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Purpose: To analyze diagnostic performance of F-18 FDG PET/CT in recurrent adenocarcinoma gallbladder (GBC) and to establish its possible impact on post-recurrence survival. Method: FDG PET/CT studies of suspected recurrent GBC were retrospectively analyzed alongside tumor markers serum CEA and CA 19-9. Abnormal FDG-avid lesions and abnormal morphological lesions were considered positive for recurrence, and were categorized as isolated abdominal wall recurrence, loco-regional recurrence, and distant metastatic disease. Histopathology, definite progression on imaging and positive response to treatment was considered as reference standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were used as diagnostic performance parameters. Post-recurrence survival was calculated whenever appropriate follow-up was available, based on the abovementioned categories of sites of recurrence using survival curves and log-rank test. Results: Out of 117 PET/CT studies, 93 (79.5%) were positive and 24 (20.5%) were negative for recurrence. 86 out of 93 were true positive and 23 of 24 were true negative. PET/CT demonstrated sensitivity, specificity, PPV, NPV and accuracy of 98.8%, 76.7%, 92.5%, 95.8% and 93.1%, respectively. Diagnostic performance of PET/CT was significantly better than combination tumor markers. Of 66 cases with available follow-up, isolated abdominal wall (port/scar site) recurrence and loco-regional recurrence demonstrated significantly higher post-recurrence survival as compared to distant metastasis; median survival being 39, 25 and 12 months, respectively. Conclusion: F-18 FDG PET/CT has better diagnostic performance than tumor markers combination. Isolated abdominal wall (port/scar site) recurrence and loco-regional recurrence on PET/CT demonstrated better survival than non-regional metastatic disease. These results suggest a possible role of PET/CT as a surveillance modality, as well as a guide to therapeutic decision-making in cases of recurrent GBC. [ABSTRACT FROM AUTHOR]

Lymph node metastasis is a considerable variable influencing postoperative American Thyroid Association (ATA) risk stratification in pediatric differentiated thyroid cancer (DTC). The primary aim of this study was to ascertain the factors predicting nodal metastasis and describe the outcomes in relation to the ATA risk. Patients 18 years or younger operated between December 2005 and December 2019 were analyzed. Demographic, clinicopathological, treatment, and outcome data were recorded. Factors associated with nodal metastasis were assessed by univariate and multivariate regression analysis. Patients were stratified into low-, intermediate-, and high-risk as per the pediatric ATA guidelines. A total of 86 patients (43% male; median [IQR] age, 12 (10–14) years) underwent surgery during the study period. Lymph node metastases were present in 70 (82.4%) patients involving the lateral (8%) and central compartment (4.7%) alone and both (88.6%) compartments. Extrathyroid extension (ETE) was present in 65%; 35%, minimal; and 30%, extensive. On univariate analysis, nodal metastasis was more frequent in male patients, multifocal tumor, lymphovascular invasion, and ETE. On multivariate analysis, only ETE was predictive of nodal disease with an odds ratio of 8. Minimal and extensive ETEs were both significantly associated with lymph node metastases when compared to the absence of ETE. The 5-year disease-free survival was 100%, 95.7%, and 66% in the low-, intermediate-, and high-risk groups respectively (p < 0.0001). Pediatric DTCs have an exceptionally high incidence of lymph node metastasis. ETE is the single most important predictor of nodal disease. The ATA pediatric risk stratification is useful in predicting clinical outcomes. [ABSTRACT FROM AUTHOR]

The 2015 American Thyroid Association (ATA) guideline have suggested modifications in the risk stratification (RS) for differentiated thyroid cancer (DTC) patients, introduced the concept of dynamic risk stratification (DRS) and redefined the role of radioactive iodine (RAI) in treatment algorithm. The aim of this retrospective audit was to assess the practical implications of these modifications in management of DTC. Methods: A total of 138 DTC patients were stratified according to ATA 2009 and 2015 guidelines into low (LR), intermediate (IR) and high (HR) risk groups. Change in RS and in intention of RAI use was calculated. Deviation in administered RAI dosage from the guidelines was assessed. 1-year follow-up data was audited to assess how the DRS modified the initial risk estimate. Results: A total of 11.6% of patients changed their RS categories in 2015 guidelines. A total of 10.1% got upstaged to HR, and 1.4% got downstaged to LR. In 2.17% of patients' intention of RAI use changed to remnant ablation from adjuvant therapy and 65% of the LR patients won't require any RAI therapy. A total of 26.7% of patients had received significantly more RAI dosage according to ATA 2015. At 1-year follow-up according to DRS 84% of LR, 75% of IR and 44% of HR patients showed excellent response (ER). Conclusion: More patients changed RS to HR than to LR. Intention of RAI use changed in only a small number of patients. Significantly higher dosage of RAI is being administered to patients in current practice. The effect of DRS in modifying the initial RS was most prominent in IR, with most showing ER to initial therapy. [ABSTRACT FROM AUTHOR]

The article describes the case of a patient with disseminated streptococcal infection who was diagnosed using F-fluorodeoxyglucose positron emission tomography/computed tomography. Topics discussed include the patient's medical history, symptoms presented by the patient, and the response of the patient to oral antibiotic therapy.

Chitosan interaction with chitosanase was examined through analysis of spectral line shapes in the NMR HSQC titration experiments. We established that the substrate, chitosan hexamer, binds to the enzyme through the three-state induced-fit mechanism with fast formation of the encounter complex followed by slow isomerization of the bound-state into the final conformation. Mapping of the chemical shift perturbations in two sequential steps of the mechanism highlighted involvement of the substrate-binding subsites and the hinge region in the binding reaction. Equilibrium parameters of the three-state model agreed with the overall thermodynamic dissociation constant determined by ITC. This study presented the first kinetic evidence of the induced-fit mechanism in the glycoside hydrolases. [ABSTRACT FROM AUTHOR]

Recognition of patterns has always been extremely important in cross-sectional imaging. Peritoneal involvement, both primary and as dissemination from abdominopelvic malignancies, is manifested in different forms, purely because of anatomical complexity. We studied series of peritoneal involvement by F-fluorodeoxyglucose positron-emission tomography/computed tomography fusion imaging and derived patterns of tracer uptake on maximum intensity projection and cross-sectional fusion images. [ABSTRACT FROM AUTHOR]

18F-FDG PET/CT was done, and the maximum intensity projection image demonstrated intense FDG uptake in infrahepatic region (image a, arrow). It highlights ability of 18F-FDG PET/CT to detect inflammatory pathologies and reinstates necessity of histopathological evaluation to decide appropriate management strategy. [Extracted from the article]

A 70-year-old female was detected with multiple space-occupying liver lesions (SOLs) and left adrenal nodule in CT scan, while being evaluated for abdominal pain. PET/CECT showed multiple FDG-avid hypodense liver lesions (black arrows in images A-D in Figure 1) and low-grade FDG-avid adrenal nodule (white arrow in image E). Granuloma mimicking local recurrence on PET/CT after liver resection of colorectal liver metastasis: a case report. [Extracted from the article]

Mucocele of the appendix is an uncommon condition characterized by luminal distension and accumulation of a mucoid material. Occasionally, it can be caused due to malignancy like cystadenocarcinoma, and the preoperative diagnosis of which is very rare. We report a case of a 64-year-old lady presenting with intermittent abdominal pain diagnosed on ultrasonography as a mucocele where preoperative F-flurodeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) findings raised a strong suspicion of malignancy. FDG PET/CT findings brought about a change in therapeutic plan, and the patient was considered for a more extensive surgical resection. The final histopathology revealed cystadenocarcinoma as the cause of appendicular mucocele, a finding hitherto undescribed on FDG PET/CT. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 50-year-old man diagnosed with extensive melorheostosis of his ribs. It notes that the patient underwent F-Fluoride positron emission tomography/computed tomography to examine his ribs. It also discusses melorheostosis, its causes, symptoms and treatment as it applies to the patient.

The article discusses the pulmonary artery and femoral vein tumor thromboembolism in a patient with osteogenic sarcoma.

Metastatic involvement of the heart is a rare occurrence and remains undiagnosed until autopsy. In some instances, patients may have cardiac symptoms, leading to ante-mortem diagnosis. Although most primary cancers have been documented to metastasize to heart, the existing literature on cancers of upper aero-digestive tract is an exception, with only a few reports. We report four cases of upper aero-digestive tract cancers, three of which arise from oral cavity, one from lower esophagus, metastasising to the myocardium, detected on 18 F - Fluoro-deoxy-glucose Positron Emission Tomography/Computed Tomography (FDG PET/CT) study , in the absence of related symptoms.

Non-neoplastic lesions have been known to mimic malignancies and metastases on positron emission tomography/computed tomography. We report the rare occurrence of multiple fluorodeoxyglucose-concentrating sclerosing hemangiomas in a patient with soft tissue sarcoma mimicking lung metastases.

Intracranial meningeal hemangiopericytomas are rare tumors that can mimic meningioma on imaging and on histopathology. However, these tumors are more aggressive with a tendency for local and metastatic recurrence, sometimes after a prolonged symptom-free interval. We report an unusual metastatic recurrence of an intracranial hemangiopericytoma, 8 years after surgery for the primary tumor and discuss the role of positron emission tomography/computed tomography in the follow-up of these patients.

Asymptomatic skeletal muscle metastasis in non-small cell lung cancer is a rare event particularly when it is detected at initial staging. This report describes how whole body imaging with [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) detected a solitary asymptomatic metastasis to the gluteus maximus muscle in a potentially resectable case of non-small cell lung cancer, thereby changing the treatment plan from surgical resection to systemic chemotherapy.