Breast Imaging

I would reinforce Dr. Moore's answer that not all breast findings need an MRI. There is no way that any of us can tell based on the information provided whether or not an MRI or other imaging will be helpful or necessary in this case - an understanding of the patient's clinical situation as well as review of the mammograms and any available pathology reports is necessary. In general, calcifications do not show up on MRI. There is no question that there are cancers that will show up on MRI that are missed by other imaging, but again each case needs to be properly evaluated before a blanket recommendation for MRI is made. There is no best imaging test for the breast, but that also does not mean that every test should be done in every person.

Yeah. I hate this question. And I get it whenever the patient's cancer was missed on mammo. I think that so much emphasis has been put on screening mammos yet it is often not well known that mammos miss up to 20% of breast cancers on screening studies. [Reference: www.cancer.gov/cancertopics/factsheet/detection/mammograms] Crummy, I know, but when you look at the stats, it's still the best we have right now for mass screening. And it is responsible for the decrease in mortality and increase in early stage diagnosis over the last decade or so. [Reference: Regular mammograms may decrease the risk for deadly breast cancer by 49%, a new case-control study suggests.

According to the Dutch investigators, the greatest reduction occurred in women aged 70 to 75 years and represented a drop of 84%.

"Our study adds further evidence that mammography screening unambiguously reduces breast cancer mortality," said senior researcher Suzie Otto, PhD, from the Department of Public Health at Rotterdam's Erasmus Medical Centre, the Netherlands, in a news release.

The study was published online December 6, 2011 in Cancer Epidemiology, Biomarkers, and Prevention]


So even though it did not pick up the first cancer, odds are that it will pick up the next one if it occurs. That's why we still order it in these cases. Ultrasound is too time consuming and misses the non invasive cancers. MRI is very expensive and not specific enough for mass screening although we do use it in high risk patients even though we don't have a whole lot of data. MRI also does not pick up DCIS well unless high grade. Some argue that a previous diagnosis of cancer automatically puts you into a high risk category and therefore you should have screening MRI annually, but that is not yet standard of care and therefore not always covered by insurance.

How should you prepare?
1>If possible, you should schedule your test for the week after your period, and not before or during period, since your breasts may be tender.

2>Do not wear talcum powder,lotion or deodorant under your arms or on your breast on the day of the exam. These can appear on the mammogram as calcium spots.

3>Describe any symptoms or problems related breast to the technologist performing the exam.

We use Breast Specific Gamma Imaging (BSGI), which is a molecular breast imaging test, at my practice in certain circumstances. This is a nuclear medicine study where a radioactive substance is injected into an IV catheter in the patient’s arm, and images of the breasts are obtained with the patient in a seated position. The test looks for spots in the breast that become “hot”, or that take up the radiotracer more avidly than the surrounding tissue. Although not all hot spots will be cancerous, they do need to be checked with further tests. If the BSGI is negative, there is a very high likelihood that no cancer is present in the breast.

At my practice, we use MRI (in addition to mammography) to screen patients at high risk for breast cancer, to further evaluate questionable mammographic, sonographic, or clinical findings, and to fully evaluate both breasts in patients newly diagnosed with breast cancer. Sometimes a patient cannot have an MRI, and in those circumstances we will usually recommend a BSGI test instead. Patients unable to have an MRI (with contrast) include: claustrophobic patients; those with pacemakers or other implanted devices that are not MRI-compatible; patients with metal aneurysm clips in their brain, or with metal fragments in their eyes; severe kidney disease; patients whose bodies are too large for the MRI unit; allergy to Gadolinium contrast dye.

We look for microcalcifications, masses, and architectural distortion on mammography; solid masses on ultrasound; and enhancing masses or lesions that “light up” with contrast on MRI. No imaging feature is 100% indicative of malignancy, and very often tissue sampling is needed to arrive at a diagnosis.

A short-term follow-up MRI is usually recommended if the radiologist saw something on the original MRI that he/she thought was most likely benign (not cancer), but wants to be more certain. If the finding doesn’t change over time, the radiologist can more confidently call it benign.

A “clogged milk duct” generally refers to a duct in the breast that looks dilated, and may have some debris within it. It is usually a benign finding, but if the radiologist is not sure why the duct is blocked, he/she may choose to either biopsy it or follow it depending on how it looks on the MRI.

Molecular breast imaging is also known as breast specific gamma imaging or BSGI. Molecular breast imaging is promising as it can find cancers with a sensitivity of less than 3mm (this is better than MRI). The drawback is the high level of radiation currently associated with MBI. There are many centers working on the technology of MBI to get the radiation level of MBI to an acceptable dose. I look forward to this advancement as I feel it would be an excellent, more sensitive screening test once the radiation level is lowered. Here is my overview of BSGI.

BSGI stands for breast specific gamma imaging. BSGI is a fairly new technique that involves injecting a radioactive substance technetium (t-99) into a patient's veins and then scanning their breast with a gamma camera.
The gamma camera takes images of the breast and the areas where the radioactive substance has concentrated (this may indicate a breast cancer) will show up darker.
Pros of BSGI are increased sensitivity for detecting tumors at a smaller size than other available imaging techniques.
Cons of BSGI are the higher amount of radiation the person is exposed to during the test.
Some considerations: This test is reasonable for a person to have performed if they are first diagnosed with breast cancer to assess for occult cancers in either breast. Another scenario is a person who cannot have an MRI but requires a more sensitive test. Currently this is NOT a test for women to have yearly, too much radiation!

To read more in depth information on BSGI please visit http://www.mybreastcanceranswers.com/bsgi-breast-specific-gamma-imaging

Resources:

http://www.medscape.com/viewarticle/727881

http://www.gm-ideas.com/

www.dilon.com

1) 3D mammograms are also called tomosynthesis and they are superior to 2D (regular) mammograms. This type of imaging is a special kind of mammogram that produces a 3D image of the breast. The image is obtained by using several low dose x-rays taken at different angles. The breast is compressed similar to the way it is for a mammogram except the x-ray tube moves in a circular arc around the breast; the imaging is completed in less than 10 seconds.
The reasons tomosynthesis is superior to 2D mammograms are:
Less breast compression (less discomfort)
Shorter length of time for test to be completed (10 seconds vs. several minutes)
More pictures are obtained in multiple different angles of the breast (more accurate)
A 3D image makes it easier to find an abnormality than traditional mammogram.

2) There are some discrepancies in the difference in amount of radiation exposure between standard mammogram versus 3D mammogram.
According to the American College of Radiology there is about twice the amount of radiation in a 3D mammogram but “it improved the accuracy with which radiologists detected cancers, decreasing the number of women recalled for a diagnostic workup.”

A study published in Radiographics, peer-reviewed journal, lists the radiation dose of tomosynthesis at 145 mrad.

Just an fyi, the National Cancer Institute lists an average two-view mammogram as delivering 200-400mrad.

Everything I read and studied listed the doses for 3D mammogram as being under 300mrad (see resources below).

Thanks,
Heather

Resources:

http://www.cancer.gov/cancertopics/pdq/screening/breast/healthprofessional/page6" target=_blank>http://www.cancer.gov/cancertopics/pdq/screening/breast/healthprofessional/page6

http://www.acr.org/SecondaryMainMenuCategories/NewsPublications/FeaturedCategories/CurrentACRNews/FDA-approves-first-3-d-mammography-system.aspx" target=_blank>http://www.acr.org/SecondaryMainMenuCategories/NewsPublications/FeaturedCategories/CurrentACRNews/FDA-approves-first-3-d-mammography-system.aspx

http://radiographics.rsna.org/content/27/suppl_1/S231.full#sec-2" target=_blank>http://radiographics.rsna.org/content/27/suppl_1/S231.full#sec-2

http://www.acrin.org/PATIENTS/ABOUTIMAGINGEXAMSANDAGENTS/ABOUTMAMMOGRAPHYANDTOMOSYNTHESIS.aspx" target=_blank>http://www.acrin.org/PATIENTS/ABOUTIMAGINGEXAMSANDAGENTS/ABOUTMAMMOGRAPHYANDTOMOSYNTHESIS.aspx

Digital tomosynthesis is very similar to a CT scan. Essentially, a machine takes many X-ray 'slices' of the breast that can then be pieced back together to create a virtual 3D image of the breast. To learn more, you can watch an animation about digital tommosynthesis at http://www.cancerquest.org/detection-digital-tomosynthesis.html .