Clinical Efficiency of Diffusion Weighted Imaging with Background Body Signal Suppression in Magnetic Resonance Mammography — Choosing a Qualitative or a Quantitative Approach

Objectives: Diffusion Weighted Imaging with Background Body Signal Suppression (DWIBS) is a new and promising imaging technique designed to improve diagnostic performance of Dynamic Contrast-Enhanced-Magnetic Resonance Mammography (DCE-MRM). The aim of our study was to assess the diagnostic efficiency of both qualitative and quantitative DWIBS in a retrospective cohort study.
Methods: We performed a registry-based study at the Department of Radiology, Lyon Sud Hospital. All consecutive MRM examinations from 02.2010 to 02.2011 were reviewed. DWIBS was interpreted blindly, both qualitatively (lesion characteristics and signal) and quantitatively (Apparent Diffusion Coefficient – ADC). The ADC cut-off value was determined using Receiver Operating Characteristics (ROC) curve analysis. Clinical efficiency indicators were calculated using either the pathological examination or the disease status after a minimum of 6 months follow-up as gold standard.
Results: The lot consisted of 78 women, with a mean age of 50.3±14 years and a total of 112 breast lesions. Qualitative DWIBS found 73 suspicious and 39 non-suspicious lesions, while the gold standard (pathological diagnosis/follow-up) reported 56 benign and 56 malignant ones. The sensitivity and specificity values for qualitative DWIBS were 84% and 53.37%, respectively. ROC curve analysis revealed the best performance for quantitative DWIBS at an ADC of 1.1×10-3 mm2/s, resulting in a sensitivity of 71.4% and a specificity of 76.8%.
Conclusion: DWIBS is a new and improved diffusion technique with a dual and efficient interpretation system applicable in clinical settings. Moreover, its use as a complement to DCE-MRM offers large potential for improving MRM efficiency in breast cancer diagnosis.