Prognostic value of baseline and interim [18F]FDG PET metabolic parameters in pediatric Hodgkin's lymphoma.

BACKGROUND: Hodgkin lymphoma (HL) in pediatric populations has a high survival rate but poses risks for long-term morbidities. Although [18F]fluoro­2­deoxy­2­d­glucose positron emission tomography ([18F]FDG PET) scans offer potential for improved risk stratification, the definitive prognostic value of quantitative [18F]FDG PET parameters remains unclear for pediatric HL. METHODS: A single-center, retrospective study included pediatric patients diagnosed with HL between 2016 and 2023 treated according to EuroNet-PHL-C1 and DAL/GPOH-HD protocols. Patients underwent baseline and interim PET/CT scans after two chemotherapy cycles. Event-free survival (EFS) was the primary endpoint, Deauville score was the secondary endpoint. Quantitative [18F]FDG PET parameters included SUVmax, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) that were evaluated using two segmentation methods (SUV 2.5, 41% SUVmax). Survival outcomes were assessed using Cox regression analysis. RESULTS: A total of 115 patients (50 males, median age 14.2 years) were studied, with a median follow-up period of 35 months. During this period, 16 cases (13.9%) of relapse or progression were noted. Baseline and interim MTV 2.5, MTV 41%, TLG 2.5, and TLG 41%, along with interim SUVmax, were significantly associated with worse EFS and correlated with post-treatment Deauville scores. In multivariable analysis, interim MTV 2.5 > 0 ml (adj. hazard ratio, HR: 3.89, p = 0.009) and interim TLG 41% ≥ 30 g (adj. HR: 7.98, p = 0.006) were independent risk factors for EFS. CONCLUSION: Baseline and interim [18F]FDG PET parameters can serve as significant prognostic indicators for EFS and treatment response in pediatric HL. These quantitative measures could enhance individualized, risk-adapted treatment strategies for children and adolescents with HL.

[Analysis of future liver remnant parameters in children after extended liver resection]. / Analiz parametrov budushchego ostatka pecheni u detei, perenesshikh ee obshirnye rezektsii.

OBJECTIVE: To analyze the initial data on future liver remnant volume and its function evaluated by 99mTc-Bromesida hepatobiliary scintigraphy in children with liver tumors. MATERIAL AND METHODS: Extended liver resections were performed in 58 patients aged 2 months - 208 months (median 26 months) for various neoplasms. Before hepatectomy, all children underwent contrast-enhanced CT with volumetry and hepatobiliary scintigraphy with 99mTc-Bromezida and subsequent quantitative assessment of its accumulation in the future liver remnant. All consecutive patients eligible for extended liver resection were retrospectively analyzed. RESULTS: The analysis included patients who underwent extended liver resection between June 2017 and March 2021. Among 91 liver resections, 58 (64%) procedures were extended hepatectomies including 2 ALPPS procedures. Median volume of future liver remnant was 44.5% (16.5-91.4), median future liver remnant function - 10.14%/min/m2 (1.8-30). Four patients with adequate liver function had insufficient volume of future liver remnant. Insufficient future liver remnant volume and its appropriate function were observed in 2 patients. Not life-threatening post-resection liver failure developed in 2 patients. CONCLUSION: Evaluation of future liver remnant function is the most sensitive method to predict post-hepatectomy liver failure in children. The cut off value of future liver remnant volume in children is below 25% and probably below 16.5%. Further data collection and research are warranted to determine significant values. These data will contribute to define the new indications for two-staged hepatectomies in children.

Quantification of the hygroscopic effect of soot aging in the atmosphere: laboratory simulations.

We use a laboratory approach for the quantification of the water uptake by particles with varying amounts of sulfates to simulate the aging of fossil fuel combustion particles in the atmosphere. Diesel fuel and aviation kerosene laboratory-made soots are chosen as representative of the hydrophobic fraction of diesel and aircraft engine-emitted particulates and commercial carbon blacks are used as surrogates for industry emissions. The transformation of soot hydration properties from hydrophobic, through hydrophilic, to hygroscopic is demonstrated based on the amount of water uptake by the laboratory-produced EC soot covered by sulfates as the amount of sulfate increases. The mechanism of water/soot interaction changes from an adsorption on active sites to a water film formation and to the dissolution of water into the water-soluble sulfate, while the amount of sulfate increases. Laboratory simulations show that coverage of EC soot by organics diminishes the effect of sulfuric acid deposition. We demonstrate that the surface chemical properties and the size of primary particles affect the amount of water taken up by the soot particles and their aging in the atmosphere.

Water interaction with laboratory-simulated fossil fuel combustion particles.

To clarify the impact of fossil fuel combustion particles' composition on their capacity to take up water, we apply a laboratory approach in which the method of deposition of compounds, identified in the particulate coverage of diesel and aircraft engine soot particles, is developed. It is found that near-monolayer organic/inorganic coverage of the soot particles may be represented by three groups of fossil fuel combustion-derived particulate matter with respect to their Hansh's coefficients related to hydrophilic properties. Water adsorption measurements show that nonpolar organics (aliphatic and aromatic hydrocarbons) lead to hydrophobization of the soot surface. Acidic properties of organic compounds such as those of oxidized PAHs, ethers, ketones, aromatic, and aliphatic acids are related to higher water uptake, whereas inorganic acids and ionic compounds such as salts of organic acids are shown to be responsible for soot hydrophilization. This finding allows us to quantify the role of the chemical identity of soot surface compounds in water uptake and the water interaction with fossil fuel combustion particles in the humid atmosphere.