Elastography
Encyclopedia
Elastography is a non-invasive method in which stiffness or strain image
s of soft tissue
are used to detect or classify tumors. A tumor or a suspicious cancer
ous growth is normally 5-28 times stiffer than the background of normal soft tissue. When a mechanical compression or vibration is applied, the tumor deforms less than the surrounding tissue. i.e. the strain in the tumor is less than the surrounding tissue. Hence a strain image may, under particular simplifying assumptions, be interpreted as representative of the underlying Young's modulus distribution. The strain distribution may be temporally variant in the presence of internal fluid flow. Elastograms (images of tissue strain) have been shown to be affected by the degree of adherence of the tumor to its surroundings, indicating a potential to extend elastography to tumor mobility characterisation to improve diagnostic accuracy and surgical guidance.
imaging is the most common medical imaging technique for producing elastograms. Some research has been conducted using magnetic resonance elastography (MRE)
and computed tomography
. However, using ultrasound has the advantages of being cheaper, faster and more portable than other techniques.
Transient elastography is used for example to measure the stiffness of the liver in vivo (FibroScan, Echosens, France). It is an alternative noninvasive method to liver biopsy
. A correlation between liver elasticity and the fibrosis score (or cirrhosis
) has been shown.
Elastography has become an efficient and easy-to-perform component of the breast ultrasound examination because tissue stiffness gauges of various types have been incorporated in a number of high-resolution linear transducers.
Siemens Tissue Strain Imaging
Real Time Strain Imaging
Acoustic Radiation Force Impulse (ARFI) Imaging
is another imaging modality being researched to non-invasively characterize liver stiffness,
Image
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...
s of soft tissue
Soft tissue
In anatomy, the term soft tissue refers to tissues that connect, support, or surround other structures and organs of the body, not being bone. Soft tissue includes tendons, ligaments, fascia, skin, fibrous tissues, fat, and synovial membranes , and muscles, nerves and blood vessels .It is sometimes...
are used to detect or classify tumors. A tumor or a suspicious cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
ous growth is normally 5-28 times stiffer than the background of normal soft tissue. When a mechanical compression or vibration is applied, the tumor deforms less than the surrounding tissue. i.e. the strain in the tumor is less than the surrounding tissue. Hence a strain image may, under particular simplifying assumptions, be interpreted as representative of the underlying Young's modulus distribution. The strain distribution may be temporally variant in the presence of internal fluid flow. Elastograms (images of tissue strain) have been shown to be affected by the degree of adherence of the tumor to its surroundings, indicating a potential to extend elastography to tumor mobility characterisation to improve diagnostic accuracy and surgical guidance.
Medical Imaging
UltrasonicUltrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
imaging is the most common medical imaging technique for producing elastograms. Some research has been conducted using magnetic resonance elastography (MRE)
Magnetic resonance elastography
Magnetic resonance elastography is a medical imaging technique that images propagating mechanical waves using MRI. It non-invasively measures the stiffness of biological tissues. Pathological tissues are often harder than the surrounding normal tissue...
and computed tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
. However, using ultrasound has the advantages of being cheaper, faster and more portable than other techniques.
Transient elastography is used for example to measure the stiffness of the liver in vivo (FibroScan, Echosens, France). It is an alternative noninvasive method to liver biopsy
Liver biopsy
Liver biopsy is the biopsy from the liver. It is a medical test that is done to aid diagnosis of liver disease, to assess the severity of known liver disease, and to monitor the progress of treatment.-History:...
. A correlation between liver elasticity and the fibrosis score (or cirrhosis
Cirrhosis
Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...
) has been shown.
Elastography has become an efficient and easy-to-perform component of the breast ultrasound examination because tissue stiffness gauges of various types have been incorporated in a number of high-resolution linear transducers.
Siemens Tissue Strain Imaging
Real Time Strain Imaging
Acoustic Radiation Force Impulse (ARFI) Imaging
Acoustic Radiation Force Impulse (ARFI) Imaging
Acoustic Radiation Force Impulse Imaging uses acoustic radiation force to generate images of the mechanical properties of soft tissue.-How it works:...
is another imaging modality being researched to non-invasively characterize liver stiffness,