Ihn Ho Cho

Yeungnam University, Gyeongsan, Gyeongsangbuk-do, South Korea

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Publications (29)39.94 Total impact

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    ABSTRACT: Purpose Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and diffusion-weighted magnetic resonance imaging (DWI) share the same role in clinical oncology and it is feasible to obtain the standardized uptake value (SUV) and apparent diffusion coefficient (ADC) simultaneously by emerging the hybrid positron emission tomography/magnetic resonance (PET/MR). This study investigated the correlation between the ADCs of rectal cancer lesions and their SUVs derived from hybrid PET/MR. Methods Nine patients with histologically proven rectal adenocarcinoma (5 men, 4 women; mean age, 70 ± 15.91 years) underwent torso 18F-FDG PET/CT and regional hybrid 18F-FDG PET/MR sequentially. A fixed threshold value of 40 % of maximum uptake was used to determine tumor volume of interest (VOI) on PET image; SUVmax, SUVpeak, and SUVmean were calculated automatically. A single freehand region of interest (ROI) was drawn on high b-value (b1000) DWI image and copied to corresponding ADC map to determine the ADCmean of rectal cancer lesion. Spearman’s rank correlation coefficient (ρ) was calculated to determine the correlation between SUVs and ADC values. Results SUVmax, SUVpeak, and SUVmean derived by hybrid PET/MR were 12.35 ± 4.66 (mean ± standard deviation), 9.66 ± 3.15 and 7.41 ± 2.54, respectively. The ADCmean value of rectal cancer lesions was 1.02 ± 0.08 × 10−3mm2/s. ADCmean was significantly and inversely correlated with SUV values (SUVmax, ρ = −0.95, p < 0.001; SUVpeak, ρ = −0.93, p < 0.001; SUVmean, ρ = −0.91, p = 0.001). Conclusions This preliminary hybrid PET/MR study demonstrates a significant inverse correlation exists between metabolic activity on 18F-FDG PET and water diffusion on DWI in rectal cancer.
    No preview · Article · Jan 2016
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    ABSTRACT: High-quality and non-invasive diagnostic tools for assessing myocardial ischemia are necessary for therapeutic decisions regarding coronary artery disease. Myocardial perfusion has been studied using myocardial contrast echo perfusion, single-photon emission computed tomography, positron emission tomography, cardiovascular magnetic resonance, and, more recently, computed tomography. The addition of coronary computed tomography angiography to myocardial perfusion imaging improves the specificity and overall diagnostic accuracy of detecting the hemodynamic significance of coronary artery stenosis. This study reviews the benefits, limitations, and imaging findings of various imaging modalities for assessing myocardial perfusion, with particular emphasis on stress perfusion computed tomography and cardiovascular magnetic resonance imaging.
    No preview · Article · Mar 2015 · The international journal of cardiovascular imaging
  • Eun Jung Kong · Ihn Ho Cho
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    ABSTRACT: We present the integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) findings of diffuse large B-cell lymphoma involving the breast in two women. They were admitted with palpable breast masses. PET/MRI revealed high (18)F-fluorodeoxyglucose (FDG) uptake in multinodular enhancing masses without other FDG-avid foci. Diffusion-weighted imaging showed restricted water diffusion and dynamic contrast MRI showed rapid increase and washout kinetics. High FDG accumulation in tumor is related to washout kinetics. We present the usefulness of integrated PET/MRI for lesion characterization and total body staging in breast lymphoma. Copyright © 2015. Published by Elsevier Inc.
    No preview · Article · Feb 2015 · Clinical Imaging
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    ABSTRACT: Purpose 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-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-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. Methods We retrospectively reviewed the medical records of 23 patients with KFD and 33 patients with ML, diagnosed histopathologically, between January 2000 and May 2013 at the Department of Pediatrics, Yeungnam University Medical Center. Among them, we analyzed the clinical manifestations, laboratory findings and characteristics, and the amount of 18F-FDG uptake between 8 KFD and 9 ML patients who had 18F-FDG PET/CT. Results The 18F-FDG PET/CT maximum standardized uptake values (SUVmax) ranged from 8.3 to 22.5 (mean, 12.0) in KFDs, and from 5.8 to 34.3 (mean, 15.9) in MLs. There were no significant differences in SUVmax between KFDs and MLs. 18F-FDG PET/CT with ML patients showed hot uptakes in the extranodal organs, such as bone marrow, small bowel, thymus, kidney, orbit and pleura. However, none of the KFD cases showed extranodal uptake (P<0.001). 18F-FDG PET/CT findings of KFD with nodal involvement only were indistinguishable from those of ML. Conclusion Patients who had extranodal involvement on PET/CT were more likely to have malignancy than KFD.
    Full-text · Article · May 2014 · Korean Journal of Pediatrics
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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.
    No preview · Article · Mar 2014
  • Ihn Ho Cho · Eun Ok Han · Ssang Tae Kim
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    ABSTRACT: Our aim was to determine the external radiation dose rates of patients undergoing positron emission tomography/computed tomography (PET/CT) and PET/magnetic resonance imaging (MRI) examinations, and to assess the factors affecting these doses. The external radiation dose rates (ERDR) from (18)F-FDG were measured using the Geiger-Müller tube at a distance of 10, 50, and 100cm from the patients' skin surface from various body regions. Results showed that at 10cm from the body surface for PET/CT examinations, the ERDR immediately after (18)F-FDG i.v. injection at time points 1 and 4 was 522.19±189.59μSvh(-1) and 256.36±74.94μSvh(-1) , respectively. At 10cm from the body surface for PET/MRI examinations, the ERDR at time points 1 and 4 were 258.76±92.09μSvh(-1) and 105.63±27.48μSvh(-1), respectively, always with a precipitous decrease over time. The (18)F-FDG dose was on average 1.93-fold higher and the ERDR was higher approximately 2.01 to 2.42-fold in PET/CT examinations than in PET/MRI examinations. In both PET/CT and PET/MRI patients, the ERDR was significantly higher with lower body weight, shorter stature, and fewer urinations etc. In conclusion, based on our results, the ERDR to patients from PET/CT scans at a distance of 10cm was twice as high than from the PET/MRI. Furthermore, to decrease ERDR to the patients, the dose injected should be adjusted to body weight and height. Factors like post injection fluid intake and urine bladder emptying, decrease ERDR. Other persons should keep a safe distance from the injected patient.
    No preview · Article · Feb 2014 · Hellenic journal of nuclear medicine
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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.
    Preview · Article · Feb 2014 · The Scientific World Journal
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    ABSTRACT: The purpose of this research is to compare and analyze SUVLBM-maximum of normal regions using VOI (the volume of interest) in order to enhance the diagnostic level in whole body images of PET/CT and PET/MRI for 26 health check-up participants. In particular, we try to set up SUVLBM-maximum data that can be used in synchronous evaluation for PET/CT and PET/MRI without contrast media. The evaluation of SUVLBM-maximum for normal regions of whole body PET/CT and whole body PET/MRI shows that the image of PET/MRI differs very significantly from the reference image of PET/CT (p<0.0001). However, they exhibit high correlations in view of statistics (R>0.8). From this research, we suggest that the decision in the evaluation of SUVLBM-maximum for PET/MRI should be made with the reduction of about 26.3%, while one should decide with the reduction of about 29.3% when the contrast media is used. It is helpful to interpret all image of PET/CT and PET/MRI using SUVLBM-maximum for convenience and efficiency.
    Preview · Article · Jan 2013
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    Ihn Ho Cho · Su Jin Kim · Eun Ok Han
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    ABSTRACT: This study derived measures to reduce exposure doses by identifying factors which affect the external radiation dose rate of patients treated with radiopharmaceuticals for PET-CT tests. The external radiation dose rates were measured on three parts of head, thorax and abdomen at a distance of 50cm from the surface of 60 PET-CT patients. It showed there are changes in factors affecting the external radiation dose rate over time after the administration of F-18 FDG. The external radiation dose rate was lower in the patients with more water intake than those with less water intake before the injection of radiopharmaceuticals at all three points: right after the injection of radiopharmaceuticals (average 4.17 mins), after the pre-PEET-CT urination step (average 77.47 mins), and right after the PET-CT test (average 114.15 mins). The study also found there is a need to increase the amount of water intake before the injection of radiopharmaceuticals in order to maintain a low external radiation dose rate in patients. This strategy is only possible under the assumption that the quality of the video has not changed after conducting this study on the relations between the image and quality. This study also found a need to use radiopharmaceuticals with the minimum amount needed for each patient because F-FDG doses affects the external radiation dose rate at the point right after the injection of radiopharmaceuticals. Urination frequency was the most significant factor to affect the external radiation dose rates at the point right after the PET-CT test and the point after the pre-PET-CT urination step. There is a need to realize the strategy to increase the urination frequency of patients to maintain the external radiation dose rate low (average 77.47 mins) before and after the injection of radiopharmaceuticals. In addition, at this point, there is a need to take advantage of personal strategies because the external radiation dose rate is lower if the fasting time is shorter, the contrast medium is used, and the amount of water intake is increased after the administration of radiopharmaceuticals. Finally this study found the need to be able to generalize these findings through an in-depth research on the factors affecting the external radiation dose rate, which includes radiopharmaceutical dose, urination frequency, the amount of water intake, fasting time and the use of contrast medium.
    Preview · Article · Dec 2012
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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.
    No preview · Article · Dec 2010 · European Journal of Nuclear Medicine
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    ABSTRACT: Background: (18)F-fluorodeoxyglucose ((18)F-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 (18)F-FDG PET/computed tomography (CT) with contrast enhancement in detecting axillary lymph node involvement in T1 breast cancer patients. Methods: Contrast-enhanced (18)F-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 (18)F-FDG PET/CT study results were compared. Results: The sensitivity, specificity, and negative and positive predictive values of contrast-enhanced (18)F-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 (18)F-FDG PET/CT cannot replace histologic staging using SLNB in patients with breast cancer, but (18)F-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.
    No preview · Article · Sep 2010
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    ABSTRACT: The oral glucose tolerance test (OGTT) for detection of diabetes is difficult to perform in clinical settings. The aim of this study is to evaluate the performance of a more practical detection test, combined fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c), as a predictor of diabetes mellitus (DM) in a Korean sample.
    Full-text · Article · Jan 2009 · Korean Diabetes Journal
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    ABSTRACT: Lipid oxidation and formation of oxygen radicals have been identified to be the important factors of atherogenesis. Because bilirubin, a potent physiological antioxidant inhibits lipid oxidation, it is suggested that low serum concentrations of bilirubin is associated with atherosclerosis. The aim of this study was to evaluate the relationship between bilirubin levels and coronary atherosclerosis.
    Full-text · Article · Aug 2008 · Korean Diabetes Journal

  • No preview · Article · Feb 2008 · Diabetes Research and Clinical Practice

  • No preview · Article · Feb 2008 · Diabetes Research and Clinical Practice
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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.
    No preview · Article · Dec 2007 · Thyroid
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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.
    No preview · Article · Dec 2007 · Clinical Rheumatology
  • J.H. Seo · S.M. Kang · S.W. Lee · B.C. Ahn · J. Lee · H.S. Bom · I.H. Cho

    No preview · Article · Mar 2007 · Journal of Nuclear Cardiology
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    ABSTRACT: Diabetic retinopathy is a leading cause of adult blindness. Some patients show early development and progression of diabetic retinopathy despite of apparently good glycemic control. This is suggesting the involvement of other contributing factors. Recent studies have shown that retinopathy and GAD autoantibody (GADA) show an inverse relationship immunologically. This study is designed to investigate the clinical manifestation of diabetes who are positive for GADA and the relationship between GADA and diabetic retinopathy.
    Full-text · Article · Jan 2007
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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.
    No preview · Article · Oct 2006 · Journal of Nuclear Cardiology