To the Editor.
—In the March 1987 issue of the Archives, Jagust et al1 reported their studies on single-photon emission computed tomography (SPECT) in senile dementia of the Alzheimer type and in multi-infarct dementia. They found a flow deficit in the frontal areas in two patients with MID, and argued on the basis of clinical and radiologic findings that their patients could have Binswanger's disease. We would like to present our SPECT results in a selected group of patients with subcortical arteriosclerotic encephalopathy. A SPECT with technetium Tc 99m—labeled hexamethylpropylene amine oxime was performed. We studied seven patients (four men and three women, mean age, 67 years) who were selected on the basis of computed tomographic and clinical criteria. The computed tomographic scans showed a symmetric low attenuation of white matter involving the centrum semiovale as well as frontal and parieto-occipital periventricular areas. In addition, there was sometimes mild