MODULE 3. Further laboratory and imaging examinations related to breast cancer diagnostics
3.1. The indications for Breast MRI – when is a breast MRI used
What is MRI?
Magnetic resonance imaging (MRI) provides information about the structure and function of the breast. Breast MRI is used to measure the size of cancer, detect other tumours in the breast and to check if the other breast also has a tumour. An MRI scan is able to form images in three different planes: axial, sagittal and coronal (Koskivuo et al., 2012).
Breast tissue is hormonally active which can cause healthy breast tissue to also uptake the contrast material. For this reason it is possible that malignant tumours cannot be seen on MRI. The best time to perform a breast MRI is during the second week of the menstrual cycle when the hormonal activity of the breast tissue is at its lowest. After discontinuing hormonal replacement therapy, one should wait for 4-6 weeks before having an MRI scan (Hukkinen, 2012 & 2013). |
Comparison of MRI with mammography and ultrasound
MRI is used as a further examination for breast screening in addition to screening with mammography and ultrasound. The sensitivity of contrast-enhanced breast MRI is about 90% which makes it the most sensitive modality for the detection of cancer. In comparison, the sensitivity of mammography is about 67.8%. The specificity of breast MRI is about 75%, which is the same as that of mammography. Although breast MRI is more sensitive than mammography, it cannot exclude all types of cancers. Some types of cancers may show better on mammography than on MRI (Hukkinen 2012 & 2013; Morrow et al 2011).
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In contrast to mammography, neither breast MRI nor ultrasound uses ionizing radiation. Ultrasound images are fuzzier, making the detection of microcalcifications difficult. Other advantages of breast MRI are its higher 3D spatial resolution, a better ability to measure the size of cancer and spot borderline cases of breast cancer. With breast MRI, both breasts and the chest wall can be examined at the same time (Shahid et al 2016).
When the density of the breast tissue increases, the sensitivity of mammography for detecting the cancer decreases. For this reason, MRI is the best modality for imaging dense breasts. MRI is also used for determining if a silicone breast implant is intact.
Disadvantages of breast MRI include an increased chance of false positive results and high cost - MRI is a very expensive modality to use when screening for cancer (Koskivuo et al 2012; Mann et al 2008).
Indications for breast MRI
MRI can provide information that mammography cannot. The sensitivity of mammography lower if the patient is a young female or she has dense breast tissue. In these cases, MRI can be invaluable (Koskivuo et al 2012).
- MRI is used as an additional tool for preoperative assessment of the size and location of the tumour.
- Breast MRI is helpful when planning a surgery for breast tumour removal. It can also decrease the number of repeat surgeries and unnecessary mastectomies.
- However, MRI is not recommended for all patients who are going to have breast tumour removal. As the results of an MRI scan can be conflicting, a biopsy should be performed to confirm the finding.
- According to the EUSOMA (European Society of Breast Cancer Specialists) guidelines, a preoperative MRI is recommended for:
- patients with a newly diagnosed invasive lobular cancer;
- patients under 60 years of age with a discrepancy in size over 1cm between mammography and ultrasound;
- in case of inconsistency between clinical imaging findings and histological findings.
- Patients at high risk for breast cancer, including patients with BRCA1, BRCA2 and TP53 mutations and patients with Cowden syndrome.
- MRI screening should be available for women with a family history of inherited predisposition for breast cancer and for women who have had previous radiotherapy to the chest area between ages 10 and 30.(Mann et al 2008; Morrow et al 2011; Suomen rintasyöpäryhmä ry. 2015; Sardanelli et al 2010;Taylor 2017; THL 2016).
- MRI screening should be available for women with a family history of inherited predisposition for breast cancer and for women who have had previous radiotherapy to the chest area between ages 10 and 30.(Mann et al 2008; Morrow et al 2011; Suomen rintasyöpäryhmä ry. 2015; Sardanelli et al 2010;Taylor 2017; THL 2016).
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References
- Hukkinen K. Milloin rintojen MRI ja UÄ? Sädeturvapäivät abstraktit, 2012. (http://www.sadeturvapaivat.fi/index.php?id=688&cat_ids=x86x#cat86)
- Hukkinen K. Rintojen magneettikuvaus. Lääketieteellinen aikakauskirja Duodecim, 2013; 20.(http://www.duodecimlehti.fi/lehti/2013/20/duo11278).
- Koskivuo I, Lääperi A, Elberkennou J, Saalasti-Koskinen U, Isojärvi J, Mäkinen E. Rintojen magneettikuvaus rintasyövän tarkentavassa diagnostiikassa. Suomen Lääkärilehti. 2012; 67 (9): 692–698. (http://www.thl.fi/attachments/halo/SLL_2012_RintojenMagneettikuvausRintasyovanDiagnostiikassa.pdf)
- Mann RM, Kuhl CK, Kinkel K, Boetes C. Breast MRI: guidelines from the European Society of Breast Imaging. Eur Radiol. 2008; 18 (7): 1307–1318.
- Morrow M, Waters J, Morris E. MRI for breast cancer screening, diagnosis, and treatment. The Lancet. 2011; 378 (19): 1804.
- Rintasyövän valtakunnallinen diagnostiikka- ja hoitosuositus. Suomen Rintasyöpäryhmä ry. https://rintasyoparyhma-yhdistysavain-fi-bin.directo.fi/@Bin/90817a345ecc1aac91bcc083068c6bf7/1497181344/application/pdf/178853/Rintasy%C3%B6p%C3%A4ryhm%C3%A4n%20valtakunnallinen%20diagnostiikka-%20ja%20hoitosuositus%202015%20%28p%C3%A4ivitys%207.11.2016%29.pdf, 2015.
- Sardanelli F, Boetes C, Borisch B, Decker T, Federico M, Gilbert FJ, Helbich T, Heywang-Köbrunner SH, Kaiser WA, Kerin MJ, Mansel RE, Marotti L, Martincich L, Mauriac L, Meijers-Heijboer H, Orecchia R, Panizza P, Ponti A, Purushotham AD, Regitnig P, Del Turco MR, Thibault F, Wilson R. Magnetic resonance imaging of the breast: Recommendations from the EUSOMA working group. European Journal of Cancer. 2010; 46: 1301.
- Shahid H, Wiedenhoefer JF, Dornbluth C, Otto P, Kenneth AK. An overview of breast MRI. Applied Radiology. 2016. (http://appliedradiology.com/articles/an-overview-of-breast-mri)
- Taylor D. Breast MRI. Inside Radiology, 2017 (https://www.insideradiology.com.au/breast-mri/)
- THL. Seulontamenetelmät. https://www.thl.fi/fi/web/terveyden-edistaminen/toimijat/terveyden-edistaminen-eri-toimialoilla/seulonnat/rintasyovan-seulonta/seulontamenetelmat, 2016.