• 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.

• Investigative Magnetic Resonance Imaging
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• v.21 no.3
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• pp.162-170
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• 2017

Purpose: To evaluate the imaging findings of desmoid tumors using various imaging modalities and to evaluate whether diffusion-weighted imaging (DWI) can help differentiate between desmoid and malignant tumors. Materials and Methods: The study included 27 patients with pathologically confirmed desmoid tumors. Two radiologists reviewed 23 computed tomography (CT), 12 magnetic resonance imaging (MRI) and 8 positron emission tomography-computed tomography (PET-CT) scans of desmoid tumors and recorded data regarding the shape, multiplicity, size, location, degree of enhancement, and presence or absence of calcification or hemorrhage. The signal intensity of masses on T1- and T2-weighted imaging and the presence or absence of whirling or band-like low signal intensity on T2-weighted imaging were recorded. The apparent diffusion coefficient (ADC) values of the desmoid tumors in nine patients with DWIs were compared with the ADC values of 32 malignant tumors. The maximum standardized uptake value ($SUV_{max}$) on PET-CT images was measured in 8 patients who underwent a PET-CT. Results: The mean size of the 27 tumors was 6.77 cm (range, 2.5-26 cm) and four tumors exhibited multiplicity. The desmoid tumors were classified by shape as either mass forming (n = 18), infiltrative (n = 4), or combined (n = 5). The location of the tumors was either intra-abdominal (n = 15), within the abdominal wall (n = 8) or extra-abdominal (n = 4). Among the 27 tumors, 21 showed moderate to marked enhancement and 22 showed homogeneous enhancement. Two tumors showed calcifications and one displayed hemorrhage. Eleven of the 12 MR T2-weighted images showed whirling or band-like low signal intensity areas in the mass. The mean ADC value of the desmoid tumors ($1493{\times}10^{-6}mm^2/s$) was significantly higher than the mean of the malignant soft tissue tumors ($873{\times}10^{-6}mm^2/s$, P < 0.001). On the PET-CT images, all tumors exhibited an intermediate $SUV_{max}$ (mean, 3.7; range, 2.3-4.5). Conclusion: Desmoids tumors showed homogenous, moderate to marked enhancement on CT and MRI scans and a characteristic whirling or band-like pattern on T2-weighted images. DWI can be useful for the differentiation of desmoid tumors from malignant soft tissue tumors.

• Journal of Chest Surgery
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• v.53 no.3
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• pp.93-103
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• 2020

Background: Risk assessment for pulmonary resection in patients with early-stage non-small-cell lung cancer (NSCLC) is important for minimizing postoperative morbidity. Depletion of skeletal muscle mass is closely associated with impaired nutritional status and limited physical ability. We evaluated the relationship between skeletal muscle depletion and early postoperative complications in patients with early-stage NSCLC. Methods: Patients who underwent curative lung resection between 2016 and 2018 and who were diagnosed with pathological stage I/II NSCLC were included, and their records were retrospectively analyzed. The psoas volume index (PVI, ㎤/㎥) was calculated based on computed tomography images from routine preoperative positron emission tomography-computed tomography. Early postoperative complications, defined as those occurring within 90 days of surgery, were compared between the lowest sex-specific quartile for PVI and the remaining quartiles. Results: A strong correlation was found between the volume and the cross-sectional area of the psoas muscle (R²=0.816). The overall rate of complications was 57.6% among patients with a low PVI and 32.8% among those with a normal-to-high PVI. The most common complication was prolonged air leak (low PVI, 16.9%; normal-to-high PVI, 9.6%), followed by pneumonia (low PVI, 13.6%; normal-to-high PVI, 7.9%) and recurrent pleural effusion (low PVI, 11.9%; normal-to-high PVI, 6.8%). The predictors of overall complications were low PVI (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.07-4.09; p=0.03), low hemoglobin level (OR, 0.686; 95% CI, 0.54-0.87; p=0.002), and smoking history (OR, 3.93; 95% CI, 2.03-7.58; p<0.001). Conclusion: Low PVI was associated with a higher rate of early postoperative complications in patients with early-stage NSCLC.

• Journal of Digestive Cancer Reports
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• v.7 no.1
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• pp.22-25
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• 2019

A 58-year-old woman presented with right flank and back pain for one month. After undergoing an abdominal computed tomography (CT), she was referred to our hospital. The abdominal CT showed a hypodense pancreatic tail mass with multiple retroperitoneal lymph node metastases. Positron emission tomography-computed tomography (PET-CT) scan showed high 18F-FDG uptake in pancreatic tumor and enlarged lymph nodes. Endoscopic ultrasound fine needle aspiration (EUS-FNA) revealed adenocarcinoma, which stained strongly in hENT1 (human equilibrative nucleoside transporter 1) on immunohistochemistry. She received gemcitabine 1,000 mg/m² + nanoparticle albumin-bound paclitaxel 125 mg/m² as a palliative chemotherapy. Follow-up abdominal CT and PET-CT after 4 cycles of chemotherapy showed that both pancreatic mass and the metastatic retroperitoneal lymph nodes were nearly disappeared. We report a case of 58-year-old female with metastatic pancreatic cancer who had a dramatic response to palliative chemotherapy (gemcitabine plus nanoparticle albumin-bound paclitaxel).

• Journal of the Korean Society of Radiology
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• v.82 no.5
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• pp.1246-1257
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• 2021

Purpose To assess the predictive factors and describe the imaging features of mediastinal lymph node (MLN) metastases in patients with head and neck cancer. Materials and Methods We compared the clinical features and disease characteristics (sex, age, site of primary tumor, histologic type, history of prior treatments, TNM stages, and metastasis in cervical LNs) of patients with head and neck cancers between the MLN metastasis and no MLN metastasis groups. We also evaluated the chest CT (distribution and maximum dimension of the largest LN) and PET/CT (maximum standardized uptake value) features of MLN metastases based on the MLN classification. Results Of the 470 patients with head and neck cancer, 55 (11.7%) had MLN metastasis, involving 150 mediastinal stations. Hypopharynx cancer, recurrent tumor, T4 stage, N2/N3 stages, and M1 stage were found to be significant predicting factors for MLN metastasis. The most common location of MLN metastasis was ipsilateral station 2 (upper paratracheal LNs, 36.4%), followed by ipsilateral station 11 (interlobar LNs, 27.3%) and ipsilateral station 10 (hilar LNs, 25.5%). Conclusion Metastasis to MLNs should be considered in patients with head and neck cancer, especially in cases that are associated with a hypopharyngeal cancer, recurrent tumor, and high TNM stages.

• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.327-342
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• 2006

Radiation therapy is an important part of cancer treatment in which cancer patients are treated using high-energy radiation such as x-rays, gamma rays, electrons, protons, and neutrons. Currently, about half of all cancer patients receive radiation treatment during their whole cancer care process. The goal of radiation therapy is to deliver the necessary radiation dose to cancer cells while minimizing dose to surrounding normal tissues. Success of radiation therapy highly relies on how accurately 1) identifies the target and 2) aim radiation beam to the target. Both tasks are strongly dependent of imaging technology and many imaging modalities have been applied for radiation therapy such as CT (Computed Tomography), MRI (Magnetic Resonant Image), and PET (Positron Emission Tomogaphy). Recently, many researchers have given significant amount of effort to develop and improve imaging techniques for radiation therapy to enhance the overall quality of patient care. For example, advances in medical imaging technology have initiated the development of the state of the art radiation therapy techniques such as intensity modulated radiation therapy (IMRT), gated radiation therapy, tomotherapy, and image guided radiation therapy (IGRT). Capability of determining the local tumor volume and location of the tumor has been significantly improved by applying single or multi-modality imaging fur static or dynamic target. The use of multi-modality imaging provides a more reliable tumor volume, eventually leading to a better definitive local control. Image registration technique is essential to fuse two different image modalities and has been In significant improvement. Imaging equipments and their common applications that are in active use and/or under development in radiation therapy are reviewed.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.237-243
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• 1999

We conducted this study to find the optimal correction factor(${\alpha}$) of Lassen's linearization algorithm which has been applied for correction of flow-limited uptake at a high flow range in $^{99m}Tc$ d,l-hexamethylpropy leneamine oxime(HMPAO) and $^{99m}Tc$ ethyl cysteinate dimer(ECD). Ten patients with chronic cerebral infarction were involved in this study. We obtained the corrected $^{99m}Tc$ HMPAO and $^{99m}Tc$-ECD brain SPECT(single photon emission computed tomography) using the algorithm with ${\alpha}$ values that varied from 0.1 to 10 and compared the results with regional cerebral blood flow determined by positron emission tomography (PET-rCBF). The multi-modal volume registration by maximization of mutual information was used for matching between PET-rCBF and SPECT images. The highest correlation coefficient between $^{99m}Tc$-HMPAO and $^{99m}Tc$-ECD brain uptake and PET-rCBF was revealed at ${\alpha}$ 1.4 and 2.1, respectively. We concluded that the ${\alpha}$ values of Lassen's linearization algorithm for $^{99m}Tc$-HMPAO and $^{99m}Tc$-ECD brain SPECT images were 1.4 and 2.1, respectively to indicate cerebral blood flow with comparison of PET-rCBF.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.6
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• pp.309-315
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• 2006

Purpose: Accurate evaluation of cervical lymph node (LN) metastasis of head and neck squamous cell canter (SCC) is important to treatment planning. We evaluated the diagnostic accuracy of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for the detection of cervical LN metastasis of head and neck SCC and performed a retrospective comparison with CT/MRI findings. Materials & Methods: Seventeen patients with pathologically proven head and neck SCC underwent F-18 FDG PET/CT and CT/MRI within 4 week before surgery. We recorded lymph node metastases according to the neck level system of imaging-based nodal classification. F-18 FDG PET/CT images were analyzed visually for assessment of regional tracer uptake in LN. We analyzed the differences in sensitivity and specificity between F-18 FDG PET/CT and CT/MRI using the Chi-square test. Results: Among the 17 patients, a total of 123 LN levels were dissected, 29 of which showed metastatic involvement. The sensitivity and specificity of F-18 FDG PET/CT for detecting cervical LN metastasis on a level-by-level basis were 69% (20/29) and 99% (93/94). The sensitivity and specificity of CT/MRI were 62% (18/29) and 96% (90/94). There was no significant difference in diagnostic accuracy between F-18 FDG PET/CT and CT/MRI. Interestingly, F-18 FDG PET/CT detected double primary tumor (hepatocellular carcinoma) and rib metastasis, respectively. Conclusion: There was not statistically significant difference of diagnostic accuracy between F-18 FDG PET/CT and CT/MRI for the detection of cervical LN metastasis of head and neck SCC. The low sensitivity of F-18 FDG PET/CT was due to limited resolution for small metastatic deposits.

• The Journal of the Korean bone and joint tumor society
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• v.20 no.2
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• pp.66-73
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• 2014

Purpose: Various diagnostic imaging modalities have been used to evaluate the effect of neoadjuvant chemotherapy for osteosarcoma early and noninvasively. We evaluated the effectiveness of imaging studies of plain radiographs and positron-emission tomography/computed tomography (PET/CT) in predicting neoadjuvant chemotherapy effect for osteosarcoma and tried to establish a general principle in interpretation of PET/CT parameters. Materials and Methods: Eighteen patients who underwent two cycles of neoadjuvant chemotherapy and surgical excision for osteosarcoma were enrolled. There were 13 males and 5 females, with a median age of 19 (11-63) years. Fifteen patients of 18 had the American Joint Committe on Cancer (AJCC) stage IIB. They had plain radiographs and PET/CT before and after neoadjuvant chemotherapy. The resected tumor specimens were pathologically examined to determine histological response grade using a conventional mapping method. Statistical analysis was performed to evaluate the correlation between histopathological necrosis rate, and radiographic finding category, post-chemotherapy maximum standardized uptake value (SUVmax), average standardized uptake value and metabolic tumor volume (MTV) as well as reduction rates of them. Results: Eight patients were good responders to neoadjuvant chemotherapy based on histological evaluation. Median SUVmax reduction rate was 73 (23-77) % in good responders and 42 (-32-76) % in poor responders. Median MTV reduction rate was 93.5 (62-99) % in good responders and 46 (-81-100) % in poor responders. While radiographic finding category was not different according to histological response (p=1.0), SUVmax reduction rate was significantly different (p=0.041). Difference in MTV reduction rates approached statistical significance as well (p=0.071). Conclusion: While radiographic finding category was not reliable to assess neoadjuvant chemotherapy effect for osteosarcoma, reduction rate of SUVmax was a useful indicator in this study. As parameters of PET/CT can be influenced by various factors of settings, different centers have to make an effort to establish their own standard of judgement with reference of previous studies.

• 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.