technetium-tc-99m-bicisate and Hallucinations

Despite its high prevalence, relatively little is known about the pathophysiology of somnambulism. Increasing evidence indicates that somnambulism is associated with functional abnormalities during wakefulness and that sleep deprivation constitutes an important drive that facilitates sleepwalking in predisposed patients. Here, we studied the neural mechanisms associated with somnambulism using Single Photon Emission Computed Tomography (SPECT) with 99mTc-Ethylene Cysteinate Dimer (ECD), during wakefulness and after sleep deprivation.. Ten adult sleepwalkers and twelve controls with normal sleep were scanned using 99mTc-ECD SPECT in morning wakefulness after a full night of sleep. Eight of the sleepwalkers and nine of the controls were also scanned during wakefulness after a night of total sleep deprivation. Between-group comparisons of regional cerebral blood flow (rCBF) were performed to characterize brain activity patterns during wakefulness in sleepwalkers.. During wakefulness following a night of total sleep deprivation, rCBF was decreased bilaterally in the inferior temporal gyrus in sleepwalkers compared to controls.. Functional neural abnormalities can be observed during wakefulness in somnambulism, particularly after sleep deprivation and in the inferior temporal cortex. Sleep deprivation thus not only facilitates the occurrence of sleepwalking episodes, but also uncovers patterns of neural dysfunction that characterize sleepwalkers during wakefulness.

Topics: Adult; Brain Mapping; Cerebrovascular Circulation; Cysteine; Female; Hallucinations; Humans; Male; Organotechnetium Compounds; Radiopharmaceuticals; Sleep Deprivation; Somnambulism; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Wakefulness; Young Adult

Topics: Cerebrovascular Disorders; Cysteine; Female; Hallucinations; Humans; Magnetic Resonance Angiography; Middle Aged; Organotechnetium Compounds; Tomography Scanners, X-Ray Computed; Tomography, Emission-Computed, Single-Photon; Vasoconstriction

Despite improved diagnostic accuracy, differentiation of dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) on the basis of clinical findings remains problematic. The purpose of this retrospective study was to evaluate the utility of technetium-99m ethyl cysteinate dimer (ECD) single-photon emission tomography (SPET) as a potential tool for the diagnosis of DLB and discrimination from AD. Cerebral perfusion patterns detected by (99m)Tc-ECD SPET were compared in patients presenting with a probable diagnosis of DLB ( n=34) or AD ( n=28). Tracer distribution was quantified using the region of interest technique in eight symmetrical paired zones and expressed as a perfusion index (ratio of mean uptake in a brain region to that in the cerebellum). Comparison of findings in the DLB and AD groups demonstrated significant differences in mean perfusion indexes in the right occipital region ( P=0.004), left occipital region ( P=0.005) and left medial temporal region ( P=0.013). Mean perfusion indexes in the right and left occipital regions were lower in DLB than in AD patients. Conversely, the mean perfusion index in the left medial temporal region was lower in AD than in DLB patients. DLB was correctly identified in 22 patients (sensitivity, 65%) while AD was correctly identified in 20 patients (specificity, 71%). In the DLB group, right and left occipital perfusion indexes were 0.95 or more in all eight non-hallucinating patients, and bilateral occipital hypoperfusion was observed in 15 of the 26 patients with visual hallucinations (57.7%). To our knowledge, this is the first study in which (99m)Tc-ECD SPET has been used exclusively for the diagnosis of DLB. The results suggest that brain perfusion scintigraphy could be helpful in distinguishing DLB from AD if diagnosis based on clinical criteria alone is difficult. The findings also support a link between visual hallucinations and structural/functional changes in the occipital region in DLB patients.

Topics: Aged; Alzheimer Disease; Brain; Cysteine; Diagnosis, Differential; Feasibility Studies; Female; Hallucinations; Humans; Lewy Body Disease; Male; Organotechnetium Compounds; Radiopharmaceuticals; Reproducibility of Results; Retrospective Studies; Sensitivity and Specificity; Tomography, Emission-Computed, Single-Photon

Visual hallucinations can occur within the central nervous system and may be associated with a lesion anywhere in the visual pathway. The purpose of this study was to assess "ictal" regional cerebral blood flow with Tc-99m ethylcysteinate dimer (ECD) SPECT in patients having acute hallucinations, and to compare the findings to the "interictal" state.. A prospective study was performed to evaluate patients admitted to the neurology department with nonpsychiatric and nonepileptic visual hallucinations. The nine patients included in the study underwent thorough neurologic and psychiatric evaluations. A computed tomographic (CT) scan was performed when each patient was admitted, and electroencephalographic (EEG) recordings were made during their hallucinations. All patients underwent a brain SPECT while having acute hallucinations (ictal SPECT), and a follow-up scan was obtained 2 to 3 weeks later.. All patients had normal ictal EEG findings during the hallucinations. Seven of nine patients had increased perfusion on the SPECT studies in one or more regions, with a mean lesion-to-contralateral ratio of 2.1 (range, 1.5 to 2.7). Three of the seven patients had findings consistent with a cerebrovascular accident. After treatment, the hallucinations disappeared in two patients and the motor deficit improved dramatically. The follow-up SPECT study showed significant improvement in all patients 1 week later. Charles Bonnet syndrome, frontal lobe dementia, and Anton syndrome were diagnosed in three other patients, and the last one had no identifiable background disease, all with normal findings of EEG, CT, and magnetic resonance examinations. They all responded readily to carbamazepine therapy, and the follow-up SPECT study showed resolution of the findings. Two of nine patients showed posterior cortical hypoperfusion, and eventually Lewy body disease was diagnosed. The SPECT showed no evidence of regional hyperperfusion.. This prospective preliminary study suggests that brain imaging using SPECT may be useful in identifying the mechanisms and evolution of blood flow abnormalities in certain subgroups of patients who have visual hallucinations and may assist in the selection of specific therapy.

Topics: Aged; Brain; Cerebrovascular Circulation; Cysteine; Electroencephalography; Female; Hallucinations; Humans; Male; Organotechnetium Compounds; Prospective Studies; Radiopharmaceuticals; Stroke; Tomography, Emission-Computed, Single-Photon