18F-FDGPET/CT in fever of unknown origin and inflammation of unknown origin: a Chinese multi-center study.

PURPOSE: To evaluate the clinical value of 18F-FDG-PET/CT for the diagnosis of fever of unknown origin (FUO) and inflammation of unknown origin (IUO) in Chinese population, as well as the characteristics of PET/CT in different category of etiological disease. METHODS: A total of 376 consecutive patients with FUO/IUO who underwent FDG-PET/CT at 12 hospitals were retrospectively studied. FDG uptake was quantitatively and visually evaluated, by using SUVmax and a 4-grade scale respectively. A questionnaire survey to the clinicians was used to evaluate the significance of PET/CT in diagnosing of FUO/IUO. Data analysis included the etiological distribution in the study population, image characteristics in different category of diseases, and clinical significance of PET/CT. RESULTS: In 376 studied patients, the infectious diseases accounted for 33.0% of patients, rheumatologic diseases for 32.4%, malignancies for 19.1%, miscellaneous causes for 6.6%, and cause unknown for 8.8%. However, the etiological distribution among hospitals was varied. In addition, the etiological disease composition ratio has changed over time in China. On PET/CT examinations, 358 (95.2%) of the patients had a positive finding. Within them, local high uptake lesion was found in 219 cases, and nonspecific abnormal uptake (NAU) was found in 187 cases. FDG uptake in malignant diseases was significantly higher than in other category diseases both on SUVmax and visual scores (t-value range from 4.098 to 5.612, all P value < 0.001). Based on a clinical questionnaire survey, PET/CT provided additional diagnostic information for 77.4% of patients, and 89.6% of patients benefited from PET/CT examination. CONCLUSIONS: FDG PET/CT is a valuable tool for clinical diagnosis of FUO/IUO, and it is of great significance in further investigating the usefulness of PET/CT in non-neoplastic diseases.

AFP-producing hepatoid adenocarcinoma of appendix: a case report of 18F-FDG PET/CT.

Hepatoid adenocarcinoma (HAC) is a rare tumor. We described here a rare case of appendix HAC. A 59-year-old man underwent F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for gradually elevated alpha-Fetoprotein level. Multiple masses in the abdominal cavity with moderate FDG uptake were revealed, suggesting malignant tumor with peritoneal metastasis. The patient underwent radical resection, and the postoperative pathological result was HAC originated from the appendix. To our knowledge, it is the first report of HAC of the appendix. Our study suggests that FDG PET/CT may help in detecting the primary tumor and the metastases of HAC.

Efficacy of conventional whole-body ¹8F-FDG PET/CT in the incidental findings of parotid masses.

OBJECTIVE: The objective of this study was to evaluate the incidence of incidental parotid masses with conventional whole-body ¹8F-deoxyglucose (FDG) PET/CT and assess the ability of PET/CT to characterize these unexpected parotid lesions. METHODS: Fifty eight incidental findings of parotid masses with routine FDG PET/CT whole-body scan were reviewed in this retrospective analysis, which were selected from the patients without any known or suspected parotid disease in our PET center, from June 2005 to May 2009. 51 cases were operated or underwent a biopsy after a short-term PET/CT study; the remaining 7 cases had a follow-up. Parotid mass that showed both noncontrast CT (irregular shape and blurry border) and PET malignant features (high FDG uptake, SUV(max) > 3.0) was considered as positive for malignancy. Correlation of FDG PET/CT with histology or follow-up outcome was performed. RESULTS: Fifty eight unexpected findings of parotid masses accounted for 0.3% of the total cases in 4 years, including 11 (19.0%) malignant tumors and 47 (81.0%) benign lesions. 13 lesions manifested single nodule with malignant CT features and intense FDG activity, of which 6 were proved to be malignant; thus, sensitivity and positive predictive values were 54.5% (6 of 11) and 46.2% (6 of 13), respectively. 45 lesions showed either single nodule with benign CT features, or a low FDG uptake (SUV(max) ≤ 3.0), of which 40 were true negatives; therefore, specificity and negative predictive values were 85.1% (40 of 47) and 88.9% (40 of 45), respectively. All parotid masses except 9 benign and 1 malignant showed a high FDG uptake. Compared with SUV only, combined interpretation of PET and CT results displayed a lower sensitivity (90.9-54.5%), but a higher specificity (19.1-85.1%) and a higher overall accuracy. CONCLUSIONS: Whole-body FDG-PET/CT at the time of surveying the entire body condition is helpful for detecting the asymptomatic parotid masses. Combined noncontrast CT is an essential evidence for improving the diagnostic accuracy of FDG-PET/CT for parotid masses.

Prognostic value of 2-[18F]fluoro-2-deoxy-D-glucose uptake as measured by PET scan in patients with non-small cell lung cancer.

This study aimed to evaluate the prognostic value of 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) uptake determined by positron emission tomography (PET) in patients with non-small cell lung cancer (NSCLC) in relation to disease stage and/or tumor histology. A retrospective review of 144 patients with newly diagnosed lung cancer undergoing PET imaging was performed. Differences in survival were compared by univariate and multivariate analyses. Univariate analysis identified three prognostic factors: stage, lesion size and the standardized 18F-FDG uptake value. The latter was a better prognostic predictor in lung cancer patients with early-stage disease than in those at advanced stages. Multivariate analysis revealed that the most important prognostic factors were tumor-node-metastasis (TNM) stage and the standardized 18F-FDG uptake value. Patients with standardized uptake values (SUVs) >8 had a 2.5 times higher mortality rate than those with values ≤8. A one-unit increase in SUV corresponded with a 7% increase in the hazard of death. SUVs provided stronger prognostic stratification in patients with adenocarcinoma than in those with squamous cell carcinoma (SCC). Furthermore, the best choice of prognostic predictor differed between the two types of lung cancer: the SUV was best for SCC, while TNM stage was most significant for adenocarcinoma. In conclusion, 18F-FDG uptake in primary lung lesions is an independent prognostic predictor in patients with NSCLC, especially those with adenocarcinoma or early-stage disease. Further stratification of patients with the same TNM stage based on SUVs may allow for the modification of individual treatment strategies, resulting in improved outcome.