• Dementia and Neurocognitive Disorders
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• v.22 no.2
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• pp.61-68
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• 2023

Background and Purpose: Analyzing brain amyloid positron emission tomography (PET) images to access the occurrence of β-amyloid (Aβ) deposition in Alzheimer's patients requires much time and effort from physicians, while the variation of each interpreter may differ. For these reasons, a machine learning model was developed using a convolutional neural network (CNN) as an objective decision to classify the Aβ positive and Aβ negative status from brain amyloid PET images. Methods: A total of 7,344 PET images of 144 subjects were used in this study. The 18F-florbetaben PET was administered to all participants, and the criteria for differentiating Aβ positive and Aβ negative state was based on brain amyloid plaque load score (BAPL) that depended on the visual assessment of PET images by the physicians. We applied the CNN algorithm trained in batches of 51 PET images per subject directory from 2 classes: Aβ positive and Aβ negative states, based on the BAPL scores. Results: The binary classification of the model average performance matrices was evaluated after 40 epochs of three trials based on test datasets. The model accuracy for classifying Aβ positivity and Aβ negativity was (95.00±0.02) in the test dataset. The sensitivity and specificity were (96.00±0.02) and (94.00±0.02), respectively, with an area under the curve of (87.00±0.03). Conclusions: Based on this study, the designed CNN model has the potential to be used clinically to screen amyloid PET images.

• Tuberculosis and Respiratory Diseases
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• v.47 no.5
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• pp.642-649
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• 1999

Background: It is very important to determine an accurate staging of the non-small cell lung cancer(NSCLC) for an assessment of operability and it's prognosis. However, it is difficult to evaluate tumor involvement of mediastinal lymph nodes accurately utilizing noninvasive imaging modalities. PET is one of the sensitive and specific imaging modality. Unfortunately PET is limited use because of prohibitive cost involved with it's operation. Recently hybrid SPECT/PET(single photon emission computed tomography/positron emission tomography) camera based PET imaging was introduced with relatively low cost. We evaluated the usefulness of coincidence detection(CoDe) PET in the detection of metastasis to the mediastinal lymph nodes in patients with NSCLC. Methods: Twenty one patients with NSCLC were evaluated by CT or MRI and they were considered operable. CoDe PET was performed in all 21 patients prior to surgery. Tomographic slices of axial, coronal and sagittal planes were visually analysed. At surgery, mediastinal lymph nodes were removed and histological diagnosis was performed. CoDe PET findings were correlated with histological findings. Results: Twenty of 21 primary tumor masses were detected by the CoDe PET. Thirteen of 21 patients was correctly diagnosed mediastinal lymph node metastasis by the CoDe PET. Pathological N0 was 14 cases and the specificity of N0 of CoDe PET was 64.3%. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of N1 node was 83.3%, 73.3%, 55.6%, 91.7%, and 76.2% respectively. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of N2 node was 60.0%, 87.5%, 60.0%,87.5%, and 90.0% respectively. There were 3 false negative cases but the size of the 3 nodes were less than 1cm. The size of true positive nodes were 1.1cm, 1.0cm, 0.5cm respectively. There were 1 false positive among the 12 lymph nodes which were larger than 1cm. False positive cases consisted of 1 tuberculosis case, 1 pneumoconiosis case and 1 anthracosis case. Conclusion: CoDe PET has relatively high negative predictive value in the enlarged lymph node in staging of mediastinal nodes in patients with NSCLC. Therefore CoDe PET is useful in ruling out metastasis of enlarged N3 nodes. However, further study is needed including more number of patients in the future.

• Imaging Science in Dentistry
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• v.34 no.2
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• pp.91-97
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• 2004

Purpose : This study was performed to evaluate the diagnostic value of both planar and SPECT imagings by comparing the results with the clinical and other imaging modalities findings. Materials and Methods: A total of 578 joints with TMJ complaints were examined using planar scintigraphy and SPECT. The planar scintigraphy and SPECT findings were analyzed and compared to the clinical findings of pain, clicking, crepitus and limitation of mouth opening. Moreover we compared the accuracy of the planar scintigraphy and SPECT methods with the one of the panoramic, transcranial, tomographic and MR imaging methods. Results: The planar scintigraphy and SPECT methods showed a high sensitivity of 0.76-0.84 and low specificity of 0.25-0.45 toward the clinical findings: pain, clicking, crepitus and mouth opening restriction. Simple radionuclide uptake ratio was high in each group of patients with pain, crepitus, limitation of mouth opening (p < 0.05) complaints, in each group with positive bone changes on panoramic, transcranial or tomographic images, and in disc displaced group. Conclusion: Although both planar and SPECT imagings have limited specificity, these techniques are sensitive for detection of internal derangement of the TMJ.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.597-600
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• 2007

PET is one of the most widely used verification methods for evaluation of metastasis on the lymph nodes of the neck in oral cancer patients. The purpose of this study was to assess the correlation between PET findings and histopathologic findings in patients who had been diagnosed as squamous cell carcinoma and performed neck dissection. Thirty-four necks in 25 patients had been evaluated on pathologic lymph nodes and the data were compared with preoperative PET scan. The sensitivity of PET at the level of the neck was 72.7%, specificity was 60%, and accuracy was 79.2%. Since FDG-PET show high false-positive results, it should be used with other diagnostic tools for evaluation of lymph node metastasis.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.499-504
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• 2009

F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET/CT) plays an important role in diagnosis of malignant tumors and adds to conventional imaging in the staging of pertoneal carcinomatosis. However, false positive cases resulting from benign disease such as tuberculosis may occur. We report two cases of peritoneal tuberculosis on F-18 FDG PET/CT which showed multiple hypermetabolic foci in the mesentery and peritoneum with increased serum cancer antigen 125 (CA 125). Subsequent F-18 FDG PET/CT showed a disappearance of pathologic uptake following treatment with anti-tuberculosis drugs.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06b
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• pp.376-378
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• 2006

본 논문에서는 소동물 양전자방출단층촬영 영상(Positron Emission Tomography, PET) 내 종양영역을 자동분할하고 분할된 윤곽선주변의 기하학적 위험구간에 따른 종양의 형태특성을 분석하기 위한 방법을 제시한다. PET 영상내 검출된 종양영역의 신뢰성을 위해 위음성(False negative, FN) 및 위양성(False positive, FP)의 위험구간을 같이 제공하는 것이 필요하다. 따라서, 방사선 특이적 특성이 반영된 명암값을 기반으로 Fuzzy C-Means(FCM) 클러스터링을 수행하여 종양영역을 자동 분할한다. 분활된 종양영역의 위험구간은 클러스터 간 공유되는 영역의 소속값을 이용하여 위음성, 위양성을 계산한다. 또한, 임의의 소속값 임계치 변화를 통해 위험구간의 변화에 따른 종양의 형태적 특성변화를 관측한다. 이러한 지역적 변화의 관측을 통해 위험구간의 형태학적 위치를 판단할 수 있어 위험구간에 따른 추가적인 잔여 암의 위치 및 형태 파악을 용이하게 한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.4
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• pp.212-220
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• 2012

Objectives: Fluorine-18 fluorodeoxyglucose positron emission tomography ($^{18}F$-FDG PET) is a non-invasive diagnostic tool for many human cancers wherein glucose uptake transporter-1 (GLUT-1) acts as a main transporter in the uptake of $^{18}F$-FDG in cancer cells. Increased expression of glucose transporter-1 has been reported in many human cancers. In this study, we investigated the correlation between $^{18}F$-FDG accumulation and expression of GLUT-1 in oral cancer. Materials and Methods: We evaluated 42 patients diagnosed with oral squamous cell carcinoma (OSCC) and malignant salivary gland tumor as confirmed by histology. 42 patients underwent pre-operative $^{18}F$-FDG PET, with the maximum standardized uptake value ($SUV_{max}$) measured in each case. Immunohistochemical staining was done for each histological specimen, and results were evaluated post-operatively according to the percentage (%) of positive area, intensity, and staining score. Results: For OSCC, $SUV_{max}$ significantly increased as T stage of tumor classification increased. For malignant salivary gland tumor, $SUV_{max}$ significantly increased as T stage of tumor classification increased. For OSCC, GLUT-1 was expressed in all 36 cases. GLUT-1 staining score (GSS) increased as T stage of tumor classification increased, with the difference statistically significant. For malignant salivary gland tumor, GLUT-1 expression was observed in all 6 cases; average GSS was significantly higher in patients with cervical lymph node metastasis than that in patients without cervical lymph node metastasis. Average GSS was higher in OSCC ($11.11{\pm}1.75$) than in malignant salivary gland tumor ($5.33{\pm}3.50$). No statistically significant correlation between GSS and $SUV_{max}$ was observed in OSCC or in malignant salivary gland tumor. Conclusion: We found no statistically significant correlation between GSS and $SUV_{max}$ in OSCC or in malignant salivary gland tumor. Studies on the various uses of GLUT during $^{18}F$-FDG uptake and SUV and GLUT as tumor prognosis factor need to be conducted through further investigation with large samples.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.1061-1065
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• 2013

Objective: To investigate the treatment effect of additional information obtained by single photon emission computed tomography (SPECT) lung perfusion imaging (LPI) in the radiotherapy planning process for patients with stage III non-small cell lung cancer (NSCLC). Methods: 39 patients with stage III NSCLC were enrolled. Gross tumor volume (GTV) was outlined by SPECT/CT images, SPECT-LPIs being used to define functional lung (FL) and non-functional lung (NFL) regions. Two sets of IMRT plans were designed to deliver 64Gy to PTV. One was a regular IMRT plan using CT images only (Plan 1), and the other was a corresponding IMRT plan using co-registered images (Plan 2). $FL_{Vx}$ (the % volume of functional lung receiving ${\geq}$x Gy) and $WL_{Vx}$ (% volume of whole lung to receive ${\geq}$x Gy) were compared by paired Student's t test. Kendalls correlation was used to analyze the factor (s) related with the FLV20 decrease. Results: Compared with plan 1, both $WL_{Vx}$ and $FL_{Vx}$ were decreased in plan 2. $WL_{V10}$, $WL_{V15}$, $WL_{V20}$, $WL_{V25}$, $WL_{V30}$ and $WL_{V35}$ decreased 9.7%, 13.8%, 17.2%, 12.9%, 9.8% and 9.8%, and $FL_{V10}$, $FL_{V15}$, $FL_{V20}$, $FL_{V25}$, $FL_{V30}$ and $FL_{V35}$ decreased 10.8%, 14.6%, 17.3%, 14.5%, 14.5% and 10.5%. $FL_{Vx}$ decreased significantly compared with $WL_{Vx}$. There were significant differences in $WL_{V10}$, $WL_{V15}$, $WL_{V20}$, $WL_{V25}$, $WL_{V3}$ and $FL_{V10}$, $FL_{V15}$, $FL_{V20}$, $FL_{V25}$, $FL_{V30}$ between plan 1 and plan 2 (P=0.002, 0.000, 0.000, 0.005, 0.027 and 0.002, 0.000, 0.000, 0.006, 0.010). According to Kendall correlation analysis, NFL had a negative relation with the percentage FLV20 decrease (r=-0.559, P<0.01), while the distance of PTV and NFL center had a significantly positive relation with the percentage of FLV20 decrease (r=0.768, P<0.01). Conclusion: Routine use of SPECT-LPI for patients undergoing radiotherapy planning for stage III NSCLC appears warranted.

• Journal of the Korean Society of Radiology
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• v.81 no.6
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• pp.1424-1435
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• 2020

Purpose The purpose of this study was to evaluate the usefulness of multiphasic CT and ¹⁸F-fluorodeoxyglucose (FDG) PET/CT for the differentiation of combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) from hepatocellular carcinoma (HCC). Materials and Methods From January 2007 to April 2016, 93 patients with pathologically confirmed HCC (n = 84) or cHCC-CCA (n = 9) underwent CT and PET/CT imaging. Contrast enhancement patterns were divided into three types based on the attenuation of the surrounding liver parenchyma: type I (early arterial enhancement with delayed washout), type II (early arterial enhancement without delayed washout), and type III (early hypovascular, infiltrative appearance, or peripheral rim enhancement). Results cHCC-CCAs (89%) had a higher PET/CT positive rate than did HCCs (61%), but the PET/CT positive rate did not differ significantly (p = 0.095). Among the 19 cases of the type II enhancement pattern, 3 (21%) of 14 HCCs and 4 (80%) of 5 cHCC-CCAs were PET/CT positive. cHCC-CCAs had a significantly higher PET/CT positive rate (p = 0.020) in the type II enhancement pattern. Conclusion The PET/CT positive rate of cHCC-CCA was significantly higher than that of HCC in lesions with a type II enhancement pattern. The ¹⁸F-FDG PET/CT can be useful for the differentiation of cHCC-CCA from HCC in lesions with a type II enhancement pattern on multiphasic CT.

• Journal of Korean Neurosurgical Society
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• v.40 no.6
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• pp.428-433
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• 2006

Objective : We investigated the pattern of glucose uptake in meningiomas using $^{18}F$-fluoro-2-deoxy-D-glucose[FDG] PET/CT. It was hypothesized that the degree of glucose uptake in each tumor could predict the histologic grade. Methods : In 19 patients with meningiomas, the Ki-67 proliferative index, standardized uptake values[SUV] of FDG uptake, tumor to contralateral gray matter ratio[TGR] of SUV, tumor size, edema grade, vascular endothelial growth factor[VEGF] expression, histopathologic grade and the blood supply pattern were assessed. Results : Of the 19 meningiomas, 8 were meningothelial, 1 fibrous, 2 transitional, 1 psammomatous, 2 angiomatous, and 5 atypical. The tumor proliferative index of Ki-67, tumor size, and peritumoral edema were larger in the histopathologic grade-2 meninigiomas than in the grade-1 meningioma group. There were no significant differences in SUV and TGR between two groups. Tumor size and peritumoral edema were significantly larger in VEGF-positive tumors than in negative tumors. Conventional angiography was performed in 12 patients. Dural supply was noted predominantly in 2 patients. Four patients had mainly pial cortical supply patterns. In tumors with more pial supply, VEGF was more frequently positive. There was a significant relation between SUV and Ki-67 and between SUV and peritumoral edema. Conclusion : We found FOG uptake in meningiomas is associated with proliferative potential, however, no clear limits of SUV and TGR can be set to distinguish between grade-1 and grade-2 meningiomas, which makes the assessment of malignancy grade using PET scan metabolic imaging difficult in individual cases.