Background: F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a promising modality for detecting active lesions of cardiac sarcoidosis (CS). However, determining whether ¹⁸F-FDG uptake in the myocardium is physiological is challenging due to metabolic shift in myocardial cells. Although methods for inhibiting physiological myocardial ¹⁸F-FDG uptake have been proposed, no standard methods exist. This study therefore aimed to compare the effect of an 18-h fast (long fasting (LF)) with heparin loading plus a 12-h fast (HEP) before ¹⁸F-FDG PET scan. Methods: We analyzed the effects of LF and HEP on the inhibition of physiological myocardial ¹⁸F-FDG uptake in healthy subjects (18 in HEP and 19 in LF) and in patients with known or suspected CS (96 in HEP and 69 in LF). In CS, the lower uptake of ¹⁸F-FDG in the myocardium was evaluated. A visual four-point scale was used to assess myocardial ¹⁸F-FDG uptake in comparison with hepatic uptake (1 lower, 2 similar, 3 somewhat higher, 4 noticeably higher). Results: Myocardial ¹⁸F-FDG uptake was 1.68 ± 1.06 in LF and 3.17 ± 1.16 in HEP in healthy subjects (p < 0.0001), whereas it was 1.48 ± 0.99 in LF and 2.48 ± 1.33 in HEP in CS patients (p < 0.0001). Logistic regression and regression trees revealed the LF was the most effective in inhibiting myocardial ¹⁸F-FDG uptake. In addition, serum free fatty acid levels on intravenous ¹⁸F-FDG injection were a possible biomarker. Conclusions: LF is effective in inhibiting myocardial ¹⁸F-FDG uptake, and consequently, it could be useful for evaluating active lesions of CS in ¹⁸F-FDG PET images.

4′-[methyl-11C]-thiothymidine (4DST) is a novel positron emission tomography (PET) tracer to assess proliferation of malignancy. The diagnostic abilities of 4DST and 2-deoxy-2-18 F-fluoro-d-glucose (FDG) for detecting regional lymph node (LN) metastases of non-small cell lung cancer (NSCLC) were prospectively compared. In addition, the relationship between the PET result and the patient's prognosis was evaluated.

We present the F-18 FDG and ¹¹C-choline PET/CT images obtained in 2 cases of hemangioblastoma. Hemangioblastoma is a highly vascular benign tumor that typically arises in the cerebellum or spine. The characteristic findings of a hemangioblastoma on both CT and MR include a peripherally located cerebellar lesion with a central cystic region and a peripherally enhanced nodule. In both patients, the uptake in the lesion was relatively low on the F-18 FDG PET/CT images and relatively high on the ¹¹C-choline PET/CT images.

Background/Objectives: Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is a valuable imaging modality for detecting malignancies and diagnosing fever of unknown origin (FUO). However, data regarding FDG accumulation in bone marrow among pediatric acute leukemia (AL) cases are limited. In this study, we aimed to compare FDG-PET/CT findings between children with AL and those with inflammatory diseases (IDs), including FUO, and develop a scoring system for differential diagnoses. Methods: We retrospectively analyzed FDG-PET/CT findings in six children with AL and 22 with IDs. The maximum standardized uptake value (SUV max), visual score (VS), and spread score (SS) were evaluated across various bone marrow sites, including vertebrae, pelvic bone, humerus, forearm, and femur. Statistical analysis consisted of Mann–Whitney U test for group comparisons and receiver operating characteristic curve (ROC)/area under the curve (AUC) analyses to assess diagnostic performance. Results: SUV max, VS, and SS were significantly higher in children with AL across all evaluated sites. The combined VS + SS scoring system yielded the highest diagnostic accuracy. A simplified version using only the VS of the middle humerus and femur plus the SS showed comparable effectiveness. Conclusions: FDG-PET/CT in children with AL showed high FDG accumulation in bone marrow areas in the whole body. The simple scoring system, which comprises FDG accumulation in the middle portion of the extremities and the whole body, appears to be helpful in distinguishing AL from IDs in children. FDG-PET/CT-based visual scoring may provide supportive information alongside conventional diagnostics in pediatric acute leukemia.