Early sensory experience influences the development of multisensory thalamocortical and intracortical connections of primary sensory cortices.

The nervous system integrates information from multiple senses. This multisensory integration already occurs in primary sensory cortices via direct thalamocortical and corticocortical connections across modalities. In humans, sensory loss from birth results in functional recruitment of the deprived cortical territory by the spared senses but the underlying circuit changes are not well known. Using tracer injections into primary auditory, somatosensory, and visual cortex within the first postnatal month of life in a rodent model (Mongolian gerbil) we show that multisensory thalamocortical connections emerge before corticocortical connections but mostly disappear during development. Early auditory, somatosensory, or visual deprivation increases multisensory connections via axonal reorganization processes mediated by non-lemniscal thalamic nuclei and the primary areas themselves. Functional single-photon emission computed tomography of regional cerebral blood flow reveals altered stimulus-induced activity and higher functional connectivity specifically between primary areas in deprived animals. Together, we show that intracortical multisensory connections are formed as a consequence of sensory-driven multisensory thalamocortical activity and that spared senses functionally recruit deprived cortical areas by an altered development of sensory thalamocortical and corticocortical connections. The functional-anatomical changes after early sensory deprivation have translational implications for the therapy of developmental hearing loss, blindness, and sensory paralysis and might also underlie developmental synesthesia.

Miniaturized Radiochemical Purity Testing for 99mTc-HMPAO, 99mTc-HMDP, and 99mTc-Tetrofosmin.

Quick methods are functional in clinical practice to ensure the fastest availability of radiopharmaceuticals. For this purpose, we investigated the radiochemical purity of the widely used 99mTc-hydroxymethylene diphosphonate, 99mTc-hexamethylpropyleneamine oxime, and 99mTc-tetrofosmin by reducing time as compared with the manufacturer's method. Methods: We applied a miniaturized chromatographic method with a reduced strip development from 18 cm to 9 cm for all 3 radiopharmaceuticals. The specific support medium and solvent system of the manufacturer's methods was kept unchanged for 99mTc-hydroxymethylene diphosphonate and 99mTc-tetrofosmin, whereas for 99mTc-hexamethylpropyleneamine oxime the instant thin-layer chromatography (ITLC) polysilicic gel (silicic acid [SA]) was replaced with a monosilicic gel (silicic gel [SG]) in the chromatographic system that uses methyl ethyl ketone as solvent. The method was applied and compared with the routine ITLC insert method in a total of 30 batches for each radiopharmaceutical. The precision of repeated tests was determined by comparison with the results of 10 replications on the same batch. Small volumes of concentrated 99mTcO4-, and 99mTc-albumin nanocolloid were used to produce potential radiochemical impurities. Correlation between the quick methods and the insert methods was analyzed using a nonparametric 2-tailed test and a 2 × 2 contingency table with the associated Fisher exact test to evaluate sensitivity and specificity. A receiver-operating-characteristic analysis was performed to evaluate the best cutoff. Results: The percentage radiochemical purity of the quick methods agreed with the standard chromatography procedures. We found that 99mTcO4 and colloidal impurities are not the only common radiochemical impurities with 99mTc-tetrofosmin, and shortening of the ITLC strip with respect to the manufacturer's method will worsen system resolution and may produce inaccuracy. Conclusion: The miniaturized methods we described represent a fast and reliable alternative for 99mTc-exametazime and 99mTc-oxidronate quality control, with the upper cutoff for acceptable radiochemical purity values being 84% and 95%, respectively. For 99mTc-tetrofosmin radiochemical purity testing, a longer strip as described in the standard method is warranted.

Radiolabeled WBC scintigraphy in the diagnostic workup of patients with suspected device-related infections.

OBJECTIVES: The aim of this study was to investigate the diagnostic performance of (99m)Tc-hexamethypropylene amine oxime labeled autologous white blood cell ((99m)Tc-HMPAO-WBC) scintigraphy in patients with suspected infections associated with cardiovascular implantable electronic devices (CIEDs). BACKGROUND: Early, definite recognition of CIED-related infections combined with accurate localization and quantification of disease burden is a prerequisite for optimal treatment strategies. METHODS: All 63 consecutive patients underwent clinical examination, blood chemistry, microbiology, and echography of the cardiac region/venous pathway of the device. Final diagnosis of infection was established in 32 of 63 patients and in 23 of 32 by microbiology. RESULTS: Sensitivity of (99m)Tc-HMPAO-WBC single-photon emission computed tomography/computed tomography (SPECT/CT) was 94% for both detection and localization of CIED-associated infection. SPECT/CT imaging had a definite added diagnostic value over both planar and stand-alone SPECT. Pocket infection was often associated with lead(s) involvement; the intracardiac portion of the lead(s) more frequently exhibited (99m)Tc-HMPAO-WBC accumulation and presented the highest rate of complications, infectious endocarditis, and septic embolism. Two false negative cases and no false positive results were observed. None of the patients with negative (99m)Tc-HMPAO-WBC scintigraphy developed CIED-related infection during follow-up of 12 months. Echography of the cardiac region/venous pathway of the device had 90% specificity, but low sensitivity (81% when intracardiac lead[s] infection only was considered). The Duke criteria had 31% sensitivity for the definite category (100% specificity) and 81% for the definite and possible categories (77% specificity). CONCLUSIONS: (99m)Tc-HMPAO-WBC scintigraphy enabled the confirmation of the presence of CIED-associated infection, definition of the extent of device involvement, and detection of associated complications. Moreover, (99m)Tc-HMPAO-WBC scintigraphy reliably excluded device-associated infection during a febrile episode and sepsis, with 95% negative predictive value.

Is 99mTc-HMPAO granulocyte scan an alternative to endoscopy in pediatric chronic inflammatory bowel disease (IBD)?

Although endoscopy with biopsy is the gold standard for the diagnosis of inflammatory bowel disease (IBD), this procedure is invasive and its repetition is stressful, especially in children. The purpose of this study was to evaluate prospectively the role of (99m)Tc-HMPAO-labeled granulocyte scintigraphy in the diagnosis and follow-up of pediatric IBD and its possible use as an alternative to colonoscopy to determine the disease extent and severity beyond its ability to differentiate ulcerative colitis from Crohn's disease. During a 10-year period, 52 children, aging between 2 and 17 years (median, 11.09 years), were subjected to (99m)Tc-HMPAO granulocyte scan 7-28 days from conventional diagnostic tests, and the results were compared with endoscopic and bioptic results. Disease severity was graded by the focal uptake intensity versus iliac bone uptake (Scan Activity Index) and compared with Endoscopy Mayo Score. In 15 out of 16 patients, IBD diagnosis was obtained with a full correspondence of location and severity of lesions, respectively, in 14 out of 16 and 13 out of 16, while in 31 out of 36 patients, IBD was correctly excluded (sensitivity of 93.7%, specificity of 86.1%, and negative predictive value of 96.4%). During the follow-up, all relapses (24) and remissions (13) were correctly recognized (sensibility and specificity of 100%). In conclusion, (99m)Tc-HMPAO granulocyte scan is an accurate minimally invasive technique with very good accuracy, able to diagnose and to grade the intensity and extent of the disease; it is also a useful tool in the follow-up of pediatric IBD where it could reliably replace the invasive endoscopic assessment in most cases.

Cerebral blood flow changes during chanting meditation.

PURPOSE: To examine changes in brain physiology during a chanting meditation practice using cerebral blood flow single-photon emission computed tomography. METHODS: Single-photon emission computed tomography scans were acquired in 11 healthy individuals during either a resting state or meditation practice randomly performed on two separate days. Statistical parametric mapping analyses were conducted to identify significant changes in regional cerebral blood flow (rCBF) between the two conditions. RESULTS: When the meditation state was compared with the baseline condition, significant rCBF increases were observed in the right temporal lobe and posterior cingulate gyrus, and significant rCBF decreases were observed in the left parietotemporal and occipital gyri. CONCLUSION: The results offer evidence that this form of meditation practice is associated with changes in brain function in a way that is consistent with earlier studies of related types of meditation as well as with the positive clinical outcomes anecdotally reported by its users.

Stability of stabilized 99mTc-D,L-HMPAO stored in vials and syringes.

UNLABELLED: Our objective was to determine the stability of stabilized (99m)Tc-hexamethylpropylene amine oxime ((99m)Tc-d,l-HMPAO) dispensed by vial and syringe, with the storage time and labeling activity varied. METHODS: (99m)Tc-d,l-HMPAO was labeled according to the manufacturer's instructions, but with modification of the (99m)TcO(4)Na activity. Two groups were prepared: 1,110 MBq (30 mCi) and 2,600-3,700 MBq (70.3-100 mCi). Five minutes after labeling, the radiochemical purity (RCP) of the vial content was determined. Afterward, the same activity was distributed into two 2-mL syringes and into the manufacturer's vial. In one of the syringes, the radiopharmaceutical stayed in contact with the needle for 4 h. At 2 and 4 h after labeling, the RCP of the vial and syringe content was checked and compared. RESULTS: The mean RCP of stabilized (99m)Tc-d,l-HMPAO labeled with 1,110 MBq (30 mCi) and stored in a vial decreased from 93.1% at 5 min to 92.1% at 2 h and to 91.1% at 4 h. With storage in a syringe, the RCP decreased from 89.8% at 2 h to 88.7% at 4 h. This diminution increased for labeling with higher activities (2,600-3,700 MBq [70.3-100 mCi]), ranging from 91.4% at 5 min, 89.0% at 2 h, and 85.3% at 4 h in a vial and from 85.9% at 2 h to 80.2% in a syringe. (99m)TcO(2) and secondary (99m)Tc-HMPAO were the main impurities at t = 0. (99m)TcO(4)(-) was an impurity that increased with time in both vials and syringes but significantly so in syringes. All these impurities were higher with labeling activities in the range of 2,600-3,700 MBq (70.3-100 mCi). Contact of the needle with (99m)Tc-d,l-HMPAO sharply decreased the RCP to 57.1% at 4 h. CONCLUSION: The RCP of stabilized (99m)Tc-d,l-HMPAO decreases significantly in both vials and syringes with high labeling activities. The product is less stable when stored in a syringe than in a vial. The fraction of dose in contact with the needle affects the RCP results.

Measurement of regional cerebral blood flow associated with the M technique-light massage therapy: a case series and longitudinal study using SPECT.

OBJECTIVES: The aim of this 2-study research project was to measure the physiologic effect of the M technique (see Appendix for description) on the brain using single photon emission computed tomography (SPECT) and compare it to conventional massage therapy. METHODS: In the first study, 4 participants received 1 M technique session. Each participant was injected through the intravenous cannula (IV) with 7 mCi (99m)Tc and scanned using SPECT before the M technique session, and then was injected with 25 mCi (99m)Tc through the IV and scanned using SPECT after the M technique session. In the second study, 1 participant received 10 conventional (Swedish) massages and one participant received 10 M technique sessions. Both participants were injected and scanned (using the identical scanning parameters as in Study 1) before, and immediately after, their 1st and 10th sessions. Baseline and 1st, and baseline and 10th sessions were compared using paired t tests. RESULTS: Although the activation changes were positively correlated for the M technique and massage participants (r = 27, p < 0.05), when activation changes around the 1st and around the 10th sessions were compared (using paired t tests), significant differences emerged. There were significant activation changes for the M technique participant [t(64) = 2.32, p < 0.05): In particular, there was a 40% activation change and directional change in regional cerebral blood flow in the right caudate, which was not seen in the massage participant. The precuneus showed an approximate 15% reduction in activation changes around the M technique session for both the 1st and 10th treatment, but not for the massage participant. CONCLUSIONS: These findings suggest that the M technique and conventional massage may both elicit blood flow brain activation changes; however, the participants' responses did differ. The M technique revealed greater changes (particular in the right caudate), and these responses increased when the M technique was repeated over time (unlike massage). These findings have implications for future research into the potential mechanism of the M technique in the treatment and care of patients.

Mitochondrial function is related to alterations at brain SPECT in depressed patients.

INTRODUCTION: 99mTc-d,l-hexamethylpropylene amine oxime (99mTc-HMPAO) retention in brain is proportional to cerebral blood flow and related to both the local hemodynamic state and to the cellular content of reduced glutathione. Alterations of the regional distribution of 99mTc-HMPAO retention, with discrepant results, have been reported at functional brain imaging of unipolar depression. Since mitochondrial involvement has been reported in depressed patients, the aim of the study was to explore whether the 99mTc-HMPAO retention at single-photon emission computed tomography in depressed patients may relate to different levels of mitochondrial function. METHODS: All patients had audiological and muscular symptoms, somatic symptoms that are common in depression. Citrate synthase (CS) activity assessed in muscle mitochondria correlated strongly with the activities of three mitochondrial respiratory chain enzymes and was used as a marker of mitochondrial function. K-means clustering performed on CS grouped eight patients with low and 11 patients with normal CS. Voxel-based analysis was performed on the two groups by statistical parametric mapping. RESULTS: Voxel-based analysis showed significantly higher 99mTc-HMPAO retention in the patients with low CS compared with the patients with normal CS in the posterior and inferior frontal cortex, the superior and posterior temporal cortex, the somato-sensory cortex, and the associative parietal cortex. CONCLUSION: Low muscle CS in depressed patients is related to higher regional 99mTc-HMPAO retention that may reflect cerebrovascular adaptation to impaired intracellular metabolism and/or intracellular enzymatic changes, as previously reported in mitochondrial disorder. Mitochondrial dysfunction in varying proportions of the subjects may explain some of the discrepant results for 99mTc-HMPAO retention in depression.

Increased regional cerebral perfusion in contralateral motor and somatosensory areas after median nerve stimulation therapy.

OBJECTIVE: To evaluate change in regional cerebral perfusion (rCBF) after median nerve stimulation (MNS) therapy in brain-damaged patients. METHODS: Twelve brain-damaged patients received 12 courses of MNS. Technetium-99m-ethyl cysteinate diethylester (99mTc-ECD) SPECT was performed before and 4 weeks after MNS initiation. Clinical response was assessed by Glasglow coma scale or clinical improvement. 12 MNS patients were grouped as good responder (GR) (n = 6) and poor responder (PR) (n = 6) according to therapy response. Scan images were analyzed by Statistical Parametric Mapping 2 (SPM2). RESULTS: In the GR group, paired Student t test between the pre- and post-MNS images showed 2 activation clusters over the left frontal and parietal lobes, including regions of the precentral gyrus, middle frontal gyrus, superior frontal gyrus, subgyral, inferior parietal lobule, and postcentral gyms (corresponding to Brodmann areas 4, 6, and 40). In the PR group, paired Student t test did not show any activation clusters. Clusters with significant differences between the GR and PR groups shared no mutual voxels with those clusters having significant regional effects after MNS in the GR group. CONCLUSIONS: Median nerve stimulation enhanced the rCBF of the contralateral motor and somatosensory cortex, which is compatible with the few previous studies using other modalities.

Effects of EMDR psychotherapy on 99mTc-HMPAO distribution in occupation-related post-traumatic stress disorder.

BACKGROUND: Post-traumatic stress disorder (PTSD) is a derangement of mood control with involuntary, emotionally fraught recollections that may follow deep psychological trauma in susceptible individuals. This condition is treated with pharmacological and/or cognitive therapies as well as psychotherapy with eye movement desensitization and reprocessing (EMDR). However, only a very limited number of studies have been published dealing with work-related PTSD, and investigations on the effect of treatment on cerebral blood flow represent an even smaller number. AIM: To investigate the short-term outcome of occupation-related PTSD after EMDR therapy by 99mTc-HMPAO SPECT. METHOD: Fifteen patients, either train drivers suffering from PTSD after having been unintentionally responsible for a person-under-train accident or employees assaulted in the course of duty, were recruited for the study. 99mTc-HMPAO SPECT was performed on these patients both before and after EMDR therapy while they listened to a script portraying the traumatic event. Tracer distribution analysis was then carried out at volume of interest (VOI) level using a three-dimensional standardized brain atlas, and at voxel level by SPM. The CBF data of the 15 patients were compared before and after treatment as well as with those of a group of 27 controls who had been exposed to the same psychological traumas without developing PTSD. RESULTS: At VOI analysis significant CBF distribution differences were found between controls and patients before and after treatment (P=0.023 and P=0.0039, respectively). Eleven of the 15 patients responded to treatment, i.e., following EMDR they no longer fulfilled the DSM-IV criteria for PTSD. When comparing only the eleven responders with the controls, the significant group difference found before EMDR (P=0.019) disappeared after treatment. Responders and non-responders showed after therapy significant regional differences in frontal, parieto-occipital and visual cortex and in hippocampus. SPM analysis showed significant uptake differences between patients and controls in the orbitofrontal cortex (Brodmann 11) and the temporal pole (Brodmann 38) both before and after treatment. A significant tracer distribution difference present before treatment in the uncus (Brodmann 36) disappeared after treatment, while a significant difference appeared in the lateral temporal lobe (Brodmann 21). CONCLUSION: Significant 99mTc-HMPAO uptake regional differences were found, mainly in the peri-limbic cortex, between PTSD patients and controls exposed to trauma but not developing PTSD. Tracer uptake differences between responders and patients not responding to EMDR were found after treatment suggesting a trend towards normalization of tracer distribution after successful therapy. These findings in occupational related PTSD are consistent with previously described effects of psychotherapy on anxiety disorders.

Decreased cerebral blood flow of thalamus in PTSD patients as a strategy to reduce re-experience symptoms.

OBJECTIVE: To investigate alterations of regional cerebral blood flow (rCBF) in subjects with post-traumatic stress disorder (PTSD). METHOD: Using [99Tcm]-hexamethyl propylenamino oxime single photon emission computed tomography, the rCBF under resting condition was compared between 19 survivors of the Taegu subway fire with PTSD and 19 comparison subjects. RESULTS: PTSD patients showed a decreased rCBF in the right thalamus and an increased rCBF in the right superior parietal lobe relative to comparison subjects (corrected P < 0.05). The rCBF in the right thalamus positively correlated with the severity of current re-experience symptoms in PTSD subjects. CONCLUSION: Our finding of the thalamic rCBF decrease in PTSD patients may be a strategy to reduce re-experience symptom, by evading the process of external and internal information which can evoke traumatic memory. In addition, the parietal rCBF increase in our PTSD patients might be related to altered information processing in PTSD.

Imaging onset and propagation of ECT-induced seizures.

PURPOSE: Regions of seizure onset and propagation in human generalized tonic-clonic seizures are not well understood. Cerebral blood flow (CBF) measurements with single photon emission computed tomography (SPECT) during electroconvulsive therapy (ECT)-induced seizures provide a unique opportunity to investigate seizure onset and propagation under controlled conditions. METHODS: ECT stimulation induces a typical generalized tonic-clonic seizure, resembling spontaneous generalized seizures in both clinical and electroencephalogram (EEG) manifestations. Patients were divided into two groups based on timing of ictal (during seizure) SPECT tracer injections: 0 s after ECT stimulation (early group), and 30 s after ECT (late group). Statistical parametric mapping (SPM) was used to determine regions of significant CBF changes between ictal and interictal scans on a voxel-by-voxel basis. RESULTS: In the early injection group, we saw increases near the regions of the bitemporal stimulating electrodes as well as some thalamic and basal ganglia activation. With late injections, we observed increases mainly in the parietal and occipital lobes, regions that were quiescent 30 s prior. Significant decreases occurred only at the later injection time, and these were localized to the bilateral cingulate gyrus and left dorsolateral frontal cortex. CONCLUSIONS: Activations in distinct regions at the two time points, as well as sparing of intermediary brain structures, suggest that ECT-induced seizures propagate from the site of initiation to other specific brain regions. Further work will be needed to determine if this propagation occurs through cortical-cortical or cortico-thalamo-cortical networks. A better understanding of seizure propagation mechanisms may lead to improved treatments aimed at preventing seizure generalization.

Differences of Tc-99m HMPAO SPECT Imaging in the Early Stage of Subcortical Vascular Dementia Compared with Alzheimer's Disease / 핵의학분자영상

PURPOSE: The aim of this study is to assess the specific patterns of regional cerebral blood flow (rCBF) in patients with the early stage of subcortical vascular dementia (SVaD) and Alzheimer's disease (AD) using Tc-99m HMPAO SPECT, and to compare the differences between the two conditions. MATERIALS AND METHODS: Sixteen SVaD, 46 AD and 12 control subjects participated in this study. We included the patients with SVaD and AD according to NINCDS-ADRDA and NINDS-AIREN criteria. They were all matched for age, education and clinical dementia rating scores. Three groups were evaluated by Tc-99m HMPAO SPECT using statistical parametric mapping (SPM) for measuring rCBF. The SPECT data of patients with SVaD and AD were compared with those of normal control subjects and then compared with each other. RESULTS: SPM analysis of the SPECT image showed significant perfusion deficits on the right temporal region and thalamus, left insula and superior temporal gyrus, both cingulate gyri and frontal subgyri in patients with SVaD and on the left supramarginal gyrus, superior temporal gyrus, postcentral gyrus and inferior parietal lobule, right fugiform gyrus and both cingulate gyri in AD compared with control subjects (uncorrected p<0.01). SVaD patients revealed significant hypoperfusion in the right parahippocampal gyrus with cingulated gyrus, left insula and both frontal subgyral regions compared with AD (uncorrected p<0.01). CONCLUSION: Our study shows characteristic and different pattern of perfusion deficits in patients with SVaD and AD, and these results may be helpful to discriminate the two conditions in the early stage of illness.

A tracer dose of technetium-99m-labeled liposomes can estimate the effect of hyperthermia on intratumoral doxil extravasation.

PURPOSE: A noninvasive method to monitor intratumoral Doxil delivery in individual patients during targeted tumor therapy is important to predict treatment response. The purpose of this study was to determine if a small tracer dose of technetium-99m (99mTc)-labeled liposomes could be used to quantify the effect of local hyperthermia on intratumoral Doxil extravasation. EXPERIMENTAL DESIGN: Experiments were carried out in a rat fibrosarcoma model with transplanted thigh tumors. Liposomes of approximately same size and composition as Doxil were radiolabeled using [technetium-99m (99mTc)]exametazime. Eight treatment groups received either Doxil, a tracer dose or a large dose of 99mTc-labeled liposomes, or a combination of tracer and Doxil, with or without hyperthermia. This design was chosen to assure that coadministration of both liposomal formulations did not influence their intratumoral distribution. Hyperthermia was done for 45 minutes. Scintigraphic images were obtained at 5 and 18 hours. At 18 hours, tumors were removed and gamma counts as well as doxorubicin concentrations were measured. RESULTS: Intratumoral extravasation of the 99mTc-labeled tracer could be imaged scintigraphically under normothermic and hyperthermic conditions. The thermal enhancement ratio was slightly higher for radiolabeled liposomes than for doxorubicin concentration. However, there was a significant positive correlation of intratumoral doxorubicin concentration and intratumoral uptake of the radiolabeled tracer (expressed as percentage of the injected dose per gram of tissue). Coadministration of radiolabeled liposomes did not negatively influence the amount of drug delivered with Doxil. CONCLUSIONS: The use of a radiolabeled tracer has potential value to monitor drug delivery and estimate the effect of an intervention aimed to increase liposomal accumulation, such as local hyperthermia.

Alteration of regional cerebral blood flow in patients with chronic pain--evaluation before and after epidural spinal cord stimulation.

BACKGROUND: Chronic pain is defined as intractable pain caused by abnormal pain transmission or impairment of the pain control system per se. Alteration of regional cerebral blood flow (rCBF) is known to occur under the presence of pain stimulation. Epidural spinal cord stimulation (SCS) is occasionally effective in relieving the symptom. OBJECTIVE: The aim of the current study is to investigate the alteration of rCBF in baseline condition and to find the association between the rCBF change and the efficacy of SCS in chronic pain. METHODS: A total of 18 patients underwent Tc-99m-HMPAO SPECT before and after SCS. Analysis with three-dimensional stereo-tactic surface projections (3D-SSP) with stereo-tactic extraction estimation (SEE) software was adopted to evaluate the rCBF. We assessed the extent score of the abnormal region in each segment (rate of the coordinates with a Z-value that exceeds three kinds of threshold value 2.0, 2.5 and 3.0 in all coordinates within a segment). According to the therapeutic response defined by visual analogue scale, we categorized patients into two groups, the good responder (GR) group (n=12) and poor responder (PR) group (n=6). In the analysis, we compared the extent score in the following two conditions. (1) Comparison between the PR group and normal control group under both baseline condition and after SCS. (2) Comparison between the GR group and normal control group under both baseline condition and after SCS. RESULTS: (1) In the PR group, increased rCBF was observed in left thalamus, bilateral precuneus and bilateral cerebellum under the baseline condition. After SCS, the range of these increased rCBF areas localized but remained. Decrease of rCBF was noted in bilateral subcallosal gyrus, superior temporal gyrus (STG) and bilateral anterior cingulate gyrus (ACG). They localized after SCS, but remained. (2) In the GR group, increased rCBF areas were noted in bilateral precuneus and bilateral cerebellum under the baseline condition. After SCS, they localized in bilateral precuneus but those of bilateral cerebellum remained. Decreased rCBF area was noted in bilateral subcallosal gyrus, STG and bilateral ACG under the baseline. After SCS, they localized in bilateral subcallosal gyrus and bilateral STG. In contrast, they enlarged in bilateral ACG. CONCLUSION: Chronic pain patients demonstrated abnormal rCBF distribution on both baseline and post SCS conditions. Increased rCBF of thalamus and precuneus under both conditions in the PR group and decreased rCBF of ACG under post SCS conditions in the GR group were characteristic patterns. Tc-99m-HMPAO SPECT with 3D-SSP and SEE analysis is likely objective and effective in monitoring and evaluating therapeutic outcome by SCS in chronic pain. In addition, it provides information that is useful in the selection of SCS candidates.

SPECT findings in children with specific language impairment.

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.

Cerebral blood flow effects of pain and acupuncture: a preliminary single-photon emission computed tomography imaging study.

BACKGROUND: The purpose of this study was to investigate the cerebral blood flow changes associated with the analgesic effect of acupuncture in patients with chronic pain. METHODS: Seven patients presenting with a chronic pain syndrome and 5 healthy controls were included. All single-photon emission computed tomography (SPECT) scans were acquired with a uniform protocol. The patient group was injected with the radioisotope hexamethyl propyleneamine oxime (HMPAO) while experiencing their usual level of pain. A baseline scan was acquired approximately 20 minutes after administration of the HMPAO. The patient then underwent acupuncture therapy with needles placed in points specifically selected to relieve pain. When the pain improved, as determined by a 10-digit score for pain assessment, the patient was reinjected with HMPAO and imaged 20 minutes later for the acupuncture scan. The reference group also had a baseline and acupuncture scan, although the acupuncture itself was performed using a standardized set of needle points. RESULTS: The reference group participants were found to have significant increases in the thalamic and prefrontal cortex activity on the acupuncture scan compared to the baseline. The baseline scans of the pain patients showed significant asymmetric uptake in the thalami compared to controls. This asymmetry reversed or normalized after the acupuncture therapy. Significant correlations were observed between the change of activity in the prefrontal cortex and ipsilateral sensorimotor area. CONCLUSION: The results from these cases show that HMPAO-SPECT is capable of detecting changes in cerebral blood flow associated with pain and that acupuncture analgesia is associated with changes in the activity of the frontal lobes, brain stem, and thalami.

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.

Single photon emission computed tomography in posttraumatic stress disorder before and after treatment with a selective serotonin reuptake inhibitor.

BACKGROUND: Posttraumatic stress disorder (PTSD) is recognized as a disorder mediated by specific neurobiological circuits. Functional imaging studies using script-driven trauma imagery and pharmacological challenges have documented altered cerebral function (activation and deactivation) in several brain regions, including the amygdala, hippocampus, prefrontal cortex and anterior cingulate. However, the neural substrates of PTSD remain poorly understood and the effect of selective serotonin reuptake inhibition on regional cerebral activity is deserving of further investigation. METHODS: Eleven adult patients (seven men, four women) (mean age+S.D.=33.6+/-9.2 years) with a DSM-IV diagnosis of PTSD, as determined by the Structured Clinical Interview for DSM-IV (SCID-I) and the Clinician-Administered PTSD Scale (CAPS), underwent single photon emission computed tomography (SPECT) with Tc-99m HMPAO pre- and post-8 weeks of treatment with the selective serotonin reuptake inhibitor, citalopram. Symptoms were assessed at baseline and at 2-week intervals with the Clinician-Administered PTSD Scale (CAPS), Montgomery-Asberg Depression Rating Scale (MADRS), and the Clinical Global Impression Scale (CGI). Image analysis of baseline and post-treatment scans was performed using Statistical Parametric Mapping (SPM). RESULTS: Treatment with citalopram resulted in significant deactivation in the left medial temporal cortex irrespective of clinical response. On covariate analysis, a significant correlation between CAPS score reduction and activation in the left paracingulate region (medial prefrontal cortex) was observed post-treatment. No significant pre-treatment differences were observed between responders and non-responders in anterior cingulate perfusion. CONCLUSIONS: These preliminary findings are consistent with clinical data indicating temporal and prefrontal cortical dysfunction in PTSD and preclinical data demonstrating serotonergic innervation of these regions. However, further studies, in particular in vivo receptor imaging studies, are needed to confirm whether these regional abnormalities correlate with clinical features and treatment response.