Breast Magnetic Resonance Imaging - Assignment Example

1. Discuss the hormonal influences on breast tissue during the normal menstrual cycle. Why is this important when scheduling a breast MRI? Answer: The human breast is made up of different types of tissues which include glandular, fatty as well as fibrous tissue. The breast is present in both males and females but it normally enlarges and develops only in the females at the time of puberty under the influence of the female sexual hormones. The breast has its own nervous as well as vascular supply. The glandular tissue of the breast comprises of lobules which are linked via the terminal ducts to form the lactiferous ducts. The breast tissue has hormonal receptors and therefore it undergoes normal cyclical changes with every menstrual cycle (Alexander 2009). The breast tissue is subjected to cyclical changes owing to the fluctuations in the levels of the hormones, estrogen and progesterone according to the different phases of the monthly cycle. During the luteal phase of the cycle, the amount of progesterone increases in the body mainly due to its production by the corpus luteum. The levels of estrogen are also high. The effect of progesterone is more pronounced also due to the rise in the number of progesterone receptors in the breast during the luteal cycle. This results in the formation of fluid, increase in the process of mitosis as well as increased synthesis of DNA in all the tissues of the breast. There is an increase in the epithelial cells of the breast accompanied with an increase in the size of the lobules and ducts in the breast. This further leads to an increase in the size of breast as well as tenderness in the breast. These account principally for the breast symptoms of the premenstrual syndrome in females. The breast may also develop cystic characteristics in this phase of the cycle which are temporary and resolve with the end of the luteal phase. The follicular phase follows the luteal phase and the initiation of menstruation occurs. This results in the destruction of the corpus luteum and the subsequent drop in the levels of estrogen and progesterone. The epithelium of the breast undergoes reduction and the ducts and the lobules are reduced to maintain their previous normal size (Bass et al 2005; Fritz et al 2010). The cyclical changes of the breast are important when scheduling the breast MRI. The normal breast MRI shows a generalized contrast enhancement and the strength of the signals increases in a stepwise fashion. But during the luteal phase, the increase in the hormones may result in the increased enhancement in certain areas of the breast owing to the cystic changes. These areas may show sharp enhancement accompanied with the intensity of the signals rising in a prompt manner rather than in the regular slow fashion in the normal breast parenchyma. Thus these cystic changes may give the false appearance of malignancies and tumors. Therefore, the MRI of the breast is to not to be done in the luteal phase. This is owing to the fact that false positive results may be obtained in this phase of the monthly cycle (Liberman 2005; Rummeny et al 2009). 2. Discuss the BRCA 1 and BRCA 2 genes. What are the implications for a patient who has a harmful BRCA gene mutation, and how are such patients managed clinically? Answer: The BRCA1 gene was identified in the year 1994 and it was found to be present on chromosome 17q12. Its association with malignancies in the breast had already been recognized in the year 1990 but the identification process of the gene was only complete in 1994. The discovery of the BRCA2 gene followed a year later and it was identified in the year 1995. The location of the gene was found to be on chromosome 13q. The BRCA1 gene undergoes the process of transcription to form a protein that has 1863 amino acids. This gene is susceptible to mutations and 600 genetic mutations of BRCA1 have been identified. On the other hand, the BRCA2 gene undergoes the process of transcription to form a protein that has 3418 amino acids. The numbers of mutations in the BRCA2 gene that have been identified are 250(Hamdan 2007; Vande Woude et al 2002). The BRCA1 and BRCA2 genes have the highest concentration in the testes and thymus. They are essential in the process of embryo development and they later increase in number in females at the time of puberty. These genes are known to be under the influence of estrogen and are directly proportional to the levels of estrogen in the human body. They are referred to as “tumor suppressor genes” owing to their role in preventing the occurrences of tumors. The proteins which are synthesized by this gene have the role of upholding the stability of the genetic sequences. They have an essential task of correcting the abnormalities in the DNA structure. They prevent the production of unstable DNA and genetic structures. They also have the function of regulating and monitoring the cell cycle as well as the checking of the process of transcription. These essential functions of the BRCA genes may be lost due to the absence or mutations in the forming of these genes. The loss of the normal regulatory functions can serve to promote the formation of tumors and malignancies (Hamdan 2007; Vande Woude et al 2002). The BRCA1 and BRCA2 genetic mutations are mainly implicated for the causation of breast as well as ovarian cancers but mutations in these genes are in addition associated with the risk of other cancers. Another interesting and important aspect with regard to these genes is that mutations are more commonly seen in the Jews as compared to the other races. In women who have a genetic mutation in BRCA1, the chances of the developing of breast as well as ovarian malignancies are 65 percent and 39 percent respectively by the attainment of the age of 70 years. The mutations in this gene are also associated with the cancers of endometrial lining of the uterus, cervix, prostate and pancreas but the possibility is significantly lower as compared to the chances of the malignancies of the breast and ovaries. On the other hand, in women with mutations in the BRCA2 gene, chances of development of the malignancies of the breast and ovaries are lower in comparison to the risk associated with BRCA1. The risk is analyzed to be 45 percent for the development of the cancers of the breast and 11 percent for the development of the cancers of the ovaries by the age of 70 years. An important implication of BRCA2 gene is in association with male breast cancer as men with this genetic mutation have 6 percent risk of the development of breast cancer. The BRCA2 gene is also linked with cancers of the pancreas, bile duct, gall bladder as well as malignant melanoma (Firth et al 2006; Vande Woude et al 2002). The patients who have been identified as having mutations in the BRCA1 and BRCA2 should be managed through an integrated clinical approach. The first and foremost step is the proper history of first degree relatives who suffered from any of the cancers that result due to mutations in these genes. This is to be followed by genetic counseling and appropriate services to other members of the family who may be at risk. This is for the early identification of the disease by means of screening methods. The supported recommendations for carriers of genetic mutations that have been identified have been highlighted and proposed by experts. These include examination of the breast by a surgeon on a regular basis after every six months. This is to be accompanied with a mammogram. The importance of MRI breast on an annual basis in these cases has also been indicated. This is owing to the fact that the mammogram has been considered to be less sensitive in these patients. Furthermore, prophylactic mastectomy is also another treatment modality offered to these patients and has been shown to have a success rate of 90 percent. The use of tamoxifen has also proved to be beneficial for the prophylactic treatment of breast cancer in these patients. It is referred to as a form of chemoprevention. Patients below the age of 40 are advised to have an annual pelvic examination accompanied with a transvaginal ultrasound and the measure of serum CA-125. These investigations are meant for the early detection of ovarian cancers. The prophylactic surgery advice is of bilateral salpingo-oopherectomy and hysterectomy after the women has completed her family. Oral contraceptive pills in people suffering from these mutations have found to reduce the risk of the cancer of the ovaries. But the effect on the breast has not been proven and it is believed that they might lead to a rise in the chances of breast cancer (Firth et al 2006; Fritz et al 2010). Dietary advice and a healthy balanced diet are highly recommended for these groups as it has been seen that these factors tend to reduce the chances of the development of cancers. This should be accompanied with engagement in physical activities as research has proved the beneficial effects of the constellation of physical activity and healthy diet in the carriers of BRCA1 and BRCA2 gene mutations. The carriers of genetic mutations in BRCA1 and BRCA2 gene should be connected with appropriate support groups. This is for the purpose of keeping them updated with new researches and for the monitoring of their health on a regular basis. It is also meant to provide them with emotional support (Firth et al 2006; Fritz et al 2010). 3. MRI can be used to assess breast implant integrity. Discuss intracapsular and extracapsular rupture and their MRI appearances. Answer: Breast implants that are widely used are the silicone implants. These implants are foreign substances and their implantation evokes a normal physiological bodily response resulting in the formation of a fibrous capsule surrounding the implanted material. This fibrous capsule provides for the demarcation of the normal breast parenchyma from the implant. The breast implants may get ruptured and the rupture may be classified into either intracapsular breast implant rupture or extracapsular breast implant rupture. The two types of ruptures are differentiated with regard to the integrity of the fibrous capsule surrounding the implant. If the implant ruptures and the silicone remains within the boundaries of the capsule surrounding it, it is referred to as an intracapsular rupture. In a similar manner, if the implanted material breaches the boundaries of the fibrous capsule and spreads beyond it, it is termed to be an extracapsular rupture. An interesting aspect with regard to extracapsular rupture is that it always coexists with an intracapsular rupture (O’Brien 2010). The intracapsular and extracapsular breast implant ruptures can be differentiated from each other on the basis of their MRI appearances. The signal intensity of the silicone gel is very high and in the case of an intracapsular rupture many lines of low signal intensity which are referred to as curvilinear lines are found to be present within the high intensity signals of the implant. This sign is known as “linguine sign.” The linguine sign needs to be distinguished from the normal radial folds which present with thick and lesser lines in comparison to the curvilinear lines. The “teardrop sign” is also an indicator of the breast implant rupture but it may also be present in the cases of seepage of the silicone gel from the fibrous capsule. Thus it cannot be considered to be a definitive diagnostic MRI sign of implant rupture. The “teardrop sign” represents as the presence of fluid assortment in the radial folds (Burgener et al 2002). The extracapsular rupture is always accompanied with an intracapsular rupture. The silicone gel extends beyond the fibrous capsule and is found within the normal breast tissue. The silicone implants already possess high signal intensities. Thus extracapsular ruptures can be identified on the MRI by the presence of high signal intensities in segmental areas of the breast tissue owing to presence of silicone in these regions due to the rupture of the fibrous capsule. Furthermore, a mammogram and an examination of the breast can be simultaneously performed for a definitive conclusion of an extracapsular rupture. It is also an essential step to always assess the MRI’s in the most appropriate manner when an intracapsular rupture is suspected to ensure and exclude the presence of an extracapsular rupture (Burgener et al 2002; O’Brien 2010). References Top of Form ALEXANDER, M. F. (2009). Nursing practice: hospital and home - the adult. [S.l.], Churchill Livingstone. Top of Form BASS, P., BURROUGHS, S., & WAY, C. (2005).Systematic pathology: a clinically-orientated core text with self-assessment. Edinburgh, Elsevier Churchill Livingstone. Top of Form BURGENER, F. A., MEYERS, S. P., TAN, R. K., & ZAUNBAUER, W. (2002). Differential diagnosis in magnetic resonance imaging. Stuttgart, Thieme. Bottom of Form Bottom of Form Bottom of Form Top of Form FIRTH, H. V., HURST, J. A., & HALL, J. G. (2006).Oxford desk reference: clinical genetics. Oxford, Oxford University Press. Top of Form FRITZ, M. A., & SPEROFF, L. (2010). Clinical gynecologic endocrinology and infertility. Philadelphia, Pa, Lippincott Williams & Wilkins. Bottom of Form Bottom of Form Top of Form HAMDAN, M. (2007). Cancer biomarkers: analytical techniques for discovery. Hoboken, N.J., Wiley-Interscience. LIBERMAN, L. (2005). Breast MRI diagnosis and intervention. New York, Springer. Top of Form OBRIEN, W. T. (2010). Top 3 differentials in radiology: a case review. New York, Thieme. Bottom of Form RUMMENY, E. J., REIMER, P. & HEINDEL, W. (2009). MR imaging of the body. Stuttgart, Thieme. Bottom of Form Top of FormVANDE WOUDE, G. F., & KLEIN, G. (2002). Advances in cancer research. Volume 84. San Diego [Calif.], Academic Press.Bottom of Form Read More