Keunyoung Kim

Prognostic value of volumetric parameters measured by F-18 FDG PET/CT in surgically resected non-small-cell lung cancer.

Objectives The aim of this study was to evaluate the usefulness of the tumor burden as characterized by the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) measured by F-18 fluoro-2-deoxyglucose (F-18 FDG) PET-computed tomography (CT) in predicting recurrence-free survival (RFS) and overall survival (OS) in surgically resected non-small-cell lung cancer (NSCLC) patients. Methods We retrospectively reviewed 91 patients with pathologically documented stages I–IIIA NSCLC. MTV and TLG were obtained according to various thresholds of the standard uptake value (SUV) of primary tumor using preoperative F-18 FDG PET-CT. We used comparison receiver-operating characteristic curve analysis to test the statistical significance of the differences among the multiple volumetric parameters calculated by various SUV cutoff values. RFS and OS were evaluated with the Kaplan–Meier method and Cox regression analysis. Results On comparison receiver-operating characteristic curve analysis, no significant difference was found among the volumetric parameters calculated using various thresholds of SUV. Regardless of the thresholds, patients with smaller MTV and lower TLG showed longer RFS and OS. MTV and TLG measured by F-18 FDG PET-CT were found to have better predictive performance than SUVmax for recurrence and death. According to multivariate analyses, MTV2.5 was revealed as a significant prognostic factor for RFS. Tumor size over 3 cm was selected as a significant prognostic indicator of OS. Conclusion Volume-based parameters of F-18 FDG PET-CT may have a role in providing prognostic information in NSCLC patients who have received surgical treatment.

Predictive value of metabolic tumor volume measured by 18F-FDG PET for regional lymph node status in patients with esophageal cancer.

Objective: The aim of the current study was to investigate the predictive value of metabolic tumor volume (MTV) measured by 18F-FDG PET/CT for regional lymph node (rLN) metastasis in patients with esophageal cancer. Methods: A retrospective review identified 54 patients with surgically resected esophageal cancer who received 18F-FDG PET/CT at diagnosis of cancer. The 18F-FDG PET/CT findings for all primary cancer and rLN involvement were compared with the pathologic diagnosis within 5 weeks after surgical resection. The pathologic diagnoses of rLN state were confirmed by surgical resection. Univariate and multivariate analyses were used to analyze the associations among the pathologic rLN status and age, sex, T stage, location, differentiation, maximum standardized uptake value (SUVmax), MTV2.5, and MTV3. Results: The rLN(+) group showed statistically significant higher value of SUVmax than the rLN(−) group (P = 0.0011). The rLN(+) group showed statistically significant higher value of MTV2.5 (P = 0.0004) and MTV3 (P = 0.0005) than the rLN(−) group. In receiver operating characteristic analysis, the SUVmax, MTV2.5, and MTV3 did not show the statistical differences for the prediction of pathologic rLN involvement in esophageal cancer. In univariate analysis, T stage, SUVmax, MTV2.5, and MTV3 were factors significantly associated with pathologic rLN involvement. However, in multivariate analysis, the MTV2.5 and MTV3 were factors significantly associated with pathologic rLN involvement in esophageal cancer. Conclusion: Based on the presented results, the MTV measured by 18F- FDG PET/CT is a useful method for the prediction of pathologic rLN status in esophageal cancer patients. Further studies are needed to confirm these results and improve statistical accuracy.

Thyroid Incidentalomas on FDG PET/CT in Patients with Non-Thyroid Cancer - a Large Retrospective Monocentric Study

Background: The purpose of this study was to compare the incidence of thyroid cancer among patients with primary non-thyroid cancer, who showed focal thyroid uptake in 18F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT). Material and Methods: We reviewed a total of 22,674 FDG PET/CTs performed at our institution between March 2005 and June 2011. A retrospective review was conducted on 433 non-thyroid cancer patients (male: n = 90, female: n = 343) who had thyroid incidentaloma on FDG PET/CT. In 286 patients, diagnostic confirmation was done by ultrasound-guided fine needle aspiration biopsy (FNAB). Results: Among 22,674 FDG PET/CT scans, 483 subjects (2.1%) showed focal thyroid uptake. Among the 286 patients who underwent FNAB, 280 were included in the study. Of those, 68 patients (24.3%) demonstrated papillary thyroid carcinoma on the final pathologic findings. We divided patients into 7 groups depending on the primary cancer. Conclusion: In patients with cancer of non-thyroid origin, incidental FDG uptake in the thyroid gland was observed in 2.1% and associated with a 24.3% risk for well-differentiated thyroid carcinoma. However, there was no statistically significant difference in the malignant risk of focal FDG uptake of the thyroid gland according to the underlying primary non-thyroid cancer type.

Predictive Value of F-18 FDG PET/CT for Malignant Pleural Effusion in Non-Small Cell Lung Cancer Patients

Background: The purpose of this study was to evaluate the accuracy of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) imaging in the detection of malignant pleural effusion and pleural metastasis in patients with non-small cell lung cancer (NSCLC). Materials and Methods: We analyzed F-18 FDG PET/CT images of 33 lung cancer patients with pleural effusion. We used 2 categorical parameters to differentiate malignant from benign pleural effusion: i) quantitative parameters using maximum standardized uptake value (SUVmax of effusion and pleura, and the following ratios: lesion to aorta (L/Ao), to cerebellum (L/Cbl), to liver (L/Liv), to nonlesion (L/NL), and to primary lung cancer (L/Prim)) and ii) various parameters determined by PET and CT scans (uptake at the pleural region, Hounsfield unit, size, and morphology of any solid abnormality). Results: Malignant pleural effusions showed significantly higher L/Prim values than benign pleural effusions. The presence of pleural abnormality on CT and pleural region uptake on PET images were found to be significantly more frequent in cases of malignant pleural disease. These parameters could differentiate malignant and benign pleural effusion according to receiver operating characteristic (ROC) analyses. There were no statistical differences between L/Prim, pleural abnormality on CT, and pleural region uptake on PET images. Abnormal pleural region uptake on PET images was the most accurate parameter identifying malignant pleural effusion by logistic regression analysis. Conclusions: Our results suggest that F-18 FDG PET/CT can be used as a reliable and noninvasive method for the differentiation of malignant and benign pleural disease in patients with NSCLC.

The clinical implication and prediction of diffuse splenic FDG uptake during cancer surveillance.

Objective: The purpose of this study was to investigate correlations between diffuse splenic FDG uptake and hematological and inflammatory parameters to clarify the significance of splenic FDG uptake on PET/CT images. Methods: We retrospectively analyzed the consecutive records of F-18 FDG PET/CT scans and selected 31 patients with diffuse splenic FDG uptake as patient group. A total of 25 patients who underwent F-18 FDG PET/CT scans for simple health checkup were enrolled as control group. ROIs were placed on the liver and spleen to measure maximal standardized uptake value (SUVmax). The spleen SUVmax was divided by the liver SUVmax to calculate the spleen/liver ratio. The correlations between the S/L ratio and various hematological parameters were evaluated. Results: The S/L ratio was positively correlated with serum C-reactive protein level, white blood cell count, and neutrophil count and negatively correlated with hemoglobin, hematocrit, and red blood cell count. Under multiple regression analysis, the Hb level and the C-reactive protein level were the significant predictors for diffuse splenic FDG uptake. Conclusion: In conclusion, our study suggests that concurrent inflammation or anemia at the time of PET/CT study could be one of various causes of diffuse splenic FDG uptake.

Factors Associated with Positive F-18 Flurodeoxyglucose Positron Emission Tomography Before Thyroidectomy in Patients with Papillary Thyroid Carcinoma

BACKGROUND The role for pre-thyroidectomy (pre-Tx) imaging with F-18 flurodeoxyglucose (FDG) positron emission tomography (PET), FDG PET-computed tomography (CT), in differentiated thyroid cancer is controversial as is the significance of positive and negative FDG uptake in this setting. We reviewed the records of patients with papillary thyroid carcinoma (PTC) who had pre-Tx FDG PET-CT to determine whether FDG uptake was associated with features noted on pre-Tx ultrasonography (US) and parameters determined after post-Tx. METHODS Patients were selected for a retrospective review of their records if they had a total Tx with central lymph node dissection for PTC and pre-Tx FDG PET-CT and US between 2006 and 2009. Sixty patients who met these criteria were studied. Patients who had a history of head and neck irradiation, surgery, or sclerotherapy with ethanol in the last 3 months were excluded. The clinicopathologic factors-age, sex, size, tumor-node-metastasis (TNM) staging, the presence of extrathyroidal extention, multifocality, cervical lymph node metastases (CLNM), Hashimoto thyroiditis, and US characteristics-were evaluated to determine whether they were associated with positive pre-Tx FDG uptake. RESULTS Forty-three (71.6%) of patients in the study had positive FDG uptake. Larger tumors and the presence of CLNM were associated with a greater likelihood of positive FDG uptake. The sensitivity, specificity, positive predictive value, and negative predictive value for CLNM detection by FDG PET-CT showed low statistical values. When considering the excellence of US for evaluating a thyroid nodule size and the presence of CLNM, the clinical value of pre-Tx FDG PET-CT is comparatively limited. CONCLUSION Pre-Tx FDG PET is not recommended for routine use in patients with PTC.

Impact of cytokines on diffuse splenic 18F-fluorodeoxyglucose uptake during positron emission tomography/computed tomography.

ObjectivesConcurrent inflammation or anemia at the time of PET/computed tomography (CT) could be one of several causes of diffuse splenic 18F-fluorodeoxyglucose (18F-FDG) uptake. In this study, we focused on cytokines to investigate interactions during this phenomenon and clarify the significance of splenic 18F-FDG uptake in PET/CT. MethodsWe selected 40 patients (17 women and 23 men) with cholangiocarcinoma, pancreatic cancer, or gallbladder cancer who had undergone PET/CT. These patients were subdivided into two groups (group A: patients showing splenic 18F-FDG uptake exceeding hepatic uptake; group B: patients showing hepatic 18F-FDG uptake exceeding splenic uptake). Blood sampling was performed for each patient on the same day as PET/CT, and 22 types of cytokines and hematologic indices were analyzed. ResultsGroup A showed higher levels of interleukin (IL)-1&bgr; (P=0.0478), IL-1RA (P=0.0044), IL-4 (P=0.0118), IL-6 (P=0.0375), IL-7 (P=0.0478), and IL-13 (P=0.0081) compared with group B. However, interferon-inducible protein-10 (IP-10; P=0.1714), IL-9 (P=0.8022), IL-8 (P=0.1631), IL-5 (P=0.5273), IL-3 (P=0.3097), IL-23 (P=0.1194), IL-2 (P=0.1099), IL-1&agr; (P=0.4439), IL-17&agr; (P=0.8811), IL-16 (P=0.3201), IL-15 (P=0.0580), interferon-&ggr; (IFN-&ggr;; P=0.5308), growth-regulated oncogene (GRO; P=0.2847), granulocyte macrophage-colony-stimulating factor (GM-CSF; P=0.0913), granulocyte-colony-stimulating factor (G-CSF; P=0.5244), and soluble CD40 ligand (sCD40L; P=0.1714) levels in group A were not statistically significantly different compared with those in the control group. In addition, the white blood cell counts and C-reactive protein levels in group A showed higher values compared with group B. IL-13 among the cytokines and C-reactive protein among the hematologic indices were significant predictors of splenic 18F-FDG uptake exceeding hepatic 18F-FDG uptake. ConclusionThis study showed that splenic 18F-FDG uptake is related to IL-1&bgr;, IL-1receptor antagonist, IL-4, IL-6, IL-7, and IL-13. These cytokines may reflect the activation of humoral immunity of the spleen.

Diffuse increased splenic F-18 fluorodeoxyglucose uptake may be an indirect sign of acute pyogenic cause rather than tuberculous in patients with infectious spondylitis.

ObjectiveThe aim of this study was to investigate whether diffuse increased splenic fluorodeoxyglucose (FDG) uptake may be an indirect sign of an acute pyogenic cause of infectious spondylitis (IS). MethodsA retrospective review identified consecutive records of patients with IS who underwent F-18 FDG positron emission tomography−computed tomography scans between January 2007 and July 2008 and recruited 23 patients (57.8±15.6 years, range: 20–81 years, eight men, 15 women) and their hematological laboratory data. The regions of interest were used to measure the maximum standardized uptake value (SUVmax) for the bone marrow (BM), liver, and spleen in each patient. We calculated the spleen/liver ratio (S/L ratio) by dividing the spleen SUVmax by liver SUVmax and the spleen/BM ratio (S/B ratio) by dividing spleen SUVmax by BM SUVmax as a parameter to assess the splenic FDG uptake. ResultsThe acute pyogenic cause of the IS group showed statistically significantly higher values of spleen SUVmax (median, 1.71 vs. 1.16, P=0.0108), S/L ratio (median, 1.08 vs. 0.88, P=0.0454), and S/B ratio (median, 1.30 vs. 0.94, P=0.0055) than the chronic tuberculous cause of the IS. The optimal cut-off values for the quantitative indices were spleen SUVmax>1.49, S/B ratio>0.957, and S/L ratio>0.889. ConclusionOn the basis of the results presented, this study demonstrated that some quantitative indices from F-18 FDG positron emission tomography/computed tomography images could be indirect signs of an acute pyogenic cause of the IS. Among the various quantitative indices, spleen SUVmax, S/B ratio, and S/L ratio were potent indicators for an acute pyogenic cause of the IS.

Hepatic FDG Uptake is not Associated with Hepatic Steatosis but with Visceral Fat Volume in Cancer Screening

PurposeWe aimed to evaluate the relation between visceral fat volume and fluorodeoxyglucose (FDG) uptake of the liver measured by maximum or mean standardized uptake value.MethodsWe retrospectively analyzed 96 consecutive records of positron emission tomography/computed tomography (PET/CT) performed for cancer screening between May 2011 and December 2011. Subjects were divided into 2 groups according to Hounsfield unit (HU) of the liver comparing with that of the spleen. The control group (20 women, 56 men) demonstrating HU of the liver equal or greater than that of the spleen included 76 patients, while the fatty liver group (2 women, 18 men) showing HU of the liver less than that of the spleen included 20 patients. We compared FDG uptake of the liver and visceral fat volume between two groups. We evaluated correlation of hepatic FDG uptake measured by maximum or mean standardized uptake value (SUV) with visceral fat volume and attenuation.ResultsThe fatty liver disease group showed higher aspartate aminotransferase (AST)of (24.42 ± 7.22, p = 0.012), alanine aminotransferase (ALT) of (25.16 ± 11.68, p = 0.001), body mass index (BMI) of (24.58 ± 3.29, p = 0.021), and visceral fat volume (3063.53 ± 1561.43, p = 0.011) than the control group. There were no statistically significant differences of mean standardized uptake value of the liver (liver SUVmean) (2.73 ± 0.19, p = 0.723), maximum standardized uptake value of the liver (liver SUVmax) (3.39 ± 0.53, p = 0.8248) and liver SUVmean/spleen SUVmean (1.13 ± 0.10, p = 0.081) between the two groups. Strong correlations were shown between liver SUVmean and BMI (r = 0.609, p < 0.001) and between liver SUVmean and visceral fat volume (r = 0.457, p < 0.001). Liver SUVmax was also strongly correlated with BMI (r = 0.622, p = 0.001) and visceral fat volume (r = 0.547, p < 0.001). There was no significant association of mean attenuation value of the liver (liver HUmean) with liver SUVmean (r = -0.003, p = 0.979) or liver SUVmax (r = -0.120, p = 0.244).ConclusionHepatic FDG uptake quantified as SUVmean or SUVmax is not correlated with hepatic steatosis but with visceral fat volume in cancer screening.

Clinical Significance of Diffuse Hepatic Visualization and Thyroid Bed Uptake on Post-Ablative Iodine-131 Whole Body Scan in Differentiated Thyroid Cancer

Background: The aim of this study was to investigate whether diffuse hepatic and thyroid bed uptake of 131I on post-ablative whole body scans (PAWBS) of patients with differentiated thyroid cancer (DTC) have any relevance for clinical outcome and parameters. Patients and Methods: We retrospectively reviewed 838 patients with DTC, who were treated at Pusan National University Hospital from 2004 to 2009. Grades of hepatic and thyroid bed uptake on 131I whole body scan were classified from 0 to 3 by visual assessment. Recurrence-free survival was evaluated with the Kaplan-Meier method and Cox regression analysis. Results: Male patients having tumors larger than 4 cm (p = 0.005), multiple tumor foci (p < 0.001), involved margins (p = 0.006), and a higher TNM stage (p < 0.001) were more likely to relapse. Thyroid bed grade (p < 0.001) and liver uptake grade (p = 0.002) were also revealed as significant prognostic factors. Intense thyroid bed uptake and faint hepatic activity were related to poor prognosis. Conclusions: We suggest that increased retention of 131I in the thyroid bed and less visualization of liver on PAWBS mean poor prognosis. This would be related to the amount of remnant thyroid tissue and ineffective destruction of it.