Value of MRI and diffusion-weighted imaging in diagnosing normal-sized pelvic lymph nodes metastases in patients with cervical cancer.

Abstract

To investigate the value of conventional MRI and diffusion-weighted imaging (DWI) in diagnosing normal-sized pelvic lymph nodes metastases in patients with cervical cancer. 102 patients with cervical cancer who underwent MRI and DWI scan were included. 137 lymph nodes were analyzed, including 44 metastatic lymph nodes (MLNs) and 93 non-metastatic lymph nodes (non-MLNs). The morphology and apparent diffusion coefficient (ADC) value of lymph nodes were measured including short-axis diameter (DS), long-axis diameter (DL), ratio of short-to-long-axis diameter (DR), fatty hilum, asymmetry, ADCmax, ADCmean and ADCmin. The Mann-Whitney U-test, independent sample t-test and Chi-square test were employed to compare the differences of all criteria between MLNs and non-MLNs. Logistic regression and decision tree were used to develop the combined diagnostic model. ROC analyses were used to evaluate the diagnostic performance. The DS and DR of MLNs were significantly higher than those of non-MLNs (p < 0.05), the ADCmax, ADCmean and ADCmin of MLNs were significantly lower than those of non-MLNs (p < 0.05). Presence of fatty hilum and asymmetric lymph nodes between MLNs and non-MLNs were significantly different (p＜0.05). Combined measurement of ADCmin, DS and DR had the highest AUC 0.937 with 90.9% sensitivity and 87.1% specificity. The accuracy of decision tree was 88.3%. MRI with DWI had potential in diagnosing normal-sized pelvic lymph nodes metastases in patients with cervical cancer. The combined evaluation of DS, DR and ADCmin of lymph nodes and decision tree of the combined measure showed better diagnostic performances than sole criteria. The short-axis diameter, ratio of short-to-long-axis diameter and ADCmin of lymph nodes have moderate value in the diagnosis of the metastases of the normal-sized lymph nodes for the patient with cervical cancer as the sole indices. The combined evaluation of DS, DR and ADCmin is much more valuable in the detection of metastatic lymph nodes.