Fig. 7
From: Breast stiffness, a risk factor for cancer and the role of radiology for diagnosis
Three non-cancerous breast specimens which on visual inspection could be classified broadly as fatty, mixed, and fibrous. Micro CT correlates well with the extent of fat and fibrous tissue found on histology. Areas that contain fat, low Hounsfield Units (HU) on CT have slow ST-HMI-derived group velocity (ms−1) and tissue that contains fibrous tissue with high HU on CT have fast ST-HMI-derived group velocity (ms−1), and mixed fat and fibroglandular tissue (medium HU) has a variable velocity that corresponds to extent of collagen and its stiffness. Fatty parenchyma type presents with highly fatty (white) histology with minimal fibrous histology (red), slow ST-HMI-derived group velocity (blue), and low HU on CT (dark). Fibrous and fatty parenchyma type presents with mixed amounts of fatty (white) and fibrous (red) histology, average ST-HMI-derived group velocity (light blue/green), and average HU on CT (mixed amounts of dark and light). Fibrous parenchyma type presents with highly fibrous (red) histology with minimal fatty histology (red), fast ST-HMI-derived group velocity (yellow), and high HU on CT (light)