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June-Key Chung

Publications and source records attributed to June-Key Chung.

At least 55 records · Page 3Linked to original sources
PubMed2004

Differentiation of mediastinal FDG uptake observed in patients with non-thoracic tumours.

In regions with a high prevalence of granulomatous diseases, benign inflammatory fluorine-18 fluorodeoxyglucose (FDG) uptake in the mediastinum is frequently observed even in healthy subjects. We examined parameters of mediastinal FDG uptake to determine whether they can differentiate malignancy from benign lesions. Seventy patients with non-thoracic tumours who had mediastinal uptake on FDG positron emission tomography (PET) were included (33 males, 37 females; age 57.5 +/- 16.9 years; 168 lymph nodes). Determination of metastasis was confirmed by biopsy or computed tomography (CT) follow-up over 12 months (metastasis, 29; benign lesions, 41). No significant difference between the metastasis group and the benign group was found in terms of residual disease in the primary site (48% vs 46%), lung invasion (29% vs 20%), number of sites of uptake (2.3 vs 2.4), smoking history (30.3% vs 46.3%) or bilateral uptake (52% vs 54%). Maximal standardised uptake values (SUVs) in the mediastinal metastasis group were higher (4.9 +/- 1.8) than those in the benign group (2.5 +/- 0.9) (P < 0.05). Using 3.4 as a cut-off value for maximal SUV, a sensitivity of 86% and a specificity of 85% were achieved (AUC = 0.917). Maximal SUV showed better predictive value than lymph node size measured on chest CT (P < 0.05). In 8 of 51 normal subjects who underwent FDG PET as a routine check-up, mediastinal FDG uptake was observed. Maximal SUV in normal subjects was 2.5 +/- 0.8, which was similar to that in the benign group. In conclusion, maximal SUV was identified as a significant parameter for determining whether mediastinal FDG uptake represents malignant metastasis. When maximal SUV exceeded 3.4, the metastasis rate was high regardless of lymph node size.

Adult↗
PubMed2004

Rapid synthesis of [18F]FDG without an evaporation step using an ionic liquid.

In this study, we describe a new 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG) synthesis without a distillation step. This involves fluorinating in an ionic liquid-containing medium. A test for the effective elution of [18F]fluoride from the anion exchange resin showed the proper selection of the base and the required eluant composition, which is an essential requirement for the automation of [18F]FDG synthesis. An 18F-labeling study by nucleophilic substitution showed that the major factors controlling the yield were the temperature and the reaction medium composition. The 18F-fluorination proceeded with a labeling efficiency of 74.6+/-7.4% (n=8) for optimized conditions. Alkaline hydrolysis and purification carried out in the liquid phase provided a final decay-corrected [18F]FDG yield of 59.1+/-5.1% (n=3), a radiochemical purity of 91.9+/-3.7% (n=3), and a reaction time of 13 min. Alkaline hydrolysis and purification carried out in the solid phase provided a final decay-corrected [18F]FDG yield of 48.8+/-6.0% (n=3), a radiochemical purity of 96.0+/-4% (n=3), and a reaction time of 19 min. The rapid and straightforward synthesis of [18F]FDG can be achieved by eliminating all evaporation steps, which is made possible by the use of ionic liquid-containing media for the fluorination step.

Chromatography, Ion Exchange↗
PubMed2004

Probabilistic map of blood flow distribution in the brain from the internal carotid artery.

Brain single photon emission computed tomographic (SPECT) images acquired after injecting Tc-99m-HMPAO into the internal carotid artery (ICA) during an intracarotid amobarbital procedure (IAP SPECT) provide anatomical information on the blood flow distribution from the ICA. In this study, probabilistic maps of the distribution of blood supply from the ICA were developed using the IAP SPECT images. Twenty-two sets of basal and IAP SPECT were collected from an existing database. IAP SPECT images were coregistered to basal SPECT images, and spatial normalization parameters used for basal SPECT images were reapplied to IAP SPECT for anatomical standardization. Pixel counts of IAP SPECT images were then normalized, and the probabilistic map of cerebral perfusion distribution (perfusion probabilistic map) for each hemisphere was determined by averaging the spatial/count-normalized IAP SPECT images. Population-based probabilistic maps representing the extent of ICA territory (extent probabilistic map) were also composed by averaging the binary images obtained by thresholding the spatially normalized IAP SPECT images. The probabilistic maps were used to quantify cerebral perfusion and reserve change after arterial bypass surgery in 10 patients with ICA stenosis. In the probabilistic maps, blood supply from the ICA was found to be most likely in the dorsolateral frontal lobe, the anterosuperior portion of the temporal lobe, and in the frontoparietal area. Of the subcortical regions, the striatum was found to be most likely to derive its blood supply from ICA. In patients with cerebral occlusive disease, improvements in basal perfusion and perfusion reserve in the bypass-grafted ICA territory were well identified and were increased by 6.2% and 4.6%, respectively, on average. The probabilistic maps developed in this study illustrate the perfusion distribution and extent of vascular territory for ICA and would be useful for objective evaluations of perfusion status in cerebrovascular disease.

Adolescent↗
PubMed2004

In vitro and in vivo properties of a human anaplastic thyroid carcinoma cell line transfected with the sodium iodide symporter gene.

To evaluate the feasibility of radionuclide gene therapy, we investigated the effect of sodium iodide symporter (NIS) gene transfection on the uptake of some beta- and gamma-emitters in human anaplastic thyroid cancer. NIS gene was transfected into human anaplastic cancer ARO cells using liposome (ARO-N) and its expression was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR). Iodide uptake by ARO-N was 109 times higher than by ARO, and 99mTc and 188Re uptake by ARO-N were 21 and 47 times higher than by ARO, respectively. The half-lives of radionuclides (125I, 99mTc, and 188Re) retention in the cells were about 12, 3 and 4 min, respectively. Biodistribution studies showed that ARO-N tumors accumulated higher amounts of radionuclides than ARO tumors. The mean accumulations of 125I, 99mTc, and 188Re in ARO-N tumors were 18.3 +/- 8.7, 14.6 +/- 7.1 and 23.2 +/- 3.5% injected dose per gram (ID/g) at 2 hours postinjection, respectively. Scintigraphic images of tumor bearing mice using 131I, 99mTc, and 188Re allowed clear visualization of ARO-N tumors. In summary, NIS gene transfection to a single anaplastic thyroid cancer cell line efficiently triggered high tumor uptake of radioiodines, 99mTc and 188Re. These results demonstrate the possibility of imaging and therapy using NIS gene transfection in anaplastic thyroid carcinoma, although the short retention time is considered the major impediment to be resolved for the successful implementation.

Animals↗
PubMed2004

Development of 99mTc-neomannosyl human serum albumin (99mTc-MSA) as a novel receptor binding agent for sentinel lymph node imaging.

BACKGROUND AND AIM: Various mannose receptor-binding agents, for example 99mTc-diethylenetriaminepentaacetic acid (DTPA)-mannosyl-polymer, have been developed for sentinel lymph node (SLN) imaging. In order to simplify the synthesis and labelling procedure and to improve the biological properties, we developed a novel mannose receptor-binding agent, 99mTc-neomannosyl human serum albumin (99mTc-MSA), for SLN imaging. METHODS: MSA was synthesized by conjugating mannopyranosylphenylisothiocyanate to human serum albumin (HSA). After reducing MSA with beta-mercaptoethanol and PD-10 column purification, a medronate solution containing stannous fluoride was added, divided into aliquots and freeze-dried. Reduced MSA was labelled with 99mTc-pertechnetate solution. The stability was checked for 24 h at 37 degrees C in human serum. The biodistribution of 99mTc-MSA in mice was investigated by intravenous injection through the tail vein and subcutaneous injection into the foot pad. The biodistributions of 99mTc-HSA and 99mTc-antimony sulphur colloid (99mTc-ASC) were also investigated for comparison. Dynamic whole-body images were obtained for 30 min after subcutaneous injection into the rats' foot pads. RESULTS: The number of mannose molecules conjugated per MSA was 15.9. The number of thiol groups produced was 19.4 per MSA after reduction with beta-mercaptoethanol. Labelling yields were always higher than 97%. 99mTc-MSA was stable for 24 h at 37 degrees C in human serum. The biodistribution in mice after intravenous injection showed high liver uptake (50.7+/-5.5% and 42.7+/-3.7% injected dose per gram at 10 and 60 min, respectively). 99mTc-MSA and 99mTc-ASC showed high accumulation in the lymph nodes after subcutaneous injection, whereas 99mTc-HSA and Tc-tin colloid did not, in both biodistribution and imaging studies. CONCLUSIONS: We have successfully developed a novel 99mTc-MSA for lymphoscintigraphy. The results of animal studies show that 99mTc-MSA has promising properties for SLN imaging.

Animals↗
PubMed2004

In vivo imaging of retinoic acid receptor activity using a sodium/iodide symporter and luciferase dual imaging reporter gene.

Retinoic acids are natural derivatives of vitamin A, and play important roles in modulating tumor cell growth by regulating differentiation, thus suggesting the potential use of these derivatives in cancer therapy and prevention. To visualize the intranuclear responses of functional retinoic acid receptors, we have developed a dual-imaging reporter gene system based on the use of sodium/iodide symporter (NIS) and luciferase in cancer cell lines. NIS and luciferase genes were linked with an internal ribosome entry site, and placed under the control of an artificial cis-acting retinoic acid responsive element (pRARE/NL). After retinoic acid treatment, I-125 uptake by pRARE/NL transfected cells was found to have increased by up to about five times that of nontreated cells. The bioluminescence intensity of pRARE/NL transfected cells showed dose-dependency. In vivo luciferase images showed higher intensity in retinoic acid treated SK-RARE/NL tumors, and scintigraphic images of SK-RARE/NL tumors showed increased Tc-99m uptake after retinoic acid treatment. The NIS/luciferase imaging reporter system was sufficiently sensitive to allow the visualization of intranuclear retinoic acid receptor activity. This cis-enhancer imaging reporter system may be useful in vitro and in vivo for the evaluation of retinoic acid responses in such areas as cellular differentiation and chemoprevention.

Animals↗
PubMed2004

Changes in the heterogeneity of cerebral glucose metabolism with healthy aging: quantitative assessment by fractal analysis.

BACKGROUND AND PURPOSE: It has been shown that heterogeneity of cerebral glucose metabolism is increased in neuropsychiatric degenerative diseases. However, proper assessment of older patients requires knowledge about the effect of aging on heterogeneity. This study characterized the effects of aging on the heterogeneity of the distribution of cerebral glucose metabolism in healthy volunteers. METHODS: Sixty-six healthy volunteers (age range, 19-75 years) underwent flurodeoxyglucose brain positron emission tomography (PET), and all the PET images were spatially normalized onto a previously segmented standard brain template to parcel the brain regions automatically. Fractal dimension was regarded as a quantitative measurement for the heterogeneity of cerebral glucose metabolism and obtained for 9 brain regions. Participants were subdivided into young/midlife and elderly groups, and the Student t test was applied to the comparison of fractal dimensions in those groups. Analysis of covariance was performed for each region to explore the effects of age, gender, age-by-gender interaction, and total counts in the brain on the observed metabolic heterogeneity. RESULTS: Fractal dimensions were higher for elderly volunteers in most brain regions. Differences between the 2 groups in fractal dimension emerged within the whole gray matter, temporal lobe, striatum, and cingulate. No significant gender differences, age-by-gender interactions, or total counts were observed. Significant age effects were observed in the whole gray matter, frontal lobe, temporal lobe, striatum, and cingulate gyrus. CONCLUSIONS: Heterogeneity in the cerebral glucose metabolism of healthy volunteers increased with age, and individual variations of heterogeneity were higher in older volunteers. However, there was no significant difference between male and female volunteers of the same age. The effect of age on heterogeneity was not regionally uniform.

Adult↗
PubMed2004

Efficacy assessment of cerebral arterial bypass surgery using statistical parametric mapping and probabilistic brain atlas on basal/acetazolamide brain perfusion SPECT.

UNLABELLED: The efficacy of cerebral arterial bypass surgery was assessed on brain perfusion SPECT using statistical parametric mapping (SPM) and a probabilistic brain atlas. METHODS: Fifteen patients with ischemia in the internal carotid artery (ICA) territory and 21 age-matched healthy volunteers were enrolled. (99m)Tc-HMPAO basal/acetazolamide brain perfusion SPECT was performed 2 wk before and after bypass surgery and also on a healthy control group. Using SPM analysis, group comparisons were made between pre- and postoperative SPECT for each basal/acetazolamide image, and improvements of perfusion and perfusion reserve were assessed. The number of significant voxels on the SPM analysis was defined as the extent of ischemia. With the use of the probabilistic brain atlas, the counts for the cerebral lobes and the ICA territory were automatically calculated for each image and compared. RESULTS: The group comparisons by SPM between patients and healthy volunteers showed a significant improvement in general perfusion status in the ICA territory. The improvement in perfusion reserve was more extensive than the improvement in perfusion. The extent of ischemia was also significantly decreased after surgery (1,693 +/- 2,604 to 371 +/- 523 voxels in basal images, P = 0.060; 11,879 +/- 6,449 to 5,997 +/- 3,864 voxels in acetazolamide images, P = 0.005). In the analysis using the probabilistic brain atlas, the preoperatively decreased perfusion was normalized after surgery, but a residual decrease in the perfusion reserve was also observed in the ICA territory. The counts in the volume of interest of the ICA territory were significantly improved (38.5 +/- 4.1 to 41.5 +/- 2.7 in basal images, P = 0.024; 34.2 +/- 4.4 to 38.8 +/- 2.9 in acetazolamide images, P = 0.003). One patient showing a decrease in perfusion had a perioperative cerebral infarct. CONCLUSION: Using SPM and a probabilistic brain atlas, the perfusion, the perfusion reserve, and changes in both after cerebral arterial bypass surgery were effectively assessed and correlated well with physiologic reasoning.

Acetazolamide↗
PubMed2004

Establishment of a human hepatocellular carcinoma cell line highly expressing sodium iodide symporter for radionuclide gene therapy.

UNLABELLED: To evaluate the possibility of radionuclide gene therapy and imaging in hepatocellular carcinoma cancer, we investigated the iodine accumulation of a human hepatocellular carcinoma cell line, SK-Hep1, by transfer of human sodium iodide symporter (hNIS) gene. By targeting NIS expression in SK-Hep1, we could also investigate whether these cells concentrate 99mTc-pertechnetate and 188Re-perrhenate as well as 125I in vitro and in vivo. METHODS: The hNIS gene was transfected to human hepatocellular carcinoma SK-Hep1 cell lines using lipofectamine plus reagent. The uptake and efflux of 125I, 99mTc-pertechnetate, and 188Re-perrhenate were measured in the transfected and parental cells. Biodistribution was studied in nude mice bearing SK-Hep1 and SK-Hep1-NIS at 10 and 30 min and at 1, 2, 6, 16, and 23 h after injection of 125I, 99mTc- pertechnetate, or 188Re-perrhenate. In tumor imaging studies, the nude mice were intravenously injected with 188Re-perrhenate and imaged with a gamma-camera equipped with a pinhole collimator at 30 and 60 min after injection. The survival rate (%) was determined by the clonogenic assay after 37 MBq/10 mL (1 mCi/10 mL) 131I and 188Re-perrhenate treatment. RESULTS: SK-Hep1-NIS, stably expressing the NIS gene, accumulated 125I up 150 times higher than that of SK-Hep1. Iodine uptake of SK-Hep1-NIS is completely blocked by perchlorate. NIS gene transfection into SK-Hep1 also resulted in 112- and 87-fold increases of 99mTc-pertechnetate and 188Re-perrhenate uptake, respectively. Iodide efflux from SK-Hep1-NIS was relatively slow, with only 10% released during the initial 5 min, and 60% remained at 25 min. In the biodistribution study using SK-Hep1-NIS-xenographed mice, the tumor uptake of 125I, 188Re-perrhenate, and 99mTc-pertechnetate was 68.0 +/- 15.0, 46.2 +/- 9.1, and 59.6 +/- 16.2 %ID/g (percentage injected dose per gram) at 2 h after injection, respectively. After 188Re-perrhenate injection in SK-Hep1 and SK-Hep1-NIS-xenographed nude mice, whole-body images clearly visualized the SK-Hep1-NIS tumor, whereas the control tumor was not visualized. The survival rate (%) of SK-Hep1-NIS was markedly reduced to 46.3% +/- 10.1% and 28.9% +/- 5.2% after 37 MBq/mL (1 mCi/10 mL) 131I and 188Re-perrhenate treatment compared with the survival rates of the parental cells. These results demonstrated that SK-Hep1-NIS could be selectively killed by the induced 131I and 188Re-perrhenate accumulation through NIS gene expression. CONCLUSION: NIS-based gene therapy using beta-emitting radionuclides has the potential to be used in hepatocellular carcinoma management.

Animals↗
PubMed2004

Noninvasive imaging for monitoring of viable cancer cells using a dual-imaging reporter gene.

UNLABELLED: Molecular imaging methods have been used recently to investigate biologic events. To develop a molecular imaging method suitable for monitoring viable cancer cells, we made a dual-imaging reporter gene system and examined the correlation between cancer cell number and signals from 2 reporter genes, sodium iodide symporter (NIS) and luciferase. METHODS: NIS and luciferase genes were linked with the internal ribosomal entry site and transfected into SK-HEP1 cells to generate SK-HEP1-NL cells. (125)I uptake assays, luciferase assays, and scintigraphic and luminescence imaging were performed on SK-HEP1-NL cells. After treating with doxorubicin, cell counting, assays, and imaging were performed. SK-HEP1 and SK-HEP1-NL cells were inoculated subcutaneously into the flanks of nude mice. After incubation, scintigraphic and luminescence images were acquired and quantitated. RESULTS: The results of radioiodide uptake, luciferase assay, and scintigraphic and luminescence imaging in vitro correlated well with viable cell numbers. Upon increasing the concentration of doxorubicin, cell numbers decreased, and this correlated with a decrease in radioactivity and luminescence intensity. The radioactivity from in vivo scintigraphic images and the intensity from luminescence images were also found to be proportional to the tumor weight. CONCLUSION: The developed dual-reporter imaging method using NIS and the luciferase gene reflected viable cancer cell numbers and could detect changes in cell number after doxorubicin treatment.

Animals↗
PubMed2003

Feasibility of sodium/iodide symporter gene as a new imaging reporter gene: comparison with HSV1-tk.

Positron emission tomography (PET) imaging reporter genes, such as HSV1-tk and D(2) receptor genes, make it possible to visualise gene expression non-invasively and repetitively in vivo. However, these systems require the synthesis of complicated substrates and the availability of expensive PET equipment. Expression of the sodium/iodide symporter ( NIS) gene can be easily monitored with radioiodines and technetium-99m using a gamma camera. To evaluate the possibility of using NIS as an imaging reporter gene, we compared its characteristics with those of the conventional HSV1-tk gene. The CM cell line was made by transfecting the HSV1-tk gene into CT-26 (mouse colon carcinoma cell line). The CTN and CMN cell lines were then made by transfecting the NIS gene into CT-26 and CM. We measured the uptake of iodine-125 iodovinyldeoxyuridine ([(125)I]IVDU) and (125)I to evaluate the expression of the HSV1-tk and NIS genes, respectively. Each cell line was injected into four flank sites in Balb/c mice. The biodistribution study was performed after intravenously injecting [(125)I]IVDU and (131)I, and (131)I scintigraphy was performed for the evaluation of NIS expression. In vitro studies indicated that CTN and CMN had 40- to 79-fold and 150- to 256-fold higher uptake of (125)I than CT-26 and CM, respectively. Furthermore, CM and CMN showed 57- to 69-fold higher uptake of [(125)I]IVDU than CT-26 and CTN. NIS gene expression and (125)I accumulation were found to be directly correlated ( R(2)=0.923), as were HSV1-tk gene expression and [(125)I]IVDU accumulation ( R(2)=0.956). Calculated signal per unit NIS and HSV1-tk mRNA expression was 23,240+/-3,755 cpm and 34,039+/-5,346 cpm, respectively. In vivo study indicated that CTN and CMN had 2.3- and 5.8-fold higher uptake of (131)I than CT-26 and CM, and 1.8- and 3.5-fold higher uptake of [(125)I]IVDU than CT-26 and CTN. Scintigraphy using (131)I easily visualised CTN and CMN tumours. In conclusion, the NIS gene may be viewed as an imaging reporter gene with comparable performance to the HSV1-tk gene for monitoring target gene expression.

Animals↗
PubMed2003

Dosimetry in leakage of (188)Re-DTPA during intracoronary balloon brachytherapy.

Rhenium-188 is reported to be one of the best radionuclides for intracoronary balloon brachytherapy. Among several preparations of (188)Re available for brachytherapy, (188)Re-diethylene triamine penta-acetic acid (DTPA) and (188)Re-mercaptoacetyltriglycine (MAG3) are recommended owing to their rapid excretion via the renal system and the absence of accumulation in the thyroid. The aim of this study was to calculate the dose of radiation exposure in a real human accident. During a 4-year clinical trial of (188)Re-DTPA balloon brachytherapy in 242 patients, there was one accident involving balloon leakage. Dosimetry was performed by both image-based and biological analysis. The radiation exposure to the whole body was calculated as 113 mGy by image-based analysis and 83 or 88 mGy by biological analysis, which was approximately half the reported dose in the case of (188)Re-perrhenate. The radiation exposures to other vital organs were also within the tolerated ranges. We conclude that (188)Re-DTPA has better clinical feasibility and safety for intracoronary balloon brachytherapy than (188)Re-perrhenate.

Angioplasty, Balloon, Coronary↗
PubMed2003

Preparation of (188) Re-labeled paper for treating skin cancer.

For homogeneous delivery of beta radiation to skin cancer, we developed a simple method for preparing (188) Re-labeled nitrocellulose paper. The homogeneity and stability of the labeled paper were investigated. Absorbed dose estimates were calculated using the Monte-Carlo method. A 74-MBq (188) Re-labeled paper with 1-cm diameter delivered 147.2 Gy up to 1-mm depth after 2-h irradiation. Animal experiments on tumor-bearing mice showed that 50 Gy is an adequate dose for treating skin cancer. Tumors disappeared 7 days after irradiation in all the groups irradiated by 50 or 100 Gy. The (188) Re-labeled paper provided a convenient, economical, effective, and non-invasive method of treating skin cancer.

Animals↗
PubMed2003

Novel one-pot one-step synthesis of 2'-[(18)F]fluoroflumazenil (FFMZ) for benzodiazepine receptor imaging.

We describe the synthesis of 2'-[(18)F]fluoroflumazenil (FFMZ), which differs from the typically used [(18)F]fluoroethylflumazenil (FEFMZ) for benzodiazepine receptor imaging. For one-pot one-step labeling, the precursors, 2'-tosyloxyflumazenil (TFMZ) and 2'-mesyloxyflumazenil (MFMZ), were synthesized in three steps. The precursors were successfully labeled with no-carrier-added (18)F-fluoride which was activated by repeated azeotropic distillation with Kryptofix 2.2.2./potassium carbonate in MeCN. An automated system for labeling and purification of [(18)F]FFMZ was developed. Labeling efficiency and radiochemical purity of [(18)F]FFMZ after synthesis by the automated system were 68% and 98%, respectively. Specific binding of [(18)F]FFMZ to central benzodiazepine receptor of rats was demonstrated by phosphoimaging.

Animals↗
PubMed2003

Therapy with 188Re-labeled radiopharmaceuticals: an overview of promising results from initial clinical trials.

The development of an in-house 188W/188Re-generator has greatly increased the use of 188Re for treating various diseases. 188Re is of widespread interest due to its attractive physical and chemical properties. Many new radiopharmaceuticals labeled with 188Re have been developed and are currently in clinical trials, such as: 188Re-labeled renal excreting agents like 188Re-mercaptoacetylglycylglycylglycine (MAG3) and 188Re-diethylenetriamine pentaacetic acid (DTPA) for prevention of coronary arterial restenosis; 188Re-labeled phosphonates such as 188Re-hydroxyethylidene diphosphonate (HEDP), 188Re-alendronate (ABP), and 188Re-ethylenediamine-N,N,N',N'-tetrakis(methylene phosphoric) acid (EDTMP) for palliation of metastatic bone pain; 188Re-labeled lipiodol such as 188Re-n-hexyldiaminedithiol (HDD)-lipiodol for treatment of liver cancer; and 188Re-labeled colloids and microspheres for treatment of diseases such as rheumatoid arthritis, peritoneal effusion, and other solid tumors. However, there is still a need to develop new 188Re-labeled radiopharmaceuticals that are more specific for target lesions such as cancer-specific monoclonal antibodies and peptides. The availability of 188Re from a generator at a reasonable cost may help increase not only the research activities but also the clinical applications of 188Re-labeled radiopharmaceuticals.

Antibodies, Monoclonal↗
PubMed2003

Differential features of metabolic abnormalities between medial and lateral temporal lobe epilepsy: quantitative analysis of (18)F-FDG PET using SPM.

UNLABELLED: Because limited resection could yield an equally good surgical outcome as standard anterior resection in temporal lobe epilepsy (TLE), the differentiation of medial from lateral TLE is important. We tried to find the differential features in metabolic abnormalities between medial and lateral TLE groups using quantitative analysis including statistical parametric mapping (SPM). METHODS: We examined 113 (18)F-FDG PET scans of TLE patients who had surgically and pathologically proven lesions and a good surgical outcome (78 medial TLE, 35 lateral TLE). Each scan was compared with those of 22 healthy control subjects to detect hypometabolic regions using a t test of the SPM method and interhemispheric asymmetry using 2-group, 2-condition analysis on SPM. Group analysis was performed between medial and lateral TLE using mirrored PET images. The sensitivity was defined as the detection rate of hypometabolism in the ipsilateral temporal lobes, and the specificity was defined as the nondetection rate in the contralateral lobes. The extent of the hypometabolism was calculated as the number of significant voxels, and the severity was calculated by the asymmetry index (ASI), in the medial or lateral temporal lobes on Statistical Probabilistic Anatomical Map template images. RESULTS: The hypometabolism in the temporal lobes was detected ipsilateral to the seizure focus in 76% of the TLE patients (76% in medial TLE, 77% in lateral TLE) but on the contralateral temporal lobes in 32% of the patients. After considering interhemispheric temporal asymmetry, the sensitivity was found to be 89%, and the specificity was 91% without differences between the medial and lateral TLE groups. In both medial and the lateral TLE, the hypometabolism was more prominent in the lateral cortical structures than in the medial structures. The hypometabolism in the medial temporal structures was found less frequently in the lateral TLE group, and the extent of the hypometabolism was significantly larger in the medial TLE group. ASIs of the medial temporal structure and superior temporal gyrus of lateral temporal structure were significantly higher in the medial TLE. CONCLUSION: SPM analysis of (18)F-FDG PET in TLE patients could localize accurately the seizure focus and helped in the discrimination of the medial TLE from the lateral TLE. We suggest the lateral TLE, rather than the medial TLE, should be considered when glucose metabolism is relatively preserved in the medial temporal structures.

Adult↗
PubMed2003

PET evidence of neuroplasticity in adult auditory cortex of postlingual deafness.

UNLABELLED: Controversy regarding functional reorganization in the adult brain remains. To investigate whether neuroplasticity is present in adults with postlingual deafness, we examined the pattern of cerebral glucose metabolism on (18)F-FDG brain PET images of postlingually deaf patients by comparing the auditory cortical activation pattern with those of age- and sex-matched healthy control subjects. We also correlated the cerebral glucose metabolism in deaf patients with the duration of deafness using statistical parametric mapping. METHODS: In the resting state (eye closed, ears unoccluded in a dark and quiet environment), (18)F-FDG brain PET scans were performed on 9 postlingually deaf patients and 9 age- and sex-matched healthy volunteers. Significant increases and decreases of regional cerebral metabolism in the patient group were estimated by comparing their PET images with those of the healthy volunteers using t statistics at every voxel. To reveal regions in which metabolism was significantly correlated with the duration of deafness, the general linear model with the duration of deafness as a covariate was tested at each voxel. RESULTS: When we compared (18)F-FDG brain PET images of postlingually deaf patients with those of age- and sex-matched healthy control subjects by performing a t test at every voxel, the glucose metabolism of deaf patients was significantly (P < 0.001) lower than that of the control subjects in both anterior cingulate gyri (Brodmann area 24 [BA24]) and superior temporal cortices (BA41, BA42) and in the right parahippocampal gyrus. No area showed a significant increase of metabolism in deaf patients with the same threshold. When we correlated glucose metabolism of deaf patients with the duration of deafness after total deprivation of hearing capability using a general linear model with the duration of deafness as a covariate at every voxel, metabolism in both anterior cingulate gyri (BA24) and superior temporal cortices (BA41, BA42) showed a significant (P < 0.005) positive correlation with the duration of deafness. CONCLUSION: This study suggests that plasticity is present in adult brains of postlingually deaf patients. In the mature brain, auditory deprivation decreased neuronal activity transiently in primary auditory and auditory-related cortices, and, over time, functional reorganization likely takes place in the auditory cortex. Plasticity was prominent in superior temporal and anterior cingulate gyri in the sensory-deprived mature brain and militated against postimplantation improvement in patients with cochlear implants.

Adult↗