Predicting perigastric lymph node metastasis in gastric cancer with CT perfusion imaging: A prospective analysis

To evaluate the diagnostic efficacy in differentiating metastatic from inflammatory perigastric lymph nodes (LN_s) in patients with gastric cancer by using CT perfusion imaging (CTPI).

A total of 115 annotated perigastric LN_s of 50 patients with gastric cancer confirmed by pathology underwent CTPI scan before operation. The scan data were postprocessed to acquire perfusion maps and parameters including blood flow (BF) and permeability surface (PS). A radiologist measured the short and long axis diameters, the short/long axis ratio and perfusion parameters of LN_s. According to the post-operative pathology result, LN_s were divided into two groups: metastatic and inflammatory nodes. Perfusion parameters and the size of LN_s between two groups were respectively compared statistically, and a receiver-operating characteristic (ROC) curve analysis was used to determine the optimal diagnostic cutoff value with sensitivity, specificity and area under the curve (AUC).

The mean values of perfusion parameters and the short/long axis diameters ratio in metastatic and inflammatory LN_s, respectively, were BF of 91.64 vs. 79.35 ml/100 mg /min (p <  0.01), PS of 43.42 vs. 35.92 ml/100 mg /min (p <  0.01), and the size ratio of 0.75 vs. 0.68 (p <  0.01). The sensitivity of 85.3%, specificity of 66.0 % and AUC of 0.816 for BF with cutoff value of 80.76 ml/100 mg /min for differentiating metastatic from inflammatory nodes were higher than those of PS or the size of LN_s (p < 0.05).

BF may be a reliable diagnostic marker of metastatic perigastric LN_s in gastric cancer.