Interregional correlations of glucose metabolism between the basal ganglia and different cortical areas: an ultra-high resolution PET/MRI fusion study using 18F-FDG

Basal ganglia have complex functional connections with the cerebral cortex and are involved in motor control, executive functions of the forebrain, such as the planning of movement, and cognitive behaviors based on their connections. The aim of this study was to provide detailed functional correlation patterns between the basal ganglia and cerebral cortex by conducting an interregional correlation analysis of the 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) data based on precise structural information. Fifteen participants were scanned with 7-Tesla magnetic resonance imaging (MRI) and high resolution research tomography (HRRT)-PET fusion system using 18F-FDG. For detailed interregional correlation analysis, 24 subregions of the basal ganglia including pre-commissural dorsal caudate, post-commissural caudate, pre-commissural dorsal putamen, post-commissural putamen, internal globus pallidus, and external globus pallidus and 80 cerebral regions were selected as regions of interest on the MRI image and their glucose metabolism were calculated from the PET images. Pearson's product-moment correlation analysis was conducted for the interregional correlation analysis of the basal ganglia. Functional correlation patterns between the basal ganglia and cerebral cortex were not only consistent with the findings of previous studies, but also showed new functional correlation between the dorsal striatum (i.e., caudate nucleus and putamen) and insula. In this study, we established the detailed basal ganglia subregional functional correlation patterns using 18F-FDG PET/MRI fusion imaging. Our methods and results could potentially be an important resource for investigating basal ganglia dysfunction as well as for conducting functional studies in the context of movement and psychiatric disorders.

Basal ganglia calcification.

Basal ganglia calcification (BGC) is now being diagnosed with increasing frequency with widespread application of computed tomography (CT) in clinical practice and is no more considered a rarity. During the period 1987 to 1995, 42 patients were noted to have BGC and it constituted 0.93% of all CT scan of brain carried out during the relevant period. These patients presented with diverse neurological and endocrine disorders i.e., epilepsy (22 patients), mental retardation (five patients), extra-pyramidal syndromes (five patients), abnormal behaviour (three patients), stroke (two patients), raised intracranial tension without localizing signs (one patient), following radiotherapy (one patient), and with hypoparathyroidism (three patients). These patients were noted to have variable degree of calcification in different parts of brain i.e., basal ganglia (42 cases), cerebellum (12 cases) and cerebral cortex (nine cases). Family history of a neurological disorder was available in five patients. This study highlights the fact that calcification of basal ganglia and other parts of the brain is often a nonspecific finding on CT scan and it may not be possible to establish a clinicopathological correlation.

Brainstem Auditory Evoked Potentials in Acute Carbon Monoxide Poisoning

Of 32 cases suffering from acute carbon monoxide (CO) poisoning brainstem auditory evoked potential (BAEP) abnormalities were exhibited in 8 cases. the abnormalities of BAEPs could be divided into two patterns: a peripheral pattern (6 cases) of prolongation of latency to wave 1 without prolongation of interpeak latency, and a central pattern (2 cases) of prolongation of latencies to all waves and interpeak latencies. The indicence of BAEP abnormality tended to increase in accordance with an unconscious duration of more than 24 hours; during acute CO poisoning. A BAEP abnormality exhibiting a peripheral pattern usually returned to normal within one month after anoxia, but cases showing central pattern of BAEP abnormality died during acute anoxic insult due to the possible involvement of the brainstem. Thus, BAEPs can be used for evaluating the functional intergrity of the auditory pathways and for providing prognostic values in acute CO poisoning.