Mammogram and Dense Breasts
CT, MRI, Ultrasound and Scintimammography
by Toya T. Powell
Nuclear Medicine Technologist

My name is Toya and I am a nuclear medicine technologist on the BC list.

Dense breasts are a difficult to diagnose situation for any imaging test.

The following is an explanation of the basics of the CT, MRI and Ultrasound and what they "see".

A CT scan is an xray procedure that shoots an xray beam through your body and by how much xray beam coumes out the other side of your body, the final picture is created by sophisticated computers.  This picture is a cross section image of your internal organs (kind of like when you make cat fish steaks by slicing through the middle of a cat fish and looking at the cat fishs' insides).  These
videos and photographs reveal any anatomical change in your tissues and body organs.   CT scans
are exceptional when it comes to seeing soft tissue in the body and also to tissue (muscle)
surrounding the bones. Because CT scans measure tissue density, they are very good at seeing calcified (anything that has calcium it it) masses.

Occasionally, when looking at soft tissues, you will be given a contrast agent (a heavy molecular
weight iodine substance) that will be absorbed by some tissues and tumors and this helps   to see. A CT scan is wonderful at picking up problems that hurt like a metestatic lesion, but are not a metastatic lesion.  The CAT scan is also very good at looking at dense tissues and can even pick up things in bone.   CT of the breast is not available at many centers and there are not many radiologists who have performed large numbers of breast CT's .

MRI does a neat thing with the magnetic fields in your body and radio waves (no xrays or radiation) to make a picture of the state of water in your your body.   The MRI vibrates the atoms in your body and the energy given off as they relax back to their normal state is detected by  powerful computers of the MRI machine which take this information and generate a picture of the internal organs.  The MRI can make cross-sectional pictures in several directions such as across the middle, from front to back and even from left to right  (in contrast to the CAT scan that can only see in cross sections).

MRI is the greatest when looking at the central nervous system and the spine (though it is not as good at seeing details in actual bone, where the CAT scan  is better.  Because this is observation on a more cellular level, MRI gives "exquisite" anatomical and somewhat functional images of your body.   Although MRI is not as good at seeing dense tissue, calcifications  and bones (which have calcium in them), it's phenomenal at looking at the difference in   tissues and tumors and excellent at seeing
changes in the marrow (where there is  more water which are loosely bound and give off a strong
signal after vibrating - bone and other dense structures with tightly bound atoms give off a weak signal after vibrating.   

An MRI is also wonderful at picking up problems that hurt like a metestatic lesion but are not  a metastatic lesion.  MRI of the breast is not available at many centers and there are not many radiologists who have performed large numbers of breast MRI's.

Ultrasound is just as the name says, it is an instrument that "sees" things by sending sound waves through tissue and how the sound wave bounces back helps the radiologist to tell if something is solid or liquid and also can tell the size of an organ or area of interest.  The ultrasonographer spreads a little thin jellatinous material over the area to be evaluated and aims a hand held remote control device called a transducer over the area.  This sends a high frequency sound wave through you that bounces off everything for several inches below where the transducer is touching.   The ultrasound is sensitive, but not specific.  It will tell you if tissue is solid or fluid filled, but it won't tell you
exactly what it is.  Ultrasound is also very good at looking at small areas (whereas the CAT scan and MRI have a more  difficult time at seeing a small area in relation to a large area).  After a diagnostic mammogram when there is a palpable mass is not shown on the mammogram , or if the mammogram is indeterminate or suspicious or if it is asymmetric then an ultrasound is usually done (it is fast, usually
easy to diagnose, inexpensive and has been performed a long time by lots of facilities).

Because each of these tests has limitations, each gives a piece of the puzzle of what is going on in dense brest tissue.  Actually, the info of each test will reveal clues as to what is going on even if all of them are normal or indeterminate.

Last, but not least, there is a nuclear medicine test for imaging the breast that is very good for dense breasts, altered breasts, and breasts with implants.

Recently my radiologist asked me to do a brain-pickin' , article searching evaluation of breast imaging.  Here is the skinny on it.  It is in a format suitable to print off and speak with your doctor or radiologist.

Putting things in perspective, nuclear breast imaging is like any other diagnostic test.   It will not always see every abnormality (this is called a false negative).   This is NOT a screening test.  There are members on this internet list who have had this procedure and it came back as false positive.  My
experience has been better than this as a technologist performing the procedure and having the procedure done on me (I have large lumpy, bumpy, dense breasts).

In the begining, the radioactive drug gallium citrate was used to image for breast cancer, but it's sensitivity and specificity were not as reproducible.  Since then, three other drugs have been used.  The most commonly used medicine is called cardiolite or sestamibi (the nuclear medicine drug used to image the heart), occasionally thallium is used (another nuclear medicine drug used to image the heart and also tumors.    It is not as accurate in very large patients), and medronate diphosphonate (the medicine used to make a bone scan on you).  There have been hundreds of articles in nuclear medicine literature on breast imaging in the journal of nuclear medicine (going back to the volume 36 number 35 May 1995 Journal of Nuclear Medicine edition called Nuclear Oncology: A Growth Industry pages 717-904.

Here is the short and sweet on nuclear breast imaging using cardiolite/sestamibi:

MAMMOSCINTIGRAPHY OR
SCINTIMAMMOGRAPHY OR
BREAST IMAGING OR
MIRALUMA

BIODISTRIBUTION:
The Sestamibi will go normally to the heart, kidneys, muscles, liver, gallbladder, gut, thyroid, salivary glands, spleen, bladder, lungs,  and soft tissue.  Heart uptake can be a problem seeing lung and breast cancers and the constant changing pattern of GI excretion sometimes makes seeing lesions in the abdomen difficult.    Lesions that are smaller than 1cm are also difficult.  Lymph node metastasis are often seen, but this test is not sensitive enough to count on it to find all lymph node involvement.

CLINICAL APPLICATIONS :
parathyroid adenomas
breast cancer (you see an approximately 6:1 ratio of normal breast to
breast cancer)
lung cancer
lymphoma
bone sarcoma

LOCALIZATION PRINCIPAL:
Unknown.  It is thought to diffuse into tumors because of their high negaive membrane potential and/or mitochondrial metabolism OR perhaps it is by transport or retention by a 170-kD p-glycoprotein that is an integral plasma membrane lipoprotein encoded by the human multidrug-resistant gene.

INTERPRETATION:
Normal breasts show a uniform diffuse uptake, with occasional increased uptake in the region of the nipples.  Bilateral patchy uptake may be seen during the first and fourth weeks of a woman's menstrual cycle.   Focal uptake is indicative of a malignant lesion, although false-positive uptake may be seen in epithelial hyperplasia.  The findings of the sestamibi scan should be correlated with those found on mammography.
Note that lesions located medially may be more difficult to visualize because of attenuation from
the breast on lateral views.

ABILITY:
approximate Sensitivity 95%
approximate Specificity 50-89.2%
approximate Positive Predictive Value 81%
approximate Negative Predictive Value 96%

MOST COMMON CAUSES OF FALSE POSITIVES:
fibroadenomas
fibrocystic change
inflammation
epithelial hyerplasia
sclerosing adenosis

MOST COMMON CAUSE OF FALSE NEGATIVES:
lesion less than 1cm in size (especially if they are in the medial
aspect of the breast)
lesions that are extremely close to the heart


TEST FACTORS THAT CAN CAUSE MISDIAGNOSIS
patient motion
poor technologist technique
infiltration of the medicine (the vein "blew")
Right ventricle and/or right atrium sometimes shows up on some people
Skin fold artifact because a large patient is not able to hold their arms up
small tumor size
tumor is located in difficult to assess locations on the image (for example, axillary area)
patients with p glycoprotein

CAVEATS (BEWARE):
Miraluma is not a screening test
Miraluma is not a replacement for or an alternative to a biopsy
The best use of this test is for:
        selection of mammogram abnormalities to biopsy
        evaluation of palpable masses in the presence of a normal or
equivocal mammo
        dense breasts
        indeterminate mammograms
        normal mammogram and/or no palpable mass
        to localize the site of abnormality or lymph node with a
neoprobeTM
        management and surgical approach when there is a known area to
biopsy
        altered (with or without implants)    breasts
        high risk patients
        high anxiety referrals

Who to Call if you want to ask questions of the experts:
Bobby Russell (Dupont Representative) 1-800-599-5744  ext 7979
Dr. Iraj Khalkhali
Dr. Alan Waxman
Linda Diggles (213) 320 8148
Edward Clifford
Dr. Douglas Van Nostrand Good Samaritan Hospital in Baltimore, MD
410-532-3710
Dr. `John Phillips (St Bernard) Jonesboro Ar 870 772-4196

I went to an excellent talk given by an articulate nuke doc named Douglas Van Nostrand from Good Samaritan Hospital in Baltimore, Maryland on Miraluma and here are the dibs on it.

Miraluma scan is also known as
Scintimammography is also known as
MIBI is also known as
Nuclear Breast Imaging is also known as
2-Methoxy Isobutyl Isonitrile scan
Mammoscintigraphy

PATIENT EDUCATION:
The medicine sestamibi is also used for heart scans in nuclear medicine.

The medicine that was originally used to image the breast in nuclear medicine is the medicine called Thallium (another nuclear medicine heart imaging radioactive medicine).  Both thallium and sestamibi are taken up by certain cancers as well as the heart.

The owners of miraluma are a company named Dupont/Merck and they say:
The Miraluma  test -- also called sestamibi breast imaging or scintimammography -- uses a radiopharmaceutical, or imaging agent, that is thought to accumulate in areas of increased metabolic activity such as that found in malignant cells. During the Miraluma test, patients receive a "trace" amount of the radiopharmaceutical by injection, after which the breasts are imaged with a gamma camera. The patient may experience a slight metallic taste after the injection of the radiopharmaceutical.  Miraluma is indicated for planar imaging as a second line diagnostic drug
after mammography to assist in the evaluation of breast lesions in patients with an abnormal mammogram or a palpable breast mass. Miraluma is not indicated for breast cancer screening to confirm the presence or absence of malignancy, and is not an alternative to biopsy. Miraluma imaging has demonstrated decreased sensitivity in lesions shown to be less than one centimeter in largest dimension.
http://www.radiopharm.com/newsroom/rls10297.htm

The miraluma scan is performed in the  nuclear medicine department (where they do your bone scans and muga scans).  ANY department of nuclear medicine can perform this study if they are trained.  It is a very easy study to perform after you perform a few of them.   If you are pregnant or breast feeding, tell your nuke tech BEFORE your miraluma scan.  If you have had a any nuclear scan in the past week tell yournuclear tech BEFORE your miraluma scan.

There is no preparation before the test.  There is no withholding of food, medication or liquids.  Miraluma scans take at least one and a half hours or more, and there may be delays, so take a book or magazines with you and plan on at least half a day.   They don't know if  they  have to take extra
images of you until they see the first images so be flexible.

Wear comfortable clothing and an easy to remove bra (or no bra).  Your nuke tech will give you an injection in the arm that is not suspected of having breast cancer or recurrence.  If you have had  a bilateral mastectomy or have lumps in both breasts then the nuke tech will ask you if you have objections to getting an injection in your foot.  You get an injection into your vein of a radioactive drug (it is not a dye) called sestamibi (2-Methoxy Isobutyl Isonitral).  The injected material usually
will not have any effect on you that you can tell, although, a few people say that they have a metallic taste in their mouths.  The medicine ia a compound bound to a tiny tracer amount of a radioactive medicine.  If there is any chance that you have to be stuck on your mastectomy side, then take some neosporin or betadine with you and insist that the tech use it before sticking you (lymphedema is no joke).    The injection must be a "good" injection because if the injection is "infiltrated" or "extravasated" (where the medicine goes into surrounding tissue outside the vein and hurts or burns as it is going in) then the test may have to be repeated because this can make lymph nodes show up falsely abnormal.

After your injection you will lie on your stomach on a table with your breast hanging free through a hole and the arm beside that breast will be raised  up by your head and the nuclear camera will be gently pressing against your arm/breast/side.  This will take 10-15minutes and you must hold still.  After this picture you slide to the other side of the table for a picture of the other side.  Then a picture of your chest is made with both arms up and the camera over your chest, this will take 10-15 minutes and you must hold still.  Sometimes an angled picture is taken with you either lying on your stomach or your back to get a better picture of your chest wall is done.  It also takes 10-15 minutes and you must hold still for it also.   If  this (cold room/hard bed) is a  pain producing situation,
then take (tylenol, etc) whatever  you would normally take  before this   test so that you can be as comfortable as  possible under the circumstances.

There are no special instructions to follow after the scan.  The miraluma scan medicine will come out of you over the next 48 hours in your bowel movements and urine.

Other helpful miraluma scan hints:
Get a copy of your last mammogram, breast ultrasound, breast ct scan, breast mri, and take the report(s) with you for your miraluma scan.  This will give you a better result by having this information for comparison.   Tell your nuke tech if you have a strong history of breast cancer in your family.   Tell your tech if you have ever had any other cancers before (especially if you have ever had lymphoma, colon cancer, radiation to the chest, or ovarian cancer).

Tell your nuke tech if you have ever had breast surgery or breast implants and when.
Tell your nuke tech if you have had any recent trauma (recent=1 year) to your breast area.

***Oftentimes you will be required to wait after your breast scan while the technologist checks the pictures with the radiologist to see if additional images are needed.  If you are asked to undergo additional pictures, there are several possible reasons for this; sometimes it is to see an area
better because it is fuzzy or looks unusual, sometimes it is because an area appears abnormal.  These extra pictures could be an xray, breast CT scan, mammogram breast MRI scan, or another spot breast scan image.

Often the extra pictures are of  an area that is not in a place where you are hurting.  The majority of the time, the resulting image reveals a coincidental finding and is nothing to be concerned about.

Occasionally, the extra image reveals an abnormality that your personal doctor will discuss with
you later.  So, please bear with the inconvenience and time for these extra pictures as they are in your best interest.


Forty-two sites participated in the investigatory work on miraluma.
The smallest reported lesion detected by miraluma is 6mm.
Miraluma is more sensitive in lesions larger than 1 cm.

OH, BY THE WAY:
Finally, be kind and considerate to your imaging folks.  If you are going to be late or can't make it at all for your miraluma scan, *please* call as soon as possible to let them know.  And insist that your tech be honest with you by telling you if there is an unavoidable delay of more than 15minutes.

GETTING THE RESULTS:

Never ask your tech for the results.   No consciencious technologist would tell you the results of your scan because this is tantamount to practicing medicine without a license.  This is illegal and punishable in all states.  At the very least this will cost a technologist their job in every hospital that I know of.

The best solution is to speak with your doctor (inform your doc that you would like to call his office for the results within 24 hours).

Like most other tests in medicine, this study alone is mediocre at best, but combined with your past medical history, you family history, your blood tests, your imaging tests, your symptoms, the expertise of your doctor, carefully  evaluated statistics and current medical research - a good
diagnosis can be achieved - and the person who can put all of this together as a big picture is your doc.

To search for articles search the web under the names above and/or one of these words:
Sestamibi
Miraluma
Scintimammography
Mammoscintigraphy

Also search the bc archives
http://www.acor.org/lists/cancer/bc_browse_sl.html
for the above words Sestamibi or Miraluma or Scintimammography

References:
Van Nostrand Nuclear Medicine Seminar in Jackson, MS 3/99
Personal Knowledge
Society of Nuclear Medicine Procedure Guidelines (1998)
Dupont Website
The Mayo Clinic Manual of Nuclear Medicine 1996
Journal of Nuclear Medicine
Personal notes from Dr. Van Nostrand talk 1998 in Memphis and 1999 in
Jackson, MS
Dr. Susan Love's Breast Book (early edition, not in recent editions)
Essentials of Nuclear Medicine Imaging (1998)

Some web sites for scintimammography include, but are not limited to:
http://www.scintimammography.org/
http://www.scintimammography.com
http://www.miraluma.com
http://www.dupontmerck.com/rpharm/yesnom/handmake.htm
http://www.bodfish.com/page7.html
http://www.chapmanhall.com/nm/nm180403.abs.html
http://www.preventcancer.org/ntest.html
http://www.jlab.org/div_dept/detector/scintmamm/Preclinical_Trials.html
http://www.dupontmerck.com/newsroom/rls10217.htm
http://asco.infostreet.com/prof/me/html/abstracts/bc/m_bc.htm
http://www.pslgroup.com/dg/29b42.htm
http://imasun.lbl.gov/~gruber/scintimammography/PICTURES/scintimam.html
http://www.medscape.com/Medscape/features/question/1997/apr/q191.html
http://www.bergenimaging.com/breastscinti/breastscintimain.html

Last Tidbit, there is nothing wrong with asking your radiologist and the imaging facility how many of a certain exam they do a year.

(First Time Writer inspired by her best friend's breast cancer)
Toya T. Powell, Nuclear Medicine Technologist:

"I am not a doctor, nor am I representing any medical society, hospital, or entity.  I am a nuclear medicine technologist who speaks from 19 years of performing bone scans,mammoscintigraphy (Miraluma), MUGA scans, tumor scans, thallium scans, lung scans, infection (gallium and white
blood cell) scans, strontium, P32, and thyroid treatments and many other scans.   Please take what I have to say with great personal consideration as this is a personal observation by a technologist who is speaking as if she were talking to a close personal friend.  The opinions stated here are my own personal OPINIONS and should be judged as such.  The information presented here is not meant to replace or circumvent discussions with your health care professional and is meant as basic medical information only."