Frontal lobe degeneration of non-Alzheimer type. III. Regional cerebral blood flow.

Results from measurements of regional cerebral blood flow (rCBF) by 133Xe inhalation are presented for neuropathologically proven cases of frontal lobe degeneration of non-Alzheimer type, Pick's disease, Alzheimer's and Creutzfeldt-Jakob's diseases with frontal predominance and one case of bilateral thalamic infarction. The pathological and neuropsychiatric findings in these cases were described in the preceding articles. rCBF-data were available in nine patients with the diagnosis of frontal lobe degeneration of non-Alzheimer type and in all four patients with Pick's disease. All 13 patients showed a pathologic flow pattern with focally reduced values in frontal, especially pre-frontal, areas of both hemispheres. The most pronounced focal pathology was seen in the Pick group. Post-central areas were typically better preserved. Two cases of Alzheimer's disease with frontal accentuation had, in addition to low frontal values, also a parietal focal reduction. Frontal flows were also reduced in two cases of Creutzfeldt-Jakob's disease while the hypofrontality fluctuated from one study to another in the case of thalamic infarcts. The extent and localization of cerebral dysfunction in patients with organic dementing disorders, including those affecting the frontal lobes, can thus be described by means of rCBF measurements. Previous studies have shown about 90% accuracy of diagnosis by rCBF compared to diagnosis at autopsy. The possibility for exact localization of the dysfunction has recently been improved by the development of a high-resolution system (254 detectors). Results from the first recordings with this system are presented.