Clinical use of 99mTc-HMPAO-labeled platelets in cerebral sinus thrombosis imaging

Magnetic resonance imaging (MRI) and computed tomography (CT) are not always conclusive for the detection of cerebral venous sinus thrombosis (CVST). Tc-99m-HMPAO-labeled platelets may be useful in cases with high clinical suspicion. Three patients with headaches with or without intraparenchymal hemorrhage that were highly suspected to have CVST, despite inconclusive anatomical imaging, were selected for inclusion in the study. Platelets were extracted by two rounds of centrifugation from 49 ml of the patient's whole blood. The platelets were labeled with Tc-99m-HMPAO and any unbound Tc-99m was removed by centrifugation. The re-suspension of Tc-99m-HMPAO-labeled platelets in cell-free plasma was reinjected into the patients. After 2 h, planar and single photon emission computed tomography (SPECT) images of the head were obtained. Extensive clots were detected in all three patients, illustrated in the planar image and even clearer in the SPECT images. We propose that Tc-99m-HMPAO-labeled platelet scan is a favorable imaging method for patients suspected to have CVST with inconclusive CT and MRI results.