Publications (23)59.84 Total impact
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Article: α2-Adrenergic agonists including xylazine and dexmedetomidine inhibit norepinephrine transporter function in SK-N-SH cells.
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ABSTRACT: α2-Adrenergic agonists simulate norepinephrine (NE) action on α2 receptors of sympathetic neurons to mediate feedback inhibition of NE release. These agents are used as valuable adjuncts for management of hypertension and for anesthesia. Their action, equivalent to NE on α2 adrenergic receptors raises the question whether α2 agonists may also target NE transporters (NETs), another major control mechanism for noradrenergic neurotransmission. We thus investigated the effect of α2 agonists on transport of the NE analog, (131)I-metaiodobenzylguanidine (MIBG). Results from this investigation showed that xylazine and dexmedetomidine dose-dependently blocked [(3)H]nisoxetine binding in neuron-like SK-N-SH cells. Furthermore, the agents acutely suppressed cellular MIBG uptake in a dose-dependent manner. This effect was uninfluenced by the α2 antagonist yohimbine, but was completely reversed by drug removal. There was no change in membrane NET density by the agents. Moreover, saturation analysis showed that xylazine and dexmedetomidine significantly increased Km without affecting Vmax, indicating competitive inhibition of MIBG transport. Thus, the α2 adrenergic agonists xylazine and dexmedetomidine, acutely suppress NET function through competitive inhibition of substrate transport, likely by direct interaction on a region that over-laps with the nisoxetine binding site.Neuroscience Letters 02/2013; · 2.11 Impact Factor -
Article: Hydrazinonicotinamide prolongs quantum dot circulation and reduces reticuloendothelial system clearance by suppressing opsonization and phagocyte engulfment.
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ABSTRACT: In this study, we investigated the effects of hydrazinonicotinamide (HYNIC)-a bifunctional crosslinker widely used to (99m)Tc radiolabel protein and nanoparticles for imaging studies-on quantum dot opsonization, macrophage engulfment and in vivo kinetics. In streptavidin-coated quantum dots (SA-QDots), conjugation with HYNIC increased the net negative charge without affecting the zeta potential. Confocal microscopy and fluorescence-activated cell sorting showed HYNIC attachment to suppress SA-QDot engulfment by macrophages. Furthermore, HYNIC conjugation suppressed surface opsonization by serum protein including IgG. When intravenously injected into mice, HYNIC conjugation significantly prolonged the circulation of SA-QDots and reduced their hepatosplenic uptake. Diminished reticuloendothelial system clearance of SA-QDots and aminoPEG-QDots by HYNIC conjugation was also demonstrated by in vivo and ex vivo optical imaging. The effects of HYNIC on the opsonization, phagocytosis and in vivo kinetics of quantum dots were reversed by removal of the hydrazine component from HYNIC. Thus, surface functionalization with HYNIC can improve the in vivo kinetics of quantum dots by reducing phagocytosis via suppression of surface opsonization.Nanotechnology 11/2012; 23(49):495102. · 3.98 Impact Factor -
Article: Usefulness of fluorodeoxyglucose positron emission tomography in malignancy of pulmonary artery mimicking pulmonary embolism.
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ABSTRACT: BACKGROUND: The role of (18) F-fluorodeoxyglucose positron emission tomography/computed tomography ((18) F-FDG PET/CT) in evaluating pulmonary artery lesions has not yet been established. The purpose of this study is to evaluate the usefulness of (18) F-FDG PET/CT imaging in differentiating malignant from benign pulmonary artery (PA) lesions. METHODS: In this retrospective study, 18 subjects with 26 low-attenuated filling defects suspicious for PA malignancy on contrast-enhanced chest CT were enrolled; all of whom subsequently underwent (18) F-FDG PET/CT. The maximum standardized uptake value (SUVmax) for all PA lesions, defined as the (18) F-FDG uptake, was measured. The final diagnosis was then determined by pathological findings, follow-up chest CT or clinical follow-up, and compared with the PET imaging. RESULTS: In total, 6 PA sarcomas, 5 tumour embolism, and 15 pulmonary thromboembolism (PTE) occurred in this cohort. Not only was the SUVmax of the malignant PA lesions (10.2 ± 10.8) was significantly higher than that associated with PTE (1.7 ± 0.3; P < 0.001), no overlap occurred between groups. Conversely, no statistically significant difference in SUVmax occurred between PA sarcomas (12.8 ± 14.7) and tumour embolism (7.0 ± 1.32; P = 1.000). CONCLUSIONS: (18) F-FDG PET/CT is a useful imaging modality for differentiating malignant from benign PA lesions in patients with inconclusive low-attenuation filling defects on contrast-enhanced chest CT.ANZ Journal of Surgery 09/2012; · 1.25 Impact Factor -
Article: Effects of coverage extent and slice skipping on mean and maximum arterial (18)F-FDG uptake ratios in patients with carotid plaque.
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ABSTRACT: PURPOSE: To investigate the effects of variable measurement methods on mean and maximum SUV ratios of (18)F-FDG uptake in carotid arteries. METHODS: (18)F-FDG PET/CT images of 74 subjects with carotid plaque were analyzed for mean and maximum target-to-background ratio (TBR) of uptake. Agreement was analyzed between TBR scores obtained using different vessel coverage and slice skipping. RESULTS: Mean TBR was increased by extending coverage from common carotid artery (CCA; 1.25) to carotid artery (CA; 1.33) and inclusion of ascending aorta (CA/AA; 1.34). Maximum TBR was increased from 1.47 to 1.54 and 1.61 by respective extensions. Both mean and maximum TBR were closely correlated between vessels. ICC and Kappa statistics revealed near perfect agreement between TBR obtained using every 2 or 3 segments and that without sipping. Bland-Altman plots showed bias by slice skipping to remain small, particularly for mean TBR. Finally, high correlations were displayed between mean and maximum TBR. CONCLUSIONS: Analysis of mean and maximum arterial (18)F-FDG uptake in patients with carotid plaque is likely to benefit from extending coverage to segments above and below the CCA. The extra burden of measurement, in turn, can be lightened by skipping up to every 2 of 3 slices without compromising accuracy of results.Annals of Nuclear Medicine 07/2012; · 1.50 Impact Factor -
Article: Incidental Focal 18F-FDG Uptake in the Prostate: Clinical Significance and Differential Diagnostic Criteria
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ABSTRACT: PurposeThe extent and intensity of 18F-FDG uptake in prostate cancer patients are known to be variable, and the clinical significance of focal 18F-fluorodeoxyglucose (18F-FDG) uptake that is incidentally found on positron emission tomography (PET) has not been established. We investigated the clinical significance of incidental focal prostate uptake of 18F-FDG on PET/computed tomography (CT) and analyzed differential findings on PET/CT between malignant and benign uptake. MethodsA total of 14,854 whole-body 18F-FDG PET/CT scans (4,806 that were conducted during cancer screening and 10,048 that were conducted to evaluate suspected or allegedcanceroutside of the prostate) were retrospectively reviewed to determine the presence, location, multiplicity and maximum standardized uptake value (SUVmax) of focal prostate uptake and combined calcification. The final diagnosis determined by serum prostate-specific antigen (PSA) level and biopsy was compared with PET findings. ResultsIncidental focal prostate uptake was observed in 148 of 14,854 scans (1.0 %). Sixty-seven of these 148 subjects who had diagnostic confirmation were selected for further analysis. Prostatecancer was diagnosed in nine of 67 subjects (13.4%). The remaining 58 subjects had no malignancy in the prostate based on normal serum PSA level (n = 53), or elevated serum PSA level with a negative biopsy result (n = 5). While 84.6% (11/13) of malignant uptake was peripherally located in the prostate glands, 60.2% (50/83) of benign uptake was centrally located (p < 0.05). The positive predictive value of peripheral focal uptake for malignancy was 25%. The SUVmax, multiplicity andcombined calcification were not significantly different between the two groups. ConclusionAlthough incidental focal 18F-FDG uptake in the prostate is not common, the incidence of cancer with focal uptake is not low. Therefore, these findings deserve further evaluation. The location of the focal prostate uptake may help with the selection of high-risk prostate cancer patients. Keywords 18F-fluorodeoxyglucose–PET/CT–Prostate gland–Prostate cancer04/2012; 45(3):192-196. -
Article: Differentiation of liver transplantation complications by quantitative analysis of dynamic hepatobiliary scintigraphy.
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ABSTRACT: We retrospectively investigated the value of dynamic Tc-diisopropyl-iminodiacetic acid hepatobiliary scintigraphy (HBS) in discriminating postsurgical complications following liver transplantation (LT). Dynamic HBS was performed for suspected post-LT complications in 201 cases. Hepatic uptake and excretion was visually graded. The portal perfusion index (PPI) and kinetic parameters were quantitatively analyzed. HBS findings were normal in all 119 (59%) cases without complications. Complications were confirmed in 82 cases: 24 had graft rejection, 48 had biliary obstruction, and 10 had hepatitis. Visual grades of uptake and excretion were abnormal for all three types of complications and showed no discriminative value. The PPI level was significantly higher for grafts with rejection (0.83 ± 0.07) compared with no complication (0.57 ± 0.08), biliary obstruction (0.69 ± 0.06), and hepatitis (0.65 ± 0.07; all P<0.0001). Receiver operating characteristic curve analysis confirmed PPI to be highly accurate for discerning rejection from no rejection (area under the curve, 0.97; sensitivity, 95.8%; specificity, 91.7%) or biliary obstruction (area under the curve, 0.93; sensitivity, 95.8%; specificity, 79.2%). PPI measured from dynamic HBS offers a highly accurate method for identifying post-LT rejection and distinguishing it from biliary obstruction or hepatitis.Nuclear Medicine Communications 12/2011; 33(3):255-61. · 1.40 Impact Factor -
Article: Combination of nitric oxide stimulation with high-dose 18F-FDG promotes apoptosis and enhances radiation therapy of endothelial cells.
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ABSTRACT: High-dose (18)F-FDG can provide targeted nuclear therapy of cancer. Endothelial cell injury is a key determinant of tumor response to radiotherapy. Here, we tested the hypothesis that activation of endothelial cell glycolytic metabolism with nitric oxide can enhance the therapeutic effect of high-dose (18)F-FDG. Calf pulmonary artery endothelial (CPAE) cells were treated with graded doses of (18)F-FDG. Glycolysis was stimulated by 24 h of exposure to the nitric oxide donor, sodium nitroprusside (SNP). Cell viability was assessed by MTT and clonogenic assays. Apoptosis was evaluated by ELISA of cytosolic DNA fragments and Western blots of cleaved caspase-3. SNP stimulation (0.1 and 1 mM) augmented CPAE cell (18)F-FDG uptake to 2.6- and 4.6-fold of controls without adverse effects. Treatment with 333 μCi/ml (18)F-FDG alone reduced viable cell number to 35.4% of controls by Day 3. Combining 0.1 mM SNP stimulation significantly enhanced the killing effect, reducing cell numbers to 19.2% and 39.2% of controls by 333 and 167 μCi/ml of (18)F-FDG, respectively. (18)F-FDG also suppressed clonogenic survival to 80.8% and 43.2% of controls by 83 and 167 μCi/ml, which was again intensified by SNP to 59.7% and 21.1% of controls. The cytotoxic effect of (18)F-FDG was attributed to induction of apoptosis as shown by increased cytosolic fragmented DNA and cleaved caspase-3 levels (26.4% and 30.7% increases by 167 μCi/ml). Combining SNP stimulation significantly increased both of these levels to 1.8-fold of control cells. High-dose (18)F-FDG combined with nitric oxide-stimulated glycolysis is an effective method to inhibit endothelial cell survival and promote apoptosis. These results suggest a potential role of this strategy for targeted radiotherapy of angiogenic vasculature.Nuclear Medicine and Biology 11/2011; 39(3):423-8. · 3.02 Impact Factor -
Article: Immunoglobulin G4-related periaortitis mimicking an intramural hematoma.
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ABSTRACT: Immunoglobulin G4 (IgG4)-related sclerosing disease in the cardiovascular system is a recently proposed disease entity, which is still unfamiliar to most clinicians. We present a case of IgG4-related periaortitis of the ascending aorta mimicking an intramural hematoma in the computed tomography (CT) scan, which led to an unnecessary surgery. IgG4-related periaortitis needs to be considered in the differential diagnosis in a patient with thickened aortic wall because the disease should be treated medically in light of its good response to steroid therapy.The Annals of thoracic surgery 10/2011; 92(4):1506-8. · 3.74 Impact Factor -
Article: Echocardiographic predictors of left ventricular function and clinical outcomes after successful mitral valve repair: conventional two-dimensional versus speckle-tracking parameters.
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ABSTRACT: We aimed to compare conventional echocardiographic versus speckle tracking-derived parameters in predicting postoperative left ventricular (LV) dysfunction and clinical outcomes after successful mitral valve repair in patients with mitral regurgitation. In 147 consecutive patients in sinus rhythm with severe MR, two-dimensional echocardiography and speckle-tracking imaging for global longitudinal, circumferential, and radial strains and strain rates were performed within 30 days before successful mitral valve repair. Echocardiography was repeated within 7 days in all patients, and more than 3 months after surgery in 112 patients. Clinical events were evaluated for 21±17 months. Multivariate linear regression analysis showed that preoperative LV systolic dimension (p=0.004) and volume (p=0.001) were independent determinants of immediate postoperative LV ejection fraction. Preoperative LV end-systolic dimension (p=0.004), LV ejection fraction (p=0.017), and circumferential strain (p=0.029) were independent predictors of late follow-up LV ejection fraction. By Cox regression analysis, preoperative end-systolic LV dimension (hazard ratio 1.26 for every 1 mm, 95% confidence interval 1.11 to 1.44, p<0.001) was the only predictor of hospital admission for heart failure. The best cutoff values of LV end-systolic dimension (≥41 mm) and volume (≥85 mL) for predicting postoperative severe LV dysfunction (ejection fraction<0.35) identified patients at high risk for event-free survival, but those of speckle-tracking parameters did not. Preoperative LV remodeling parameters, such as LV end-systolic dimension and volume, are superior to speckle tracking-derived deformation parameters in predicting LV dysfunction and clinical events after successful mitral valve repair in patients with severe mitral regurgitation.The Annals of thoracic surgery 06/2011; 91(6):1816-23. · 3.74 Impact Factor -
Article: Impairment of fear memory consolidation in maternally stressed male mouse offspring: evidence for nongenomic glucocorticoid action on the amygdala.
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ABSTRACT: The environment in early life elicits profound effects on fetal brain development that can extend into adulthood. However, the long-lasting impact of maternal stress on emotional learning remains largely unknown. Here, we focus on amygdala-related learning processes in maternally stressed mice. In these mice, fear memory consolidation and certain related signaling cascades were significantly impaired, though innate fear, fear memory acquisition, and synaptic NMDA receptor expression in the amygdala were unaltered. In accordance with these findings, maintenance of long-term potentiation (LTP) at amygdala synapses, but not its induction, was significantly impaired in the maternally stressed animals. Interestingly, amygdala glucocorticoid receptor expression was reduced in the maternally stressed mice, and administration of glucocorticoids (GCs) immediately after fear conditioning and LTP induction restored memory consolidation and LTP maintenance, respectively, suggesting that a weakening of GC signaling was responsible for the observed impairment. Furthermore, microinfusion of a membrane-impermeable form of GC (BSA-conjugated GC) into the amygdala mimicked the restorative effects of GC, indicating that a nongenomic activity of GC mediates the restorative effect. Together, these findings suggest that prenatal stress induces long-term dysregulation of nongenomic GC action in the amygdala of adult offspring, resulting in the impairment of fear memory consolidation. Since modulation of amygdala activity is known to alter the consolidation of emotionally influenced memories allocated in other brain regions, the nongenomic action of GC on the amygdala shown herein may also participate in the amygdala-dependent modulation of memory consolidation.Journal of Neuroscience 05/2011; 31(19):7131-40. · 7.11 Impact Factor -
Article: High FDG uptake in PET/CT predicts worse prognosis in patients with metastatic gastric adenocarcinoma.
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ABSTRACT: We evaluated the role of FDG-PET/CT in patients with metastatic gastric adenocarcinoma before palliative chemotherapy to predict prognosis and chemotherapeutic response. The study included 35 consecutive newly diagnosed patients with metastatic gastric adenocarcinoma who underwent FDG-PET/CT before palliative chemotherapy. Maximum standardized uptake value (SUVmax) of the primary tumor was assessed to evaluate survival and chemotherapeutic response. Survival analysis was performed for time to progression and overall survival using the Kaplan-Meier method. Cox proportional hazard models were used to determine independent prognostic factors. All primary tumors were visualized using FDG-PET/CT (mean SUVmax = 8.1 ± 4.5, range 2.5-22.1). Sensitivity, specificity, and accuracy of FDG-PET/CT in detection of solid organ metastasis were 95.2% (20/21), 100% (14/14), and 97.1% (34/35), respectively. No significant difference of primary tumor SUVmax was found among the chemotherapeutic response groups. Univariate survival analysis demonstrated ECOG performance status (≥2), presence of solid organ metastasis, number of organs involved in distant metastasis (≥2), and SUVmax of the primary tumor (>8) as significant predictors for poor overall survival. Multivariate survival analysis showed SUVmax of the primary tumor (P = 0.048), presence of solid organ metastasis (P = 0.015), and ECOG performance status (P = 0.002) as significant independent prognostic predictors for overall survival. High FDG uptake of the primary tumor in patients with metastatic gastric adenocarcinoma is associated with poor overall survival. Assessment of tumor FDG uptake has limited value for prediction of chemotherapeutic response, but provides useful information regarding prognosis.Journal of Cancer Research and Clinical Oncology 03/2010; 136(12):1929-35. · 2.56 Impact Factor -
Article: Diagnostic efficacy of PET/CT plus brain MR imaging for detection of extrathoracic metastases in patients with lung adenocarcinoma.
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ABSTRACT: We aimed to evaluate prospectively the efficacy of positron emission tomography (PET)/computed tomography (CT) plus brain magnetic resonance imaging (MRI) for detecting extrathoracic metastases in lung adenocarcinoma. Metastatic evaluations were feasible for 442 consecutive patients (M:F=238:204; mean age, 54 yr) with a lung adenocarcinoma who underwent PET/CT (CT, without IV contrast medium injection) plus contrast-enhanced brain MRI. The presence of metastases in the brain was evaluated by assessing brain MRI or PET/CT, and in other organs by PET/CT. Diagnostic efficacies for metastasis detection with PET/CT plus brain MRI and with PET/CT only were calculated on a per-patient basis and compared from each other. Of 442 patients, 88 (20%, including 50 [11.3%] with brain metastasis) had metastasis. Regarding sensitivity of overall extrathoracic metastasis detection, a significant difference was found between PET/CT and PET/CT plus brain MRI (68% vs. 84%; P=0.03). As for brain metastasis detection sensitivity, brain MRI was significantly higher than PET/CT (88% vs. 24%; P<0.001). By adding MRI to PET/CT, brain metastases were detected in additional 32 (7% of 442 patients) patients. In lung adenocarcinoma patients, significant increase in sensitivity can be achieved for detecting extrathoracic metastases by adding dedicated brain MRI to PET/CT and thus enhancing brain metastasis detection.Journal of Korean medical science 12/2009; 24(6):1132-8. · 0.84 Impact Factor -
Article: Toxicity of cassia and cinnamon oil compounds and cinnamaldehyde-related compounds to Sitophilus oryzae (Coleoptera: Curculionidae).
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ABSTRACT: The toxicity to adult Sitophilus oryzae (L.) (Coleoptera: Curculionidae) of two cassia oils (Especial and true), four cinnamon oils (technical, #500, bark, and green leaf), and (E)-cinnamaldehyde and its 41 structurally related compounds was examined by residual and vapor-phase toxicity bioassays. Results were compared with those of dichlorvos. In residual bioassays, cassia and cinnamon oils exhibited good insecticidal activity. Based on 48-h LD50 values, the toxicity of allyl cinnmate (0.0003 mg/cm2) was comparable with that of dichlorvos (0.00025 mg/cm2). Potent insecticidal activity also was observed with benzaldehyde, beta-caryophyllene, cinnamonitrile, hydrocinnamyl acetate, (E)-4-hydroxycinnamic acid, and alpha-terpineol (LD50 = 0.003-0.009 mg/cm2). Structure-activity relationships indicate that types of functional groups rather than hydrophobicity or vapor pressure parameters seem to play a role in determining the toxicities to adult S. oryzae. In vapor-phase toxicity tests with weevils, these compounds were more effective in closed containers than in open ones. These results indicate that the effect of the compounds was largely a result of action in the vapor phase. Cassia and cinnamon oils and test compounds described merit further study as potential fumigants for the control of S. oryzae because of their greater activity as a fumigant.Journal of Economic Entomology 01/2009; 101(6):1960-6. · 1.70 Impact Factor -
Article: Potential value of radionuclide cisternography in diagnosis and management planning of spontaneous intracranial hypotension.
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ABSTRACT: Spontaneous intracranial hypotension (SIH) is caused by spontaneous spinal cerebrospinal fluid (CSF) leaks. However, there is debate regarding clinical indication of radionuclide cisternography (RNC) for identification of the actual site of a CSF leak. We therefore investigated the potential value of RNC in SIH. RNC was performed on 30 patients with SIH. Patients were managed with conservative management only or epidural blood patches (EBPs) according to clinical conditions and RNC findings. RNC revealed direct signs of spinal CSF leaks in 80% of patients. Of this group, complete resolution of headache was obtained in 12 (71%) of 17 patients who received EBP vs. 1 (14%) of 7 patients treated with conservative management only (p=0.02). Complete headache relief with conservative management only was seen in one (14%) patient with direct signs of spinal CSF leaks compared to five (83%) patients without direct signs (p=0.03). RNC is useful for diagnosis and better management planning of SIH.Clinical Neurology and Neurosurgery 08/2008; 110(7):657-61. · 1.58 Impact Factor -
Article: Reversal of vascular 18F-FDG uptake with plasma high-density lipoprotein elevation by atherogenic risk reduction.
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ABSTRACT: Vascular 18F-FDG uptake marker represents inflammation in atherosclerotic lesions, but whether inflammation can be reversed by risk-modifying interventions has not, to our knowledge, been demonstrated. In this study, we evaluated the change of vascular 18F-FDG uptake in response to lifestyle intervention on serial PET/CT scans and further assessed how the findings relate to atherogenic risk reduction. A total of 60 healthy adults underwent 18F-FDG PET/CT scans and atherogenic risk-factor assessment at baseline and again after 17.1 +/- 8.3 mo of practicing lifestyle modification. The PET/CT images were evaluated for the presence of vascular 18F-FDG lesions, and vessel-to-blood-pool 18F-FDG ratios were measured. Indices from summed ratios of positive lesions were compared and correlated to atherogenic risk factors. At follow-up, significant reductions in diastolic blood pressure (P < 0.05), total cholesterol (P < 0.05), and low-density lipoprotein level (P < 0.05) and an increase in high-density lipoprotein (HDL) level (P < 0.0001) were demonstrated. On the initial PET/CT scan, 50 of 60 subjects showed 1 or more 18F-FDG-positive lesions (5.9 +/- 5.0/subject), leading to a total of 352 vascular sites. On follow-up, 18F-FDG-positive lesions were significantly reduced to 2.1 +/- 2.2 sites per subject (P < 0.0001) and a total of 124 sites (64.8% reduction). Follow-up 18F-FDG-positive rates were significantly reduced for the aorta and iliac arteries. In addition, significant reductions in the whole-body 18F-FDG index from 1.39 +/- 1.23 to 0.53 +/- 0.59 (P < 0.0001) and carotid 18F-FDG index from 0.08 +/- 0.16 to 0.03 +/- 0.06 (P = 0.01) were shown. The whole-body 18F-FDG index correlated with total cholesterol (P < 0.05) and HDL level (P < 0.05), and the magnitude of reduction in the 18F-FDG index closely correlated to the amount of increase in plasma HDL level (P = 0.005). Our study demonstrated that vascular 18F-FDG uptake is reversed in response to atherogenic risk reduction by lifestyle intervention and that the magnitude of improvement correlates to increases in plasma HDL levels. Thus, serial 18F-FDG PET/CT may be useful for monitoring improvements in the inflammatory component of atherosclerotic lesions in response to risk modification.Journal of Nuclear Medicine 08/2008; 49(8):1277-82. · 6.38 Impact Factor -
Article: Myocardial perfusion defects and coronary risk factors in symptomatic and asymptomatic elderly women.
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ABSTRACT: We investigated the relation between risk factors of coronary artery disease (CAD) and myocardial ischemia detected by (201)Tl SPECT in elderly women. 306 women aged >or=75 yr (79.1 +/- 3.6 yr) who underwent pharmacologic (201)Tl SPECT for suspected CAD based on symptoms or CAD risk factors were included. Coronary risk factors were evaluated by medical records, and included diabetes mellitus (DM), hypertension, hypercholesterolemia, cigarette smoking, greater age (>or=80 yr), and obesity. Summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) were calculated based on stress and redistribution SPECT images for semi-quantification. The symptomatic group (n = 110) had a 34.5% perfusion defect rate. The asymptomatic group (n = 196) had a significantly lower perfusion defect rate of 16.8%. However, this significantly increased to 29.4% and 22.0% in the presence of diabetes mellitus (DM) and hypertension, respectively. In addition, the summed stress score of asymptomatic patients (12.4 +/- 6.0) was not lower but comparable to that of symptomatic patients (10.0 +/- 6.0). In elderly women suspected of CAD, pharmacologic perfusion imaging can be used to identify myocardial ischemia in patients with angina as well as asymptomatic subjects with concurrent DM or hypertension.The International Journal of Cardiovascular Imaging 03/2008; 24(3):277-81. · 2.29 Impact Factor -
Article: Comparison of uptake characteristics and prognostic value of 201Tl and 18F-FDG in esophageal cancer.
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ABSTRACT: Patients with esophageal cancer often undergo (201)Tl myocardial imaging for preoperative risk evaluation, thereby providing an excellent opportunity to assess tumor handling of (201)Tl. We thus compared the characteristics of (201)Tl and (18)F-FDG uptake by esophageal cancer and further investigated their prognostic values. The study included 100 newly diagnosed esophageal cancer patients who underwent preoperative (201)Tl SPECT and (18)F-FDG PET exams. Tumor to mediastinal uptake (T/M) ratio and retention index (RI) of (201)Tl, tumor (18)F-FDG pSUV, tumor size, location, and stage were assessed. Survival analysis was performed for disease-free survival using the Kaplan-Meier method. Cox proportional hazard models were used to determine independent risk factors. (201)Tl SPECT and (18)F-FDG PET visualized the primary tumor in 85/100 (85.0%) and 91/100 (91.0%) patients, respectively (p = 0.03). There were close correlations between early and delayed (201)Tl T/M ratios (r = 0.83, p < 0.0001) and between T/M ratios and (18)F-FDG pSUV (r = 0.56 and 0.57, respectively, both p < 0.0001). Both T/M ratios and (18)F-FDG pSUV correlated significantly with tumor stage (rho = 0.45, 0.40, and 0.59, respectively, all p < 0.0001). Survival analysis revealed tumor size, (201)Tl negative tumors, (18)F-FDG negative tumors, delayed (201)Tl T/M ratio, RI, stage, and (18)F-FDG pSUV to be significant univariate predictors for disease-free survival. Multivariate survival analysis showed stage (p = 0.02) to be a significant independent prognostic predictor. In patients with esophageal cancer, assessment of tumor (201)Tl uptake, as with (18)F-FDG, may provide potentially useful information regarding tumor characteristics.World Journal of Surgery 01/2008; 32(1):69-75. · 2.36 Impact Factor -
Article: Incidence and radio-uptake patterns of femoral head avascular osteonecrosis at 1 year after renal transplantation: a prospective study with planar bone scintigraphy.
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ABSTRACT: We prospectively investigated the incidence of femoral head avascular osteonecrosis (AVN) and radio-uptake patterns of femoral heads on bone scintigraphy at 1 year after renal transplantation. A total of 237 subjects (473 femoral heads) were included. A bone scintigraphy was performed at 12 +/- 1.1 months after renal transplantation, and 17 hips were painful at the time of bone scintigraphy. We graded the radioactivity in each femoral head as normal (grade 0), mildly increased (grade I), and definitely increased (grade II). Typical photon defects in the upper lateral femoral heads were evaluated separately. AVN was confirmed with clinical follow-up of more than 1 year and MRI and/or plain radiography findings. Femoral head AVN was detected in 15 of the 237 patients and 23 of the 473 femoral heads. When grade I and II activities were used as positive criteria, bone scintigraphy had a sensitivity of 91.3% (100% with pain) and specificity of 74.0% (100% with pain) for AVN diagnosis. When only grade II activity was considered positive, the rates were 56.5% (80.0% with pain) and 99.5% (100% with pain), respectively. The presence of a typical photon defect had a low sensitivity of 47.8%, although the specificity was high (99.1%). The incidence of femoral head AVN was low among a prospective cohort of renal transplantation recipients at the time of 1 year after engraftment. Planar bone scintigraphy is sufficient to diagnose AVN in symptomatic patients at risk for femoral head AVN using grade I and II activities as positive criteria.Nuclear Medicine Communications 12/2006; 27(11):919-24. · 1.40 Impact Factor -
Article: Depressed heart rate response to vasodilator stress for myocardial SPECT predicts mortality in patients after myocardial infarction.
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ABSTRACT: As heart rate (HR) response during vasodilator stress myocardial perfusion studies can be a marker of HR variability, we investigated its prognostic value in patients after myocardial infarction (MI). Subjects were 147 survivors of MI who underwent vasodilator stress thallium-201 scintigraphy. HR response was measured as peak to basal (P/B) ratios during vasodilator infusion. End points for survival analysis were all-cause deaths, non-fatal recurrent MI, and soft events. Results: HR response was significantly depressed in the post-MI patients compared to controls (p<0.0005). HR response correlated to LVEF (r=0.37, p<0.0001) and summed stress scores (r=-0.18, p<0.05), but not with antianginal medication. During 58+/-30 mo of follow-up, there were 15 deaths, 7 recurrent MI, and 11 soft events. Low HR response, old age, low LVEF, and high difference score were significant univariate risk factors for death. Multivariate analysis identified low HR response (p=0.03), high stress score (p=0.02), and low LVEF (p=0.05) as independent predictors of mortality. The predictive value of HR response was incremental to that offered by other variables (p=0.02). HR response, readily attained during vasodilator stress myocardial perfusion studies, may provide useful additional prognostic information in post-MI patients.The International Journal of Cardiovascular Imaging 11/2006; 22(5):663-70. · 2.29 Impact Factor -
Article: Focal parenchymal lung lesions showing a potential of false-positive and false-negative interpretations on integrated PET/CT.
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ABSTRACT: OBJECTIVE: We describe a number of benign focal lung lesions with increased 18F-FDG uptake that simulate lung cancer and malignant lesions that lead to false-negatives due to little 18F-FDG uptake on integrated PET/CT images. CONCLUSION: The integration of clinical history, morphologic findings of lung parenchymal lesions on the CT component, and metabolic activities on the PET component of integrated PET/CT can help reduce false interpretation of the study. A lung biopsy may be needed for lesions showing increased 18F-FDG uptake on PET for tissue confirmation irrespective of their morphology on CT.American Journal of Roentgenology 04/2006; 186(3):639-48. · 2.78 Impact Factor
Top co-authors
Top Journals
Institutions
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2004–2013
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Sungkyunkwan University
- • Department of Nuclear Medicine
- • Samsung Medical Center
Seoul, Seoul, South Korea
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2009–2011
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Seoul National University
- • Department of Biological Sciences
- • Department of Agricultural Biotechnology
Seoul, Seoul, South Korea
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