Structural and functional neuroimaging findings in substance-related disorders

Diagnostic role of 99mTc hexamethyl-propyleneamine oxime brain single photon emission computed tomography in Sydenham's chorea

BACKGROUND

The objective of this study was to determine whether technetium-99m hexamethyl-propyleneamine oxime (HMPAO) brain single photon emission computed tomography (SPECT) imaging is capable of detecting perfusional abnormalities in Sydenham's chorea (SC) patients and contributing to diagnosis of SC.

METHODS

In this study, 17 SC patients were evaluated. HMPAO SPECT was performed on all patients at the acute phase and six of them at the recovery phase. Magnetic resonance imaging (MRI) of the brain was performed to 13 patients. SPECT images of basal ganglia and thalamus were evaluated both visually and by measuring the radioactivity uptakes. Ten subjects constituted the control group.

RESULTS

HMPAO SPECT was visually evaluated as indicating hyperperfusion in the basal ganglia and thalamus in 16 patients, and evaluated as normal in one patient at the acute phase. The radioactivity uptakes of basal ganglia and thalamus of the patients at the acute phase were found statistically higher than those of the patients at the recovery phase, and also higher than those of the control group (P < 0.05). A significant difference between the radioactivity uptake of the patients at the recovery phase and those of the control group was not found (P > 0.05). Only one patient did not show any abnormality in both acute and recovery phases. MRI study did not show any abnormality in the basal ganglia and thalamus.

CONCLUSION

It is suggested that brain SPECT can contribute to the diagnosis of SC as an objective tool. Resolving of the hyperperfusion at the recovery phase provides further support for the diagnosis of SC.

Alcohol abuse and traumatic brain injury: quantitative magnetic resonance imaging and neuropsychological outcome

Prior or concurrent alcohol use at the time of traumatic brain injury (TBI) was examined in terms of post-injury atrophic changes measured by quantitative analysis of magnetic resonance imaging (MRI) and neuropsychological outcome. Two groups of TBI subjects were examined: those with a clinically significant blood alcohol level (BAL) present at the time of injury (TBI + BAL) and those without a significant BAL (TBI-only). To explore the potential impact of both acute and chronic alcohol use, subjects in both groups were further clustered into one of four subgroups (NONE, MILD, MODERATE or HEAVY) based upon available information regarding their pre-injury alcohol use. One-way analysis of covariance (ANCOVA) and multiple analysis of covariance (MANCOVA) were used with subject grouping as the main factor. Age, injury severity as measured by Glasgow Coma Scale (GCS) score, years of education, total intracranial volume (TICV), and the number of days post-injury were included as covariates where appropriate. Increased general atrophy was observed in patients with (a) a positive BAL and/or (b) a history of moderate to heavy pre-injury alcohol use. In addition, performance on neuropsychological outcome variables (WAIS-R and WMS-R Index scores) was generally worse in the subgroups of patients with positive BAL and a history of preinjury alcohol use, as compared to the other TBI groups though not statistically significant. Implications of alcohol use, at the time of brain injury, are discussed.

Dysphoric mania induced by high-dose mirtazapine: a case for 'norepinephrine syndrome'?

The antidepressant mirtazapine antagonizes central presynaptic alpha2-adrenergic auto- and heteroreceptors resulting in increased central norepinephrine and serotonin activity. Histamine H2 receptors are also antagonized, as are postsynaptic serotonin 5-HT2 and 5-HT3 receptors, leading to serotonergic activity primarily via 5-HT1A receptors. Based on the case report of a patient who developed mania with higher than recommended dosage of mirtazapine, we review the literature on the atypical nature of manic symptoms with mirtazapine. Eight subjects, including those in our study, were identified as having developed mirtazapine-induced mania with atypical features, consisting of dysphoria, irritability, insomnia, psychomotor agitation and abnormal gait. Predisposing features may have included the presence of underlying brain dysfunction and certain selective serotonin reuptake inhibitor-mirtazapine combinations. Dysphoric mania with atypical features may be induced by mirtazapine, providing support for a common hypothesis such as 'central norepinephrine hyperactivity' as the basis for development of mania with mirtazapine.