Abstract
The results of two studies are reported.
I.Bone scintigraphy with Tc-99m-MDP was performed in 41 patients (29 males, 12 females) on maintenance hemodialysis with bone pain or high Alk-Pase. These bone scintigrams were classified into 3 groups, each of which was correlated to laboratory data (serum Ca, , Alk-Pase, c-PTH).
Group I showed increased RI accumulation in the bone, particularly in the calvarium, maxilla, mandible, vertebra and costochondral junction, and was observed in 19 patients (9 males, 10 females). The mean duration of hemodialysis in this group was 8.2 years, and Alk-Pase and c-PTH were increased.
Group II demonstrated unclear bone images because of high background activity and normal or low accumulation of Tc-99m-MDP in the bones, and was observed in 11 patients (10 males, 1 female). The mean duration of hemodialysis was 4.8 years. Alk-Pase and c-PTH were not increased in this group.
Group III showed extraosseous accumulation of Tc-99m-MDP in the lung, kidney or soft tissue. Visceral metastatic calcification was observed in 4 patients (3 males, 1 female). Massive soft tissue localization of Tc-99m-MDP was observed in 7 patients (all males).
The mean duration of hemodialysis in this group was 6.8 years.Hyperphosphatemia and high level of Ca×Pproduct was observed.
Our scintigraphic classification is convenient and might contribute to an understanding of pathophysiological bone change in such patients.
II. Subtotal parathyrodiectomy (PTX) was employed in 11 of 41 patients on chronic hemodialysis with renal osteodystrophy and secondary hyperparathyroidism in order to improve bone lesions.These patients were studied before and after subtotal PTX using 6 different procedures; conventional radiography (phalanges, calvarium, vertebra), microdensitometry (metacarpal bone), bone mineral analysis (radius), measurement of EMI number with X-CT (frontal bone), bone scintigraphy (whole body), and radionucleid (RN) activity ratio (frontal bone/brain) with single photon emission CT (SPECT). Each procedure detected an improvement of the demineralization after subtotal PTX. Mild improvement of bone change was detected using the bone mineral analyzer and X-CT. On the bone scan, the diffuse increased activity in the calvarium, maxilla and mandible was less prominent aftersurgery in all 11 patients. To quantify the bone changes revealed by the bone scan, we devised a new method; the RN activity ratio (frontal bone/brain) with SPECT.The ratio decreased markedly after surgery.This new method seems to be the most useful one for detecting dynamic bone changes sensitively and quantitatively, because the bone scan showed prominent change in the calvarium, and not in the radius, in patients with renal osteodystrophy.
