Objective
To investigate diffusion-weighted imaging (DWI) in differentiation of metastatic from nonmetastatic axillary lymph nodes (ALNs) in clinically stages I and II breast cancer.
Patients and methods
A total of 255 ALNs from 30 female patients with histologically proved breast cancer were assessed by 1.5 T scanner. DWI was implemented at values of 50, 400, and 800 s/mm. Short-axis diameter, presence of fatty hilum, and apparent diffusion coefficient (ADC) values (minimum and maximum and mean) of metastatic and nonmetastatic ALNs were compared. Cutoff ADC values to discriminate between benign and malignant ALNs were analyzed with receiver coefficient characteristic (receiver operating characteristic) curves.
Results
The final histopathological examination revealed 69.4% ( = 177) metastatic and 30.6% ( = 78) nonmetastatic ALNs. There was no statistically significant difference in short-axis diameter between the two groups ( = 0.82). However, there was a significantly correlation between loss of fatty hilum and presence of metastases ( < 0.001), and ADC values [0.85 ± 0.35 × 10 mm/s vs. 1.28 ± 0.51 × 10 mm/s (ADC minimum), 1.15 ± 5.30 × 10 mm/s vs. 1.937 ± 0.78 × 10mm/s (ADC maximum), and 0.90 ± 0.44 × 10 mm/s vs. 1.32 ± 0.55 × 10 mm/s (ADC mean)], of metastatic ALNs were significantly lower than those of nonmetastatic ALNs ( < 0.001). The optimal mean ADC cutoff value for differentiation between metastatic and nonmetastatic ALNs was less than 1.22 × 10 mm/s, which had a higher specificity (77%) and accuracy (82.4%) as compared with ADC minimum and ADC maximum.
Conclusion
DWI-MRI and ADC values are promising imaging methods that can assess metastatic ALNs in early breast cancer with high sensitivity, specificity, and accuracy.