MR diffusion weighted imaging with background signal suppression in breast cancer

Objective: To explore the feasibility of echo planar imaging with short time inversion recovery (STIR-EPI) diffusion weighted imaging with background signal (DWIBS) suppression in breast cancer. Methods: The diffusion weighted imaging (DWI)with background suppression (b=800 mm2/s) was performed in 26 patients with breast cancer. Apparent diffusion coefficient(ADC) of all lesions were measured and compared. 3D maximum intensity projection (3D-MIP)and reverse black and white technique were used to show the lesions. DWI and DWIBS were performed and compared for the detection of breast cancer. Randomized blocks analysis of variance was used for the ADC values in different breast tissues, the ADC values in breast cancer and benign lesion were compared using t test. The paired chi square test was used for the detection rate of breast cancer in two different imaging methods. Results: Most of the breast cancers were hyperintense on DWI (b=800 mm2/s). The ADC value of cancer tissue was (0.93±0.25) x 10-3 mm2/s, tumor necrosis was (2.06±0.17) x 10-3 mm2/s, normal breast tissue was (1.92±0.23) x 10-3 mm2/s and metastatic lymph node was (1.10±0.14) x 10-3 mm2/s and the differences were statistically significant between two structures (P<0.01). The signal of the tissues around the breast cancer was decreased on DWIBS with 3D-MIP and reverse black and white technique and similar to positron emission tomography(PET). DWIBS sequence detected more breast cancers (92.3%) and metastatic lymph nodes (88.4%) than DWI sequence did (57.6% and 42.3%, respectively, χ2=8.307, P<0.05; χ2= 12.235, P<0.05). The ADC values in breast cancer (1.09±0.17) x 10-3 mm2/s and benign lesion (2.15±0.53) x 10-3 mm2/s had significant statistical differences (t=8.626,P<0.05). Conclusion: Diffusion weighted MRI with background suppression can detect more lesions than DWI and can be potentially applied for the detection of the breast cancer combining the ADC value. (authors)