18F-Fluorocholine, 18F-FDG, and 18F-Fluoroethyl Tyrosine PET/CT in Parathyroid Cancer.

We report on a 71-year-old woman presenting with biochemical features indicating recurrent disease in long-term follow-up of left-sided parathyroid carcinoma. She had undergone several surgical procedures including total thyroidectomy, partial resection of the esophageal wall, and curative neck radiation 12 years previously. PET/CT using F-fluorocholine revealed high uptake in local relapse in the lower neck, comparable to F-FDG, whereas only faint uptake was observed with F-fluoroethyl tyrosine. As shown in this case, imaging with FDG and F-fluorocholine is feasible in (recurrent) parathyroid carcinoma and clearly superior to F-fluoroethyl tyrosine.

Thyroid screening in HIV-infected patients with antiretroviral therapy.

BACKGROUND: The literature reports an increased incidence of thyroid disorders in human immunodeficiency virus (HIV)-positive persons. We therefore retrospectively analyzed the strategy of collecting thyroid parameters on a routine basis. METHODS: Overall 410 patients (147 women, 263 men; age, 10-74 years; median age, 45 years) were included. For screening purposes, three parameters were determined; basal thyroid-stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3). Descriptive and statistical analyses were performed in the patient groups with increased bTSH (> 4.0 µU/ml) and with decreased fT4 (< 8.9 pg/ml) to evaluate possible correlation with age, gender, duration of antiretroviral therapy (ART), substance classes of ART (nucleosidal reverse transcriptase inhibitors (NRTIs), nonnucleosidal reverse transcriptase inhibitors, and protease inhibitors (PIs)), Centers for Disease Control and Prevention (CDC) disease stage, lowest number of CD4 cells during course of disease, and coexistent hepatitis C. RESULTS: Elevated bTSH was found in 27 patients (median, 5.26 µU/ml), who also showed a correlation with ART duration and NRTI use. Decreased fT4 was seen in 53 persons, and a correlation with PI intake was observed. Of these patients, 31 exhibited normalization in follow-up. Decreased fT3 was observed in eight cases related to nonthyroid illness, and fT3 was elevated in ten patients. No overt hyperthyroidism was noticed; three cases of subclinical hyperthyroidism were transient. CONCLUSIONS: In the examined group of patients, the prevalence of abnormal thyroidal parameters was 23 %. Decreased fT4, which does not require therapy, was observed most frequently (12 %) and correlated with PI use. On the other hand, elevated bTSH (6 %) correlated with ART duration and NRTI use. In mild subclinical hypothyroidism as observed in this patient population, thyroxine medication is not indicated in principle. Annual TSH screening is probably sufficient in HIV-infected patients with no clinical symptoms suggestive for thyroid disease.

Malignant disease as an incidental finding at ¹8F-FDG-PET/CT scanning in patients with granulomatous lung disease.

PURPOSE: Fluorine-18 fluorodeoxyglucose (¹8F-FDG)-PET/computed tomography (CT) is used for assessment of the extent and activity of disease in patients with inflammatory granulomatous lung disease, in particular sarcoidosis and tuberculosis. The aim of this retrospective analysis was to assess the value of ¹8F-FDG-PET/CT in the identification of previously unknown malignant disease during routine investigation of granulomatous lung disease. MATERIALS AND METHODS: From July 2008 to December 2013, a total of 122 patients with tuberculosis (76 male and 46 female patients; age range 19.6-88.6 years, mean 52.8±16.6 years) and 85 patients with sarcoidosis (46 male and 39 female patients; age range 17.8-76.5 years, mean 48.6±13.8 years) underwent ¹8F-FDG-PET/CT. Reports were generated in consensus by both a nuclear medicine physician and a radiologist. Possibly malignant findings underwent biopsies and/or follow-up. Quantitative parameters (maximum standardized uptake value) were pooled and compared from reference lesions in each group. RESULTS: Malignant disease was suspected in 18 of 122 tuberculosis patients and in eight of 85 sarcoidosis patients. Malignancy was finally confirmed in six patients with tuberculosis and in two patients with sarcoidosis. In one single case a malignant lung tumour had been overlooked on PET/CT. Patients were also analysed according to their age. In the patient group older than 60 years, four malignancies were confirmed in 44 tuberculosis patients and in one in 20 sarcoidosis patients, whereas in patients aged between 30 and 60 years only three of 63 tuberculosis and one of 58 sarcoidosis cases showed malignancy compared with the 18 false-positive findings on a total patient basis. The most common site of malignant disease was the chest. Besides the intrathoracic findings, two cases of malignancy were detected outside the thorax. Quantitative evaluation did not reveal any statistically significant difference between the tuberculosis and sarcoidosis groups. CONCLUSION: Differentiation between granulomatous inflammation and malignancy is challenging with ¹8F-FDG-PET/CT because of a large number of false-positive findings. The highest probability of detecting coexistent malignant disease was seen in patients older than 60 years who were suffering from tuberculosis. An important feature for identification of malignant disease, especially in the assessment of intrathoracic findings, has turned out to be the CT pattern; quantitative evaluation, in contrast, seems to have little clinical value.