pyrophosphate and Cerebral-Infarction

We sought to determine the clinical utility of using a bone-scanning agent in addition to a brain-scanning agent for the imaging of cerebral and cranial lesions. Images were obtained in 51 patients with Tc-99m diethylene-triamine-pentacetic-acid (DTPA) followed by Tc-99m pyrophosphate (PPi) within 2--5 days. The scans were qualitatively analyzed and the lesion-to-background count density ratios were determined from the corresponding brain and skull images. Only four of 20 cerebral infarctions were better demonstrated with PPi, whereas they were better with DTPA in 14 patients. They were equally good in two patients. The average lesion-to-background count-density ratio for infarction was 1.555 +/- 0.335 with DTPA and 1.428 +/- 0.573 with PPi (p < 0.05). Primary brain tumors were better visualized with DTPA in four out of five cases (p < 0.05). Metastases to brain showed up better with DTPA in 15 of 16 patients (p < 0.05), whereas all ten metastases to skull were seen better with PPi (p < 0.01). These results support previous reports regarding the radiopharmaceutical of choice for tumor imaging but not for infarction. This may be due to the differences in blood clearance for the various imaging agents.

Topics: Brain Neoplasms; Cerebral Infarction; Diphosphates; Humans; Pentetic Acid; Skull Neoplasms; Technetium; Tomography, Emission-Computed