^18F-FDG PET/CT在肺癌性淋巴管病的影像学特征及诊断价值

Imaging features and diagnostic value of ^18F-FDG PET/CT in pulmonary lymphangitic carcinomatosis

目的 探讨肺癌性淋巴管病（PLC）^18F-FDG PET/CT的影像学特征及其诊断价值。方法 回顾性分析我院2016年8月至2017年9月临床确诊的53例PLC患者，均行PET/CT＋薄层屏气CT扫描。利用CT扫描数据对PET图像进行衰减校正，采用TrueX＋飞行时间法重建图像并进行分析、总结。测定各感兴趣区的平均标准化摄取值（SUVmean）并计算标准化比值（SUR），比较不同区域的SUVmean和SUR的差异。结果 53例PLC患者中，51例（96%，51/53）可见增厚小叶间隔伴放射性摄取，增厚小叶间隔所在肺野SUVmean明显高于正常肺野，差异有统计学意义（1.46±0.92 vs.0.58±0.18，t=19.85，P〈0.01）；增厚小叶间隔肺野/纵隔血池的SUR高于正常小叶间隔肺野/纵隔血池的SUR，差异有统计学学意义（0.84±0.38 vs.0.40±0.21，t=12.77，P〈0.01）。51例（96%，51/53）可见支气管血管束放射性摄取增强。PLC累及支气管血管束SUVmean明显高于正常支气管血管束，差异有统计学意义（3.85±1.67 vs.0.90±0.19，t=15.45，P〈0.01）。增粗支气管血管束/纵隔血池的SUR高于正常支气管血管束/纵隔血池的SUR（2.89±0.94 vs.0.59±0.19，t=12.62，P〈0.01）。51例（96%，51/53）可见肺门及纵隔淋巴结肿大伴放射性摄取增强。结论 典型PLC患者的PET/CT融合显像特征为支气管血管束增粗伴放射性浓聚；PLC累及小叶间隔结节样增厚伴放射性摄取增高；肺门和纵隔淋巴结肿大或显示伴放射性异常浓聚。PET/CT融合显像结合局部SUVmean和SUR的测定，不但可以更早地诊断PLC病灶，而且可以提高对PCL病灶诊断的准确率。

Objective To explore the imaging features and diagnostic value of 18F-FDG PET/CT in pulmonary lymphangitic carcinomatosis（PLC）. Methods Retrospective analysis on 53 PLC cases was performed. The patients underwent PET/CT＋ thin breath hold CT scanning. The PET images were attenuated by CT scanning data and reconstructed by TrueX＋time of flight method. The mean standardized uptake value（SUVmean） of each region of interest was measured, and the standardized uptake ratios（SUR） value was calculated. The difference of the SUVmean and SUR values in different regions was compared. Results Among the 53 patients with PLC, 51（96%, 51/53） displayed interlobular septal thickening of the interlobular septa with radioactive uptake, and the lung SUVmean was significantly higher than that of the normal lung field（1.46±0.92 vs. 0.58±0.18, t=19.85, P〈0.01）. The interlobular septal thickening lung/mediastinal blood pool SUR was higher than that of the normal septal lung/mediastinal blood pool SUR（0.84±0.38 vs. 0.40±0.21, t=12.77, P〈0.01）, and 51 cases（96%, 51/53） manifested bronchovascular bundle uptake enhancement. The SUVmean of PLC involving bronchovascular bundle was significantly higher than that of normal bronchovascular bundle（3.85±1.67 vs. 0.90±0.19, t=15.45, P〈0.01）. The SUR of the thickened bronchi vascular bundle/mediastinal blood pool was higher than that of the normal bronchovascular bundle/mediastinal blood pool SUR（2.89±0.94 vs. 0.59±0.19, t=12.62, P〈0.01）. In 51 cases（96%, 51/53）, the swelling of the hilum and mediastinal lymph nodes was enhanced with radioactivity. Conclusions PET/CT fusion imaging of typical patients with PLC is characterized by the thickening of bronchial vascular bundles with radioactive concentration and thickening of the interlobular septal nodules with increased uptake of radioactivity. Moreover, the hilar and mediastinal lymph nodes were enlarged or normal with abnormal concentration of radioactivity. PET/CT fusion imaging combined with local SUVmean and SUR can measurements not only enables the early and accurate diagnosis of PLC lesions.