Tissue stiffness is often related to underlying disease. For millennia, physicians have used palpation as a diagnostic tool to detect various ailments such as lesions, aneurysms, and inflammation. Stiff masses found during routine physical exams can be an early indication of disease, as in the cases of breast and prostate cancer. In some ailments, such as liver fibrosis, disease progression is marked by a gradual change in tissue stiffness. The ability to noninvasively measure tissue stiffness can therefore be a valuable tool in the diagnosis, staging, and management of disease.