Scintigraphic detection of gastric calcification in dialysis patients.

The value of 99mTc HEDP bone scintigraphy as a means of detecting metastatic gastric calcification was studied in 45 chronic dialysis patients and in 55 former dialysis patients. For this group, all bone scans were obtained within 2 months after successful transplantation; radiotracer uptake by the stomach was not observed. In 15 of the first 35 chronic dialysis patients studied, gastric uptake was demonstrated without radioactive accumulation in the thyroid region. In all the dialysis patients, however, background activity had been normalized before scintigraphy by means of hemodialysis using recirculating dialysate. Without the latter, radioactive accumulation in the stomach was no longer noted. Thus, gastric uptake was presumably due to the formation of in vivo free pertechnetate, as a result of the dialysis method used, and in vitro experiments supported this hypothesis. These findings show that free pertechnetate can cause visualization of the stomach in the absence of thyroid imaging. The results of this study further indicate that bone scintigraphy is not a sensitive method for detecting metastatic gastric calcification in uremia.