Lesion size determines accuracy of thallium-201 brain single-photon emission tomography in differentiating between intracranial malignancy and infection in AIDS patients.

Background And Purpose: Discrimination between enhancing mass lesions in acquired immunodeficiency syndrome (AIDS) patients with conventional CT and MR imaging remains difficult. We determined the effect of lesion size on thallium-201 brain single-photon emission tomography (SPECT) imaging in differentiating primary brain lymphoma from cerebral toxoplasmosis.

Methods: We retrospectively identified 35 AIDS patients with a total of 48 focal enhancing mass lesions on contrast-enhanced brain CT and/or MR images who subsequently underwent thallium-201 brain SPECT imaging.