Preoperative testing to find a parathyroid tumor
is now considered 'standard of care'. In other words, virtually all
patients should have a localizing study prior to having
parathyroid surgery. The Sestamibi scan is discussed in several other areas of
this large parathyroid web site--which is
undoubtedly the preferred parathyroid test. If this is the first page you
have read regarding the tests used to find diseased parathyroid glands,
then PLEASE read our "Finding
Bad Parathyroid Glands" page FIRST.
HOWEVER, you must understand that these scans are wrong more than they
are right. Listen up folks, sestamibi scans are usually wrong, and even
when positive are wrong 60% of the time. Be careful with the information
that your doctor gets about a scan... it is probably wrong, not right!
Note: If a Minimally Invasive Parathyroid
Surgery (which is performed in an outpatient setting) is planned, then the only preoperative test necessary is a Sestamibi scan the morning of the operation.
You can bet on this... if you get more than one scan, then your doctor
(surgeon) is not an expert.
The following tests are performed very infrequently
and under very specific and unique circumstances.
Use of CAT scan to Find an Overactive Parathyroid
CAT scanning has always been a poor localizing test for enlarged parathyroids. There are currently very rare indications for the use of CAT scans in this setting and this test should
never be performed routinely. We have no good pictures to show
because they don't exist! Please don't fall for the hype and get a
"4-D" CAT scan. And if you do get one and decide to come to our
center for your surgery, don't bother sending us the CAT scan. We will not
look at it.
Use of MRI scan to Find an Overactive Parathyroid
Theoretically, the MRI scan is more sensitive and specific than the CAT scan when looking for enlarged parathyroid glands. Since many endocrine tumors enhance on a T-2 weighted MRI scan this is
theoretically preferred over CAT scanning. The photo shows a T-2 weighted MRI of a parathyroid adenoma in the lower left neck within the
tracheo-esophageal groove. The indications for MRI scanning for parathyroid
glands, however, are still extremely uncommon. It is our strongest opinion that
there is almost never an indication for an MRI in patients with
hyperparathyroidism. It almost never works and insurance companies should
never pay for it. We consult on over 3000 patients with
hyperparathyroidism per year and we have NEVER ordered an MRI. This test
does not work!
Ultrasound to Find a Bad Parathyroid Gland
Ultrasound is an inexpensive and non-invasive way to look for parathyroid adenomas. Although it is less sensitive and specific than the MRI scan, it is still
on occasions because it is readily available, fast and low in cost. Again, most patients do not need any of the localizing studies discussed on this page (CAT scanning, MRI, or ultrasound).
Prior to Minimally Invasive Parathyroid Surgery, a Sestamibi scan is mandatory. Since about 1995, the need for using any scanning method other than sestamibi is extremely infrequent. Ultrasound fails to find a parathyroid adenoma half of the
time if your endocrinologist or surgeon does the scan himself, but it
fails to find the parathyroid tumor 82% of the time if you get the scan
done at a radiology clinic. Therefore, it may be cheap, easy, painless, and safe, but its not very good
and is usually a waste of time and money (unless done by the
endocrinologist). Even when it does "suggest" the location of an adenoma, it is wrong 20 percent of the time, therefore, it is not accurate enough to allow a surgeon to take out this one gland without examining all three other parathyroids. Therefore, ultrasound will not allow a small operation or the use of local anesthesia.
Don't fall for the hype. If ultrasound worked great, we'd be doing it
every day... but we use it about once per year (one per 3000 cases).
Scanning is the preferred method to find diseased parathyroid glands.
We have several pages discussing parathyroid scanning using Sestamibi.
However, as noted above, sestamibi is wrong more often than it is
right! If a sestamibi scan is negative, it is wrong 100% of the
time. When a sestamibi scan is positive, it is wrong 60% of the time. Far
too much emphasis is placed on scans. Stop getting scans folks, and stop
going to doctors who keep getting scans--it means they don't know what to
do. They feel better and more confident if the scan is positive--however,
even when it is positive it is wrong more than it is right. Stop putting
so much emphasis on the scans folks!