Single-photon emission computed tomography studies with 99mTc-hexamethylpropyleneamine oxime in dementia: effects of acute administration of L-acetylcarnitine.

The acute effects of intravenously administered L-acetylcarnitine (LAC) were evaluated with single-photon emission computed tomography (SPECT) and 99mTc-hexamethylpropyleneamine oxime in 30 demented patients (21 with a clinical diagnosis of Alzheimer's dementia and 9 with mixed-type dementia). Two SPECT scans were performed: in basal conditions, and 30 min after the administration of 500, 1,000, 1,500, or 2,000 mg LAC intravenously. Tracer activity ratios were determined in 10 pairs of cerebellar, cortical and subcortical regions. After administration of the lowest dose of LAC, no changes from the basal values were observed in any of the regions examined. The higher doses of the drug significantly elevated the tracer activity in cortical regions, particularly in the parietal lobe, which showed an impaired regional cerebral blood flow in the basal study. These effects of LAC and their relation with the cholinomimetic properties of the drug are discussed.

[99mTc]-HM-PAO SPECT in Parkinson's disease.

Thirty-six patients affected by Parkinson's disease were studied using single photon emission computed tomography (SPECT) and [99mTc]-HM-PAO as a tracer. The scanning procedure was performed 16-24 h after discontinuation of specific therapy. Tracer activity ratios were determined in 10 pairs of cerebellar, cortical, and subcortical regions. Data were compared with those of 10 age-matched controls. Most of the regions examined did not show any relevant change between parkinsonian and control subjects. Notably, mean activity in striatal regions were similar in the two groups. Increased activity in caudate-putamen was found in patients who were on chronic DOPA therapy. Side-to-side asymmetries in the basal ganglia increased with the severity of the disease. Significant reductions of tracer uptake, from control values, were observed bilaterally in the parietal cortex. These deficits were more pronounced in patients with mental deterioration and in subjects who had been chronically treated with anticholinergic drugs. Parietal perfusion deficits in parkinsonian patients resemble those described in Alzheimer's dementia. These findings suggest that the heterogeneous alterations of regional cerebral blood flow (rCBF) in parkinsonian patients reflect the multifactorial pathophysiology of the disease.

[Cerebral changes shown by computed tomography in children with acute lymphatic leukemia after therapy]. / Alterazioni cerebrali riscontrate con TC in bambini affetti da leucemia linfatica acuta fuori terapia.

The authors discuss the CT findings of the late brain damage by the radiochemotherapic treatment for the prophylaxis of meningeal leukemia in 50 patients, 1 divided by 15 years old. The more frequent CT findings are: enlargement of the subaracnoid spaces; ventricular dilatation; hypodensity of cerebral parenchima; calcifications. These findings correspond to two clinical and anatomo-pathological conditions: subacute leucoencephalopathy and mineralizing microangiopathy. A greater damage on central nervous system was demonstrated in younger children (5 years old) at the time of prophylaxis of meningeal leukemia, that were irradiated with NSD = 950 ret.