Diagnostic value of diffusion kurtosis imaging quantitative parameters in lymph node metastasis of rectal cancer / 肿瘤研究与临床

ABSTRACT

Objective:To investigate the diagnostic value of diffusion kurtosis imaging (DKI) quantitative parameters in lymph node metastasis of rectal cancer.Methods:The clinicopathological data of 79 patients with rectal cancers in Shanxi Province Cancer Hospital from November 2016 to March 2017 were retrospectively analyzed. All patients underwent routine magnetic resonance image (MRI) sequence and DKI sequence examinations before the operation. The tumor region of interest (ROI) was delineated by two radiologists. Matlab software was applied to calculate DKI quantitative parameters including apparent diffusion coefficient (ADC), mean diffusivity (MD) and mean kurtosis (MK) in two groups, respectively; and the consistency analysis was performed by using the interclass correlation coefficients (ICC). According to the results of postoperative pathology, all patients were divided into lymph node metastasis group and lymph node non-metastasis group; ADC, MD, MK of both groups were compared. The pathological diagnosis results were taken as the gold standard, receiver operating characteristic (ROC) curves of DKI quantitative parameters in the diagnosis of lymph node metastasis of rectal cancer were plotted, the area under the curve (AUC) was calculated, the optimal diagnostic threshold was determined based on the Yoden index, and the sensitivity and specificity were calculated.Results:The ICC of ADC, MD and MK calculated by two physicians were 0.934 (0.833-0.975), 0.963 (0.905-0.981) and 0.971 (0.949-0.991), respectively, showing a good inter-observer consistency. Among the 79 patients with rectal adenocarcinoma, 36 cases were in lymph node metastasis group and 43 cases were in lymph node non-metastasis group. MK value in lymph node metastasis group was higher than that in lymph node non-metastasis group, and the difference was statistically significant (0.97±0.08 vs. 0.89±0.09; t = -4.07, P < 0.001), while the ADC and MD values in lymph node metastasis group were lower than those in lymph node non-metastasis group, and the differences were not statistically significant (all P > 0.05). The AUC of MK value in the diagnosis of lymph node metastasis of rectal cancer was 0.735, and the corresponding sensitivity and specificity were 55.56% and 88.37%, respectively. Conclusions:DKI quantitative parameter MK has a certain diagnostic value in predicting lymph node metastasis of rectal cancer.