TC-99M-BICISATE (NEUROLITE) SPECT BRAIN IMAGING AND COGNITIVE IMPAIRMENT IN DEMENTIA OF THE ALZHEIMER-TYPE - A BLINDED READ OF IMAGE SETS FROM A MULTICENTER SPECT TRIAL

A blinded read of images obtained with Tc-99m-bicisate and single phot on emission computed tomography (SPECT) was conducted to determine if a relationship exists between the severity of abnormalities on SPECT b rain images and the severity of cognitive impairment in patients with dementia of the Alzheimer type (DAT) and to examine the interreader ag reement for visual reading of images in a multicenter SPECT study. Ima ges for a total of 86 subjects were available for the blinded read. Th e images for 28 subjects were rated as noninterpretable due to technic al inadequacies. Images for 58 subjects (45 DAT patients and 13 normal volunteers) from 10 SPECT centers were selected for further analyses. The severity of abnormality was rated as mild, moderate, or severe by three readers. In DAT patients, a significant negative correlation (p < 0.05) of Mini-Mental State Examination (MMSE) score with global sev erity of abnormality was noted for two of the three readers. A signifi cant correlation (p < 0.05) between MMSE score and severity of abnorma lity was observed for all three readers for the posterior temporoparie tal region. The blinded readers rated a median of 92.3% of normal volu nteers' images as normal and a median of 82.2% of DAT patients' images as abnormal. For the regional severity of abnormality, the median per centage interrater agreement across all regions ranged from 95 to 100% in normal volunteers and from 81 to 98% in DAT patients. These result s suggest that SPECT brain imaging with Tc-99m-bicisate provides funct ional information about the severity of cognitive impairment in DAT pa tients. With experienced readers and high-resolution SPECT cameras, bl inded read of SPECT images can be used for assessment of research resu lts in a multicenter design.