Fig. 8.

Malignant non-mass lesions in a 47-year-old patient. (a) A lesion with high signal intensity on HR-DWI (b = 850 s/mm²) was detected. Both readers classified it as a non-mass lesion and reader A measured it as 47 mm and reader B measured it as 53 mm. (b) The lesion showed low ADC value. The mean ADC value of the lesion was 0.738 × 10⁻³ mm²/s. (c) High-resolution contrast-enhanced T₁WI showed a non-mass lesion with segmental distribution and clumped-pattern enhancement. However, the lesion is difficult to distinguish from BPE especially in the lower part of the breast tissue. (d) The diagnosis was DCIS of intermediate nuclear grade. The pathological maximum diameter of the lesion was 73 mm. The discrepancy with lesion size in HR-DWI is suspected that the lesion extended widely in the horizontal direction. Lesions outlined in yellow correspond to DCIS of intermediate nuclear grade. ADC, apparent diffusion coefficient; BPE, background parenchymal enhancement; DCIS, ductal carcinomas in situ; HR-DWI, high resolution-diffusion-weighted imaging; T₁WI, T₁-weighted image.