Occasionally tumors of the parathyroid gland cannot be detected by standard x-ray diagnostic
procedures (CT scans, MRIs, and ultrasounds). In order for the tumor to be removed
surgically it must first be localized. To do this often requires a procedure known as
parathyroid arteriography and parathyroid venous sampling.
This procedure begins by placing a catheter through a blood vessel in the groin. The
catheter is then guided through blood vessels to reach the area of the neck. The blood
vessels in this region flow in and out of the thyroid and parathyroid. An X-ray dye is then
injected through the catheter into the arteries of the thyroid/parathyroid (parathyroid
arteriography). The alternative is taking a small sample of the veins found in this same
region (parathyroid venous sampling).
Researchers prefer parathyroid arteriography because it causes less discomfort to the
patient and requires less experience to do the procedure. However, parathyroid
arteriography provides positive results in only 50% of patients undergoing the procedure.
Parathyroid venous sampling provides greater amounts of positive results but the readings
are often imprecise. Parathyroid tissue secretes a hormone known as PTH (parathyroid
hormone). The release of PTH is stimulated by low levels of calcium in the blood.
The idea behind the study is to inject a dye into the area of the parathyroid that will
cause a release of PTH. Several parathyroid venous samplings will be taken following the
abrupt elevation of PTH. This will provide information on the effectiveness of an
intraarterial hypocalcemic stimulus (injection of dye into the arteries of the parathyroid
when calcium blood levels are low) and venous sampling as techniques to improve localizing
Although noninvasive diagnostic studies [ultrasound (US), computed tomography (CT),
sestamibi scanning, magnetic resonance imaging (MRI)] detect parathyroid pathology in
one-half the patients referred to NIH with recurrent or persistent hyperparathyroidism (1),
the invasive studies (direct aspiration for PTH, arteriography, venous sampling) must be
performed in the remaining patients to provide definitive preoperative localization (2).
Arteriography is positive in less than half the patients who must then proceed to
parathyroid venous sampling, a technique requiring broad experience and yielding positive,
but imprecise results as regards localization. The abrupt lowering of calcium in blood
perfusing a parathyroid adenoma should stimulate the release of PTH which could be detected
by simultaneous venous sampling. This principle, the intraarterial injection of a
secretagogue with subsequent sampling for released hormone, has been applied successfully in
the localization of insulinomas (3) and gastrinomas (4). In fact, portal venous sampling is
no longer performed in this group of patients, having been completely replaced by the
intraarterial injection of secretin or calcium as appropriate secretagogues for gastrin and
Since release of PTH from parathyroid adenomas is stimulated by hypocalcemic perfusions, we
propose to perform serial venous sampling from a catheter positioned in the SVC to detect
abrupt elevations of PTH following the injection of contrast agent into each of the vessels
selectively catheterized at the time of parathyroid arteriography (superior thyroid
arteries, thyrocervical trunks, internal mammary arteries). Samples from the SVC catheter
will be obtained at 20 second intervals up to one minute and in some patients simultaneous
peripheral samples. An elevation of parathyroid hormone 1.5 times above the baseline will
be considered diagnostic. This technique will be applied routinely at each injection of
standard parathyroid arteriography even in the absence of an angiographically-visualized
adenoma: an elevation of PTH will provide localizing information comparable to venous
sampling. In addition, when any of the imaging studies suggest that a particular anatomic
site is the likely location of the patient's adenoma, sodium citrate, a calcium chelating
agent, will be injected into the artery supplying this region. Blood samples will be
obtained in similar fashion to those samples taken with contrast injections to measure PTH
release following sodium citrate injection and determine whether this is a more effective
Patients over the age of 2 who are enrolled in 91-DK-0085, "Studies of Hyperparathyroidism
and Related Disorders", or patients who are undergoing parathyroid localization as part of
routine patient care while enrolled in other Clinical protocols will be considered for the
Patients will be excluded if:
There is any contraindication to arteriography.
The Patient is pregnant.