Nephrology Dialysis Transplantation, Vol 13, Issue 90003 33-36, Copyright © 1998 by Oxford University Press
P Ambrosoni, C Heuguerot, I Olaizola, G Acuna, L Fajardo, A Petraglia, H Caorsi, J Lopez, M Kurdian, V Jorgetti and A Aznarez
The usefulness of technetium-99m-sestamibi (99mTc-MIBI) in patients with
secondary hyperparathyroidism on haemodialysis was assessed. We studied 33
patients with parathyroid scintigraphy with i.v. (99mTc-MIBI). Static
images in a scintillation camera were taken at 15 and 120 min after the
injection. With PxCa<80, we performed an inhibition test with
calcitriol i.v. 2 &mgr;g, three times a week, for 2 weeks. The MIBI
study and assessment of intact parathyroid hormone (iPTH) were performed
before (baseline study) and after inhibition. A 'focal positive study'
corresponded to one or more areas of abnormal hypercaptation in relation to
surrounding thyroid tissue seen in early images and persisting in later
images, and a 'negative study' did not correspond to the previous image. In
the baseline study, iPTH in the positive MIBI group was significantly
greater than in the negative group. Eight positive MIBI patients had a bone
biopsy; six corresponded to severe osteitis fibrosa and two to mild
osteitis fibrosa. In the negative MIBI group, four of the six patients who
had bone biopsy had mild forms of osteitis fibrosa (Fisher=0.03); the other
two had low turnover forms. A positive inhibition test was defined when the
basal uptake disappeared after calcitriol administration. In these
patients, we observed a significant decrease of iPTH, not observed in the
negative inhibition test. In 10 patients who had been parathyroidectomized,
those with &agr; positive basal MIBI result had a nodular parathyroid
hyperplasia. We conclude that a scintigraphic parathyroid study with
99mTc-MIBI showed a good correlation with functional parathyroid status.
With the same inhibition test, only some glands were inhibited, suggesting
that this could be the expression of different vitamin D receptor densities
in inhibited glands and/or a different kind of proliferation in those
glands. This test would be of value in functional studies when a
therapeutic decision must be made.Keywords: chronic
renal failure; haemodialysis; 99mTc-MIBI parathyroid scintigraphy;
parathyroid hyperplasia; secondary hyperparathyroidism
ORIGINAL ARTICLES
Can we use 99mTc-MIBI in functional studies of the parathyroid gland?
Hospital de Clinicas Dr Manuel Quintela, Montevideo, Uruguay; Hospital das Clinicas, Sao Paulo, Brazil; Corresponding author address: Centro de Nefrologia 'Renis', Mario Cassinoni 1681, CP 11200, Montevideo, Uruguay
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