Ultrasound and MRI
Ultrasound exams involve the doctor running a probe over each breast in a systematic way in order to survey the entire breast. The probe transmits ultrasound waves into the breast and receives returning waves from the breast tissues. As a result, a computer generates a picture on a monitor. Breast cancers which are composed of different tissue from normal breast tissue, are well demonstrated.
The radiologist runs a probe over the entire breast in a systematic manner to evaluate all areas thoroughly. Most specialist practices do an ultrasound as a routine to supplement the mammogram. This increases the sensitivity ie the ability to pick up cancer regardless of how subtle or well hidden they might be.
Ultrasound: The cancer is darker than surrounding tissue, has an irregular margin and casts a shadow
Ultrasound: note spiky margins and shadowing of cancer. Size is 8 x 11mm
Ultrasound is a painless and safe examination even in younger patients and pregnant women. In many practices ultrasound is used as a supplemental test to mammograms reducing the chances of missing a cancer on the mammogram. It is especially useful in women whose dense breast tissue reduce the sensitivity of a mammogram.
Although it is appealing to avoid the squashed breasts and theoretical radiation risks of a mammogram by having only an ultrasound instead, breast ultrasound cannot replace mammograms for cancer screening. Mammograms give us ultra-high resolution pictures of the entire breast. It shows up microcalcifications and subtle architectural distortion, that often are not visible on ultrasound. These features may be the only sign of an early cancer. Mammograms are always compared to previous year’s mammograms and slight changes can also be a sign of early cancer formation. It’s not practical to do the same comparisons with ultrasound. Almost all the studies that show that regular screening saves lives, have been done with mammograms.
In younger patients, we do prefer to do only ultrasounds, but patients over 35 should always have a mammogram.
Mammograms are the gold standard for breast imaging and the only test proven to save lives. However, in patients younger than 35 and in pregnant patients, an ultrasound is done without the mammogram.
In most practices, all mammogram patients will have an ultrasound immediately after the mammogram as we believe that combining the tests increases our accuracy.
Sometimes we do a six month follow up using only ultrasound especially if the area of concern was best seen on ultrasound in the first place.
MRI of the breasts is the most accurate method we have for diagnosing breast cancers. Women at high risk of developing breast cancer (more than 1 in 5 chance. Usually related to family history or BRCA gene mutation carriers) are advised to have an annual breast MRI.
The patient lies face down in the MRI machine and a small amount of dye is injected via a drip which will cause cancers to light up on the scans.Subtle cancers that are only visible on MRI can be biopsied under MRI guidance
Subtle cancers that are only visible on MRI can be biopsied under MRI guidance
A patient goes into the MRI tunnel lying flat on her stomach, her breasts hanging down. A drip is put up and a small amount of intravenous contrast injected during the scan
MRI is also used to help determine extent or multiplicity of a newly diagnosed breast cancer which is particularly helpful in patients scheduled for limited surgical excision.
Lastly, in patients with complex mammograms and ultrasounds where we cannot be certain that cancer is excluded, MRI is an excellent problem solver.
Cancer shown as white mass(lump) against black fatty background – 2D, 3D and with colour appliaction which shows likelihood of malignancy. Red most likely, blue least likely