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In the diagnosis and staging of oncologic patients, [ 18 F]-fluorodeoxyglucose positron emission tomography (FDG-PET) is well recognized as an important functional imaging modality. FDG-PET also has been used for cancer screening in healthy individuals. In general, the normal thyroid gland shows absent or low uptake on FDG-PET, which is often identified as an incidental finding on PET. Today, thyroid FDG uptake can be seen in three patterns: diffuse; focal; and diffuse-plus-focal. Diffuse thyroid uptake is mainly considered an indicator of chronic thyroiditis. Focal thyroid uptake has been associated with malignancy (range 25-50%). Diffuse-plus-focal uptake is not well recognized and might also indicate a risk of malignancy. Understanding the patterns of thyroid FDG uptake is thus important for nuclear medicine physicians or radiologists when giving recommendations to the referring physician. In this pictorial review, we show the clinical significance of different patterns of thyroid uptake on FDG-PET [PET/computed tomography (CT)], including ultrasonography (US) findings.

Bone scintigraphy with technetium-99m ( 99m Tc)-labeled diphosphonates is one of the most frequently performed radionuclide procedures. Accumulation of 99m Tc-labeled diphosphonate is well recognized to reflect conditions of accelerated bone turnover and metabolism. Therefore, it is a functional imaging modality for detecting metastatic bone tumors, metabolic bone disease, traumatic injury, and inflammation. This pictorial essay describes the possible patterns of distribution of abnormal uptake for differential diagnosis of metastatic bone tumor, as well as the diagnostic pitfalls of bone scintigraphy.

Objective: Endothelial dysfunction is an initial step in atherosclerotic cardiovascular disease. However, involvement of vascular inflammation in endothelial dysfunction is not fully investigated in humans because of the lack of diagnostic modality to noninvasively evaluate vascular inflammation. We assessed the relationship between endothelial function and vascular inflammation evaluated by [(18)F]-fluorodeoxyglucose-positron emission tomography/computed tomographic imaging., Approach and Results: We examined endothelial function and vascular inflammation by flow-mediated dilation (FMD) of the brachial artery and [(18)F]-fluorodeoxyglucose-positron emission tomography/computed tomographic imaging of carotid arteries, respectively, in 145 subjects (95 men and 50 women; mean age, 61.8±9.5 years) who underwent a risk-screening test for cardiovascular disease in Kurume University Hospital. Vascular inflammation was measured by blood-normalized standardized uptake value, known as a target:background ratio (TBR). We investigated whether absolute changes from baseline of %FMD after antihypertensive treatment for 6 months (Δ%FMD) were correlated with those of TBR in 33 drug-naive patients with essential hypertension. Multiple logistic regression analysis revealed that age (odds ratio, 1.767 for 10-year increase), male sex (odds ratio, 0.434), low-density lipoprotein-cholesterol (odds ratio, 1.630 for 26-mg/dL increase), and TBR values (odds ratio, 1.759 for 0.2 increase) were independently associated with %FMD in 145 patients. There was an inverse correlation between Δ%FMD and ΔTBR; ΔTBR was a sole independent associate of Δ%FMD in hypertensive patients (r=-0.558; P<0.001)., Conclusions: The present study showed that vascular inflammation in the carotid arteries evaluated by [(18)F]-fluorodeoxyglucose-positron emission tomography/computed tomography was one of the independent correlates of decreased %FMD, thus suggesting the association of vascular inflammation with endothelial dysfunction in humans., (© 2016 American Heart Association, Inc.)

Objective: To prospectively evaluate the breast cancer detection of prone breast positron emission tomography (PET) images in comparison with supine whole-body PET images., Material and Methods: One hundred and eighteen female patients (age range 28-91 years) with 122 lesions suspected of having breast cancer underwent fluorine-18 fluorodeoxyglucose PET for preoperative staging. After the whole-body image was acquired, prone breast PET imaging was performed. The findings from both images were compared with the histopathologic results. Sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy were used to compare the diagnostic accuracy of prone breast PET images with that of whole-body PET images., Results: Sensitivity, specificity, positive predictive value, NPV, and accuracy of whole-body PET images were 83, 50, 97, 17, and 80%, and of prone breast PET images they were 95, 50, 96, 43, and 93%. Ten of 114 breast cancerous lesions (8.8%) were detected on prone breast PET images alone. Statistical difference was found between the sensitivity, accuracy, and NPV of prone breast PET images and those of whole-body PET images (P<0.0001 for sensitivity and accuracy and P<0.0009 for NPV)., Conclusion: Our data about the 122 lesions, suspected of breast cancer, with regard to the usefulness of prone breast PET imaging indicate that prone breast PET images are effective in detecting breast cancer.