Yan R, et al. Korean J Radiol. 2015 Jul-Aug;16(4):919-928. https://doi.org/10.3348/kjr.2015.16.4.919

Objectives The aim of this study was to evaluate the ¹⁸F-sodium fluoride (¹⁸F-NaF) coronary uptake compared to coronary intravascular ultrasound (IVUS) in patients with symptomatic coronary artery disease. Background ¹⁸F-NaF PET enables the assessment of vascular osteogenesis by interaction with surface hydroxyapatite, while IVUS enables both identification and quantification of intra-plaque components. Methods Forty-four patients with symptomatic coronary artery disease were included in this prospective controlled trial, 32 of them (30 patients with unstable angina and 2 patients with stable angina), representing the final study cohort, got additional IVUS. All patients underwent cardiac ¹⁸F-NaF PET/CT and IVUS within 2 days. ¹⁸F-NaF maximum tissue-to-blood ratios (TBR_max) were calculated for 69 coronary plaques and correlated with IVUS plaque classification. Results Significantly increased ¹⁸F-NaF uptake ratios were observed in fibrocalcific lesions (meanTBR_max = 1.42 ± 0.28), thin-cap atheroma with spotty calcifications (meanTBR_max = 1.32 ± 0.23), and thick-cap mixed atheroma (meanTBR_max = 1.28 ± 0.38), while fibrotic plaques showed no increased uptake (meanTBR_max = 0.96 ± 0.18). The ¹⁸F-NaF uptake ratio was consistently higher in atherosclerotic lesions with severe calcification (meanTBR_max = 1.34 ± 0.22). The regional ¹⁸F-NaF uptake was most likely localized in the border region of intensive calcification. Coronary lesions with positive ¹⁸F-NaF uptake showed some increased high-risk anatomical features on IVUS in comparison to ¹⁸F-NaF negative plaques. It included a significant severe plaque burden (70.1 ± 13.8 vs. 61.0 ± 13.8, p = 0.01) and positive remodeling index (1.03 ± 0.08 vs. 0.99 ± 0.07, p = 0.05), as well as a higher percentage of necrotic tissue (37.6 ± 13.3 vs. 29.3 ± 15.7, p = 0.02) in positive ¹⁸F-NaF lesions. Conclusions ¹⁸F-NaF coronary uptake may provide a molecular insight for the characterization of coronary atherosclerotic lesions. Specific regional uptake is needed to be determined by histology.

Graves' disease (GD) is one of the most common autoimmune conditions, but the mechanisms underlying the associated induction of autoimmunity are not known. We explored the role of peripheral lymphocyte subpopulations in disease pathogenesis. In total, 32 patients and 40 age- and sex-matched healthy controls were recruited in this study. Peripheral levels of T, B, NK, CD4⁺ T, CD8⁺ T, Th1, Th2, Th17, and Treg cells were measured using flow cytometry. For all patients, we compared all lymphocyte subpopulations between GD patients and healthy controls. Changes in patient lymphocyte subsets were compared before and after treatment. The absolute numbers of circulating Th17 cells (0.45 ± 1.16, p > 0.05) between GD patients and healthy controls were not significantly different. However, the percentage of Th17 cells was significantly increased (0.25 ± 0.11, p < 0.05). The absolute numbers and percentages of circulating Tregs in GD patients were significantly decreased compared with those in healthy participants (11.61 ± 2.75, p < 0.05). There was a significant difference in Treg absolute numbers between the untreated and drug-treated groups. Furthermore, we found that the Treg percentage in untreated patients (mean=4.78) was not significantly different from that in the drug-treated group (mean=4.81). In addition, circulating Treg absolute numbers in GD patients with exophthalmos were significantly lower than those in GD patients without exophthalmos (9.96 ± 4.16, p < 0.05). A similar trend was observed in GD patients with weight loss (11.97 ± 3.28, p < 0.05). GD pathogenesis was associated with a lower Treg population and an increased Th17/Treg ratio (T helper cell 17/ regulatory T cells). Th17 cells in this study were not related to the disease. Furthermore, anti-thyroid drug therapy improved immune-mediated system disorders. Finally, we found lower absolute numbers of circulating Tregs in GD patients with certain positive signs, such as exophthalmos and/or weight loss. Thus, immune changes are correlated with partial clinical manifestations.

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is routinely used in diffuse large B cell lymphoma (DLBCL) for staging, assessment of remission and recurrence, and estimation of therapeutic efficacy. In this study, we aimed to assess the role of an early interim PET/computed tomography (CT) in the evaluation of response in DLBCL.