Fig 1.
Schematic diagram of tumorigenesis in breast cancer (adapted from [7, 8]).
(a) Healthy milk duct. (b) Proliferation of tumor cells within the duct is accompanied by desmoplasia in the extra-cellular matrix. (c) Changes in the morphology collagen fiber bundles from a wavy and tortuous state to a straight and taut state, and the emergence of a site where the fiber orientation is predominantly radial with respect to the tumor boundary. (d) Invasion of cancer cells to surrounding glandular tissue from this site. (e) Invasion of the cancer cells to nearby ducts. (f) A fully invasive tumor state. The dashed red curve represents the envelope of the tumor components that would appear as a region with elevated Young’s modulus.
Fig 2.
Schematic diagram of experimental setup: Ultrasound-based quasi-static elasticity imaging is a compression-based method to evaluate the mechanical properties of tissue in-vivo.
First, an ultrasound transducer is gently pressed into the tissue, while acquiring a sequence of images. These images are used in a cross-correlation algorithm in order to determine the displacement field within the tissue. This deformation is then used in an inverse problem to determine the spatial distribution of elastic parameters.
Fig 3.
(A) and (C): B-mode ultrasound images of two typical fibroadenomas. (B) and (D): Corresponding Young’s modulus images generated using elasticity imaging. The tumor boundary is represented by a black curve that is drawn using 50 modulus value. The modulus distribution within the tumors is relatively homogeneous and the margins of the tumor are smooth.
Fig 4.
(A) and (C): B-mode ultrasound images of two typical invasive ductal carcinomas. (B) and (D): Corresponding Young’s modulus images generated using elasticity imaging. The tumor boundary is represented by a black curve that is drawn using 50 peak tumor modulus value. The modulus distribution within the tumors is heterogeneous and the margins of the tumors are rough.
Fig 5.
Value of the heterogeneity parameter for the five invasive ductal carcinomas (represented by red squares) and fibroadenomas (represented by green circles).
The average value for the IDCs is 2.13 and the average value for the FAs is 1.76. Using H > 1.8 as a criterion for malignancy yields 90% diagnostic accuracy.