Ihn Ho Cho

Yeungnam University, Daikyū, Daegu, South Korea

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Publications (24)34.1 Total impact

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    ABSTRACT: Kikuchi-Fujimoto disease (KFD) is a benign disease, which is characterized by a cervical lymphadenopathy with fever, and it often mimics malignant lymphoma (ML). 2-[(18)F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) is a powerful imaging modality for the diagnosis, staging and monitoring of ML, with the limitations including the nonspecific FDG uptake in infectious or inflammatory processes. This study compared clinical manifestations and PET/CT findings between KFD and ML patients.
    Korean Journal of Pediatrics 05/2014; 57(5):226-31.
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    ABSTRACT: Purpose Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases. Methods Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85 ± 13 min after 18F-FDG injection of 403 ± 45 MBq) and then (125 ± 19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison. Results Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64 ± 0.70; in-phase, 1.29 ± 1.01; opposed-phase, 1.29 ± 1.15; water-weighted, 1.71 ± 1.07; fat weighted, 0.56 ± 1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63 ± 1.62; SUVmax, 4.30 ± 2.88) and contrast-enhanced PET/CT (SUVmean, 3.88 ± 2.30; SUVmax, 6.53 ± 4.04) in PET-positive lesions (SUVmean, ρ = 0.93; SUVmax, ρ = 0.95), although hybrid PET/MR presented a decrease of SUVs compared with contrast-enhanced PET/CT (mean reduction; SUVmean, 32.44 ± 15.64 %; SUVmax, 35.16 ± 12.59 %). Conclusions Despite different attenuation correction approaches, the SUV of PET-positive lesions correlated well between hybrid PET/MR and contrast-enhanced PET/CT. However Dixon MR images acquired for attenuation correction were insufficient to provide anatomic information of PET images because of low spatial resolution. Thus, additional MR sequence with fast and higher resolution may be necessary for anatomic information.
    Nuclear Medicine and Molecular Imaging. 03/2014;
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    ABSTRACT: The purpose of this research is to establish an overall data set associated with the VOI (Volume of Interest), which is available for simultaneous assessment of PET/MRI and PET/CT regardless of the use of contrast media. The participants as objects of this investigation are 26 healthy examinees in Korea, SUV (standardized-uptake-value)s-maximum evaluation for whole-body F-18 FDG (fluorodeoxyglucose) PET/MRI image using VOI of normal region has exhibited very significant difference to that for whole-body F-18 FDG PET/CT image (significant probability value (P) < 0.0001). However, there appeared high correlation between them in view of statistics (R-square (R) > 0.8). It is shown that one needs to decide SUVs-maximum for PET/MRI with the reduction of 25.0~26.4% from their evaluated value and needs to decide with the reduction of 28.8~29.4% in the same situation but with the use of contrast media. The use of SUVLBM-maximum (SUVLean Body Mass-maximum) is very advantageous in reading overall image of PET/CT and PET/MRI to medical doctors and researchers, if we consider its convenience and efficiency. We expect that this research enhances the level of the early stage accurate diagnosis with whole-body images of PET/MRI and PET/CT.
    The Scientific World Journal 01/2014; 2014:194925. · 1.22 Impact Factor
  • Progress in Medical Physics. 01/2013; 24(1):68.
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    ABSTRACT: The purpose of this study was to determine the incidence of incidental pituitary uptake on whole-body 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and to investigate its clinical significance. The files of 40,967 patients who underwent whole-body FDG PET/CT were retrospectively reviewed. Quantification of pituitary metabolic activity was obtained by using the maximum standardized uptake value (SUVmax). Hormone assays and pituitary MRIs were performed to assess pituitary lesions. Focally increased pituitary FDG uptake on PET/CT was found in 30 of 40,967 patients, accounting for an incidence of 0.073%. The mean SUVmax of 30 patients was 8.9±6.6 (range: 3.2-32.6). Histological diagnosis was obtained in three patients and included two growth hormone-secreting adenomas and one non-functioning adenoma. Hormone assays were performed on serum samples from 11 patients, 2 of whom were shown to have hypersecretion of pituitary hormone. MRI was performed on 19 patients. Abnormal MRI findings suggesting a pituitary mass were found in 18 of 19 cases (94.7%). The mean SUV(max) calculated without correction for partial volume effect for macroadenomas was significantly higher than the SUVmax for microadenomas (11.5±8.4 vs 4.8±1.3; p<0.05). There were no cases diagnosed with metastasis to the pituitary gland during clinical follow-up. Incidental pituitary FDG uptake was a very rare finding. Cases with incidental pituitary FDG uptake were diagnosed primarily with clinically non-functioning adenomas, and there were also a few functioning adenomas. Further evaluations, including hormone assays and pituitary MRI, are warranted when pituitary uptake is found on FDG PET/CT.
    European Journal of Nuclear Medicine 12/2010; 37(12):2334-43. · 4.53 Impact Factor
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    ABSTRACT: Background 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography ((PET) safely predicts axillary status in patients with breast cancer, but is not sufficiently accurate in early breast cancer patients. This study analyzed the value of 18F-FDG PET/computed tomography (CT) with contrast enhancement in detecting axillary lymph node involvement in T1 breast cancer patients. Methods Contrast-enhanced 18F-FDG PET/CT was performed within 20 days of surgery in 143 breast cancer patients with tumors ≤2 cm in size. The patients underwent either axillary lymph node dissection (ALND) or sentinel lymph node biopsy (SLNB), and histopathology reports were used to provide the definitive diagnosis against which the contrast-enhanced 18F-FDG PET/CT study results were compared. Results The sensitivity, specificity, and negative and positive predictive values of contrast-enhanced 18F-FDG PET/CT in detecting axillary involvement were 70.0%, 92.2%, 88.8%, and 77.8%, respectively, in the entire series of 143 patients, with eight false-positive and 12 false negative results. The false-negative results were associated with the number of metastatic lymph nodes and the rate of FDG uptake. Conclusion Contrast-enhanced 18F-FDG PET/CT cannot replace histologic staging using SLNB in patients with breast cancer, but 18F-FDG PET/CT increases the sensitivity for predicting axillary node metastasis, and allows for a selective approach to either ALND or SLNB, even in patients with T1 breast cancer.
    Nuclear Medicine and Molecular Imaging. 09/2010; 44(3):170-176.
  • Korean Diabetes Journal 01/2009; 33(4).
  • Diabetes Research and Clinical Practice 02/2008; 79. · 2.54 Impact Factor
  • Diabetes Research and Clinical Practice 02/2008; 79. · 2.54 Impact Factor
  • Korean Diabetes Journal 01/2008; 32(4).
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    ABSTRACT: Ectopic thyroid is a rare entity and can occur at any location in the midline position. A role for the ectopic thyroid in the pathogenesis of hypothyroidism and nongoitrous cretinism has been emphasized. To assess the clinical characteristics of an ectopic thyroid by analyzing 49 cases reported in Korea. This study was a retrospective review of 19 cases who were diagnosed by thyroid scan at our institutions together with 30 cases reported in the Korean medical literature, found using KoreaMed. Most cases of ectopic thyroid were diagnosed in patients aged between 1 and 29 years; it was more common in females (43 patients). A lingual thyroid was found in 23 patients, a sublingual thyroid in 17 patients, combined type in 7 patients, a prelaryngeal thyroid in 1 patient, and an intratracheal thyroid in 1 patient. Only four cases had the thyroid gland in the normal position. The chief complaints at presentation were palpable mass in 20 patients, growth retardation in 10 patients, and a lump sensation in the throat in 6 patients. Twenty-six of 42 patients (61.9%) had hypothyroidism, and 16 patients (38.1%) had euthyroidism. As for the treatment modalities, 18 of 26 patients with hypothyroidism and 4 of 16 patients with normal thyroid function received thyroid hormone medication; 3 of 26 patients with hypothyroidism and 8 of 16 patients with euthyroidism underwent resection of the ectopic thyroid. Our study suggests that radionuclide thyroid scanning and function testing may be useful not only for the diagnosis of an ectopic thyroid but also before deciding on the therapeutic modality; patients should be followed up to detect changes in thyroid function and malignant transformation.
    Thyroid 12/2007; 17(11):1117-21. · 3.84 Impact Factor
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    ABSTRACT: We report a case of giant cell arteritis involving the aorta and several large arteries identified by integrated positron emission tomography (PET)/computed tomography (CT) obtained in a patient with a high erythrocyte sedimentation rate (ESR). A 63-year-old man with anemia and a high ESR noted on a regular medical examination was transferred to our department. The patient complained of only a low-grade general weakness for several months; there were no specific symptoms or signs. A PET was recommended. The image showed strong (18)F-fluorodeoxyglucose ((18)F-FDG) uptake at the ascending aorta, aortic arch, descending aorta, thoraco-lumbar aorta, brachial artery, and the carotid artery wall, bilaterally. Suspicious for large-vessel vasculitis, a temporal artery biopsy was performed, which confirmed giant cell arteritis. After treatment with prednisolone, the high ESR and anemia resolved, and (18)F-FDG uptake decreased on follow-up integrated PET/CT.
    Clinical Rheumatology 12/2007; 26(11):1959-62. · 1.77 Impact Factor
  • Journal of Nuclear Cardiology 03/2007; 14(2):S10. · 2.65 Impact Factor
  • The Journal of Korean Diabetes Association. 01/2007; 31(5).
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    ABSTRACT: Adenosine 5'-triphosphate (ATP), a potent and inexpensive coronary vasodilator, was introduced as a pharmacologic stress agent for thallium 201 single photon emission computed tomography (SPECT). However, there has been no direct comparison of ATP and adenosine as myocardial stressors in the same subjects. Thirty-six patients underwent consecutive Tl-201 SPECT imaging with adenosine and ATP in a randomly assigned order. There were no changes in clinical status and no invasive procedures were performed between the two tests. The hemodynamic response and side effects were monitored, and myocardial tracer uptake was assessed by use of a visual grading system and quantitative analysis via a CEqual map. The hemodynamic changes and adverse effects did not differ significantly between the two groups. There were no changes in the detection of any perfusion defect on a per-subject basis, except in one. The exact agreement rate for the visual grading of the myocardial tracer uptake was 84.8%. However, the average extent of the perfusion defect and the severity score were higher with adenosine. The hemodynamic changes and the degree of myocardial uptake were similar between the adenosine and ATP infusion. However, quantitative analysis by use of a CEqual map revealed smaller perfusion defects and lower severity scores in subjects undergoing Tl-201 SPECT with ATP.
    Journal of Nuclear Cardiology 10/2006; 13(5):621-8. · 2.65 Impact Factor
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    ABSTRACT: Heme oxygenase-1 (HO-1) has been described as an inducible protein that is capable of cytoprotection via radical scavenging and the prevention of apoptosis. Chronic exposure to hyperglycemia can lead to cellular dysfunction that may become irreversible over time, and this process has been termed glucose toxicity. Yet little is known about the relation between glucose toxicity and HO-1 in the islets. The purposes of the present study were to determine whether prolonged exposure of pancreatic islets to a supraphysiologic glucose concentration disrupts the intracellular balance between reactive oxygen species (ROS) and HO-1, and so this causes defective insulin secretion; we also wanted to evaluate a protective role for HO-1 in pancreatic islets against high glucose levels. The intracellular peroxide levels of the pancreatic islets (INS-1 cell, rat islet) were increased in the high glucose media (30 mM glucose or 50 mM ribose). The HO-1 expression was induced in the INS-1 cells by the high glucose levels. Both the HO-1 expression and glucose stimulated insulin secretion (GSIS) was decreased simultaneously in the islets by treatment of the HO-1 antisense. The HO-1 was upregulated in the INS-1 cells by hemin, an inducer of HO-1. And, HO-1 upregulation induced by hemin reversed the GSIS in the islets at a high glucose condition. These results suggest HO-1 seems to mediate the protective response of pancreatic islets against the oxidative stress that is due to high glucose conditions.
    Journal of Korean Medical Science 07/2006; 21(3):418-24. · 1.25 Impact Factor
  • Journal of Korean Medical Science 01/2006; 21(3). · 1.25 Impact Factor
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    01/2006;
  • The Journal of Korean Diabetes Association. 01/2006; 30(4).
  • Kyung Ah Chun, Ihn Ho Cho
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    ABSTRACT: This study was performed to determine the after-effects of pharmacologic stress (adenosine) on left ventricular (LV) function-end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (LVEF)-with Tl-201 and Tc-99m MIBI SPECT. A total of 263 patients were grouped according to the time interval between isotope injection and imaging. Group A: within 1 hour (n = 99; men, n = 48; women, n = 51; mean age: 63.2 years), subgrouped as patients with no perfusion defect (NPD; n = 61), reversible defect (RD; n = 33), and fixed defect (FD; n = 5). Group B: 1 to 2 hours (n = 110; men, n = 66; woman, n = 44; mean age, 63 years), NPD (n = 64), RD (n = 26), and FD (n = 20). 3) Group C: 2 to 3 hours (n = 54; men, n = 30; women, n = 24; mean age, 62 years); NPD (n = 22), RD (n = 17), and FD (n = 15). All patients were in sinus rhythm during the study and had no prior history of myocardial infarction. In group A, in the patients with RD, poststress LVEF was significantly depressed after adenosine infusion (53.1 +/- 9.5% vs 58.3 +/- 10.2%, P < 0.001) and showed a wall motion abnormality, which was worse after stress than during rest. The mean difference in LVEF (DeltaLVEF) between rest and stress was 5.2%. The DeltaLVEF in those patients with RD was significantly higher than that in the NPD (0.9%, P < 0.01) or FD (2.1%, P < 0.05) subgroups. Twenty of the 33 patients (60.6%) with RD showed an increase in LVEF > or = 5% from poststress to rest, and the poststress ESV (43.3 +/- 19.0 mL) was significantly higher than the ESV (38.5 +/- 18.4 mL, P < 0.01) at rest, but there was no significant difference in the EDV (90.5 +/- 26.4 vs 89.7 +/- 26.2 mL). In group B, DeltaLVEF was 1.5%, 4.4%, and 1.2% in patients with NPD, RD, and FD respectively. In group C, DeltaLVEF was 2.5%, 3.2%, and 0.9% in patients with NPD, RD, and FD respectively, and there was no significant difference in DeltaLVEF among patients. In group C, 4 of 17 patients (23.5%) with RD showed an increase in LVEF > or = 5% from poststress to rest. These results showed that adenosine stress-induced postischemic LV dysfunction is well noted on early quantitative gated SPECT in patients with RD and can also be observed on delayed gated SPECT, even though the incidence of LV dysfunction is less than that in early gated SPECT.
    Clinical Nuclear Medicine 02/2005; 30(1):18-22. · 2.86 Impact Factor