PurposeIn oncology, texture features extracted from positron emission tomography with 18-fluorodeoxyglucose images (FDG-PET) are of increasing interest for predictive and prognostic studies, leading to several tens of features per tumor. To select the best features, the use of a random forest (RF) classifier was investigated.MethodsSixty-five patients with an esophageal cancer treated with a combined chemo-radiation therapy were retrospectively included. All patients underwent a pretreatment whole-body FDG-PET. The patients were followed for 3 years after the end of the treatment. The response assessment was performed 1 month after the end of the therapy. Patients were classified as complete responders and non-complete responders. Sixty-one features were extracted from medical records and PET images. First, Spearman’s analysis was performed to eliminate correlated features. Then, the best predictive and prognostic subsets of features were selected using a RF algorithm. These results were compared to those obtained by a Mann-Whitney U test (predictive study) and a univariate Kaplan-Meier analysis (prognostic study).ResultsAmong the 61 initial features, 28 were not correlated. From these 28 features, the best subset of complementary features found using the RF classifier to predict response was composed of 2 features: metabolic tumor volume (MTV) and homogeneity from the co-occurrence matrix. The corresponding predictive value (AUC = 0.836 ± 0.105, Se = 82 ± 9%, Sp = 91 ± 12%) was higher than the best predictive results found using the Mann-Whitney test: busyness from the gray level difference matrix (P < 0.0001, AUC = 0.810, Se = 66%, Sp = 88%). The best prognostic subset found using RF was composed of 3 features: MTV and 2 clinical features (WHO status and nutritional risk index) (AUC = 0.822 ± 0.059, Se = 79 ± 9%, Sp = 95 ± 6%), while no feature was significantly prognostic according to the Kaplan-Meier analysis.ConclusionsThe RF classifier can improve predictive and prognostic values compared to the Mann-Whitney U test and the univariate Kaplan-Meier survival analysis when applied to several tens of features in a limited patient database.

Metabolic tumour volume is a major prognostic factor for DFS and OS in patients with oesophageal squamous cell carcinoma. Higher SUVmax values were paradoxically associated with longer survival. The location of the tumour also appeared to affect prognosis.

This paper presents a new algorithm to lump fluid compounds into hypothetical components. It has been designed to bridge the gap between the increasing amount of analytical data provided by modern lab equipments and the simplified fluid description required in compositional model studies. The main feature of the method is a lumping scheme based on the similarities of a few proper- ties of all the compounds identified by chromato- graphic analysis. An iterative clustering algo- rithm around mobile centers yields a classifica- tion into pseudo-components optimum with respect to the considered equation of state. It can be adapted to any equation of state, any number of compounds or properties. An other noticeable feature of this proce- dure is the definition of a mixed calculation of critical properties. A criterion to choose between an accurate calculation of true critical proper- ties and the classical mixing rules is suggested. Numerical simulations of PVT behavior were completed for an oil and a gas condensate defined by 150 compounds. The clustering algorithm deter- mined simplified fluids lumped into 7 and 5 components. True critical properties calculation for the hypothetical components and classical mixing rules were tested and the mixed calculation proved to be the best.

Tetrodotoxin is one of the most potent neurotoxins in the aquatic world. This review of published and unpublished reports aims to describe the poisoning cases that have occurred in mainland France and overseas territories. Six articles were included, with 13 poisoning events, individuals or collective (number (n) = 53 patients). Moreover, 13 unpublished poisoning events from toxicovigilance networks were found (n = 17). All cases happened in overseas territories: French Guyana (n = 7), New Caledonia (n = 11), Reunion (n = 35) and French Polynesia (n = 17). The median age was 36 years. The most frequent signs were neurological (81.8%), digestive (54.5%) and general (52.3%). Three cases of dysgueusia and nine cases of urogenital discomfort were observed in French Polynesia. Twelve severe cases were reported, including seven deaths. Only three events (11.5%) were documented by a tetrodotoxin assay. Two families of fish accounted for 91.6% of the poisonings: 33.3% due to the Diodontidae family and 58.3% to the Tetraodontidae family. Although rare, information and collection campaigns on tetrodotoxin poisoning are, therefore, essential.

This paper presents the application of a semi-automatic history matching tool to real field cases. The process of history matching a reservoir model is a difficult and time-consuming step in the course of a reservoir engineering study. The gradient method has now been widely accepted as an efficient way of aiding the reservoir engineer during this process. The sensitivities of the dynamic observations with respect to the model parameters give some very valuable qualitative and quantitative information about the best history matching parameters. A history matching tool has been developed to make the most of the gradient information. Tests are carried out on two 3D 3-phase field cases in real industrial conditions. We show that the computing times are still a critical issue for the validity of the method. Results and methodology are presented and the practical benefits of such techniques for the reservoir engineer are assessed. P. 121