technetium-tc-99m-exametazime and Attention-Deficit-Disorder-with-Hyperactivity

Although abnormalities in the regional cerebral blood flow (rCBF) responses to methylphenidate (MPH) treatment have been reported in children with attention deficit hyperactivity disorder (ADHD), there are few prospective longitudinal studies assessing the long-term effects of MPH and discontinuation effects after chronic treatment.. The authors studied ten drug-naive children (2 girls, 8 boys, mean age+/-S.D.=9.60+/-1.96) diagnosed with ADHD by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) diagnostic criteria, using (99m)Tc-HMPAO-single photon emission computed tomography (SPECT). Patients were studied at baseline (visit 1), after 2 months of MPH treatment (visit 2) and after a drug-free period of 2 months following 12 months of MPH treatment (visit 3) at doses of 1 mg/kg/day. We evaluated SPECT data visually and semi-quantitatively.. Two months of chronic MPH treatment resulted in visually detectable improvement in hypoperfusion in the right frontal cortex and all areas of temporal cortex with the exception of left lateral temporal cortex. This improvement was still detectable on visual evaluations of SPECT data after 2 months of treatment discontinuation. The treatment effects that were detected visually were not statistically significant in semi-quantitative analyses.. Treatment effects of chronic MPH treatment may persist long after the discontinuation of the treatment.

Topics: Attention Deficit Disorder with Hyperactivity; Blood Flow Velocity; Brain Mapping; Central Nervous System Stimulants; Child; Female; Follow-Up Studies; Humans; Male; Methylphenidate; Pilot Projects; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Attention deficit hyperactivity disorder (ADHD) is a developmental, neurobehavioral syndrome with an onset in childhood. The aim of this study was to investigate the existence of regional perfusion changes in ADHD by means of Tc-99m HMPAO brain SPECT. Thirteen children with a diagnosis of ADHD and 7 healthy, age-matched controls were included in this study. Hypoperfusion was observed on the right temporal cortex in 9, and on the left temporal cortex in 3 children. The distribution of the lesions showed right lateral temporal cortex involvement in 3, right medial temporal cortex in 9 and left medial temporal cortex in 8 children. Asymmetric perfusion was seen on the caudate nucleus in 4, on the thalamus in 3 and on the frontal cortex in 6 children. There was a significant difference between children with ADHD and controls in right medial temporal cortex: cerebellum and right lateral temporal cortex: cerebellum ratios. Hypoperfusion in the right medial temporal cortex was significantly and inversely correlated with Du Paul teachers' questionnaire rating scale (r = -0.71, p = 0.006). It has been postulated that difficulty in self regulating response to stimuli in ADHD is mediated by underfunctioning of the orbital frontal cortex and subsequent connection to the limbic system. Decreased temporal cortex perfusion may dysfunction of the limbic system or the orbito-frontal-limbic axis.

Topics: Attention Deficit Disorder with Hyperactivity; Brain; Cerebellum; Cerebrovascular Circulation; Child; Female; Humans; Male; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Temporal Lobe; Tissue Distribution; Tomography, Emission-Computed, Single-Photon

The goal of this study was to test whether clinician-rated regional cerebral blood flow (rCBF) as rendered by SPECT imaging is a meaningful predictor of patient response to CNS stimulants. Chart reviews were used to identify patients who reported prior significant positive and negative responses to CNS stimulants. Each patient in the study had received resting and concentration SPECT scans using Tc99m exametazime. Differences in cerebral blood flow for frontal regions of interest were assessed in three conditions (resting, concentration, and their difference, or "delta") using ANCOVAs and age-matched ANOVAs. Prefrontal pole deltas were found to be highly sensitive and specific predictors of response to CNS stimulants, with pole activation predicting adverse responses and pole deactivation predicting good responses. Positive and negative predictive values were greater than .75 for both poles. We conclude that SPECT renderings of rCBF, particularly in the prefrontal cortex, are a potentially powerful clinical tool for anticipating response to stimulant medications, both positive and adverse.

Topics: Adolescent; Adult; Attention; Attention Deficit Disorder with Hyperactivity; Central Nervous System Stimulants; Child; Dominance, Cerebral; Female; Frontal Lobe; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Neuropsychological Tests; Prefrontal Cortex; Psychomotor Performance; Regional Blood Flow; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Young Adult

It has been reported that both obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) might be related to impairments in frontal-striatal brain circuits. Besides, these two disorders are frequently comorbid. However, there are no published studies directly comparing the neurobiological findings in these two disorders. The objective of the study was to investigate the differences in cortical blood flow between patients with OCD and ADHD.. Thirteen drug-naive OCD subjects (mean age +/- SD: 10.4 +/- 2.8), and 13 drug-naive ADHD subjects (mean age +/- SD: 10.5 +/- 2.2) were included in the study. Cerebral blood flow (CBF) was evaluated with Tc-99m-hexamethylpropyleneamine oxime (Tc99m HMPAO) brain single photon emission tomography (SPECT) during standard resting conditions in all cases. P value was set to <.006 after Bonferroni correction.. OCD cases had significantly higher right prefrontal (p=.003) CBF than ADHD cases. There were no significant CBF differences in other brain regions. OCD symptom severity was not related to CBF.. This is one of the very few studies which directly investigated brain imaging in pediatric OCD subjects. Results are consistent with previous studies reporting increased prefrontal CBF in OCD subjects. We also found that, consistent with the previous literature, ADHD subjects had lower prefrontal cortex CBF. Studies which compare subjects with comorbid ADHD and OCD with pure forms of these disorders are necessary to have a better understanding of similarities and differences of these two disorders.

Topics: Attention Deficit Disorder with Hyperactivity; Cerebral Cortex; Cerebrovascular Circulation; Child; Female; Humans; Male; Obsessive-Compulsive Disorder; Radiopharmaceuticals; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Findings from 99mTc-HMPAO SPECT measurements at rest in a group of 19 school-age children with specific language impairment (SLI) were compared to a group of 12 children with attention-deficit hyperactivity disorder (ADHD). The regional cerebral blood flow (CBF) distributions were different in the two groups. Children with SLI showed significantly lower CBF values in the right parietal region and in the subcortical region compared to the ADHD group. In addition, the SLI group had symmetric CBF distributions in the left and right temporal regions, whereas the ADHD group showed the usual asymmetry with left-sided hemispheric predominance in the temporal regions. The findings give further evidence for anomalous neurodevelopment with deviant hemispheric lateralization as an important factor in the aetiology of SLI. They also point to the role of subcortical structures in language impairment in childhood. Earlier focus on cortical structures in SLI research needs to be widened to include subcortical regions as well.

Topics: Adolescent; Attention Deficit Disorder with Hyperactivity; Basal Ganglia; Brain; Cerebrovascular Circulation; Child; Female; Functional Laterality; Humans; Language Disorders; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon