Background: Accurate determination of the extrahepatic extent and intrahepatic distribution of disease is very important in patients with primary and metastatic liver disease for deciding whether a patient receives potentially curable surgery or palliative treatment. Our objective was to evaluate the efficacy of delayed phase FDG-PET/CT imaging in lesion detection and to define its clinical impact compared to triple-phase contrast enhanced CT (CECT).

The coexistence of thyroid functioning nodules and Graves' disease is called Marine-Lenhart syndrome. This condition is estimated to occur in 0.8-2.7% of patients with Graves' disease with few cases reported in the literature. Criteria for the diagnosis are not well defined. Here, we present a case of hyperthyroidism characterized by the presence of stimulating TSH receptor antibodies and severe bilateral exophthalmos. A thyroid uptake and scan revealed an elevated 24-hour iodine-131 uptake and a discrete hot nodule in the upper pole of the right lobe which was also observed with a thyroid ultrasound. The patient was diagnosed with Marine-Lenhart syndrome complicated by thyroid eye disease and was treated with methimazole followed by thyroidectomy and orbital decompression. We review the existing literature and propose criteria for the diagnosis and treatment of this condition.

Although radioactive iodine imaging and therapy are one of the earliest applications of theranostics, there still remain a number of unresolved clinical questions as to the optimization of diagnostic techniques and dosimetry protocols. I-124 as a positron emission tomography (PET) radiotracer has the potential to improve the current clinical practice in the diagnosis and treatment of differentiated thyroid cancer. The higher sensitivity and spatial resolution of PET/computed tomography (CT) compared to standard gamma scintigraphy can aid in the detection of recurrent or metastatic disease and provide more accurate measurements of metabolic tumor volumes. However the complex decay schema of I-124 poses challenges to quantitative PET imaging. More prospective studies are needed to define optimal dosimetry protocols and to improve patient-specific treatment planning strategies, taking into account not only the absorbed dose to tumors but also methods to avoid toxicity to normal organs. A historical perspective of I-124 imaging and dosimetry as well as future concepts are discussed.

Injecting drug use (IDU) is a major risk factor for contracting HIV-1 infection. Both HIV and IDU are neurotoxic, and their coexistence may lead to increased dysfunction of brain metabolic processes. The objective of this research was to investigate the effects of HIV-1 infection and IDU on 18 F-FDG PET brain metabolism. Methods: 18 F-FDG PET brain imaging, with a standard clinical protocol, was performed on 59 subjects who belonged to 3 groups: HIV-positive/IDU-positive (n 5 17), HIV-negative/ IDU-positive (n 5 13), and HIV-negative/IDU-negative controls (n 5 29). A voxel-based analysis of the 18 F-FDG PET brain images was performed using statistical parametric mapping. The images were spatially normalized to a standard 18 F-FDG template, proportionally scaled to compensate for count differences, and then appropriately smoothed. Statistical 2-sample t tests were performed to determine regional metabolic distribution differences in the 3 groups. Results: Diffuse hypermetabolism in the subcortical and deep white matter, the basal ganglia, and the thalami was observed in HIV-1 infection. IDU resulted in increased brainstem metabolism and decreased activity in cortical structures including bilateral medial frontal lobes and the right inferior frontal and temporal cortices. The cortical hypometabolism was more extensive in HIV-1-infected subjects, involving the left temporoparietal and right parietal cortices and bilateral medial frontal lobes. Conclusion: Voxel-based analysis of 18 F-FDG PET brain images demonstrated statistically significant differences in regional metabolism for the 3 studied groups. It also showed that HIV-1 infection may have a synergistic effect with IDU, resulting in more extensive cortical hypometabolism. Correlation of these findings with other quantitative approaches and neurocognitive functioning is warranted.

(124)I PET/CT is a valuable clinical imaging tool/agent, both in determining the extent of disease in the setting of metastatic DTC and in the functional volumetric and kinetic evaluation of target lesions.

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Patients in early pregnancy are more likely to have a technically successful CTPA scan compared to later in pregnancy and show similar opacification to non-pregnant women. This suggests a possible paradigm shift from the current approach to suspected PE in pregnant patients.

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