F-fluorodeoxyglucose Positron Emission Tomography Findings Research Articles

Analysis of18F-fluorodeoxyglucose positron emission tomography findings in patients with pituitary lesions

Background/AimsAlthough magnetic resonance imaging (MRI) is a good visual modality for the evaluation of pituitary lesions, it has limited value in the diagnosis of mixed nodules and some cystic lesions. We evaluated the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG PET) for patients with pituitary lesions.Methods18F-FDG PET and MRI were performed simultaneously in 32 consecutive patients with pituitary lesions. The relationships between FDG uptake patterns in PET and MRI findings were analyzed.ResultsOf 24 patients with piuitary adenomas, 19 (79.2%) showed increased uptake of 18F-FDG in the pituitary gland on PET scans. All patients with pituitary macroadenomas showed increased 18F-FDG uptake on PET scans. Meanwhile, only five (50%) of the 10 patients with pituitary microadenomas showed positive PET scans. Interestingly, of two patients with no abnormal MRI findings, one showed increased 18F-FDG uptake on PET. For positive 18F-FDG uptake, maximum standardized uptake values (SUVmax) > 2.4 had 94.7% sensitivity and 100% specificity. In addition, SUVmax increased in proportion to the size of pituitary adenomas. Most cystic lesions did not show 18F-FDG uptake on PET scans.ConclusionsAbout 80% of pituitary adenomas showed positivity on PET scans, and SUVmax was related to the size of the adenomas. PET may be used as an ancillary tool for detection and differentiation of pituitary lesions.

18F-fluorodeoxyglucose positron emission tomography immediately after chemoradiotherapy predicts prognosis in patients with locoregional postoperative recurrent esophageal cancer

The objectives of this study were to reveal the utility of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) within 7 days after chemoradiotherapy to predict prognosis in patients with postoperative recurrent esophageal cancer. Patients scheduled to undergo concurrent chemoradiotherapy for postoperative locoregional recurrence of esophageal cancer were recruited. Selection criteria were: (1) locoregional recurrence, (2) no previous radiation therapy, (3) planning treatment with concurrent chemoradiotherapy, (4) FDG-PET performed <2 weeks before chemoradiotherapy, and (5) no serious diabetes. FDG-PET was performed <7 days after chemoradiotherapy. No more treatment after chemoradiotherapy was given until disease progression was diagnosed according to the Response Evaluation Criteria in Solid Tumors (RECIST). Correlations of FDG-PET findings with cause-specific survival and local control rates were investigated prospectively. Twenty patients were enrolled. Median observation period of patients who survived was 45.0 months. Median maximum standardized uptake value (SUV(max)) after chemoradiotherapy was 2.4, and median SUV(max) before chemoradiotherapy was 8.4. Cause-specific survival and local control rates were significantly better for patients with SUV(max) < or = 2.4 after chemoradiotherapy (log-rank test, P = 0.033 and 0.010, respectively). SUV(max) before chemoradiotherapy tended to be correlated only with cause-specific survival rate (log-rank test, P = 0.076). Change in metabolic activity of FDG was significantly correlated with local control rate (log-rank test, P = 0.042). FDG-PET performed even <7 days after chemoradiotherapy predicts prognosis in patients with postoperative recurrent esophageal cancer.

Empiric High-Dose 131-Iodine Therapy Lacks Efficacy for Treated Papillary Thyroid Cancer Patients with Detectable Serum Thyroglobulin, but Negative Cervical Sonography and 18F-Fluorodeoxyglucose Positron Emission Tomography Scan

Some patients with elevated serum thyroglobulin (Tg) but a negative diagnostic whole body scan (WBS) after initial therapy for differentiated thyroid carcinoma may benefit from empirical radioactive iodine (RAI) therapy. However, previous studies enrolled patients with negative diagnostic WBS, regardless of neck ultrasonography (USG) and/or (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET), which have become the preferred diagnostic procedures in such patients. The aim of this study was to evaluate the usefulness of empirical RAI therapy in patients with elevated stimulated Tg level and negative USG/FDG-PET findings after initial therapy for papillary thyroid carcinoma (PTC). This comparative study enrolled 39 patients with elevated stimulated Tg, negative diagnostic WBS, and negative USG/FDG-PET 1 yr after initial treatment. Empirical RAI therapy was performed in 14 patients (treatment group), whereas 25 patients were followed up without therapy (control group). There was no significant between-group difference in basal clinicopathological parameters. None of the 14 patients in the treatment group showed iodine uptake on posttreatment WBS. Five of 14 patients (36%) in the treatment group and eight of 25 (32%) in the control group had recurrence during the median 37 months of follow-up (P = 0.99). Changes in serum stimulated Tg concentrations did not differ between the two groups. Empirical RAI therapy and posttreatment WBS were not useful diagnostically or therapeutically in patients with positive serum stimulated Tg if such patients had negative USG and negative FDG-PET findings after initial treatment of PTC.

Diagnostic value of 18F-fluorodeoxyglucose positron emission tomography for pancreatic neuroendocrine tumors with reference to the World Health Organization classification

The 2004 classification of the World Health Organization (WHO) has demonstrated an efficacy for prediction of the prognosis of pancreatic neuroendocrine tumors. This study aimed to assess the predictive value of preoperative (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in relation to the 2004 WHO criteria. The histology of 21 pancreatic endocrine tumors resected at our hospital was reviewed and the tumors were classified according to the 2004 WHO criteria. FDG-PET findings were analyzed by comparing the findings with CT scans. FDG uptake was positive in 10 primary endocrine tumors (47%), but no uptake was seen in 11 tumors. In relation to the 2004 WHO classification, 1 out of 8 well-differentiated tumors with benign behavior was positive by PET (12.5%), 4 out of 7 well-differentiated tumors with uncertain behavior were positive (57%) and 4 low-grade malignant tumors were positive (100%). According to the WHO criteria, the rate of positive FDG uptake increased as the malignant potential increased. The metastases of low-grade malignant tumors also showed a positive FDG uptake. In conclusion, from our limited experience, FDG-PET appears to be useful for identifying pancreatic neuroendocrine tumors with a higher malignant potential. In addition, FDG-PET can detect distant metastases and may contribute to better staging of advanced disease.

Multifocal Nodular Lymphoid Hyperplasia of the Lung Differently Identified by18F-Fluorodeoxyglucose Positron Emission Tomography (FDG‐PET)

Nodular lymphoid hyperplasia (NLH) is a rare lung disease classified as a non-neoplastic pulmonary lymphoid lesion. It is believed that 36 % of cases present with multifocal lesions, and although there are some reports in which (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) results are positive, the FDG uptakes vary and the imaging findings are very similar to those of lung cancer or malignant lymphoma. We present a case of surgically resected multifocal NLH which was differently identified by chest computed (CT) tomography appearance and FDG-PET findings.

Radiology–Pathology Conference: sclerosing hemangioma of the lung

Sclerosing hemangioma (SH) is a relatively rare, benign neoplasm of the lung. Although there are relatively characteristic imaging findings, biopsy remains the definitive diagnostic test. We report the radiology and pathology of a patient with a SH, with emphasis on the computed tomographic and (18)F-fluorodeoxyglucose positron emission tomography findings, and review the literature on this unusual tumor.

Nasopharyngeal carcinoma staging by (18)F-fluorodeoxyglucose positron emission tomography

Nasopharyngeal carcinoma (NPC) has a high rate of neck lymph node and/or distant metastasis. We evaluated the value of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in staging NPC, especially in the detection of distant metastasis. A total of 95 patients, including 85 with primary and 10 with recurrent, NPC were enrolled. Dual-phase FDG-PET was used, in addition to the conventional workup. Eighty-one patients without distant metastases underwent repeat studies 3-4 months after initial radical treatment. Of 14 patients with distant metastases, all had lesions detected by FDG-PET, and the conventional workup detected the metastases in only 4. Two patients had false-positive MRI findings for neck node metastasis, but the FDG-PET findings were accurate. Four patients without distant metastases on their initial workup were found to have new lesions on FDG-PET 3-4 months after initial treatment. Patients with advanced node disease had a significantly greater incidence of distant metastases on FDG-PET, especially for N3 disease. Of the 95 patients, the FDG-PET results for distant metastasis were true positive in 14 patients, false positive in 8, and true negative in 73. None of our patients had a false-negative result. For a patient base, the sensitivity and specificity of FDG-PET for distant metastasis was 100% and 90.1% (95% confidence interval 81.5-95.6%), respectively, in this study. The accuracy was 91.6% (95% confidence interval 84.1-96.3%), the positive predictive value was 63.6 (95% confidence interval 40.7-82.8%), and the negative predictive value was 100%. FDG-PET stages N and M disease of NPC more accurately and sensitively than does the conventional workup. Patients with advanced node disease, particularly N3 disease, would benefit the most from FDG-PET.