• The Korean Journal of Nuclear Medicine
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• v.36 no.2
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• pp.91-101
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• 2002

Purpose : The aim of this study was to identify the brain areas in which reductions of regional cerebral blood flow (rCBF) were correlated with decline of general mental function, measured by Mini-Mental State Examination (MMSE). Materials and Methods : Tc-99m HMPAO brain SPECT was peformed in 9 probable AD patients at the initial and follow-up periods of 1.8 years (average) after the first study. MMSE scores were also measured in both occasions. The mean MMSE score of the initial study 16.4 (range: 5 - 24) and the mean MMSE score of the follow-up was 8.1 (range: 0 - 17). Each SPECT image was normalized to the cerebellar activity and a correlation analysis was peformed between the level of rCBF in AD patients and the MMSE scores by voxel-based analysis using SPM99 software. Results : Significant correlation was found between the blood-flow decrease in left inferior prefrontal region (BA 47) and left middle temporal legion (BA 21) and the MMSE score changes. Additional areas such as anterior and posterior cingulate cortices, precuneus, and bilateral superior and middle prefrontal regions showed the similar trends. Conclusions : A relationship was found between reduction of regional cerebral blood flow in left prefrontal and temporal areas and decline of cognitive function in Alzheimer's disease(AD) patients. This voxel-based analysis is useful in evaluating the progress of cognitive function in Alzheimer's disease.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.23-32
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• 2001

Purpose: Cortical dysplasia (CD) designates a diverse group of malformations resulting from one or more abnormalities in the development of the cerebral cortex. We investigated the findings of interictal SPECT and the diagnostic usefulness of interical and ictal SFECT according to pathological grading (PG) in comparison with MRI. Materials and Methods: This study included 16 patients (M:F=9:7, age: $19.9{\pm}11.8$ yrs) with pathologically proven CD. Tc-99m ECD SPECT was performed in all patients: interictal 11, interictal and ictal 3, ictal 2. MRI were obtained in all patients and image analysis was done blindly as to the result of SPECT. Pathologic findings of CD were classified into grade 1 G1, dyslamination), grade 2 (G2, dysplastic neurons) and grade 3 (G3, balloon cells). We compared SFECT with MRI in lesions-to-lesions and analyzed the result according to PG. Results: In SFECT and MRI. 38 and 27 lesions were visually recognized. In 14 interictal SPECT, variable findings in 35 lesions were demonstrated: 25 were hypoperfusion, 7 hyperperfusion, 2 heterotopic perfusion in the white matter. By comparison between two studios, missed lesions were founded: SPECT were 1 lesion, MRI 12. Review of missed 12 lesions of MRI were followed according to PG: G1 patients were 16.7% (4/19), G2 40.0% (6/15), and G3 50% (2/4). Conclusion: Interictal SFECT in CD showed variable findings such as hypoperfusion, hyperperfusion or heterotopic perfusion. However, for detection of missed CD on MRI, SFECT may help to detect a functional abnormality of the lesion with high PG.

• The Korean Journal of Nuclear Medicine
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• v.34 no.6
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• pp.445-455
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• 2000

Purpose: We evaluated the distribution of hypoperfusion in patients with traumatic brain injury (TBI) and the relationship of thalamic hypoperfusion to severity of cognitive and behavioral sequelae. Materials and Methods: Tc-99m ECD SPECT and MRI were performed in 103 patients (M/F=81/22, mean age $34.7{\pm}15.4$ yrs) from 0.5 to 55 months (mean 10.3 months) after TBI. The patients were divided into three groups showing no abnormalities (G1), focal (G2) and diffuse injury (G3) on MRI. Psychometric tests assessed 11 cognitive or behavioral items. In all patients, we evaluated the distribution of hypoperfused areas in SPECT, and in 57/103 patients, neuropsychological (NP) abnormalities in patients with thalamic hypoperfusion were compared with those of patients without thalamic hypoperfusion. Results: The perfusion deficits were most frequently located in the frontal lobe (G1, 42.3%: G2 34.5%: G3 33.3%), temporal lobe ($24{\sim}26%$) thalami ($21{\sim}22.4%$), parietal and occipital lobe (${\leq}10%$). Numbers of NP abnormalities in the cases of cortical hypoperfusion with or without concomitant thalamic hypoperfusion were following: the former $4.7{\pm}1.5$ and the latter $3.2{\pm}1.4\;in\;G1,\;5.0{\pm}1.1\;and\;4.8{\pm}1.2\;in\;G2,\;6.8{\pm}1.8\;and\;6.3{\pm}1.1\;in\;G3$, respectively. This difference according to thalamic hypoperfusion was significant in G1 (p=0.002), but was not significant in G2 or G3. Conclusion: SPECT in patients with TBI had demonstrated hypoperfusion mostly involving the frontal, temporal and thalami. In normal group on MRI, frontal hypoperfusion was more prominent than that of any other group, Furthermore in this group, SPECT could predict severity of NP outcome by concomitant thalamic hypoperfusion with cerebral cortical abnormalities.

• The Korean Journal of Nuclear Medicine
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• v.36 no.6
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• pp.357-367
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• 2002

Purpose: While cerebral blood flow and cerebrovascular reserve could be evaluated with basal/acetazolamide Tc-99m-HMPAO SPECT in cerebrovascular disease, objective quantification is necessary to assess the efficacy of the revascularization. In this study we adopted the SPM method to quantify basal cerebral blood flow and cerebrovascular reserve on basal/acetazolamide SPECT in assessment of the patients who underwent bypass surgery for linternal carotid artery (ICA) stenosis. Materials and Methods: Twelve patients ($51{\pm}15$ years) with ICA stenosis were enrolled. Tc-99m-HMPAO basal/acetazolamide perfusion SPECT was peformed before and after bypass surgery. After spatia1 and count normalization to cerebellum, basal cerebral blood flow and cerebrovascular reserve were compared with 21 age-matched normal controls and postoperative changes of regional blood flow and reserve were assessed by Statistical Parametric Mapping method. Mean pixel values of each brain region were calculated using probabilistic anatomical map of lobes. Perfusion reserve was defined as the % changes after acetazolamide over basal counts. Results: Preoperative cerebral blood flow and cerebrovascular reserve were significantly decreased in involved ICA territory, comparing with normal control (p<0.05). Postoperative improvement of cerebral blood flow and cerebrovascular reserve was observed in grafted ICA territories, but cerebrovasculr reserve remained with significant difference with normal control. Improvement of the cerebrovascular reserve was most prominent in the superior temporal and the angular gyrus, nearest to the anastomosis sites. Conclusion: Using SPM quantification method on hasal/acetazolamide Tc-99m-HMPAO SPECT, the cerebral blood flow and cerebrovascular reserve could be assessed before revascularization and so could the efficacy of the bypass surgery.

• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.247-261
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• 1999

Purpose: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO, Materials and Methods: Thirty four right-handed normal volunteers (20 males, 14 females, mean age $40.3{\pm}24.9$ years, range 4 to 82 years) were underwent rost/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in (rental, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Results: Mean values of right to left ratios range from 1.004 to 1.018, rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalamic rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was $29.9{\pm}12.9%$. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Conclusion: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.2
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• pp.107-111
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• 2009

Purpose: The authors analyzed how the regional cerebral blood flow(rCBF) findings of patients with major depression differ from the normal control, and our results were compared to previous reports. Materials and Methods: Twelve patients fulfilling DSM-IV criteria for major depression who were off all psychotropic medications for > 4weeks(male: 7, female: 5, age range: $19{\sim}52$ years, average age: $29.3{\pm}9.9$ years) and 14 normal volunteers(male: 8, female: 6, age range: $19{\sim}53$ years, average age: $31.4{\pm}9.2$ years) were recruited. Images of brain perfusion SPECT were obtained using Tc-99m ECD and patterns of the rCBF were compared between patients with major depression and the healthy control subjects. Results: The patients with major depression showed increase of the r-CBF in right lingual gyrus, right fusiform gyrus, left lingual gyrus, left precuneus, and left superior temporal gyrus, and showed decrease of r-CBF in right pons, left medial frontal gyrus, cingulate gyrus of left limbic lobe, cingulate gyrus of right frontal lobe, and cingulate gyrus of right limbic lobe compared to the normal control. Conclusion: The Tc-99m ECD brain perfusion SPECT findings in our study did not differ from the previously reported regional cerebral blood flow pattern of patients with major depression. Especially, decreased rCBF pattern typical to major depression patients in the right pons, left medial frontal gyrus, and cingulate regions was clearly demonstrated.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.8-16
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• 2008

Purpose: To assess the effect of extracranial-intracranial (EC-IC) bypass surgery on hemodynamic improvement, we evaluated serial regional cerebral hemodynamic change of the middle cerebral artery (MCA) in symptomatic patients with atherosclerotic occlusion of the internal carotid artery (ICA) or MCA using $^{99m}Tc$-ECD acetazolamide stress brain perfusion SPECT (Acetazolamide SPECT). Materials and Methods: The patients who had suffered a recent stroke with atherosclerotic ICA or MCA occlusion underwent EC-IC bypass surgery and Acetazolamide SPECT at 1 week before and three to six months after surgery. For image analysis, attenuation corrected images were spatially normalized to SPECT templates with SPM2. Anatomical automated labeling was applied to calculate mean counts of each Volume-Of-Interest (VOI). Seven VOIs of bilateral frontal, parietal, temporal regions of the MCA territory and the ipsilateral cerebellum were defined. Using mean counts of 7 VOIs, cerebral perfusion index and perfusion reserve index were calculated. Results: Seventeen patients (M:F =12:5, mean age $53{\pm}2yr$) were finally included in the analysis. The cerebral blood flow of the parietal region increased at 1 week (p = 0.003) and decreased to the preoperative level at 3-6 months (p = 0.003). The cerebrovascular reserve of the frontal and parietal regions increased significantly at 1 week after surgery (p<0.01) and improved further at 3-6 months. Conclusion: Cerebrovascular reserve of the MCA territory was significantly improved at early postoperative period after EC-IC bypass and kept improved state during long-term follow-up, although cerebral blood flow did not significantly improved. Therefore, cerebrovascular reserve may be a good indicator of postoperative hemodynamic improvement resulted from bypass effect.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.18 no.1
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• pp.31-37
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• 2007

Objectives : A voxel based investigation of cerebral blood flow was conducted to identify functional differences during resting state between children with early-onset schizophrenia and normal controls. Methods : 19 children and adolescents with early-onset schizophrenia(8 boys and 11 girls, mean age $14.0{\pm}1.7$ years old) and 17 comparison children(13 boys and 4 girls, mean age $11.0{\pm}1.9$ years old) were examined by HMPAO-SPECT. The SPECT images were compared using statistical parametric mapping analyses, controlling for age and sex. Results : Increased cerebral blood flow in left medial and inferior frontal gyrus, right superior and middle frontal gyrus, both inferior temporal gyrus, and right cerebellar tonsil was found in children and adolescents with early-onset schizophrenia compared to control subjects. In addition, decreased cerebral blood flow in right thalamus, left posterior cingulate gyrus, right anterior cingulate gyrus and relatively wide areas from left medical frontal gyrus to superior parietal lobule were found in children and adolescents with early-onset schizophrenia compared to control subjects. Conclusion : The results of the current study provide additional evidences for brain areas involving the onset of schizophrenia in early age.

• The Korean Journal of Nuclear Medicine
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• v.31 no.3
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• pp.330-338
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• 1997

This study investigated the method to adjust acquisition time(a) and injection dose (i) to make the best basal and subtraction images in consecutive SPECT. Image quality was assumed to be mainly affected by signal to noise ratio(S/N). Basal image was subtracted from the second image consecutively acquired at the same position. We calculated S/N ratio in basal SPECT images($S_1/N_1$) and subtraction SPECT images(Ss/Ns) to find a(time) and i(dose) to maximize S/N of both images at the same time. From phantom images, we drew the relation of image counts and a(time) and i(dose) in our system using fanbeam-high-resolution collimated triple head SPECT. Noise by imaging process depended on Poisson distribution. We took maximum tolerable duration of consecutive acquisition as 30 minutes and maximum injectible dose as 1,850MBq(50 mCi)(sum of two injections) per study. Counts of second-acquired image($S_2$), counts($S_s$) and noise($N_s$) of subtraction SPECT were as follows. $C_1$ was the coefficient of measurement with our system. $$S_2=S_1{\cdot}(\frac{30-a}{a})+background{\cdot}(1-\frac{30-a}{a})+C_1{\cdot}(30-a){\cdot}{\epsilon}{\cdot}(50-i)$$ $$Ss=S_2-\{S_1{\cdot}(\frac{30-a}{a})+background{\cdot}(1-\frac{(30-a)}{a})\}$$ $$Ns={\sqrt{N_2^2+N_1^2{\cdot}\frac{(30-a)^2}{a^2}}={\sqrt{S_2+S_1{\cdot}\frac{(30-a)^2}{a^2}}$$ In case of rest/acetazolamide study, effect(${\epsilon}$) of acetazolamide to increase global brain uptake of Tc-99m-HMPAO could be 1.5 or less. Varying ${\epsilon}$ from 1 to 1.5, a(time) and i(dose) pair to maximize both $S_1/N_l$ and Ss/Ns was determined. 15 mCi/17 min and 35mCi/13min was the best a(time) and i(dose) pair for rest/acetazolamide study(when ${\epsilon}$ were 1.2) and came to be used for our clinical routine after this study. We developed simple method to maximize S/N ratios of basal and subtraction SPECT from consecutive acquisition. This method could be applied to ECD/HMPAO and brain activation studies as well as rest/acetazolamide studies.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.24 no.1
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• pp.21-27
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• 2013

Objectives : Dysregulation of the central noradrenergic system may be involved in the pathophysiology of attention-deficit hyperactivity disorder (ADHD). The aim of this study was to examine the differences in pre- and post-treatment cerebral perfusion according to the MspI polymorphisms of the alpha-2A-adrenergic receptor gene (ADRA2A) in children with ADHD. Methods : Thirty seven drug-naive ADHD children (8.9+1.8 years old, M=32, F=5) were genotyped. Baseline single-photon emission computed tomography (SPECT) and clinical assessments were performed for ADHD children. After treatment with methylphenidate for eight weeks, SPECT and clinical assessment were repeated. Results : No differences in baseline clinical assessments or cerebral perfusion were observed according to the MspI genotype. However, after treatment, ADHD children with the G/G genotype at the MspI polymorphism showed hyperperfusion in the right cerebellar declive (p=.001, uncorrected) and hypoperfusion in the left lentiform nucleus and left cingulate gyrus (p<.001 and p=.001, uncorrected), compared to children without the G/G genotype. Conclusion : Although the results of this study should be interpreted cautiously, they suggest a possible role of the MspI polymorphisms of the ADRA2A gene in methylphenidate-induced changes in cerebral perfusion.