Technetium-99m Hexamethylpropylene Amine Oxime Brain Research Articles

Clinical Value of Perfusion Abnormalities of Brain on Technetium-99m HMPAO Single-Photon Emission Computed Tomography in Children With Sydenham Chorea.

We evaluated whether perfusion brain abnormalities by single-photon emission computed tomography (SPECT) imaging improves diagnostic and prognostic assessment in Sydenham chorea. Twenty-three children with acute autoimmune chorea underwent technetium-99m hexamethylpropyleneamine oxime brain SPECT imaging. In 16 children, SPECT was repeated during the follow-up. A pattern of basal ganglia hyperperfusion was observed in 20 (87%) patients. In 4 of 10 patients with generalized chorea, perfusion was comparable in right and left striatum and right and left thalamus. In 13 patients with hemi-chorea and in 3 with generalized chorea, unilateral hyperperfusion was detected. Three patients with generalized chorea had normal perfusion. Tracer uptake of basal ganglia of the patients at the acute phase was higher than at the follow-up ( P < .001). SPECT seems a useful noninvasive tool in pediatric patients with Sydenham chorea to support the clinicians during the acute phase of disease and to monitor the course of autoimmune chorea.

Plantar Flexion with Noxious Dorsal Foot Stimulation in Brain Death

Plantar flexion with plantar stimulation has been well described in brain death, and is compatible with brain death. However, plantar flexion with stimulation to the dorsal surface of the foot has not been reported previously in brain dead patients. Case report with Technetium-99m hexamethylpropyleneamine oxime brain scan and video. A 46-year-old woman suffered severe anoxic brain injury following massive pulmonary embolism 5days after arthroscopic knee surgery. Neurologic examination was consistent with brain death, with the exception of plantar flexion when noxious stimulation was applied to the dorsal surface of the great toe on each side. Ancillary testing with a technetium-99m nuclear scan demonstrated absence of cerebral perfusion, supporting the diagnosis of brain death. Noxious stimulation to the dorsal surface of the foot may trigger spinally mediated plantar flexion in patients with brain death.

Decreased cerebral blood flow in the limbic and prefrontal cortex using SPECT imaging in a cohort of completed suicides

Suicide has a high comorbidity with impulsivity and depression, and finding imaging biomarkers indicative of patients at high risk for suicidal behavior is invaluable to the clinician. Using single-photon emission computed tomography (SPECT) imaging, we have previously reported regional cerebral blood flow (rCBF) decreases in the medial prefrontal cortex, ventral tegmental area and subgenual cingulate cortex (Brodmann area 25 (BA 25)), a region found to be hypoperfused with treatment-resistant depression. From 2007 to 2010, we have extended our analysis to include nine additional completed suicides. In all, 27 healthy, age- and gender-matched subjects from a previously acquired healthy brain study served as controls to our 21 completed suicides. All 21 suicides had been previously diagnosed with depression according to Diagnostic and Statistical Manual of Mental Disorder-IV criterion. Voxel-by-voxel analyses were performed using statistical parametric mapping to compare the differences in technetium-99m hexamethylpropylene amine oxime brain uptake between the groups. Factor analysis of the data identified the top 10 regions of hypoperfusion in the suicidal group, including the bilateral superior frontal lobes, the right precuneus, the rolandic operculum, postcentral gyrus, left caudate and insular cortex. We also demonstrate more focal decreases in rCBF in the subgenual cingulate cortex (BA 25) in 18 subjects, supporting our previous hypothesis that hypoperfusion of BA 25 may be a risk factor for suicide in depressed patients. This work suggests that SPECT might be useful in predicting risk for suicide completion in subjects with depression or treatment-resistant depression. Further investigation of this work is necessary to better understand the predictive value of this finding.

Evaluation of dysthymic disorder with technetium-99 m hexamethylpropylene amine oxime brain single-photon emission tomography.

Dysthymic disorder is a chronic disorder characterised by the presence of a depressed mood and is classified as a distinct category in DSM-IV, separately from major depression. Although brain imaging studies have been performed in major depressive disease, there have to date been no reports of such studies in dysthymic disorder. In this study 36 patients with dysthymic disorder were compared with 16 normal subjects using technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography. A relative blood flow ratio was calculated for each region of interest using the average tissue activity in the region divided by activity in the cerebellum. There were significant differences in the bilateral inferior frontal, bilateral parietal, right superior frontal and left posterior temporal regions in the patients with dysthymic disorder compared with the healthy controls. These findings support the hypothesis that the biological bases for dysthymic disorder and major depression are similar. Recognition of these regional abnormalities may have clinical utility in both the diagnosis and the treatment of dysthymic disorder. Further studies are needed to confirm our results and to assess the influence of treatment in patients with dysthymic disorder.

A technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography study in adolescent patients with major depressive disorder.

We have not encountered any brain single-photon emission tomography (SPET) study performed in adolescent depressed patients in the literature. Therefore, we used technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) brain SPET in adolescent patients with major depressive disorder (MDD) to examine the possible changes in cerebral perfusion and the possible association between perfusion indices and clinical variables. Fourteen adolescent out-patients (nine females, five males; mean+/-SD age: 13.11+/-1.43 years; range: 11-15 years) fulfilling the DSM-IV criteria for MDD and 11 age-matched healthy control subjects (six females, five males; mean+/-SD age: 13.80+/-1.60 years; range: 12-15 years) were included in the study. 99Tc-HMPAO brain SPET was performed twice in the patient group and once in the control group. The first SPET investigation was performed under non-medicated conditions and the second was performed after depressive symptoms had subsided. A relative perfusion index (PI) was calculated as the ratio of regional cortical activity to the whole brain activity. We found significant differences between the PI values of the untreated depressed patients and those of the controls, indicating relatively reduced perfusion in the left anterofrontal and left temporal cortical areas. No significant differences in regional PI values were found between the remitted depressed patients and the controls. Our study suggests that adolescent patients with MDD may have regional cerebral blood flow deficits in frontal regions and a greater anterofrontal right-left perfusion asymmetry compared with normal subjects. The fact that these abnormalities in perfusion indices have a trend toward normal values with symptomatic improvement suggests that they may be state-dependent markers for adolescent MDD.

Evaluation of Outcome of Delayed Neurologic Sequelae after Carbon Monoxide Poisoning by Technetium-99m Hexamethyl-propylene Amine Oxime Brain Single Photon Emission Computed Tomography

Using brain computed tomography (CT) and single photon emission computed tomography (SPECT) with technetium-99m hexamethylpropylene amine oxime (99mTc HM-PAO) in 13 patients with delayed neurologic sequelae after carbon monoxide poisoning, we tried to evaluate the clinical outcome of delayed CO sequelae. Among the 13 initial brain CTs, seven showed low density in the cerebral white matter and one revealed hypodensity in both globi pallidi. Of the 7 follow-up CT scans, 3 have remained unchanged, but in 4 cases more aggravating patterns with cortical atrophy without the clinical correlation were observed. There was no correlation between the CT findings and the outcome of delayed CO sequelae. All initial SPECTs in 13 patients with delayed CO sequelae showed diffuse patchy hypoperfusion throughout the cerebral cortex. Among the follow-up SPECTs in 7 patients, 6 patients showed increased cerebral perfusion with the concomitant clinical improvement, but the SPECT of a patient in bedridden state had remained unchanged, compared with the initial SPECT. There seemed to be good correlation between the findings of SPECT and the outcome of delayed CO sequelae. In conclusion, 99mTc HM-PAO brain SPECT is more sensitive than CT, and may be a useful test in evaluating the clinical outcome of delayed neurologic sequelae after CO poisoning.

Signs of cerebral atrophy on single-photon emission tomography.

Cerebral atrophy often coexists with other brain disorders and by itself may alter the pattern of cerebral perfusion. If unrecognized, it may confound diagnoses based on brain single-photon emission tomography (SPET). In this retrospective study, we describe and evaluate criteria for the diagnosis of cerebral atrophy on technetium-99m hexamethylpropylene amine oxime brain SPET studies. The SPET scans of 11 patients with cerebral atrophy and ten controls were evaluated for the presence of a prominent interhemispheric fissure, presence of prominent cerebral sulci, separation of thalamic nuclei, and pronounced separation of caudate nuclei. The SPET studies were interpreted by two independent observers blind to the findings of magnetic resonance imaging, which provided the final diagnosis of cerebral atrophy. The combination of the four scintigraphic signs was accurate in the diagnosis of cerebral atrophy in 95% of the cases and had a sensitivity of 91% and a specificity of 100%.

Quantification of technetium-99m hexamethylpropylene amine oxime brain uptake in routine clinical practice using calibrated point sources as an external standard: phantom and human studies

Quantitative methods for calculation of regional cerebral blood flow with technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) have been proposed. These methods are very labour intensive and therefore are not useful in routine clinical practice. We describe a simple alternative method, using calibrated point sources as a scaling factor, whereby the tomographic slices are displayed as regional 99mTc-HMPAO brain uptake per cm3 brain tissue in 10(-6) of the injected lipophilic dose. The method was validated on Jaszczak and Hoffman phantoms using a three-detector system with HR parallel and HR fan-beam collimators. Under the optimal conditions described in this paper, the measured to real activity ratio was 1.00 (SD = 0.06). The reproducibility of the cerebellar uptake in a group of ten normal volunteers and five patients was studied. Intra-individually a mean deviation of 12.6% was observed for the total group. For those persons with a heart rate difference of less than 5 units between the two studies, a mean deviation of 7.2% was obtained. Quantitative 99mTc-HMPAO brain uptake images can be useful for longitudinal studies, especially for follow-up, activation and pharmacological studies.