 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.
Note: If a Minimally Invasive Parathyroid
Surgery (which is performed under local anesthesia in an outpatient setting) is planned, then
often the only preoperative test necessary is a Sestamibi scan the morning of the operation.
The following tests are performed very infrequently
and under very specific and unique circumstances.
Use of CAT scan to Find an Overactive Parathyroid
Gland
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!
Use of MRI scan to Find an Overactive Parathyroid
Gland
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 the preferred anatomic localizing test 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, and should be reserved for only
for patients who have had a FAILED first operation or for those who's Sestamibi
scan shows the tumor to be next to the heart. Again, MRI scans should probably be reserved for patients with recurrent or persistent disease who have already had one unsuccessful operation.
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, therefore, it may be cheap, easy, painless, and safe, but its not very good either. 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.
Sestamibi
Scanning is the preferred method to find diseased parathyroid glands.
We have several pages discussing parathyroid scanning using Sestamibi.
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