Purpose: To evaluate the diagnostic value of diffusion-weighted MR imaging for differentiating metastatic and hyperplastic pelvic lymph nodes in patients with cervical carcinoma.
Materials and methods: In this prospective study, 61 untreated patients were scanned with both morphological MR and diffusion-weighted imaging (DWI). Bilateral pelvic lymphadenectomy was then performed in all patients. Of the 1118 total dissected and histopathologically evaluated pelvic lymph nodes, 153 enlarged nodes with short-axis diameter larger than 5 mm were included for further study. The mean ADC values of all enlarged lymph nodes and the relative ADC values between tumors and nodes were also measured and, respectively, compared between the metastatic and hyperplastic node groups.
Results: The mean ADC value of metastatic [(1.046 ± 0.198) × 10⁻³ mm²/s] nodes was significantly lower than that of hyperplastic [(1.289 ± 0.194) × 10⁻³ mm²/s] nodes (P < 0. 001). The relative ADC values between tumor and nodes were significantly lower in malignant [(0.19 ± 0.17) × 10⁻³ mm²/s] than hyperplastic [(0.4 ± 0.21) × 10⁻³ mm²/s] nodes (P < 0. 001). When a mean ADC value of 1.15 × 10⁻³ mm²/s was used as a threshold value for differentiating metastatic from hyperplastic nodes, the best results were obtained with a sensitivity of 83.3%, specificity of 74.7%, and accuracy of 78.4%.
Conclusion: DWI is useful in differentiating metastatic and hyperplastic pelvic lymph nodes in patients with cervical carcinoma.