DIAGNOSIS OF BREAST CANCER: MRI
What is the role of an MRI (Magnetic Resonance Imaging) in the evaluation of a breast mass?
Breast MRI is the future of breast radiology. It is a powerful tool in detecting early cancers which are not even seen on mammograms. Because of the cost, it is used as a problem solving modality. Its the most sensitive tool available hence certain lesions seen on MRI may not be seen on other imaging modalities hence MRI-guided localization or a biopsy system are needed.
Which women may need to undergo an MRI?
Women at high risk can undergo screening MR mammography. The American College of Radiology, in its 2004 practice guidelines, has outlined these indications for breast MRI as follows:
High risk patients having BRCA 1, BRCA2 genes or Cowden's syndrome or Li freumani syndrome
Response to neoadjuvant chemotherapy
Axillary node metastases with an unknown primary
Postoperative tissue evaluation
Silicone and non-silicone breast augmentation
How is an MRI performed?
MRI breast is performed only on 1.5T or higher strength magnets. Dedicated breasts coils give high resolution. The patients lies down in prone position( i.e. lies on stomach) with the breasts hanging into the cups of the coil. Gentle compression on the inner and outer surfaces of the breasts are applied to decrease motion artifact. Dynamic contrast enhanced scans are performed after completion of plain scans. The entire examination takes about 30-45 mins.
Breast MRI has emerged as the most sensitive modality for evaluation of the breast; however, it is limited by low specificity. Breast MRI does not replace mammography for screening of breast cancer in the general population however provides additional information and is recommended as a problem solving modality.