Background SMARCA4-deficient thoracic tumor (SMARCA4-DTT) is a distinct entity of undifferentiated thoracic malignancies newly introduced in 2015. Due to its unique clinical characteristic with aggressive thoracic tumor mostly observed in heavy smoker man with emphysema, with poor prognosis, many physicians are becoming increasingly aware of the disease; however, reports on 2-deoxy-2-[18F] fluoroglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) have been limited; thus, this disease is not yet widely known to nuclear medicine clinicians. As a first step in discussing the usefulness of [18F]FDG PET/CT for this disease, we present a case in which [18F]FDG PET/CT played a clinically important role. Case A 74-year-old heavy smoker man with an anamnesis of severe emphysema characterized by pleural thickening and abnormal enhancement in CT underwent 18F-FDG PET/CT for further examination. [18F]FDG-avid pleural nodules infiltrating into the chest wall were detected and pathologically diagnosed as SMARCA4-DTT with biopsy. Conclusion SMARCA4-deficient thoracic tumor should be considered in a [18F]FDG-avid aggressive thoracic tumor in heavy smoker men with emphysema.

No abstract

Background To assess the impact of time-of-flight (TOF) positron emission tomography (PET)/computed tomography (CT) image reconstruction on assessment of Takayasu arteritis (TKA). We reviewed 14 patients (15 cases) who underwent TOF-PET/CT. PET images were reconstructed using ordered-subsets expectation maximisation ± TOF. Uptake in 10 vascular regions was assessed using the four-point visual grading system (3, higher than liver uptake; 0, no uptake). The grades in the TOF-PET/CT and non-TOF-PET/CT groups were compared using the sign test. Relationships between visual grade and arterial FDG uptake pattern in the 10 regions and clinical findings were assessed. Results Except for the highest visual grade, the visual grades in all regions were significantly higher in the TOF-PET/CT group (p=0.003). FDG uptake pattern and region were not significant determinants of the effect of TOF reconstruction. Assessment of disease activity was inconsistent between the groups in 6 (4%) of 150 regions when grade 2/3 was defined as active and in 5 (3.3%) of 150 when grade 3 was defined as active. Conclusions Visual grades were significantly higher in all regions when assessed by TOF-PET/CT. Use of the same reconstruction algorithm before and after treatment is recommended when evaluating the response to treatment.