• Dementia and Neurocognitive Disorders
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• v.23 no.1
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• pp.54-66
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• 2024

Background and Purpose: Dementia subtypes, including Alzheimer's dementia (AD), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD), pose diagnostic challenges. This review examines the effectiveness of ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography (¹⁸F-FDG PET) in differentiating these subtypes for precise treatment and management. Methods: A systematic review following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines was conducted using databases like PubMed and Embase to identify studies on the diagnostic utility of ¹⁸F-FDG PET in dementia. The search included studies up to November 16, 2022, focusing on peer-reviewed journals and applying the goldstandard clinical diagnosis for dementia subtypes. Results: From 12,815 articles, 14 were selected for final analysis. For AD versus FTD, the sensitivity was 0.96 (95% confidence interval [CI], 0.88-0.98) and specificity was 0.84 (95% CI, 0.70-0.92). In the case of AD versus DLB, ¹⁸F-FDG PET showed a sensitivity of 0.93 (95% CI 0.88-0.98) and specificity of 0.92 (95% CI, 0.70-0.92). Lastly, when differentiating AD from non-AD dementias, the sensitivity was 0.86 (95% CI, 0.80-0.91) and the specificity was 0.88 (95% CI, 0.80-0.91). The studies mostly used case-control designs with visual and quantitative assessments. Conclusions: ¹⁸F-FDG PET exhibits high sensitivity and specificity in differentiating dementia subtypes, particularly AD, FTD, and DLB. This method, while not a standalone diagnostic tool, significantly enhances diagnostic accuracy in uncertain cases, complementing clinical assessments and structural imaging.

• Tuberculosis and Respiratory Diseases
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• v.74 no.4
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• pp.181-186
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• 2013

We report a rare synchronous presentation of primary lung cancer and adrenal pheochromocytoma. A 59-year-old woman was diagnosed with right upper lobe non-small cell lung carcinoma measuring 2.8 cm and a right adrenal gland mass measuring 3.5 cm, which displayed increased metabolic activity on $^{18}F$-fluorodeoxyglucose positron emission tomography-computed tomography. The adrenal lesion was revealed to be asymptomatic. The patient underwent right adrenalectomy and histological examination revealed a pheochromocytoma. Ten days later, right upper lobectomy was performed for lung cancer. This case indicates that incidental adrenal lesions found in cases of resectable primary lung cancer should be investigated.

• Radiation Oncology Journal
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• v.37 no.1
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• pp.51-59
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• 2019

Purpose: We evaluated failure pattern and treatment outcomes of observational approach on regional lymph node (LN) in cutaneous melanoma of extremities and sought to find clinico-pathologic factors related to LN metastases. Material and Methods: We retrospectively reviewed 73 patients with cutaneous melanoma of extremities between 2005 and 2016. If preoperative 18-F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) findings were non-specific for regional LNs, surgical resection of primary tumors with adequate margins was performed without sentinel lymph node biopsy (SLNB) and/or complete lymph node dissection (CLND), irrespective of tumor thickness or size. In patients with suspicious or positive findings on PET/CT or CT, SLNB followed by CLND or CLND was performed at the discretion of the surgeon. We defined LN dissection (LND) as SLNB and/or CLND. Results: With a median follow-up of 38 months (range, 6 to 138 months), the dominant pattern of failure was regional failure (17 of total 23 events, 74%) in the observation group (n = 56). Pathologic LN metastases were significant factor for poor regional failure-free survival (hazard ration [HR] = 3.21; 95% confidence interval [CI], 1.03-10.33; p = 0.044) and overall survival (HR = 3.62; 95% CI, 1.02-12.94; p = 0.047) in multivariate analysis. In subgroup analysis for cN0 patients according to the preoperative PET/CT findings, LND group showed the better trend of LRFFS (log rank test, p = 0.192) and RFFS (p = 0.310), although which is not statistically significant. Conclusion: Observational approach on regional LNs on the basis of the PET/CT in patients with cutaneous melanoma of extremities showed the dominant regional failure pattern compared to upfront LND approach. To reveal regional lymph node status, SLND for cN0 patients may of importance in managing cutaneous melanoma patients.

• The Korean journal of internal medicine
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• v.39 no.2
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• pp.327-337
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• 2024

Background/Aims: The prognostic significance of ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography (PET/CT) in peripheral T-cell lymphomas (PTCLs) are controversial. We explored the prognostic impact of sequential ¹⁸F-FDG PET/CT during frontline chemotherapy of patients with PTCLs. Methods: In total, 143 patients with newly diagnosed PTCLs were included. Sequential ¹⁸F-FDG PET/CTs were performed at the time of diagnosis, during chemotherapy, and at the end of chemotherapy. The baseline total metabolic tumor volume (TMTV) was calculated using the the standard uptake value with a threshold method of 2.5. Results: A baseline TMTV of 457.0 cm³ was used to categorize patients into high and low TMTV groups. Patients with a high TMTV had shorter progression-free survival (PFS) and overall survival (OS) than those with a low TMTV (PFS, 9.8 vs. 26.5 mo, p = 0.043; OS, 18.9 vs. 71.2 mo, p = 0.004). The interim ¹⁸F-FDG PET/CT response score was recorded as 1, 2-3, and 4-5 according to the Deauville criteria. The PFS and OS showed significant differences according to the interim ¹⁸F-FDG PET/CT response score (PFS, 120.7 vs. 34.1 vs. 5.1 mo, p < 0.001; OS, not reached vs. 61.1 mo vs. 12.1 mo, p < 0.001). Conclusions: The interim PET/CT response based on visual assessment predicts disease progression and survival outcome in PTCLs. A high baseline TMTV is associated with a poor response to anthracycline-based chemotherapy in PTCLs. However, TMTV was not an independent predictor for PFS in the multivariate analysis.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.2
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• pp.137-142
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• 2009

Purpose: This study was performed to find the current problems of positron emission tomography/computed tomography(PET/CT) data on CD for inter-hospital transfer. Materials and Methods: The subjects were 746 consecutive $^{18}F$-fluorodeoxyglucose PET/CT data CDs from 56 hospitals referred to our department for image interpretation. The formats and contents of PET/CT data CDs were reviewed and the email questionnaire survey about this was performed. Results: PET/CT data CDs from 21 of 56 hospitals(37.5%) included all transaxial CT and PET images with DICOM standard format which were required for authentic interpretation. PET/CT data from the others included only secondary capture images or fusion PET/CT images. According to this survey, the main reason of limited PET/CT data on CD for inter-hospital transfer was that the data volume of PET/CT was too large to upload to the Picture Archiving and Communication System. Conclusion: The majority of hospitals provided limited PET/CT data on CD for inter-hospital transfer, which could be inadequate for accurate interpretation and clinical decision making. It is necessary to standardize the format of PET/CT data on CD for inter-hospital transfer including all transaxial CT and PET images with DICOM standard format.

• 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.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.126-133
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• 2015

Purpose: To evaluate the outcomes of adjuvant radiotherapy (RT) and to analyze prognostic factors of survival in the International Federation of Gynecology and Obstetrics (FIGO) IB-IIA uterine cervical cancer. Materials and Methods: We retrospectively reviewed the medical records of 148 patients with FIGO IB-IIA uterine cervical cancer who underwent surgery followed by adjuvant RT at the Yonsei Cancer Center between June 1997 and December 2011. Adjuvant radiotherapy was delivered to the whole pelvis or an extended field with or without brachytherapy. Among all patients, 57 (38.5%) received adjuvant chemotherapy either concurrently or sequentially. To analyze prognostic factors, we assessed clinicopathologic variables and metabolic parameters measured on preoperative 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). To evaluate the predictive performance of metabolic parameters, receiver operating characteristic curve analysis was used. Overall survival (OS) and disease-free survival (DFS) were analyzed by the Kaplan-Meier method. Results: The median follow-up period was 63.2 months (range, 2.7 to 206.8 months). Locoregional recurrence alone occurred in 6 patients, while distant metastasis was present in 16 patients, including 2 patients with simultaneous regional failure. The 5-year and 10-year OSs were 87.0% and 85.4%, respectively. The 5-year and 10-year DFSs were 83.8% and 82.5%, respectively. In multivariate analysis, pathologic type and tumor size were shown to be significant prognostic factors associated with both DFS and OS. In subset analysis of 40 patients who underwent preoperative PET/CT, total lesion glycolysis was shown to be the most significant prognostic factor among the clinicopathologic variables and metabolic parameters for DFS. Conclusion: Our results demonstrated that adjuvant RT following hysterectomy effectively improves local control. From the subset analysis of preoperative PET/CT, we can consider that metabolic parameters may hold prognostic significance in early uterine cervical cancer patients. More effective systemic treatments might be needed to reduce distant metastasis in these patients.

• Journal of Yeungnam Medical Science
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• v.30 no.2
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• pp.116-119
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• 2013

A burnt-out prostate cancer tumor is a very rare clinical entity. The term 'burnt-out' refers to a primary tumor that has spontaneously and nearly completely regressed without treatment. Since metastasis of prostate cancer is usually encountered in the presence of advanced disease, distant metastasis with an undetectable primary tumor is very rare. We report herein a case of a burnt-out prostate cancer tumor that metastasized to the thoracic (T) spine and caused cord compression. A 66-year-old man visited the Emergency Department due to weakness of both legs for the past two days. His blood and urine tests were normal at the time. His spine magnetic resonance imaging (MRI) scans looked like bone metastasis that involved the T-7 vertebral body and a posterior element, and caused spinal cord compression. Other images, including from the brain MRI, neck/chest/abdomino-pelvic computed tomography (CT) scan and 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) and endoscopy, revealed no lesions that suggested malignancy. After total corpectomy T-7 and screw fixation/fusion at T5 to T10, the pathology report revealed a metastatic carcinoma that was strongly positive for prostate-specific antigen (PSA). The serum PSA value was 1.5 ng/mL. The transrectal 12-core prostate biopsy and ultrasonography showed no definitive hypoechoic lesion, but one specimen had slight (only 1%) adenocarcinoma with a Gleason score of 6 (3+3). The final diagnosis was burned-out prostate cancer with an initial normal PSA value. Although metastatic disease with an unknown primary origin was confirmed, a more aggressive approach in seeking the primary origin could provide a more specific treatment strategy and greater clinical benefit to patients.

• Journal of radiological science and technology
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• v.36 no.4
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• pp.313-318
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• 2013

Positron emission tomography/computed tomography (PET/CT) imaging with fluorodeoxyglucose (FDG) have been used as a powerful fusion modality in nuclear medicine not only for detecting cancer but also for staging and therapy monitoring. Nevertheless, there are various causes of FDG uptake in normal and/or benign tissues. The purpose of present study was to investigate whether additional delayed imaging can improve the diagnosis to differentiate the rates of FDG uptake at axillary lymph nodes (ALN) between malignant and benign in breast cancer patients. 180 PET/CT images were obtained for 27 patients with ALN uptake. The patients who had radiotherapy and chemotherapy were excluded from the study. $^{18}F$-FDG PET/CT scan at 50 min (early phase) and 90 min (delayed phase) after $^{18}F$-FDG injection were included in this retrospective study. The staging of cancers was confirmed by final clinical according to radiologic follow-up and pathologic findings. The standardized uptake value (SUV) of ALN was measured at the Syngo Acquisition Workplace by Siemens. The 27 patients included 18 malignant and 9 ALN benign groups and the 18 malignant groups were classified into the 3 groups according to number of metastatic ALN in each patient. ALNs were categorized less than or equal 3 as N1, between 4 to 9 as N2 and more than 10 as N3 group. Results are expressed as the mean${\pm}$standard deviation (S.D.) and statistically analyzed by SPSS. As a result, Retention index (RI-SUV max) in metastasis was significantly higher than that in non-metastasis about 5 fold increased. On the other hand, RI-SUV max in N group tended to decrease gradually from N1 to N3. However, we could not prove significance statistically in malignant group with ANOVA. As a consequence, RI-SUV max was good indicator for differentiating ALN positive group from node negative group in breast cancer patients. These results show that dual-time-point scan appears to be useful in distinguishing malignant from benign.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.249-256
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• 2006

Purpose: Although computed tomography (CT) is widely used for diagnosing liver metastasis from colorectal cancer, diagnostic accuracy of CT is not satisfactory. Magnetic resonance (MR) imaging and F-18 FDG PET has been reported to be superior to CT. However, studies on direct comparison of PET and MR are scarce. We compared the diagnostic accuracy of FDG PET and MR in detecting liver metastasis from colorectal cancer. Materials and Methods: Among 363 colorectal cancer patients who underwent F-18 FDG PET (ECAT, Siemens-CTI, Knoxville; Gemini, Philips, Milpitas, U.S.), 26 patients (M:F=17:9, age=$62{\pm}11$) underwent MR to evaluate suspicious metastatic liver lesions. Finally, 35 liver lesions detected by CT from 26 patients were enrolled for analysis. PET and MR results were compared with pathologic reports, clinical findings or follow-up results. Results: Of the 35 lesions, 18 lesions (51.4%) were diagnosed as liver metastases, while remaining 17 (48.6%) as benign. The sensitivity and the specificity of PET were 94.4% and 94.1%, respectively, compared to 100% and 82.4% for MR. MR and PET was concordant in 30 lesions (85.7%: 17 metastatic (94.4%) and 13 benign (76.5%) lesions. ROC curve analysis revealed maximal SUV of 3.1 as the optimum standard in differentiating metastatic from benign liver lesions (AUC=0.897, p<0.001, sensitivity 83.3%, specificity 94.1%). For small lesions less than 1 cm ln diameter (n=20), diagnostic accuracy of PET was comparable to that of MR. Conclusion: F-18 FDG PET showed good diagnostic performance in detecting liver metastasis from colorectal cancer, which was comparable to MR.