• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2000년도 추계학술발표논문집
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• pp.262-265
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• 2000

영상에서의 경계선추출은 영상의 강도의 변화를 이용한 경계영역의 가시화 기법이므로 gray level 영상이 가지는 강도를 이용하여 에지를 찾을 수 있다. 뇌 영상에는 MRI 영상과 같이 해부학적인 정보가 큰 영상과, PET 영상같이 perfusion으로 분석해야 할 영상이 있는데 그 경계가 뚜렷한 MRI 영상과 달리 PET 뇌 영상은 영상의 특성상 경계영역의 구분이 모호한 실정이다. 본 논문에서는 이러한 영상의 특성에 따라 뇌 영상에서 영상 강도에 대해 등분할을 한 후 vectorgram에서 magnitude의 영역을 선택하여 영상을 분할 하였다. 그리고 PET 와 MRI영상과 현미경 영상에 대한 결과를 비교하였다. Vertcrgram은 에지정보를 가지는 영상에 대해 벡터요소를 그래프화 한 것으로 방향성에 대한 평가를 통해 영역 분할을 하였다. 이러한 PET 영상의 2차원 분할 방법은 3차원 PET 영상 분석에 응용될 수 있을 것이다.

• Journal of Genetic Medicine
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• 제9권2호
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• pp.84-88
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• 2012

Purpose: Neurofibromatosis type 1 (NF1), which is caused by mutations of the NF1 gene, is the most frequent single gene disorder to affect the nervous system. Unidentified bright objects (UBOs) are commonly observed on brain magnetic resonance imaging (MRI) in patients with NF1. However, their clinical and pathologic significance is not well understood. The purpose of this study was to investigate the correlation between UBOs and cerebral glucose metabolism measured by $^{18}F$-2-Fluoro-2-deoxy-D-glucose ($^{18}F$-FDG) positron emission tomography (PET) in Korean patients with NF1. Materials and Methods: Medical records of 75 patients (34 males and 41 females) with NF1 who underwent brain MRI and PET between 2005 and 2011 were evaluated retrospectively. Clinical data including demographics, neurological symptoms, and brain MRI and PET findings, were reviewed. Results: UBOs were detected in the brain MRI scans of 31 patients (41%). The region most frequently affected by UBOs was the basal ganglia. The most frequent brain PET finding was thalamic glucose hypometabolism (45/75, 60%). Of the 31 patients with UBOs, 26 had thalamic glucose hypometabolism on brain PET, but the other 5 had normal brain PET findings. Conversely, of the 45 patients with thalamic glucose hypometabolism on brain PET, 26 showed UBOs on their brain MRI scans, but 19 had normal findings on brain MRI scans. Conclusion: UBOs on brain MRI scans and thalamic glucose hypometabolism on PET appear to be 2 distinctive features of NF1 rather than correlated symptoms. Because the clinical significance of these abnormal imaging findings remains unclear, a longitudinal follow-up study of changes in clinical manifestations and imaging findings is necessary.

• Asian Pacific Journal of Cancer Prevention
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• 제17권6호
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• pp.2775-2780
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• 2016

Background: Precise staging of lung cancer is usually evaluated by PET-CT and brain MRI. Recently, however, whole-body diffusion-weighted magnetic resonance imaging (WB-DWI) has be applied. The aim of this study is to determine whether the diagnostic performance of lung cancer staging by WB-DWI is superior to that of PET-CT+brain MRI. Materials and Methods: PET-CT + brain MRI and WB-DWI were used for lung cancer staging before surgery with 59 adenocarcinomas, 16 squamous cell carcinomas and 6 other carcinomas. Results: PET-CT + brain MRI correctly identified the pathologic N staging in 67 patients (82.7%), with overstaging in 5 (6.2%) and understaging in 9 (11.1%), giving a staging accuracy of 0.827. WB-DWI correctly identified the pathologic N staging in 72 patients (88.9%), with overstaging in 1 (1.2%) and understaging in 8 patients (9.9%), giving a staging accuracy of 0.889. There were no significant differences in accuracies. PET-CT + brain MRI correctly identified the pathologic stages in 56 patients (69.1%), with overstaging in 7 (8.6%) and understaging in 18 (22.2%), giving a staging accuracy of 0.691. WB-DWI correctly identified the pathologic stages in 61 patients (75.3%), with overstaging in 4 (4.9%) and understagings in16(19.7%), giving a staging accuracy of 0.753. There were no significant difference in accuracies. Conclusions: Diagnostic efficacy of WB-DWI for lung cancer staging is equivalent to that of PET-CT + brain MRI.

• Korean Journal of Radiology
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• 제23권1호
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• pp.112-123
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• 2022

Objective: To investigate the relationship between ¹⁸F-FDG PET/CT semi-quantitative parameters and the International Association for the Study of Lung Cancer, American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) histopathologic classification, including histological subtypes, proliferation activity, and somatic mutations. Materials and Methods: This retrospective study included 419 patients (150 males, 269 females; median age, 59.0 years; age range, 23.0-84.0 years) who had undergone surgical removal of stage IA-IIIA lung adenocarcinoma and had preoperative PET/CT data of lung tumors. The maximum standardized uptake values (SUVmax), background-subtracted volume (BSV), and background-subtracted lesion activity (BSL) derived from PET/CT were measured. The IASLC/ATS/ERS subtypes, Ki67 score, and epidermal growth factor/anaplastic lymphoma kinase (EGFR/ALK) mutation status were evaluated. The PET/CT semi-quantitative parameters were compared between the tumor subtypes using the Mann-Whitney U test or the Kruskal-Wallis test. The optimum cutoff values of the PET/CT semi-quantitative parameters for distinguishing the IASLC/ATS/ERS subtypes were calculated using receiver operating characteristic curve analysis. The correlation between the PET/CT semi-quantitative parameters and pathological parameters was analyzed using Spearman's correlation. Statistical significance was set at p < 0.05. Results: SUVmax, BSV, and BSL values were significantly higher in invasive adenocarcinoma (IA) than in minimally IA (MIA), and the values were higher in MIA than in adenocarcinoma in situ (AIS) (all p < 0.05). Remarkably, an SUVmax of 0.90 and a BSL of 3.62 were shown to be the optimal cutoff values for differentiating MIA from AIS, manifesting as pure ground-glass nodules with 100% sensitivity and specificity. Metabolic-volumetric parameters (BSV and BSL) were better potential independent factors than metabolic parameters (SUVmax) in differentiating growth patterns. SUVmax and BSL, rather than BSV, were strongly or moderately correlated with Ki67 in most subtypes, except for the micropapillary and solid predominant groups. PET/CT parameters were not correlated with EGFR/ALK mutation status. Conclusion: As noninvasive surrogates, preoperative PET/CT semi-quantitative parameters could imply IASLC/ATS/ERS subtypes and Ki67 index and thus may contribute to improved management of precise surgery and postoperative adjuvant therapy.

• 한국의학물리학회지:의학물리
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• 제31권4호
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• pp.189-193
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• 2020

An MR-based attenuation correction (MRAC) map plays an important role in quantitative positron emission tomography (PET) image evaluation in PET/magnetic resonance imaging (MRI) systems. However, the MRAC map is affected by the magnetic field inhomogeneity of MRIs. This study aims to evaluate the characteristics of MRAC maps of physical phantoms on PET/MRI images. Phantom measurements were performed using the Siemens Biograph mMR. The modular type physical phantoms that provide assembly versatility for phantom construction were scanned in a four-channel Body Matrix coil. The MRAC map was generated using the two-point Dixon-based segmentation method for whole-body imaging. The modular phantoms were scanned in compact and non-compact assembly configurations. In addition, the phantoms were scanned repeatedly to generate MRAC maps. The acquired MRAC maps show differently assigned values for void areas. An incorrect assignment of a void area was shown on a locally compact space between phantoms. The assigned MRAC values were distorted using a wide field-of-view (FOV). The MRAC values also differed after repeated scans. However, the erroneous MRAC values appeared outside of phantom, except for a large FOV. The MRAC map of the phantom was affected by phantom configuration and the number of scans. A quantitative study using a phantom in a PET/MRI system should be performed after evaluation of the MRAC map characteristics.

• Asian Pacific Journal of Cancer Prevention
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• 제15권22호
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• pp.9879-9884
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• 2014

Aim: The purpose of the current study was to conduct a systematic review of the published literature to evaluate the diagnostic accuracy of FDG-PET, PTE/CT, MRI and scintigraphy for multiple myeloma related bone disease. Methods: Through a search of PubMed, EMBASE, and the Cochrane Library, two reviewers independently assessed the methodological quality of each study. We estimated pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), and two sample Z-tests were conducted to evaluate for differences in sensitivity, specificity, area under the curve (AUC), and the $Q^*$ index between any two diagnostic modalities. Results: A total of 17 studies were reviewed. The MRI had a pooled sensitivity of 0.88, specificity of 0.68, AUC of 0.897, and $Q^*$ index of 0.828, whereas for MIBI, the corresponding values were 0.98, 0.90, 0.991, and 0.962, respectively, and for bone scan, they were 066, 0.83, 0.805, and 0.740, respectively. The corresponding values of MIBI were 0.98, 0.90, 0.991, and 0.962, respectively. For PET and PET/CT, the values were 0.91, 0.69, 0.927 and 0.861, respectively. Statistically significant differences were not found in the sensitivity, specificity, AUC, and $Q^*$ index between MRI, scintigraphy, FDG-PET and PET/CT. Conclusions: On the condition that X ray is taken as a reference in our study, we suggested that FDG-PET, PTE/CT, MRI and scintigraphy are all associated with high detection rate of bone disease in patients with MM. Thus, in clinical practice, it is recommended that we could choose these tests according to the condition of the patient.

• 대한골관절종양학회지
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• 제11권1호
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• pp.32-39
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• 2005

목적: 최근에는 연부 종양의 진단에 FDG-PET을 이용하기 위한 연구가 다양하게 이루어지고 있다. 그러나, 그 임상적 유용성에 대해서는 알려져 있지 않다. 이 연구의 목적은 기존의 진단법과 비교하여 FDG-PET의 유용성을 평가하는 데 있다. 대상 및 방법: 연구 대상은 2001년 3월에서 2002년 3월 사이에 연부 조직 종양으로 진단받은 29명의 환자(남자 16명, 여자 13명, 평균 47세)를 대상으로 하였다. 모든 환자군에서 기존의 검사법과 FDG-PET을 시행하였다. 타당성 검증에서 국소 병변은 모든 경우 조직검사로 판단하였고, 전이 병변은 조직 검사와 6개월 간의 추시 결과로 판단하였다. 각각의 진단은 독립적으로 시행되었으며, 진단의 정확도와 누적 비용-정확도율을 측정하였다. 결과: 국소 병변의 진단에서 MRI와 FDG-PET의 민감도, 특이도, 정확도는 각각 91%, 57%, 83% 와 95%, 43%, 83%이었다. 원격 전이의 진단에서 기존의 검사법과 FDG-PET의 민감도, 특이도, 정확도는 각각 77%, 89%, 87% 와 92%, 94%, 93%이었다. 누적 비용-정확도율은 145,000원/% 이었다. 종양의 등급별 민감도 분석에서 고등급의 종양이 가장 비용-효용성이 높았다. 결론: 국소부위의 재발과 잔존 종양의 진단에서 FDG-PET의 정확도는 MRI와 차이가 없었다. 반면, 원격 전이의 진단은 FDG-PET이 기존의 검사 보다 정확하였다. 고등급 종양의 경우 저등급 종양보다 FDG-PET의 유용성이 큰 것을 알 수 있었다.

• 대한골관절종양학회지
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• 제16권1호
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• pp.47-50
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• 2010

섬유형성이상은 골수가 섬유-골성 조직으로 치환되는 흔한 양성 골 질환이다. 암환자에서 병기의 결정과 추적 검사 시 암 전이의 발견에 PET/CT의 역할이 증가됨에 따라 우연히 발견된 FDG 섭취 증가를 보이는 섬유형성이상에서 암 전이와의 감별이 중요하다. PET/CT를 시행한 46세의 유방암 환자에서 좌측 대퇴골에 국소 FDG 섭취를 보여 암 전이로 의심되었으나 단순촬영과 자기공명 영상 소견에서 섬유형성이상으로 진단한 환자의 증례를 보고하고자 한다. 이 환자에서 단순활영과 자기공명영상 소견은 PET/CT에서 유방암 전이로 오인된 섬유형성이상의 감별에 도움이 되었다.

• Radiation Oncology Journal
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• 제30권4호
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• pp.173-181
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• 2012

Purpose: To evaluate the prognostic value of preoperative neck lymph node (LN) assessment with $^{18}F$-fluorodeoxyglucose positron emission tomography ($^{18}F$-FDG PET), computed tomography (CT), and magnetic resonance imaging (MRI) in oral cavity squamous cell carcinoma (OSCC) patients with pathologically positive LN. Materials and Methods: In total, 47 OSCC patients with pathologically positive LN were retrospectively reviewed with preoperative $^{18}F$-FDG PET and CT/MRI. All patients underwent surgical resection, neck dissection and postoperative adjuvant radiotherapy and/or chemotherapy between March 2002 and October 2010. Histologic correlation was performed for findings of $^{18}F$-FDG PET and CT/MRI. Results: Thirty-six (76.6%) of 47 cases were correctly diagnosed with neck LN metastasis by $^{18}F$-FDG PET and 32 (68.1%) of 47 cases were correctly diagnosed by CT/MRI. Follow-up ranged from 20 to 114 months (median, 56 months). Clinically negative nodal status evaluated by $^{18}F$-FDG PET or CT/MRI revealed a trend toward better clinical outcomes in terms of overall survival, disease-free survival, local recurrence-free survival, regional nodal recurrence-free survival, and distant metastasis-free survival rates even though the trends were not statistically significant. However, there was no impact of neck node standardized uptake value ($SUV_{max}$) on clinical outcomes. Notably, $SUV_{max}$ showed significant correlation with tumor size in LN (p < 0.01, $R^2$ = 0.62). PET and CT/MRI status of LN also had significant correlation with the size of intranodal tumor deposit (p < 0.05, $R^2$ = 0.37 and p < 0.01, $R^2$ = 0.48, respectively). Conclusion: $^{18}F$-FDG PET and CT/MRI at the neck LNs might improve risk stratification in OSCC patients with pathologically positive neck LN in this study, even without significant prognostic value of $SUV_{max}$.

• Radiation Oncology Journal
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• 제35권4호
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• pp.340-348
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• 2017

Purpose: To evaluate the diagnostic accuracy of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) in predicting pelvic lymph node (LN) metastases in patients with cervical cancer. Materials and Methods: From January 2009 to March 2015, 114 patients with FIGO stage IA1-IIB uterine cervical cancer who underwent hysterectomy with pelvic lymphadenectomy and took CT, MRI, and PET/CT before surgery were enrolled in this study. The criteria for LN metastases were a LN diameter ${\geq}1.0cm$ and/or the presence of central necrosis on CT, a LN diameter ${\geq}1.0cm$ on MRI, and a focally increased FDG uptake on PET/CT. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for pelvic LN metastases were estimated. Results: The sensitivity, specificity, PPV, NPV, and accuracy for detection of pelvic LN metastases were 51.4%, 85.9%, 41.3%, 90.1%, and 80.3% for CT; 24.3%, 96.3%, 56.3%, 86.8%, and 84.6% for MRI; and 48.6%, 89.5%, 47.4%, 90.0%, and 82.9% for PET/CT, respectively. The sensitivity of PET/CT and CT was higher than that of MRI (p=0.004 and p= 0.013, respectively). The specificity of MRI was higher than those of PET/CT and CT (p=0.002 and p=0.001, respectively). The difference of specificity between PET/CT and CT was not statistically significant (p=0.167). Conclusion: These results indicate that preoperative CT, MRI, and PET/CT showed low to moderate sensitivity and PPV, and moderate to high specificity, NPV, and accuracy. More efforts are necessary to improve sensitivity of imaging modalities in order to predict pelvic LN metastases.