值差>20 HU)采样;方法Ⅲ:对不均匀增强病变(15侧)的非强化区(增强前后CT值差<20 HU)采样.以血容量(BV)、血流量(BF)、平均通过时间(MTT)和表面通透性(PS)作为评价CT灌注的参数(平均值/平均秩和).结果方法Ⅰ、Ⅱ、Ⅲ中病变区BF分别为97.92/56.81、140.49/72.67、26.49/24.33,BV分别为14.11/57.40、20.46/71.40、4.51/22.50,MTT分别为13.99/54.50、12.69/51.43、15.85/57.57,PS分别为18.30/56.41、22.77/64.87、9.75/34.20.统计学分析显示:方法Ⅰ与Ⅲ,方法Ⅱ与Ⅲ的CT灌注参数BF、BV、PS有显著性差异(P<0.01).结论不同的CT灌注采样方法能导致不同的评价结果.采样方法Ⅰ适用于增强不明显或增强均匀的病变;采样方法Ⅱ和Ⅲ适宜于对增强明显不均匀的病变进行细致分析.

Objective The aim of this study was to compare the differences in sampling methods of CT perfusion for soft tissue neoplasms in the head and neck regions. Methods Seventy-four patients （78 head and neck lesions） were examined by CT perfusion. The sampling methods of CT perfusion were divided into three types based on the size and attenuation of the lesions. Method I （78 lesions） ： the size of region of interest （ROI）, placed on the lesion, covered 90%-- 100% of the area of the lesion. Method H （ 15 lesions） ： the ROI was placed on the enhanced region of the lesion （ 〉 20 HU） after the contrast medium was injected. Method IH （15 lesions） ： the ROI was placed on the unchanged region of lesion （ 〈 20 HU） after the contrast medium was used. The parameters of CT perfusion, including blood flow （ BF）, blood volume （ BV）, mean transit time （MTT） and permeability surface （ PS）, were measured. The Kruskal-Wallis test was applied to determine a statistically significant difference among the sampling methods. Results The parameters （mean value / mean score） of method Ⅰ , Ⅱ and Ⅲ ： BF were 97.92/ 56.81, 140.49/72. 67 and 26.49/24.33; BV were 14. 11/57. 40, 20. 46/71. 40 and 4. 51/22. 50; MTT were 13.99/54.50, 12.69/51.43 and 15.85/57.57 ; PS were 18.30/56.41,22.77/64.87 and 9.75/34.20, respective- ly. There were significant differences in the parameters of CT perfusion（ BF, BV and PS）between method I and IH , method H and IH （P 〈0.01）. Conclusion Different sampling methods result in different outcomes of CT perfusion. The sampling method I may be more useful to evaluate the evenly enhanced lesions or lesions without enhancement. The sampling method H and IH can be utilized to elaborate and analyze the lesions with uneven enhancement.