Magnetic Resonance Elastography
Many disease processes are characterized by changes in the mechanical properties of previously healthy tissue or the development of regions of tissue with substantially different mechanical properties than surrounding normal tissue. This accounts for the efficacy of palpation as a clinical technique to detect cancer and other abnormalities. Indeed, many tumors of the thyroid, breast and prostate are still first detected by this centuries-old diagnostic technique. Unfortunately, palpation is a subjective technique, and small abnormalities and those located in areas that are inaccessible by a physician cannot be detected by touch. Furthermore, conventional imaging methods such as ultrasound, computerized tomography (CT) and magnetic resonance imaging (MRI) do not provide information that is in any way analogous to palpation.
The research goal of Dr. Ehman's lab is to develop, validate, explore and identify high-impact applications of a new MRI-based diagnostic imaging technology for quantitatively assessing the mechanical properties of tissues. This technique is called magnetic resonance elastography (MRE). Mechanical waves are generated in tissue, and a remarkably sensitive phase-contrast MRI technique using synchronous motion-sensitizing gradients is used to directly image the pattern of wave propagation. Specially developed mathematical algorithms are used to analyze the wave images and to generate quantitative images depicting the stiffness and other mechanical properties of tissue.
MRE is a useful imaging tool that is able to:
- Noninvasively "palpate by imaging" regions of the body that are beyond the reach of the physician’s hand
- Delineate tumors and other abnormalities before they are severe enough to detect by touch
- Provide greater sensitivity for assessing changes in tissue mechanical properties
- Provide useful new quantitative imaging biomarkers for characterizing tissue properties