Magnetic resonance elastography
|Magnetic resonance elastography|
Magnetic resonance elastography of the brain. A T1 weighted anatomical image is shown in the top-left, and the corresponding T2 weighted image from the MRE data is shown in the bottom-left. The wave image used to make the elastogram is shown in the top-right, and the resulting elastogram is in the bottom-right.
|Purpose||measures the mechanical properties of soft tissues|
Magnetic resonance elastography (MRE) is a non-invasive medical imaging technique that measures the mechanical properties (stiffness) of soft tissues by introducing shear waves and imaging their propagation using MRI. Diseased tissues are often stiffer than the surrounding normal tissue. For instance, breast cancers are much harder than healthy fibroglandular tissue. This characteristic has been used by physicians for screening and diagnosis of many diseases, through palpation. MRE calculates the mechanical parameter as elicited by palpation, in a non-invasive and objective way.
Magnetic resonance elastography works by using an additional gradient waveform in the pulse sequence to sensitize the MRI scan to shear waves in the tissue. The shear waves are generated by an electro-mechanical transducer on the surface of the skin. Both the mechanical excitation and the motion sensitizing gradient are at the same frequency. This encodes the amplitude of the shear wave in the tissue in the phase of the MRI image. An algorithm can be used to extract a quantitative measure of tissue stiffness from the MRI in an elastogram.
Magnetic resonance elastography was first introduced by Muthupillai et al. in 1995 and is being investigated to be used for a multitude of diseases that affect the tissue stiffness. It has been used clinically used for the assessment of liver fibrosis.
- Muthupillai R; Lomas, DJ; Rossman, PJ; Greenleaf, JF; Manduca, A; Ehman, RL (1995). "Magnetic resonance elastography by direct visualization of propagating acoustic strain waves". Science. 269 (5232): 1854–1857. doi:10.1126/science.7569924. PMID 7569924.
- Mariappan YK; Glaser, KJ; Ehman, RL (2010). "Magnetic resonance elastography: A review". Clinical Anatomy. 23 (5): 497–511. doi:10.1002/ca.21006. PMC .
- Meng Yin; Talwalker, JA; Glaser, KJ; Manduca, A; Grimm, R; Rossman, P; Fidler, JL; Ehman, RL (2007). "Assessment of Hepatic Fibrosis with Magnetic resonance elastography". Clinical Gastroenterology and Hepatology. 5 (10): 1207–1213. doi:10.1016/j.cgh.2007.06.012. PMC .
- Huwart L; Sempoux, C; Vicaut, E; Salameh, N; Laurence, A; Danse, E; Peeters, F; Beek, L; Rahier, J; Sinkus, R; Horsmans, Yves; Beers, BE (2008). "Magnetic Resonance Elastography for the noninvasive staging of liver fibrosis". Gastroenterology. 135 (1): 32–40. doi:10.1053/j.gastro.2008.03.076.
- Asbach P; Klatt, D; Schlosser, B; Biermer, M; Muche, M; Rieger, A; Loddenkemper, C; Somasundaram, R; Berg, T; Hamm, B; Braun, J; Sack, I (2010). "Viscoelasticity-based Staging of Hepatic Fibrosis with Multifrequency MR Elastography". Radiology. 257 (1): 80–86. doi:10.1148/radiol.10092489.
|Wikimedia Commons has media related to Magnetic resonance elastography.|