Diffusion-weighted magnetic resonance imaging in evaluating malignant lymph node invasion in patients with female genital neoplasms

Abstract

Background / Aim: Functional imaging, including diffusion-weighted magnetic resonance imaging (DWI MRI) and ADC map, provides promising results in discrimination benign from malignant pelvic and inguinal lymph nodes in patients with gynecological malignancies. Aim of the study was to assess diagnostic performances of DWI in differentiation between benign and malignant pelvic and inguinal lymph nodes in patients with gynecological malignancies. Methods: The prospective clinical study was conducted at Clinical Center of Vojvodina from 2013 to 2016, comprising 80 patients with malignant gynecological tumors. Preoperatively, all patients underwent MRI examination, followed by standard surgical treatment with complete pelvic and/or inguinal lymphadenectomy. Histopathological examination of surgically removed material and lymph nodes separated in pelvic and inguinal anatomic groups was performed after the surgery. Results: The total of 2320 of lymph nodes were mapped and histopathologically examined in 80 patients included in the study. Metastases in lymph nodes were histopathologically confirmed in 28 patients (35%). Measured ADC values were significantly lower in metastatic (mean ? SD, ADC: 0.8725 x 10-3 mm2/s ? 0.0125) than benign lymph nodes (mean ? SD, ADC: 1.116 x 10-3 mm2/s ? 0.1848; P=0.001). If ADC value of 0.860 x 10- 3 mm2 / s is determined as a cut off value for discrimination between benign and malignant lymph nodes, DWI sensitivity was 89%, specificity 85% and overall accuracy was 86%. Combination of ADC value criteria and size-based criteria yields MRI the following diagnostic performances in discrimination between benign and malignant lymph nodes: sensitivity 95%, specificity 92%, overall accuracy 92.5%, positive predictive value 46% and negative predictive value 99.6%. Conclusion: DWI MRI sequence is fast, simple, noninvasive method which aids significantly to MRI diagnostic performances in discrimination between benign and malignant pelvic and inguinal lymph nodes.