Incidental diagnosis of an acute cerebrovascular event on 99mTc- HMDP bone scintigraphy performed due to suspicion of amyloidosis

Abstract

Acute cerebrovascular event (ACE) is a neurological deficit caused by a central nervous system (CNS) injury secondary to insufficient supply of oxygenated blood to the brain. It can be hemorrhagic or ischemic, with the latter being more common. It affects approximately 16 million people worldwide each year, and in Latin America, an incidence of 35-183 per 100,000 habitants has been reported. The main risk factors are smoke, alcohol, hypertension, and family history. The most commonly used diagnostic method is brain computed tomography (CT), and the most accurate one is brain magnetic resonance imaging (MRI). There are few documented cases of increased uptake in bone scintigraphy with meta-stable technetium-99m (99mTc) and hydroxymethylene diphosphonate (HMDP) in the infarct area. The physiopathological mechanism behind this increased uptake observed in infarcts is uncertain, but there are some hypotheses, with the most accepted one being related to intracellular calcium metabolism implicated in ACE. We present the case of a 78-year-old woman with left hemiparesis and central facial paralysis, who underwent brain CT and MRI, leading to the diagnosis of an ACE. Subsequently, a bone scintigraphy was performed using 99mTc-HMDP, revealing increased uptake of the radiopharmaceutical in the infarct area.