Purpose: We compared diffusion-weighted imaging (DWI) of the breast using 2 different b-values to determine the optimal b-value for greatest signal contrast between tumors and normal tissue of the breast.
Materials and methods: We performed DWI of the breast at b-values of 1000 s/mm(2) and 1500 s/mm(2) in 120 patients (121 lesions, 19 benign, 102 malignant) and visually scored image quality with regard to artifact and visibility of tumors. We quantitatively evaluated the signal-to-noise ratio (SNR) of the tumor and contrast-to-noise ratio (CNR) and contrast ratio (CR) between the tumor and normal breast parenchyma.
Results: The CR of invasive carcinoma (IC), ductal carcinoma in situ (DCIS), and benign tumors significantly improved with b=1500 s/mm(2) compared with b=1000 s/mm(2). The SNR and CNR were significantly lower with b=1500 s/mm(2) than b=1000 s/mm(2) despite the increasing number of excitations at b=1500 s/mm(2). At b=1500 s/mm(2), the difference in SNR, CNR, and CR between IC and DCIS and benign tumors was statistically significant.
Conclusion: DWI may depict breast tumors more clearly with b=1500 s/mm(2) than b=1000 s/mm(2).