Arthur Cho

The role of 18F-fluorodeoxyglucose–positron emission tomography in the assessment of disease activity in patients with Takayasu arteritis

OBJECTIVE The assessment of disease activity in Takayasu arteritis (TA) is difficult in clinical situations because clinical symptoms and laboratory parameters do not always reflect the actual inflammation of the arterial wall. We undertook this study to comprehensively investigate the role of (18) F-fluorodeoxyglucose-positron emission tomography (FDG-PET) in the assessment of disease activity in patients with TA. METHODS We performed a retrospective chart review of 53 FDG-PET scans in 38 patients with TA. We measured (18) F-fluorodeoxyglucose ((18) F-FDG) accumulation in the vascular wall of the large vessel using semiquantitative (visual grade) and quantitative (standard uptake value intensity) analyses. Clinical disease activity was evaluated based on the National Institutes of Health criteria for active TA, and erythrocyte sedimentation rates (ESRs) and C-reactive protein (CRP) levels were measured. RESULTS At baseline, active vascular (18) F-FDG uptake (visual grade ≥2) was observed in 18 of 24 patients with active disease and in 5 of 14 patients with inactive disease. There was a significant association between clinical disease activity and disease activity judged by FDG-PET (P = 0.008). Visual grade, standard uptake value intensity, and the number of vascular lesions with active (18) F-FDG uptake were significantly higher in patients with active disease and correlated well with the ESR and CRP levels. In 15 followup FDG-PET scans, the changes in visual grade, areas of active vascular (18) F-FDG uptake, and standard uptake value intensity reflected changes in clinical disease activity. CONCLUSION (18) F-FDG uptake was associated with clinical disease activity and markers of inflammation, and FDG-PET reflected changes in clinical disease activity in patients with TA. FDG-PET may be a useful tool for aiding in the assessment of disease activity in patients with TA.

High tumor metabolic activity as measured by fluorodeoxyglucose positron emission tomography is associated with poor prognosis in limited and extensive stage small-cell lung cancer

Purpose: We investigated the prognostic effect of incorporating metabolic assessment by 18F-fluoro-2-deoxyglucose uptake on positron emission tomography/computed tomography (18F-FDG-PET/CT) into a conventional staging system in small-cell lung cancer (SCLC). Experimental Design: Seventy-six consecutive patients with pathologically proven SCLC were enrolled. All patients underwent standard treatment after pretreatment 18F-FDG-PET/CT scanning. The mean values of maximal standardized uptake values (meanSUVmax) of the malignant lesions upon 18F-FDG-PET/CT were calculated. The Cox proportional hazards model was used with performance status, lactate dehydrogenase, stage, and meanSUVmax. Results: Patients with high meanSUVmax were significantly related with the established poor prognostic factors, such as higher lactate dehydrogenase (P = 0.04) and extensive disease (ED; P = 0.01). Furthermore, in multivariate analysis, patients with high meanSUVmax were associated with poor survival outcomes compared with patients with low meanSUVmax [adjusted hazard ratio, 3.74; 95% confidence interval (95% CI), 1.67-8.37; P = 0.001, for death and adjusted hazard ratio, 2.25; 95% CI, 1.21-4.17; P = 0.01 for recurrence/progression]. In subgroup analysis, limited disease (LD) with high meanSUVmax showed significantly shorter overall survival than LD with low meanSUVmax [high versus low meanSUVmax, 20.1 months (95% CI, 7.9-23.2) versus 35.3 months (95% CI, 27.6-42.9); P = 0.02]. ED with high meanSUVmax had significantly shorter overall survival than ED with low meanSUVmax [high versus low meanSUVmax, 9.5 months (95% CI, 4.9-13.9) versus 17.7 months (95% CI, 12.0-20.1); P = 0.007]. These findings were replicated in progression-free survival analysis. Conclusions: In SCLC, tumor metabolic activity as assessed by FDG-PET is a significant prognostic factor and identifies subgroups of patients at higher risk of death in both LD and ED SCLC.

The utility of F-18 FDG PET/CT in the evaluation of pancreatic intraductal papillary mucinous neoplasm.

Purpose: To assess the utility of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in evaluating pancreatic intraductal papillary mucinous neoplasm (IPMN). Materials and Methods: We included 31 patients with pancreatic IPMN who underwent F-18 FDG PET/CT and multidetector CT (MDCT). Each pancreatic lesion was classified as benign or malignant. On PET, the maximal standardized uptake value was measured in each pancreatic lesion. Results: PET/CT was superior to MDCT in diagnosing malignant IPMN. All 22 concordant results gave accurate diagnoses. Of 9 discordant results, MDCT misdiagnosed 7 IPMNs, whereas PET/CT misinterpreted 2. Malignant IPMNs showed significantly higher maximal standardized uptake values (mean ± standard deviation, 6.7 ± 3.6) than benign IPMNs (mean ± standard deviation, 2.1 ± 1.0) (P < 0.001). Conclusions: F-18 FDG PET/CT outperformed MDCT in detecting malignant IPMN.

Drug-loaded gold plasmonic nanoparticles for treatment of multidrug resistance in cancer.

To investigate the possibility of treating multidrug-resistant tumors with targeted chemo-photothermal treatment, we conducted in vitro and in vivo studies using a doxorubicin (DOX)-resistant DLD-1 cell line (DLD-1/DOX) and nude mice with human xenograft tumors, respectively. The chemo-photothermal treatment consisted of DOX-loaded-poly(lactic-co-glycolic acid)-Au half-shell nanoparticles with targeting moieties of anti-death receptor-4 monoclonal antibody conjugated to the Au surface. The cells or xenografted tumors treated with nanoparticles were exposed to near infrared light for 10 min, which caused an increase in temperature to 45 °C. Chemo-photothermal treatment resulted in a large reduction in the rate of tumor xenograft growth on DLD-1/DOX tumor-bearing mice with a much smaller dose of DOX than conventional DOX chemotherapy. These results demonstrate that targeted chemo-photothermal treatment can provide high therapeutic efficacy and low toxicity in the treatment of multidrug-resistant tumors.

Thyroid Incidentalomas Identified by 18F-FDG PET: Sonographic Correlation

OBJECTIVE The purpose of this study was to evaluate the risk of malignancy of thyroid incidentalomas detected on (18)F-FDG PET and the diagnostic accuracy of sonography for differentiating benign from malignant focal thyroid incidentalomas that were detected on FDG PET. MATERIALS AND METHODS Retrospective review was performed of a database of 87 focal thyroid lesions seen on FDG PET and sonography. Forty-two focal lesions were malignant. We compared the accuracy of the maximum standard uptake value (SUV) to differentiate benign from malignant thyroid lesions. We classified the thyroid nodules as probably benign or suspicious for malignancy by the sonographic features. Statistical analyses compared two subgroups by sonographic classifications between benign and malignant thyroid lesions. RESULTS The maximum SUV of the malignant nodules was not significantly higher than that of benign lesions. Thirty-seven (75.5%) of 49 lesions with suspicious sonographic findings revealed malignancy on cytopathology, compared with five (13.2%) of 38 lesions that showed probably benign sonographic findings. These differences were statistically significant using a kappa test (kappa = 0.675, p = 0.001) and logistic regression (odds ratio = 26.2, p = 0.001). CONCLUSION The probability (48.3%) of malignancy of focal thyroid incidentalomas seen on FDG PET is high. The maximum SUV of thyroid cancer is not significantly higher than that of benign lesions. The probability (13.2%) of malignancy is much lower when the sonographic findings appear benign, as compared with a significantly higher probability (75.5%) of malignancy when the sonographic findings are suspicious for malignancy.

The role of (18) F-fluorodeoxyglucose-positron emission tomography in the assessment of disease activity in patients with takayasu arteritis.

OBJECTIVE The assessment of disease activity in Takayasu arteritis (TA) is difficult in clinical situations because clinical symptoms and laboratory parameters do not always reflect the actual inflammation of the arterial wall. We undertook this study to comprehensively investigate the role of (18) F-fluorodeoxyglucose-positron emission tomography (FDG-PET) in the assessment of disease activity in patients with TA. METHODS We performed a retrospective chart review of 53 FDG-PET scans in 38 patients with TA. We measured (18) F-fluorodeoxyglucose ((18) F-FDG) accumulation in the vascular wall of the large vessel using semiquantitative (visual grade) and quantitative (standard uptake value intensity) analyses. Clinical disease activity was evaluated based on the National Institutes of Health criteria for active TA, and erythrocyte sedimentation rates (ESRs) and C-reactive protein (CRP) levels were measured. RESULTS At baseline, active vascular (18) F-FDG uptake (visual grade ≥2) was observed in 18 of 24 patients with active disease and in 5 of 14 patients with inactive disease. There was a significant association between clinical disease activity and disease activity judged by FDG-PET (P = 0.008). Visual grade, standard uptake value intensity, and the number of vascular lesions with active (18) F-FDG uptake were significantly higher in patients with active disease and correlated well with the ESR and CRP levels. In 15 followup FDG-PET scans, the changes in visual grade, areas of active vascular (18) F-FDG uptake, and standard uptake value intensity reflected changes in clinical disease activity. CONCLUSION (18) F-FDG uptake was associated with clinical disease activity and markers of inflammation, and FDG-PET reflected changes in clinical disease activity in patients with TA. FDG-PET may be a useful tool for aiding in the assessment of disease activity in patients with TA.

Visually Discernible [18F]Fluorodeoxyglucose Uptake in Papillary Thyroid Microcarcinoma: A Potential New Risk Factor

CONTEXT A significant number of papillary thyroid microcarcinomas (PTMCs), despite excellent prognosis, show aggressive features such as extrathyroidal extension (EE) and lymph node metastasis (LNM) that may not always be detected preoperatively or intraoperatively. The relapse rate appears also substantial. OBJECTIVE To assess the value of [(18)F]fluorodeoxyglucose (FDG) uptake in PTMC as a potential risk factor for preoperative risk stratification. METHODS This retrospective study included 87 patients (17 males and 70 females; mean age = 51.2 yr, range 29-74 yr) with a unifocal PTMC who underwent preoperative FDG-positron emission tomography (PET)/computed tomography (CT)and total thyroidectomy and central lymph node dissection. Statistical analyses were performed to compare the gender, age, tumor size, and FDG uptake in PTMC with the presence of histopathologically proven EE and central LNM (cLNM). RESULTS Of the 87 patients, 44 (51%) had EE, and 27 (31%) had cLNM. PET/CT showed visually discernible FDG uptake in 46 PTMCs (53%). FDG positivity of PTMCs was the only significant variable correlated with both EE and cLNM; there was a significant difference in the prevalence of both EE (70 vs. 29%) and cLNM (41 vs. 19.5%) between the FDG-positive and FDG-negative groups. In contrast, other already known risk factors, i.e. gender, age, and size, showed a correlation with only one or neither of EE and cLNM. CONCLUSION The results indicate that visual FDG positivity in PTMCs is a potential risk factor that can be useful for preoperative risk stratification. Prospective studies would be warranted to assess the long-term benefit and cost effectiveness of preoperative FDG-PET/CT.

Prognostic Value of Total Lesion Glycolysis by 18F-FDG PET/CT in Surgically Resected Stage IA Non–Small Cell Lung Cancer

Despite the favorable prognosis of stage IA non–small cell lung cancer (NSCLC), the disease recurs after complete surgical resection in 20%–30% of patients. This study determined the prognostic value of various metabolic parameters of 18F-FDG PET/CT in surgically resected stage IA NSCLC. Methods: We retrospectively reviewed 248 patients with stage IA NSCLC who underwent lobectomy and complete lymph node dissection after PET/CT. A region of interest was drawn on the primary lesion, and metabolic indices such as metabolic tumor volume, maximum standardized uptake value (SUVmax), and total lesion glycolysis (TLG) were measured using an SUV cutoff of 2.5. Results: The patients included 134 men and 114 women, and the mean age was 63.03 ± 10.01 y; 129 were stage T1a (≤2 cm) and 119 were T1b (>2 cm). The median follow-up period was 36.6 mo. Recurrence took place in 15 patients. The mean (±SD) SUVmax, metabolic tumor volume, and TLG were 4.55 ± 3.75, 5.92 ± 5.57, and 14.42 ± 17.35, respectively. The cutoffs of SUVmax and TLG were 3.7 and 13.76, respectively. The 5-y overall survival (OS) was 95.1% in low-SUVmax patients and 82.2% in high-SUVmax patients (P = 0.02). The 5-y OS was 93.7% in low-TLG patients and 78.3% in high-TLG patients (P = 0.01). On multivariate analysis, TLG was a risk factor for OS (hazard ratio, 3.159; P = 0.040), but SUVmax showed marginal significance (P = 0.064). The concordance index of the TLG model was 0.676 (95% CI, 0.541–0.812). Conclusion: TLG was a significant prognostic factor for OS in patients with stage IA NSCLC.

Prognostic Value of 18F-Fluorodeoxyglucose Positron Emission Tomography in Patients with Resectable Pancreatic Cancer

Purpose We evaluated the prognostic value of 18F-2-fluoro-2-deoxyglucose positron emission tomography (FDG PET) in patients with resectable pancreatic cancer. Materials and Methods We retrospectively reviewed the medical records of pancreatic cancer patients who underwent curative resection, which included 64 consecutive patients who had preoperative FDG PET scans. For statistical analysis, the maximal standardized uptake value (SUVmax) of primary pancreatic cancer was measured. Survival time was estimated by the Kaplan-Meier method, and Coxs proportional hazard model was used to determine whether SUVmax added new predictive information concerning survival together with known prognostic factors. p<0.05 indicated statistical significance. Results Overall survival (OS) and disease-free survival (DFS) were respectively 42.9 months (27.6-58.2; 95% CI) and 14.9 months (10.1-19.7; 95% CI). When subjects were divided into two groups according to SUVmax with a cutoff value of 3.5, the high SUVmax group (n=32; SUVmax >3.5) showed significantly shorter OS and DFS than the low SUVmax group. Multivariate analysis of OS and DFS showed that both high SUVmax and poor tumor differentiation were independent poor prognostic factors. Conclusion Our study showed that degree of FDG uptake was an independent prognostic factor in pancreatic cancer patients who underwent curative resection.

Usefulness of FDG PET/CT in determining benign from malignant endobronchial obstruction

ObjectiveTo evaluate the usefulness of FDG PET/CT to differentiate malignant endobronchial lesions with distal atelectasis from benign bronchial stenosis.MethodsThis retrospective study reviewed 84 patients who underwent contrast-enhanced chest CT and then PET/CT and had histological (n = 81) or follow-up imaging (n = 3) confirmation. Two chest radiologists reviewed initial chest CT and determined endobronchial lesions to be malignant or benign. Two nuclear medicine physicians reviewed PET/CT for FDG uptake at the obstruction site and measured SUV. Malignancy was considered when increased FDG uptake was seen in the obstruction site, regardless of FDG within the atelectatic lung.ResultsThe sensitivity, specificity and accuracy of chest CT was 95%, 48% and 84%, compared with 95%, 91% and 94% for PET/CT. Benign obstructive lesions showed statistically lower FDG uptake than malignant obstructions (benign SUV 2.5 ± 0.84; malignant SUV 11.8 ± 5.95, p < 0.001). ROC analysis showed an SUV cut-off value of 3.4 with highest sensitivity of 94% and specificity of 91%.ConclusionIncreased FDG PET/CT uptake at the obstruction site indicates a high probability of malignancy, while benign lesions show low FDG uptake. Careful evaluation of FDG uptake pattern at the obstruction site is helpful in the differentiation between benign and malignant endobronchial lesions.