• Journal of Gastric Cancer
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• v.18 no.3
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• pp.218-229
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• 2018

Purpose: This study investigated whether the metabolic avidity of primary tumors and/or metastatic lymph nodes (LNs) measured by $^{18}F$-fluorodeoxyglucose ($^{18}F-FDG$) positron emission tomography/computed tomography (PET/CT) was related to survival after surgery in patients with advanced gastric cancer (AGC). Materials and Methods: One hundred sixty-eight patients with AGC who underwent preoperative $^{18}F-FDG$ PET/CT and curative resection were included. The $^{18}F-FDG$ avidity of the primary gastric tumor and LNs was determined quantitatively and qualitatively. The diagnostic performance of $^{18}F-FDG$ PET/CT was calculated, and the prognostic significance of $^{18}F-FDG$ avidity for recurrence-free survival (RFS) and overall survival (OS) was assessed. Results: In all, 51 (30.4%) patients experienced recurrence, and 32 (19.0%) died during follow-up (median follow-up duration, 35 months; range, 3-81 months); 119 (70.8%) and 33 (19.6%) patients showed $^{18}F-FDG$-avid primary tumors and LNs, respectively. $^{18}F-FDG$ PET/CT showed high sensitivity (73.8%) for the detection of advanced pathologic T ($pT{\geq}3$) stage and high specificity (92.2%) for the detection of advanced pN (${\geq}2$) stage. $^{18}F-FDG$ avidity of LNs was significantly associated with RFS (P=0.012), whereas that of primary tumors did not show significance (P=0.532). Univariate and multivariate analyses revealed that $^{18}F-FDG$ avidity of LNs was an independent prognostic factor for RFS (hazard ratio=2.068; P=0.029). Conclusions: $^{18}F-FDG$ avidity of LNs is an independent prognostic factor for predicting RFS. Preoperative $^{18}F-FDG$ PET/CT can be used to determine the risk and prognosis of patients with AGC after curative resection.

• 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.

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.263-265
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• 2005

A 25 years old male patient with Hodgkin's disease, considered as complete remission, underwent $^{18}F$-FDG whole body PET/CT. $^{18}F$-FDG whule body PET/CT showed unexpected hypermetabolic nodule in left quadratus femoris muscle suggesting local recurrence. Subsequent MRI also revealed well-enhancing nodular lesion with intermediate and high signal intensity on T1WI and T2WI, respectively. The lesion was confirmed as nodular fasciitis by pathologic examination of the excited specimen.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.253-255
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• 2008

A 61-year-old man had a F-18 FDG PET/CT scan for evaluation of a common bile duct cancer identified on CT. The PET/CT image showed a hypermetabolic mass in the common bile duct, and a focal area of increased F-18 FDG uptake in segment IV of the liver, which corresponded to a hypoattenuated lesion on non-enhanced CT, and was consistent with hepatic metastasis. The patient underwent choledochojejunostomy with hepatic resection, and pathologic findings were compatible with an eosinophilic abscess in the liver. This case demonstrates that F-18 FDG uptake by an eosinophilic abscess can mimic hepatic metastasis in a patient with a malignancy.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.357-360
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• 2009

Malignant mesothelioma of the peritoneum is a rare neoplasm with a rapidly fatal course. The tumour arises from the mesothelial cells lining the pleura and peritoneum or, rarely, in the pericardium or tunica vaginalis. This neoplasm is characterized by being difficult to diagnose, having a rapid evolution and a poor response to therapy. Mesothelioma is very glucose avid, and malignant pleural mesothelioma has been reported concerning the utility of F-18 FDG PET or PET/CT. But little has been known about the imaging finding of malignant peritoneal mesothelioma on F-18 FDG PET/CT. We report a case of malignant peritoneal mesothelioma mimicking peritoneal carcinomatosis of F-18 FDG PET/CT.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.395-401
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• 2009

Purpose: We evaluated $^{18}F$-FDG PET/CT findings in initially diagnosed adenoid cystic carcinoma (ACC) of the head and neck in association with pathological subtype, staging, uptake comparison with squamous cell carcinoma (SqCC) and prognosis. Materials and Methods: The subjects were 16 patients with initially diagnosed ACC of head and neck who underwent pretreatment $^{18}F$-FDG PET/CT. Histological subtype (solid pattern vs. tubular/cribriform pattern), $SUV_{max}$ of size-matched SqCC of the head and neck as control group, disease-free survival (DFS) were compared with the $SUV_{max}$ of ACC of the head and neck. Results: Of total 16 patients, 6 had solid pattern and the remaining 10 had tubular/cribriform pattern. The $SUV_{max}$ were significantly higher in solid pattern group than in tubular/cribriform pattern group ($6.7{\pm}3.2$ vs. $4.2{\pm}0.9$, p=0.03). PET/CT found unexpected distant metastasis in 18.7% of patients (3/16) and changed the therapeutic plan in those patients. The $SUV_{max}$ of ACC was significantly lower than that of size-matched SqCC ($5.1{\pm}2.4$ vs. $13.6{\pm}6.0$, p<0.001). DFS was not significantly different according to the histological subtype. In contrast, patients with high $^{18}F$-FDG uptake ($SUV_{max}$ ${\geq}$6.0) had significantly shorter DFS than those with low $^{18}F$-FDG uptake ($SUV_{max}$ <6.0). Conclusion: $^{18}F$-FDG uptake of ACC of the head and neck is significantly associated with histological subtype and DFS. $^{18}F$-FDG PET/CT may be useful for detecting unexpected metastasis. Since $^{18}F$-FDG uptake of tubular/cribriform ACC compared with SqCC is relatively low, it is necessary to interpret PET images carefully in patients without alleged ACC.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.218-228
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• 2008

Purpose: Our purpose was to evaluate spinal bony metastasis which could be missed on an F-18 FDG PET/CT (FDG PET/CT) alone, and to characterize discordant metastatic lesions between FDG PET/CT and bone scan. Material and Methods: FDG PET/CT and bone scans of 43 patients with spinal bony metastasis were analyzed retrospectively. A McNemar test was performed comparing the FDG PET/CT alone to the FDG PET/CT plus bone scan in the spinal bony metastases. A one-way chi-square test was performed to characterize the metastases that were missed on the FDG PET/CT alone. To evaluate discordant lesions between FDG PET/CT and bone scan, we performed logistic regression analyses. The independent variables were sites (cervical, thoracic, and lumbar), size (large and small), and maximum SUVs, and the dependant variable was bone scan uptake (positive and negative MDP uptake). Results: A significant difference was found between the FDG PET/CT alone and the FDG PET/CT combined with the bone scan (p < 0.01). Using the FDG PET/CT only, diffuse osteoblastic metastasis was missed with a significantly higher frequency (p = 0.04). In the univariate analysis, cervical vertebra and small size were related to negative MDP uptake, and thoracic vertebra and large size were related to positive MDP uptake. However, in the multivariate analysis, only the large size was related to positive MDP uptake. Conclusion: A bone scan in addition to the FDG PET/CT increased the ability to evaluate spinal bony metastases, especially for diffuse osteoblastic metastasis. Large metastasis was related to positive bone scan uptake in spinal bony metastasis.

• The Korean Journal of Nuclear Medicine
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• v.33 no.6
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• pp.466-474
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• 1999

Purpose: The purpose of this study was to evaluate the diagnostic accuracy of [$^{18}F$]FDG PET in the diagnosis of recurrent head and neck cancer after the completion of surgery and radiotherapy in patients with head and neck cancers. Materials and Methods: In fifty-nine patients with head and neck cancers whole body [$^{18}F$]FDG PET studies were performed. According to the different therapeutic modalities, patients were divided into four groups (Group I; pre-treatment, Group II: surgery, Group III; radiotherapy, Group IV; both surgery and radiotherapy). [$^{18}F$]FDG PET images were compared with clinical, CT and histopathologic findings. Results: for detection of metastatic lymph nodes in 14 patients of pre-treatment group (group I), the sensitivity and specificity of PET were 100% (10/10) and 75% (3/4), and those of CT were 80% (8/10) and 100% (4/4). For detection of recurrence in 45 patients of post-treatment group, overall sensitivity and specificity of PET were 96.2% (25/26) and 78.9% (15/19) [(100% and 75% in group II, 80% and 10% in group III, and 100% and 100% in group IV)] without significant difference from pre-treatment group (P>0.1). In detecting recurrence, the sensitivity and specificity of [$^{18}F$]FDG PET were 90.9% (10/11) and 20% (1/5) in 16 patients who underwent [$^{18}F$]FDG PET within 2 months after the completion of treatment. The specificity of these patients was significantly lower than that of 29 patients (100% of sensitivity and specificity) who underwent [$^{18}F$]FDG PET 2 months after treatment (p<0.05). Conclusion: [$^{18}F$]FDG PET is an accurate diagnostic modality for the detection of recurrence in head and neck cancer. Post-therapy [$^{18}F$]FDG PET should be obtained at least 2 months after the completion of surgery or radiotherapy.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.157-161
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• 2008

Malignant pleural mesothelioma (MPM) has a poor prognosis and a strong association with exposure to asbestos. Although there are not generally accepted guidelines for treatment of MPM, recent reports suggest that multi modality therapy combining chemotherapy, radiotherapy, and surgery can improve the survival of patients with MPM. Therefore exact staging is required to decide the best treatment option. However, it is well known that there are many difficulties in determining precise preoperative stage, predicting prognosis, and monitoring response to therapy with conventional imaging modalities such as CT and MRI in MPM. Recently PET with $^{18}F-FDG$ comes into the spotlight as an important staging method. There is increasing evidence that PET is superior to other conventional imaging modalities in diagnosis and staging of MPM. Particularly PET/CT improves the diagnostic and staging accuracy over PET or CT alone in MPM because it provides anatomic imaging data as well as functional information. PET and PET/CT are also useful for monitoring response to therapy and SUV is reported as a prognostic factor in MPM.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.110-112
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• 2008

Endometrial carcinoma is one of the most common gynecologic malignancies and which is predominant in postmenopausal women. Clinically many patients are hospitalized in early stage due to clinical sign and symptom such as vaginal bleeding and in this case, patient's prognosis is known to be good. However, considerable number of patients with advanced and relapsed disease reveal poor prognosis. Therefore, exact staging work up is essential for proper treatment as is primary lesion detection. $^{18}F-FDG-PET$ has been widely used for the evaluation of gynecologic malignancies such as cervical carcinoma and ovarian cancer. In contrast, FDG PET application to endometrial carcinoma is limited until now and there is no sufficient data to validate the usefulness of FDG PET for this disease yet. However, several studies showed promising results that FDG PET is sensitive and specific in detection of recurrent or metastatic lesions. Therefore further active investigation in this field can facilitate the use of FDG PET for endometrial carcinoma.