Breast tissues by introducing shear waves and
Breast cancer is the most common cancer diagnosed, and is the second leading cause of cancer-related deaths in women. Pathological tissues are often stiffer than the surrounding normal tissue. With that being said, malignant breast tumors are much harder than healthy breast tissue. Magnetic resonance elastography, or MRE is a non-invasive imaging technique that measures the stiffness of soft tissues by introducing shear waves and imaging their propagation using MRI. MRE was originally presented by Raja Muthupillai and his colleagues at the Mayo Clinic in 1995. The largest amount MRE experience in the clinical setting is in chronic liver disease. However, MRE has many applications in other organ systems; such as the spleen, kidneys, breasts, and many more. MRE is a highly promising, emerging technology in it’s field. Magnetic resonance elastography is used in the diagnostic detection of stiff tissue and malignant tissue; including the evaluation of breast tissue for diagnosis of breast cancer. The purpose of this essay is to evaluate the imaging technique magnetic resonance elastography in the preventative measures of breast cancer. It is a non-ionizing and non-invasive procedure that uses the same physical aspects that physicians use when performing manual palpation (Low, Kruse, & Lomas, 2016). Bio-mechanical changes occur within the human body when it becomes diseased, which alters the rigidity of these tissues. Tissues that are healthy and tissues that may be diseased can be differentiated based on the differing physical stiffness of the tissue. This is where magnetic resonance elastography comes into play. Magnetic resonance elastography technology is able to compute the given information that is gathered from the patient, and has the ability to be more detailed than conventional diagnostic imaging modalities (Institute of Physics, 2013). Breast cancer is the most common cancer diagnosed in women, and is the second leading cause of cancer-related deaths in women. Although rare, breast cancer can occur in men, adolescents and children (Johns Hopkins University, 2015). The cancer is made up of a group of diseases, with many different subgroups of both invasive and non-invasive types. Breast cancers are divided into carcinomas and sarcomas. Carcinomas originate from the epithelial tissue in the breast, and can be divided into various subgroups. The two major subgroups are in situ and invasive carcinoma. In situ translates to pre-invasive, which means the cancer cells have grown inside pre-existing ducts or lobules and have not invaded tissue within the breast. Cancer cells that have invaded the outside breast ducts and lobules are called invasive carcinomas, and these cells grow into the connective tissue of the breast. Invasive carcinomas can potentially metastasis and spread to other parts of the body. In situ carcinoma has a high possibility of becoming invasive. A rare type of breast cancer, called sarcoma, are cells that originate from the connective tissue, or stromal cells of the breast. Cancer of the inner lining of blood vessels and phyllodes tumors is called angiosarcoma, which is cancer originating from these cells. Carcinomas make up the majority of breast cancer diagnosis; while Sarcoma only makes up about one percent of diagnosis. Symptoms of breast cancer include a mass in the breast or under arm, or changes to breast skin or nipple. Skin changes due to breast cancer may include redness, dimpling, scaling, ulceration, and nipple inversion. However, some patients experience no symptoms of breast cancer. These patients are diagnosed by diagnostic imaging (Johns Hopkins University, 2015). Magnetic resonance elastography is a non-ionizing and non-invasive procedure that measures tissue stiffness in the breast via mechanical waves sent through the tissue with a special magnetic resonance imaging technique. Magnetic resonance elastography records the images depicting the propagation of the shear waves, and an algorithm converts the information of the wave image into an elastogram. Speed of shear wave propagation is closely related to tissue stiffness. This means that the faster the speed, the stiffer the tissue (Low, Kruse, & Lomas, 2016). Magnetic resonance elastography records the images depicting the propagation of the shear waves, and an algorithm converts the information of the wave image into an elastogram. It basically performs as “virtual palpation.” Magnetic resonance elastography uses the same physical aspects that physicians use when performing manual palpation. The magnetic resonance elastography drivers which push against the breasts, are positioned inside the cavities of a breast RF coil. The patient lies on top of the RF coil in the prone position with their breasts hanging inside the cavities. The driver is maneuvered right, left, superior, inferior, and/or anterior to one or both breasts (Solamen, 2017). The patient is then scanned. Two popular elastographic techniques are used in breast elastpgraphy. These techniques differ in the type of stress applied to the tissue. These types of elastography are strain and shear-wave elastography (Youk, Gweon, & Son, 2017). Strain elastography produces an image based on the displacement of the tissue relative to an external or patient source, which is manual compression of the transducer. Measuring the amount of the force or stress during compression can be difficult. In some instances, the absolute elasticity cannot be calculated. On the other hand, shear-wave elastography displays visual color overlay of elastic information by using the acoustic radiation force (Youk, Gweon, & Son, 2017). The acoustic radiation force is induced by the ultrasound push pulse, which is generated by the transducer. This provides quantitative elasticity parameters, all in real time. The most broad range of detection is found and based on the current optimized setup. Which can range between 47 kPa and 4 MPa, exceeding the modulus of normal soft tissue. This suggests the possibility of using this technique for stiffer materials’ mechanical characterization. Depending on sample stiffness and experimental setup, the detectable difference was found to be as low as 157 kPa (Zhou, Goss, Hernandez, Mansour, & Exner, 2016). It was found that the detection limit of strain imaging can exceed the soft tissue range, up to 4MPa, with detectable difference as low as 157kPa, by comparing strain imaging data to standard mechanical testing data statistically; depending on sample stiffness and experimental setup (Cui et al, 2015). Magnetic resonance elastography can be incorporated into a conventional magnetic resonance imaging examination to provide a single appointment that is quick, accurate, and comprehensive for the patient. In a recent study conducted by a cancer institute based in Brazil, scientists compared the findings of conventional magnetic resonance imaging and magnetic resonance elastography of the breast. In hopes to differentiate silicone-induced granuloma from seroma/hematoma of breast implant capsules, and determine whether there is correlation between the two modalities. The magnetic resonance elastography study showed correlation with conventional magnetic resonance imaging results in all cases of silicone-induced granuloma and seroma/hematoma (De Faria Castro Fleury et al, 2017). Magnetic resonance elastography was able to differentiate between solid and cystic lesions. Magnetic resonance elastography of breast implant masses presented compatible results with those found by conventional magnetic resonance imaging to differentiate collections from solid lesions (De Faria Castro Fleury et al, 2017). Magnetic resonance elastography offers a wide range of imaging coverage as well as technique allowing three-dimensional performance. Breast elastography can also enhance the effectiveness of an ultrasound by a considerable amount when differentiating a benign breast tumor from malignant breast tumor. Enhancing the effectiveness of an ultrasound by this considerable margin can reduce the amount of biopsies needed by the physician. Even if this technique may appear more useful in the study of focal pathologies, magnetic resonance elastography can also add important details that help define the components of epithelial and connective tissue and the varying elasticity they posses (Seo, & Woo, 2013). Additionally, shear-wave elastography can provide information on predicting breast cancer prognosis, as well as the prediction of a patient’s reaction to certain chemotherapy treatments. A magnetic resonance elastography examination can assess the proximity and elasticity of tumors in the digestive tract that would other wise be extremely difficult to reach with conventional modalities such as ultrasound probes. Including abdominal and mediastinal lymph nodes and pancreatic masses, thus improving the diagnostic yield of the procedure. There are numerous benefits to magnetic resonance elastography. As stated previously in this essay, magnetic resonance elastography is a non-invasive procedure that could potentially improve the specificity of conventional breast magnetic resonance imaging. Magnetic resonance elastography also has higher accuracy of measuring breast tissue stiffness due to the increased image quality if this technology (Venkatesh & Ehman, 2014). Patients experience the benefits of magnetic resonance elastography in other ways as well. For many patients, magnetic resonance elastography is thought to be safer. Some patients consider magnetic resonance elastography to be more comfortable than other imaging modalities. The cost of the procedure is less expensive than conventional procedures for many patients (Venkatesh & Ehman, 2014). Magnetic resonance elastography has been approved by the national Food and Drug Administration, and is available to the public as a magnetic resonance imaging upgrade since 2010. As more research is dedicated to the study of magnetic resonance elastography, I believe more benefits will be discovered. Magnetic resonance elastography was originally presented by Raja Muthupillai and his colleagues at the Mayo Clinic in 1995. Since then MRE technology has grown and improved substantially. The largest amount magnetic resonance elastography research and study in the clinical setting is in chronic liver disease. However, magnetic resonance elastography has many applications in other organ systems; including but not limited to spleen, kidneys, and breasts. Breast cancer is the most common cancer diagnosed, and is the second leading cause of cancer-related deaths in women. Magnetic resonance elastography technology has great potential in regards to diagnostic imaging. Magnetic resonance elastography is used in the diagnostic detection of stiff tissue and malignant tissue; including the evaluation of breast tissue for diagnosis of breast cancer. Numerous studies and research has gone into this for-running technology, and several benefits have come from magnetic resonance elastography. As well as many technological advancements and clinical applications. However, this technology has yet to be fully evaluated in some aspects and unfortunately, new break throughs have not taken place for further exploration. The future of magnetic resonance elastography is very promising. Although magnetic resonance elastography is a relatively new technology in it’s field, I think magnetic resonance elastography could be an overall beneficial tool in the field of diagnostic imaging. That being said, certain break throughs and discoveries need to be made before this technology can meet it’s potential. It is my belief that magnetic resonance elastography has the possibility to become the new standard in diagnostic imaging technology.