99-mTc-HMPAO single photon emission computed tomography examinations in genetically determined neurometabolic...

The aim of our study was to determine regional cerebral blood flow (rCBF) abnormalities in different types of enzymopathies.

Among the patients with genetically determined enzymopathies 3 patients had aminoacidopathies, and 11 had different types of encephalopathies, from which 10 had mitochondrial encephalomyopathy (MEMP), and 1 patient had hyperuricaemic encephalopathy. Besides the mentioned 14 patients, 1 had ceroid lipofuscinosis and another patient had tuberous sclerosis. The further distribution of the MEMP patients' group was the following--5 patients had MEMP with lactic acidosis, 5 had Leigh's disease (subacute necrotizing encephalopathy), from which 1 had cytochrome-c-oxidase deficiency (COX). Additionally in all patients were performed cerebral MRI and SPECT examination 10 min. after intravenous administration of 20 Mbq/kg 99 mTc-HMPAO.

Fourteen out of 16 SPECT findings were pathologic, showing decreased focal frontal/temporal/temporoparietal cerebral blood perfusion. Aminoacidopathic group--all the 3 patients revealed pathologic signs from the aminoacidopathic patients' group. Among them the ornithine transcarbamylase (OTC) heterozygous female patient with left-sided hemiparesis caused by hyperammonemic stroke at 10 month-age, showed right sided temporoparietal, occipital and left frontal hypoperfusion, nearly 6 years after the cerebral vascular attack. This finding might be resulted because of diaschisis. Mitochondrial encephalo-myopathic (MEMP) group--all the four patients with MEMP and lactic acidosis showed focal hypoperfusion in the temporal region, while the perfusion was normal in the COX deficient patient and in 2 Leigh's disease (subacute necrotizing encephalopathy) patients. In the remaining 1 Leigh's patient frontotemporal hypoperfusion was found. In all patients there were non specific structural abnormalities detected by MRI: cortical and subcortical atrophy, and scattered demyelination foci. In the case of ceroid lipofuscinosis the MRI showed cerebral atrophy and cerebellar hypoplasia, and the SPECT showed right frontal and occipital hypoperfusion, bilateral parietal physiological riping process. The patient with tuberous sclerosis showed bilateral temporo-occipital hypoperfusion.

(1) SPECT images demonstrated hypoperfusion rCBF changes in 14 out of all 16 patients. (2) Regional cerebral/cerebellar hypoperfusion was detected by SPECT in mitochondrial encephalomyopathies, with lactate acidosis and aminoacidopathies giving high informative value about the cerebral perfusion.