Length Scale Matters: Real-Time Elastography versus Nanomechanical Profiling by Atomic Force Microscopy for the Diagnosis of Breast Lesions

Figure 3

Mechanical response of benign and cancerous breast lesions assessed by elastography and AFM nanomechanical testing. (a) (Top) Fibroadenoma: in B-mode image oval circumscribed hypoechogenic lesion of 22.3mm diameter, assessed as BI-RADS 3; elastogram reveals lesion with little strain shown as mosaic pattern of blue and dominantly green assessed as Tsukuba score 2, strain ratio 0.66. (Middle) AFM testing of a biopsy from the lesion in (a) shows a unimodal but broad stiffness distribution indicating both cellular and extracelluar components within the specimen. The histogram peaking at the maximum value of 6 kPa reveals strong stromal response as illustrated by the H&E image recorded post-AFM on the same specimen (bottom). Scale bar, 200 μm. (b) (Top) Invasive ductal breast cancer: in B-mode image irregular hypoechogenic lesion of 8.8mm diameter with architectural distortion, assessed as BI-RADS 5, lesion with even strain in the lesion as well as in the surrounding tissue assessed as Tsukuba score 5, strain ratio 3.65. (Middle) The AFM data show heterogeneous stiffness distribution with a soft peak at 0.6 kPa followed by an exponential decay, which is characteristic of malignant tumor. (Bottom) This is consistent with the post-AFM histopathology, revealing an invasive ductal breast carcinoma with infiltrating nests of cancer cells that have evoked a desmoplastic tissue response. Scale bar, 200 μm.