Dynamic contrast-enhanced MRI to assess hepatocellular carcinoma response to Transarterial chemoembolization using LI-RADS criteria: A pilot study

Purpose To identify quantitative dynamic contrast-enhanced (DCE)-MRI perfusion parameters indicating tumor response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE). Materials and methods This prospective pilot study was approved by our institutional review board; written and informed consent was obtained for each participant. Patients underwent DCE-MRI examinations before and after TACE. A variable flip-angle unenhanced 3D mDixon sequence was performed for T1 mapping. A dynamic 4D mDixon sequence was performed after contrast injection for assessing dynamic signal enhancement. Nonparametric analysis was conducted on the time-intensity curves. Parametric analysis was performed on the time-concentration curves using a dual-input single-compartment model. Treatment response according to Liver Reporting and Data System (LI-RADS) v2018 was used as the reference standard. The comparisons within groups (before vs. after treatment) and between groups (nonviable vs. equivocal or viable tumor) were performed using nonparametric bootstrap taking into account the clustering effect of lesions in patients. Results Twenty-eight patients with 52 HCCs (size: 10–104 mm) were evaluated. For nonviable tumors (n = 27), time to peak increased from 62.5 ± 18.2 s before to 83.3 ± 12.8 s after treatment (P< 0.01). For equivocal or viable tumors (n = 25), time to peak and mean transit time significantly increased (from 54.4 ± 24.1 s to 69.5 ± 18.9 s, P < 0.01 and from 14.2 ± 11.8 s to 33.9 ± 36.8 s, P= 0.01, respectively) and the transfer constant from the extracellular and extravascular space to the central vein significantly decreased from 14.8 ± 14.1 to 8.1 ± 9.1 s−1 after treatment (P= 0.01). Conclusion This prospective pilot DCE-MRI study showed that time to peak significantly changed after TACE treatment for both groups (nonviable tumors and equivocal or viable tumors). In our cohort, several perfusion parameters may provide an objective marker for differentiation of treatment response after TACE in HCC patients

Tumor invasion and matrix metalloproteinases

Matrix metalloproteinases (MMPs) are proteolytic enzymes which play a major role in tumour invasion. They are mainly produced by host stromal cells in most carcinomas and their expression implies a close co-operation between tumour and stromal cells. Increasing data also demonstrate that, in association with a process of epithelial-to-mesenchymal transition, many MMPs can be expressed by tumour cell themselves. Their most well-known role is the degradation of extra-cellular matrix macromolecules which in turn may regulate tumour invasion in some conditions. This ECM degradation generates some matrikins which are also implicated in tumour invasion and angiogenesis. Moreover, MMPs are also implicated in the degradation of cell adhesion molecules and release and activation of growth factors

Pour une histoire du risque

L’histoire du risque que propose ce livre déborde largement les notions de statistique, de calcul probabilitaire et de traitement assurantiel des dangers. Si, en effet, le risque a une histoire, le risque est aussi histoire, car il concerne le rapport des sociétés au temps. Tout rapport au risque tente, à partir de l’expérience passée, de saisir un avenir probable pour agir dans le présent. Chaque contexte, chaque époque, chaque territoire, chaque communauté appréhende les dangers selon ses ressources culturelles d’une part, et selon les enjeux politiques, sociaux et économiques qui la traversent d’autre part. Le risque est un fait de culture, reflétant la façon dont la société se représente elle-même, envisage les phénomènes qui la menacent et définit l’altérité qui la borne. Des historiens de tous horizons ont recours, dans ces pages, au concept de risque pour comprendre le passé, pour examiner leur objet de recherche sous un angle différent, qu’il s’agisse d’histoire des sciences et techniques ou du droit, ou d’histoire environnementale, sociale ou politique. Cette démarche commune dévoile des convergences insoupçonnées et permet aux auteurs de renouer avec un problème d’une intelligibilité historique globale, problème crucial qui a pourtant été abandonné par la très grande majorité des historiens au cours des dernières décennies