MODULE 3. Further laboratory and imaging examinations related to breast cancer diagnostics
3.8. Contrast agents
Gadolinium
Intravenous gadolinium is used to detect the increased circulation of blood at the site of the tumour. The increased circulation is caused by tumour induced angiogenesis and by the increased permeability of capillaries. The function of gadolinium as a contrast agent is based on its capability to shorten both T1 and T2 relaxation times.
The dosage of gadolinium is based on the patient’s weight. Pure gadolinium is toxic and has to be bound to a chelating agent that binds the gadolinium ion when the chelated compound is inside the human body. Properties of the chelate affect how the contrast agent is transported in the body (Lammentausta 2014). |
Contrast enhancement media in breast MRI
Breast tissue may intake too much contrast enhancement media for hormonal reasons. This can be avoided by several ways described in here.
- The patient should discontinue hormone replacement therapy 4-6 weeks before breast MRI
- Pre-menopausal women should be examined during day 6-13 of the menstrual cycle
- In urgent cases recommendations can’t always be followed and the situation should be taken into consideration in image interpretation.
Hypersensitivity reactions caused by contrast media
Acute allergic reactions are rare (less than 0.01% of cases). 80% of those cases are mild reactions such as nausea or urticaria and other skin reactions. The most severe reaction is anaphylactic shock which needs urgent care or even resuscitation measures. Patients must always be interviewed about the risk factors, allergies and previous contrast media reactions before injecting contrast agents in order to avoid allergic reactions (Lammentausta 2014).
GFR and NFS
Kidney function must be checked by calculating the glomerular filtration rate (GFR) before injecting any contrast media. Gadolinium-based contrast media can cause a rare but serious adverse effect called nephrogenic systemic fibrosis (NFS). NFS is a serious syndrome involving fibrosis of the skin, joints and internal organs.
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References
- Koskivuo I, Lääperi A, Elberkennou J, et al. Rintojen magneettikuvaus rintasyövän tarkentavassa diagnostiikassa. Suomen Lääkärilehti. 2012; 67 (9): 692–698. (http://www.thl.fi/attachments/halo/SLL_2012_RintojenMagneettikuvausRintasyovanDiagnostiikassa.pdf)
- Lammentausta E. MRI-tehosteaineet – onko gadoliniumin käyttökään enää turvallista? Suomen Radiologiyhdistys. Sädeturvapäivät. 2014. 68-69.
- Magneettivarjoaineiden aiheuttama nefrogeenisen systeemisen fibroosin riski. Käypä hoito. Suomalainen Lääkäriseura Duodecim. http://www.kaypahoito.fi/web/kh/suositukset/suositus?id=nak08078, 2013.