Application of high-resolution magnetic resonance imaging in preoperative staging diagnosis of rectal cancer / 国际外科学杂志

ABSTRACT

Objective:To evaluate the value of high-resolution magnetic resonance imaging (MRI) in the preoperative diagnosis of T and N staging of rectal cancer.Methods:Retrospective analysis of preoperative MRI and postoperative pathological data of 386 patients undergoing radical resection of rectal cancer from February 2016 to September 2018, including 246 men (63.7%), aged from 29 to 89 years old, with average (61.6±11.0) years. Two observers with experience in abdominal MR performed independent double-blind readings of MR data. T and N stages were determined according to the TNM stage system (7th Edition). The assessment of malignant lymph node probability (low, medium, high) was based on factors such as lymph node size, boundary contours, and signal strength, and ADC values of three different probability of malignant lymph nodes were compared. Statistical methods included Cohen′s kappa coefficient, Mann-Whitney′s, Kruskal-Wallis, Chi-square, Fisher′s exact test, and ROC curve.Results:MR correctly evaluated the T stage of 351 patients (90.9%; kw=0.90±0.08), and the inter-observer coefficient k=0.85±0.09. For lymph node staging, the coefficient between high-probability malignant lymph node estimation and pathology was kw=0.65±0.13. The ADC values of malignant lymph nodes were significantly different in different probability groups ( P<0.001), which were (1.27±0.24)×10 -3mm 2/s (low probability), (1.19±0.18)×10 -3mm 2/s (medium probability), (0.79±0.12)×10 -3mm 2/s (high probability). The ROC curve showed that the ADC value could distinguish high-probability malignant lymph nodes (AUC=0.872), and its diagnostic threshold was ADC≤1.0×10 -3mm 2/s. Conclusion:MR is an accurate imaging method for T stage and N stage of rectal cancer. By combining factors such as lymph node size, morphology, and signal characteristics, the prediction efficiency of high-probability malignant lymph nodes can be improved. The ability of ADC values to identify high-probability malignant lymph nodes highlights its importance in the diagnostic process.