Schwannomatosis/neurofibromatosis type 2 associated multiple schwannomas visualized on FDG-PET/CT

Abstract Objective In this retrospective, single-center observational study, we investigated whether discontinuing metformin for at least 48 h prevents metformin-induced [18F]fluorodeoxyglucose (FDG) uptake in all segments of the colon. Methods Patients with type 2 diabetes who were using metformin before undergoing an FDG PET/CT scan were included. Two groups were created: patients who discontinued metformin for less than 48 h (< 48 h group) and patients who discontinued metformin for between 48 and 72 h (≥ 48 h group). A control group comprised non-diabetic patients who were not using metformin before undergoing an FDG PET/CT. We visually scored the uptake of FDG in four segments of the colon—the ascendens, transversum, descendens, and rectosigmoid—using a four-point scale (1–4) and considered scores of 3 or 4 to be clinically significant. Results Colonic FDG uptake in the ≥ 48 h group (n = 23) was higher than uptake in the control group (n = 96) in the colon descendens [odds ratio (OR) 14.0; 95% confidence interval (CI) 4.8–40.9; p value: 0.001] and rectosigmoid (OR 11.3; 95% CI 4.0–31.9; p value: 0.001), and there was no difference in the colon ascendens and transversum. Colonic FDG uptake in the < 48 h group (n = 25) was higher than uptake in the ≥ 48 h group (n = 23) in the colon transversum (OR 4.8; 95% CI 1.3–18.5; p value: 0.022) and rectosigmoid (p value: 0.023), and there was no difference in the colon ascendens and descendens. Conclusions Discontinuing metformin for 48 h before undergoing an FDG PET/CT still gives a high uptake in the distal parts of the colon when compared with non-diabetic patients who are not using metformin. Discontinuing metformin for 48 h seems to be useful for scanning the more proximal segments of the colon.

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Imaging biomarkers for malignant peripheral nerve sheath tumors in neurofibromatosis type 1

Neurology ◽

10.1212/wnl.0000000000008092 ◽

2019 ◽

Vol 93 (11) ◽

pp. e1076-e1084 ◽

Cited By ~ 7

Author(s):

Shivani Ahlawat ◽

Jaishri O. Blakeley ◽

Fausto J. Rodriguez ◽

Laura M. Fayad

Keyword(s):

Fdg Pet ◽

Neurofibromatosis Type ◽

Nerve Sheath Tumors ◽

Peripheral Nerve Sheath Tumors ◽

Pet Ct ◽

Adc Values ◽

Adc Mapping ◽

Fdg Pet Ct

ObjectiveTo determine the utility of quantitative metrics obtained from fMRI using diffusion-weighted imaging (DWI)/apparent diffusion coefficient (ADC) mapping compared with metabolic (18F-fluorodeoxyglucose [FDG]-PET/CT) imaging in patients with neurofibromatosis type 1 (NF1) for the characterization of peripheral nerve sheath tumors (PNSTs) as benign or malignant.MethodsThis Institutional Review Board–approved, Health Insurance Portability and Accountability Act–compliant study retrospectively reviewed imaging of 55 PNSTs in 21 patients with NF1. Imaging included anatomic (unenhanced T1, fluid-sensitive, contrast-enhanced T1-weighted), functional DWI (b = 50, 400, 800 s/mm2) and ADC mapping, magnetic resonance sequences, and FDG-PET/CT imaging. Anatomic (size), functional (minimum ADC values), and metabolic (maximum standardized uptake values [SUVmax]) imaging characteristics were recorded. ADC values were correlated with SUVmax. With histologic correlation for all malignant PNSTs (MPNSTs) or clinical or imaging stability (>12 months) for benign lesions used as reference standards, diagnostic accuracy was calculated.ResultsOf 55 PNSTs, there were 19 (35%) malignant and 36 (65%) benign PNSTs. Benign PNSTs were overall smaller than MPNSTs (largest diameter 4.3 ± 1.3 vs 8.2 ± 3.3 cm, respectively, p = 0.014). Benign PNSTs had higher ADCmin (×10−3 mm2/s) than MPNSTs (1.6 ± 0.4 vs 0.6 ± 0.2, respectively, p < 0.0001) and lower SUVmax than MPNSTs (3.2 ± 1.8 vs 8 ± 3.9, p < 0.0001, respectively). ADCmin correlated inversely with SUVmax (correlation coefficient r = −0.0.58, p < 0.0001). Maintaining a sensitivity of 100% with threshold values of ADCmin ≤1 or SUVmax >3.2, DWI yielded a specificity of 94% while FDG-PET/CT offered a specificity of 83%.ConclusionsBoth quantitative metabolic imaging and functional imaging offer high sensitivity for the characterization of PNSTs in NF1; however, DWI/ADC mapping offers increased specificity and may be a more useful modality.Classification of evidenceThis study provides Class II evidence that for patients with NF1, MRI using DWI/ADC mapping accurately distinguishes malignant and benign PNSTs.

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Schwannomatosis in a child – or early neurofibromatosis type 2

The Journal of Laryngology & Otology ◽

10.1258/002221502760132692 ◽

2002 ◽

Vol 116 (7) ◽

pp. 551-555 ◽

Cited By ~ 3

Author(s):

A. M. Shaida ◽

D. G. O’Donovan ◽

D. A. Moffat

Keyword(s):

Neurofibromatosis Type ◽

Neurofibromatosis Type 2 ◽

Age Group ◽

Distinct Entity ◽

Genetic Features ◽

Paediatric Age ◽

Multiple Schwannomas

A case of multiple cervical schwannomas in a five-year-old boy, without other evidence of neurofibromatosis type 2, is described. Schwannomatosis is a disorder characterized by the presence of multiple schwannomas in the absence of neurofibromatosis type 2 that has only been recognized in the last 15 years. The clinical and genetic features of neurofibromatosis types 1 and 2 and schwannomatosis are compared and contrasted. This patient with possible schwannomatosis is presented to illustrate the potential pitfalls of making this diagnosis in the paediatric age group and to increase awareness of the debate on whether this is a distinct entity or a form fruste of neurofibromatosis type 2.

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Phenotyping Type 2 Diabetes in Terms of Myocardial Insulin Resistance and Its Potential Cardiovascular Consequences: A New Strategy Based on 18F-FDG PET/CT

Journal of Personalized Medicine ◽

10.3390/jpm12010030 ◽

2022 ◽

Vol 12 (1) ◽

pp. 30

Author(s):

José Raul Herance ◽

Rafael Simó ◽

Mayra Alejandra Velasquez ◽

Bruno Paun ◽

Daniel García-Leon ◽

...

Keyword(s):

Insulin Resistance ◽

Type 2 Diabetes ◽

Fdg Pet ◽

Cardiovascular Events ◽

Fdg Uptake ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct ◽

Myocardial Insulin Resistance

Background: Systemic insulin resistance is generally postulated as an independent risk factor of cardiovascular events in type 2 diabetes (T2D). However, the role of myocardial insulin resistance (mIR) remains to be clarified. Methods: Two 18F-FDG PET/CT scans were performed on forty-three T2D patients at baseline and after hyperinsulinemic–euglycemic clamp (HEC). Myocardial insulin sensitivity (mIS) was determined by measuring the increment in myocardial 18F-FDG uptake after HEC. Coronary artery calcium scoring (CACs) and myocardial radiodensity (mRD) were assessed by CT. Results: After HEC, seventeen patients exhibited a strikingly enhancement of myocardial 18F-FDG uptake and twenty-six a marginal increase, thus revealing mIS and mIR, respectively. Patients with mIR showed higher mRD (HU: 38.95 [33.81–44.06] vs. 30.82 [21.48–38.02]; p = 0.03) and CACs > 400 (AU: 52% vs. 29%; p = 0.002) than patients with mIS. In addition, HOMA-IR and mIS only showed a correlation in those patients with mIR. Conclusions: 18F-FDG PET combined with HEC is a reliable method for identifying patients with mIR. This subgroup of patients was found to be specifically at high risk of developing cardiovascular events and showed myocardial structural changes. Moreover, the gold-standard HOMA-IR index was only associated with mIR in this subgroup of patients. Our results open up a new avenue for stratifying patients with cardiovascular risk in T2D.

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The difference between steroid diabetes mellitus and type 2 diabetes mellitus: A whole-body 18F-FDG PET/CT study

10.21203/rs.3.rs-22012/v1 ◽

2020 ◽

Author(s):

Qingqing Zhao ◽

Jinxin Zhou ◽

Yu Pan ◽

Huijun Ju ◽

Liying Zhu ◽

...

Keyword(s):

Diabetes Mellitus ◽

Type 2 Diabetes ◽

Skeletal Muscle ◽

Type 2 Diabetes Mellitus ◽

Glucose Metabolism ◽

Fdg Pet ◽

Glycogen Storage ◽

Pet Ct ◽

Fdg Pet Ct

Abstract Background 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, and plays an important role in diabetes research. Here, PET/CT imaging of SDM and type 2 diabetes mellitus (T2DM) rats was used to observe the changes of glucose metabolism in major glucose metabolism organs and immunohistochemical analysis to explore the possible pathogenesis of SDM. Results The SDM rat model was successfully established, which showed increased FBG and insulin levels; 18F-FDG PET/CT imaging showed increased FDG uptake in skeletal muscle, but no significant increase in liver uptake (15d);Immunohistochemistry showed that islet α-cell and β-cell proliferation, GLUT-4 and IRS-1, PI3Kp85α expression in skeletal muscle increased, and glycogen storage in 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; IRS-1 expression in skeletal muscle decreased, and GLUT-4 and PI3Kp85α did not change significantly. Conclusion 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 the increase of gluconeogenesis in the liver may be the cause of its increased blood glucose.

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