Incidental accumulation of Technetium-99m pertechnetate in subacute cerebral infarction: A case report

When interpreting nuclear medicine images, unexpected findings are sometimes encountered. Recognizing these findings and determining the mechanism of their occurrence could have a significant impact on early diagnosis of critical diseases and the appropriate management of patients.

A 59-year-old man was admitted to the emergency room due to left hemiparesis, left hemifacial palsy, and mild dysarthria. After 2 wk of hospitalization, the patient complained of dry eyes and mouth. Thus, salivary scintigraphy was performed to evaluate the functional status of his salivary glands. Incidental accumulation in the right frontoparietal area was found on salivary scintigraphy. Fluid-attenuated inversion recovery phase magnetic resonance (FLAIR phase MR) image showed diffuse high signal intensity in the same area. Anterior and posterior horns of the right lateral ventricle were obliterated and the midline was slightly shifted to the left side due to right frontoparietal swelling. On salivary scintigraphy, Tc-99m pertechnetate was incidentally accumulated in a subacute cerebral infarction lesion. Two years after the diagnosis of acute infarction, the second series of salivary scintigraphy showed no abnormal activity in the brain. FLAIR phase MR image also demonstrated markedly decreased high signal intensity in the previous infarction lesion without evidence of swelling indicating chronic cerebral infarction.

This case highlights that Tc-99m pertechnetate could accumulate in a subacute cerebral infarction lesion. The mechanism of an unexpected uptake of Tc-99m pertechnetate in unusual sites should be evaluated and kept in mind for better interpretation.