A no-reference respiratory blur estimation index in nuclear medicine for image quality assessment

International audienceBackground - Few indexes are available for nuclear medicine image quality assessment, particularly for respiratory blur assessment. A variety of methods for the identification of blur parameters has been proposed in literature mostly for photographic pictures but these methods suffer from a high sensitivity to noise, making them unsuitable to evaluate nuclear medicine images. In this paper, we aim to calibrate and test a new blur index to assess image quality.Material and Methods – Blur index calibration was evaluated by numerical simulation for various lesions size and intensity of uptake. Calibrated blur index was then tested on gamma- camera phantom acquisitions, PET phantom acquisitions and real-patient PET images and compared to human visual evaluation.Results – For an optimal filter parameter of 9, non-weighted and weighted blur index led to an automated classification close to the human one in phantom experiments and identified each time the sharpest image in all the 40 datasets of four images. Weighted blur index was significantly correlated to human classification (ρ= 0.69 [0.45 ;0.84], p<0.001) when used on patient PET acquisitions.Conclusion – The provided index allows to objectively characterize the respiratory blur in nuclear medicine acquisition, whether in planar or tomographic images and might be useful in respiratory gating applications

Incremental value of 18F-fluorocholine PET/CT in the localization of double parathyroid adenomas

International audienceA 73-year-old man displaying primary hyperparathyroidism with severe hypercalcemia (Ca: 4.1 mmol/l, PTH > 600 pmol/l) was referred for preoperative localization of a parathyroid adenoma. 99mTc-pertechnetate and 99mTc-sestaMIBI dual tracer scintigraphy displayed a mild focal uptake in the projection of the right thyroid lobe with negative ultrasonography. 18F-Fluorocholine PET/CT was quickly performed considering this discrepancy and not only confirmed the scintigraphic findings but also revealed a second contralateral focus of increased uptake, both later confirmed by operative consideration (the two other parathyroid glands are considered normal by the surgeon), pathology, and intraoperative parathyroid hormone assessment

Usefulness of hepatobiliary scintigraphy in the evaluation of hepatic cystic lesions in children

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Textural analysis in FDG PET of locally advanced non-small cell lung cancer: Prognostic value of entropy

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Pulmonary cavitations with increased 18F-FDG uptake revealing a thoracic endometriosis

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Acute heat stress amplifies exercise-induced metabolomic perturbations and reveals variation in circulating amino acids in endurance-trained males.

New findingsWhat is the central question of this study? Whole-body substrate utilisation is altered during exercise in hot environments, characterised by increased glycolytic metabolism: does heat stress alter the serum metabolome in response to high intensity exercise? What are the main finding and its importance? Alongside increases in glycolytic metabolite abundance, circulating amino acid concentrations are reduced following exercise under heat stress. Prior research has overlooked the impact of heat stress on protein metabolism during exercise, raising important practical implications for protein intake recommendations in the heat.AbstractUsing untargeted metabolomics, we aimed to characterise the systemic impact of environmental heat stress during exercise. Twenty-three trained male triathletes ( V̇O2peak${\dot V_{{{\rm{O}}_2}{\rm{peak}}}}$  = 64.8 ± 9.2 ml kg min-1 ) completed a 30-min exercise test in hot (35°C) and temperate (21°C) conditions. Venous blood samples were collected immediately pre- and post-exercise, and the serum fraction was assessed via untargeted 1 H-NMR metabolomics. Data were analysed via uni- and multivariate analyses to identify differences between conditions. Mean power output was higher in temperate (231 ± 36 W) versus hot (223 ± 31 W) conditions (P -1 , hot, 167 ± 9 beats min-1 , P rec ), core temperature change (ΔTrec ) (P  0.05). Environmental heat stress increased glycolytic metabolite abundance and led to distinct alterations in the circulating amino acid availability, including increased alanine, glutamine, leucine and isoleucine. The data highlight the need for additional exercise nutrition and metabolism research, specifically focusing on protein requirements for exercise under heat stress