title: Absence of thallium-201 brain uptake in progressive multifocal leukoencephalopathy in AIDS patients.
abstract: OBJECTIVE
  To evaluate the presence of thallium-201 brain uptake determined by thallium-201 brain SPECT (Tl-201 SPECT) in patients with progressive multifocal leukoencephalopathy (PML) and AIDS.
  
  
  METHODS
  Six AIDS patients with stereotactic biopsy diagnosis of PML were prospectively evaluated with Tl-201 SPECT, Magnetic Resonance Imaging (MRI), and proton magnetic resonance spectroscopy (1H-MRS). Tl-201 SPECT results were compared with 2 patients with AIDS and biopsy proven primary CNS lymphoma.
  
  
  RESULTS
  In all patients with PML, Tl-201 SPECT studies showed lack of uptake while MRI demonstrated subcortical white matter focal brain lesions and 1H-MRS disclosed metabolic abnormalities. Intense thallium uptake (uptake ratios of 3.2 and 5.6) was demonstrated in the 2 patients with primary CNS lymphoma.
  
  
  CONCLUSIONS
  The present study shows that PML lesions are not detectable on Tl-201 SPECT while MRI and 1H-MRS demonstrate abnormalities, and intense thallium-201 uptake may be detected in primary CNS lymphoma. These results suggest that Tl-201 SPECT is a method which, combined with other non-invasive techniques such as MRI and 1H-MRS, may help in the diagnostic approach of PML and to differentiate PML from other high proliferative brain lesions characterized by positive thallium uptake.
authors.affiliation: Department of Neurology, Santa Creu i Sant Pau Hospital, Autonomous University of Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Iranzo
authors.forename: J
authors.initials: J
authors.lastname: Martí-Fábregas
authors.forename: P
authors.initials: P
authors.lastname: Domingo
authors.forename: A
authors.initials: A
authors.lastname: Catafau
authors.forename: J
authors.initials: J
authors.lastname: Molet
authors.forename: A
authors.initials: A
authors.lastname: Moreno
authors.forename: J
authors.initials: J
authors.lastname: Pujol
authors.forename: X
authors.initials: X
authors.lastname: Matias-Guiu
authors.forename: J
authors.initials: J
authors.lastname: Cadafalch
mesh_terms: D015526:AIDS Dementia Complex / Q000000981:diagnostic imaging*; D017088:AIDS-Related Opportunistic Infections / Q000000981:diagnostic imaging*; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging; D001932:Brain Neoplasms / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D006801:Humans; D007968:Leukoencephalopathy, Progressive Multifocal / Q000000981:diagnostic imaging*; D016483:Lymphoma, AIDS-Related / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D013794:Thallium Radioisotopes