Value of multi-slice spiral CT image texture analysis in diagnosing lymphatic metastasis of rectal cancer / 中华放射学杂志

ABSTRACT

Objective To investigate the value of multi-slice spiral CT image texture analysis in differentiating metastatic (MLN) from non-metastatic lymph nodes (NLN) in patients with rectal cancer.Methods Thirty five patiets with rectal cancer who were pathologically confirmed by total mesorectum excision were included retrospectively,with regional lymph nodes (short-axis diameter of larger than 3 mm)found in preoperative CT images.All the patients underwent preoperative abdominal and pelvic dynamic contrast-enhanced CT scan.Regional lymph nodes were identified according to pathological findings,and were divided into MLN and NLN groups.The short-axis diameter,short-to long-axis diameter ratio of lymph nodes were manually measured and calculated,and the texture features,including skewness,kurtosis,variance,entropy and inverse difference moment,were analyzed.The above parameters between MLN and NLN groups were compared using independent sample t test or Mann-Whitney U test.ROC curve analysis was performed regarding the statistically significant parameters and the areas under curve (AUC) were calculated.Multivariate Logistic regression analysis was accomplished to obtain the independent predictive factor of diagnosing regional lymph nodes.Results A total of 68 regional lymph nodes were obtained and consisted of 31 MLNs and 37 NLNs.The short-axis diameter,kurtosis,and entropy of the MLN group were significantly higher than those of the NLN group (all P＜0.05).Whereas,the short-to long-axis diameter ratio,skewness,variance,and inverse difference moment did not differ significantly between the two groups (all P＞0.05).The AUC for distinguishing MLN from NLN of the short-axis diameter,kurtosis and entropy were 0.79,0.67,and 0.85,respectively.Multivariate logistic regression analysis showed that only entropy (odds ratio=8.48,95％ confidence interval was 3.01 to 23.92,P＜0.01) was screened out as the independent variable,which suggested that the entropy was the unique predictor for characterizing regional lymph nodes of rectal cancer.Conclusion Multi-slice spiral CT images texture analysis can facilitate the accurate differentiation between MLN and NLN in patients with rectal cancer,and especially the entropy has the optimal reference significance.