The clinical significance of pituitary uptake on routine whole body 18F-fluorodeoxyglucose (FDG) positron emission tomography/computer tomography (PET/CT) is not completely characterized. We seek to assess the potential differential diagnosis/underlying etiology of pituitary FDG uptake incidentally identified on routine PET/CT scans. A total of 24,007 PET/CT whole body scans in recent 5 years were retrospectively reviewed. Patients with maximum standardized uptake value (SUVmax) > 4.1 in the pituitary glands were identified. Cases with a known history of pituitary disorders were excluded. Nineteen cases were identified with incidental pituitary FDG uptake which all had a final pathological diagnosis/clinical follow up. Among them, there were 9 primary pituitary tumors, with SUVmax ranging from 4.7 to 29.3 (13.6 ± 9.8); 3 metastatic malignancy with SUVmax ranging from 7.3 to 32.3 (16.0 ± 10.6); 3 Langerhans cell histiocytosis (LCH) with SUVmax ranging from 6.0 to 26.0 (15.0 ± 10.2); 1 pituitary lymphocytic hypophysitis with SUVmax of 4.7. Of note, 3 cases with SUVmax of 7.5,7.9 and 9.6 showed no relevant clinical symptoms with negative results on subsequent magnetic resonance (MR) and were counted as benign physiologic uptake. The most common differential diagnosis of incidental pituitary uptake on routine whole body PET/CT scans was primary pituitary tumors, followed by metastatic malignancy, Langerhans cell histiocytosis, and inflammatory lymphocytic hypophysitis. Of note, benign physiologic uptake without corresponding lesions could also occur in our population.

No abstract

No abstract

Aims Steroid diabetes mellitus (SDM) is a metabolic syndrome caused by an increase in glucocorticoids, and its pathogenesis is unclear. 18F-FDG PET/CT can reflect the glucose metabolism of tissues and organs under living conditions. Here, PET/CT imaging of SDM and type 2 diabetes mellitus (T2DM) rats was used to visualize changes in glucose metabolism in the main glucose metabolizing organs and investigate the pathogenesis of SDM. Methods SDM and T2DM rat models were established. During this time, PET/CT imaging was used to measure the %ID/g value of skeletal muscle and liver to evaluate glucose uptake. The pancreatic, skeletal muscle and liver were analyzed by immunohistochemistry. Results SDM rats showed increased fasting blood glucose and insulin levels, hyperplasia of islet α and β cells, increased FDG uptake in skeletal muscle accompanied by an up-regulation of PI3Kp85α, IRS-1, and GLUT4, no significant changes in liver uptake, and that glycogen storage in the liver and skeletal muscle increased. T2DM rats showed atrophy of pancreatic islet β cells and decreased insulin levels, significantly reduced FDG uptake and glycogen storage in skeletal muscle and liver. Conclusions The pathogenesis of SDM is different from that of T2DM. The increased glucose metabolism of skeletal muscle may be related to the increased compensatory secretion of insulin. Glucocorticoids promote the proliferation of islet α cells and cause an increase in gluconeogenesis in the liver, which may cause increased blood glucose.

Hybrid baculovirus-adeno-associated virus (BV-AAV) containing enhanced green fluorescent protein (eGFP) reporter gene or human sodium-iodide symporter (hNIS) reporter gene flanked by inverted terminal repeats (ITRs) derived from AAV (BV-CMV-eGFP-ITR and BV-CMV-hNIS-ITR) were constructed and used to investigate the feasibility of using hybrid BV-AAV transgenic vector to mediate hNIS reporter gene imaging for monitoring bone marrow-derived mesenchymal stem cells (BM-MSCs) transplantation therapy as a novel biotechnological platform in radionuclide reporter gene imaging. The results showed that the infection efficiency of BV-CMV-eGFP-ITR in BM-MSCs reached 84.25 ± 1.38%, and there were no obvious adverse effects on BM-MSCs. The (125)I(-) and (99m)TcO₄(-) uptake assays showed that the radionuclide accumulation induced by BA-AAV-mediated hNIS was highly efficient in infected BM-MSCs. Furthermore, there was a robust correlation between the infected BM-MSCs cell number and the (125)I(-) accumulation amount (R(2) = 0.9026). The micro-SPECT/CT imaging showed that BV-CMV-hNIS-ITR-infected BM-MSCs accumulated radioiodine efficiently in vivo, exhibiting obvious radiotracer accumulation in transplantation sites. Further quantitative analysis revealed that 30 min might be the optimal imaging time point. Moreover, the revealed high target/individual organ background ratios also supported the feasibility of BV-AAV-mediated hNIS reporter gene imaging for monitoring BM-MSCs transplantation in most of commonly used transplantation sites, thus highlighting this promise biotechnological platform in radionuclide reporter gene imaging for stem cell transplantation therapy.

A 39-year-old woman with complains of polydipsia and dieresis was admitted to endocrinology service for evaluation and potential treatment of diabetes insipidus. During the hospitalization, the patient was found to have unexplained fever, for which an FDG PET/CT was performed to explore the source. The images revealed multiple regions of abnormal hypermetabolism throughout the body. Notably, there was an intense activity in the region of pituitary stalk. Pathological results after biopsy showed pituitary involvement of Langerhans cell histiocytosis.

Accurate diagnosis and grading are critical for pancreatic neuroendocrine neoplasm (pNEN) management. This study compares the diagnostic and grading value of 68Ga-DOTATATE PET/MR and 18F-FDG PET/MR for pNENs separately as well as in combination. A total of 36 patients with histologically confirmed pNENs, who underwent both 68Ga-DOTATATE PET/MR and 18F-FDG PET/MR within 2 weeks from 2020 to 2021, were retrospectively collected and analyzed. The maximum standardized uptake values of 68Ga-DOTATATE (G-SUVmax) and 18F-FDG (F-SUVmax) on PET and the minimum values of apparent diffusion coefficient (ADCmin) on MR were measured on the lesions with known histological grading (25 by surgery, 11 by biopsy). Receiver-operating characteristic analysis was applied to determine the cutoffs of these parameters or their combinations for differentiation between G1 and G2, as well as between low-grade and high-grade pNENs. The Spearman rank correlation coefficient was used to assess the correlation between the imaging parameters and the maximum tumor diameters. The detection rate of 68Ga-DOTATATE PET imaging alone was 95%, 87.5%, and 37.5% for G1, G2, and G3, respectively. Adding 18F-FDG PET or MR sequences of PET/MR increased the detection rate to 100% in all grades. Among the three parameters, G-SUVmax had the highest diagnostic rate in predicting tumor grade. It presented a sensitivity of 87.5% and a specificity of 80.0% with a cutoff value of 42.75 for differentiating G2 from G1 pNETs and a sensitivity and specificity of 100% and 71.4% with a cutoff value of 32.75 in predicting high-grade pNENs. The ratio of G-SUVmax to F-SUVmax (G-SUVmax/F-SUVmax) showed slight improvement in the diagnostic rate, while the product of G-SUVmax and ADCmin (G-SUVmax*ADCmin) did not improve the diagnostic rate. 68Ga-DOTATATE PET/MR alone is sufficient for the diagnosis of pNENs and the prediction of various grades.

Objective The incidence of papillary thyroid microcarcinoma (PTMC) has increased sharply during the past decades. Yet, whether or not nodal dissection should be performed remains controversial. This article aims to assess the high-risk factors associated with cervical lymph node metastasis (LNM) in patients with PTMC, which may potentially guide clinical management decision-making. Methods Medical records of 449 PTMC patients who underwent thyroidectomy in our hospital from August 2016 to July 2017 were retrospectively reviewed. Clinical and pathological factors of the patients were anonymously extracted from the charts and analyzed. Result The patients were classified into two subgroups according to maximum tumor size measured through post-surgical pathology: smaller PTMC group (≤5 mm) and larger PTMC group (>5 mm). Larger tumor size was found to be associated with a higher rate of LNM ( P = .001), particularly central lymph node metastasis (CLNM) ( P = .001). Tumor size was also associated with extrathyroidal tumor extension (ETE) ( P < .001), bilateral lesions ( P = .015), and BRAFv600e mutation ( P = .004). LNM was found to be more common in older patients (>55 y) ( P = .030), and those with multifocal cancer ( P < .001). In PTMC patients with unilateral lesions without ETE, tumor size was not significantly associated with LNM ( P = .121). Conclusions For the PTMC population, tumor size was an independent risk factor for LNM, particularly for patients of old age (>55 y), and multifocality. However, in PTMC patients with unilateral lesions without extrathyroidal extension, tumor size was not related to the risk of LNM. These findings may potentially guide clinical decision-making in terms of cervical nodal dissection.