能谱CT多物质解析评价继发性下肢淋巴水肿分级

Spectral CT Multi-material Decomposition in Evaluation of Secondary Lower Extremity Lymphedema: A Prospective Study

目的:探讨能谱CT多物质解析算法在继发性下肢淋巴水肿分级评价中的应用价值。材料及方法:前瞻性收集2019年6月至2020年6月因继发性下肢淋巴水肿入我院就诊并行能谱CT断层扫描的患者,由两名具有5年以上CT诊断经验的医师共同对能谱CT图像进行分析,采用阈值法测量患侧与健侧下肢体积,计算(患侧下肢体积-健侧下肢体积)/健侧下肢体积的百分比,根据2016版国际淋巴学会共识,将入组患者分为轻度、中度、重度;使用能谱CT多物质解析算法分别测量患侧与健侧下肢脂肪含量,得出脂肪体积分数,采用配对t检验分别分析轻、中、重度患者患侧与健侧下肢脂肪体积分数之间的差异;采用秩和检验分别分析轻、中、重度患者两两之间患侧下肢脂肪体积分数的差异。结果:最终入组患者40例,女/男(36/4),年龄范围32~71岁,中位年龄(53±10)岁,病程(3±5)年,轻度8例,中度14例,重度18例。轻、中、重度患者的患侧与健侧下肢脂肪体积分数之间差异均有统计学意义;轻、中、重度患者两两之间患侧下肢脂肪体积分数差异无统计学意义。结论:能谱CT多物质解析算法可以量化继发性下肢淋巴水肿的脂肪含量比,但不能单独用于下肢病变的分级评价中。

Objective: To explore the application value of spectral CT multi-material decomposition(MMD)algorithm in the grading of secondary lower extremity Lymphedema. Materials and methods: Prospective collection of patients who underwent spectral CT admitted to our hospital from June 2019 to June 2020 were prospectively collected. The spectral CT images were analyzed by two radiologists with more than five years of experience in CT diagnosis. The volume of the both lower limbs were measured using the threshold value software.Based on the percentage increase in the volume of the affected side compared to the healthy side, the enrolled patients were divided into three grades: mild, moderate, and severe. Percentage fat volume fraction(FVF) images were generated by using the MMD algorithm on spectral CT to measure the fat content of the affected and healthy lower limbs respectively. Paired t test were used to analyze the difference of the percentage FVF between the affected and healthy side in mild, moderate, severe patients. Results: Forty patients(female/male, 36/4 cases, with age range of 32-71 years old, median age of(53 ± 10) years) were finally enrolled, and the course of disease was(3 ± 5) years. There were 8 cases in mild group, 14 cases in moderate group and 18 cases in severe group. There were statistical differences in the percentage FVF between the affected and healthy side in mild, moderate and severe patients. There was no statistical difference in the percentage FVF of the affected side among mild,moderate and severe patients.Conclusion: The spectral CT MMD algorithm can quantify the percentage FVF of Secondary Lower Extremity Lymphedema, but it cannot be used alone in the grading of secondary lower extremity lymphedema.