Role of Diffusion-Weighted Imaging and Apparent Diffusion Coefficient in Differentiating between Local Tumor Recurrence and Benign Breast Changes after Breast Conservative Surgery

Objective: To assess the role of DWI and the ADC in differentiating between local tumor recurrence and benign breast changes after breast conservative surgery. Patients and Methods: 26 patients with breast conservation surgery were included in our study. MRI study was done using fat suppressed T2- weighted fast spin-echo, STIR, T1-weighted fast spin-echo. DWI series were acquired using echo planar imaging pulse sequences incorporating with diffusion gradients and finally dynamic contrast study. Results: Among the twenty sex patients underwent MR imaging in our study, 7 patients were diagnosed at histopathology as local tumor recurrence, 11 patients had surgical scarring, 6 patients had seromas, one patient had hematoma and one patient had fat necrosis. Local tumor recurrence showed lower ADC values (mean ADC=0.95±0.37x10^-3 mm^2/s) than that of benign lesions (mean ADC=1.69±0.16x 10^-3 mm^2/s). The sensitivity and specificity of DWI in the differentiating local tumor recurrence from benign breast lesions were 100% and 94.7%, respectively. Conclusion: DWI is easy to obtain in short scan time, easy to evaluate and ADC values can differentiate between local tumor recurrence and benign breast changes after breast conservation surgery with high sensitivity specificity.