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ABSTRACTThe reconstruction of blood velocity in a vessel from contrast-enhanced X-ray CT projections is a complex inverse problem. In this work, we investigate an inversion approach based on the adjoint method with a partial differential equation as constraint. The proper orthogonal decomposition method is used to accelerate the reconstruction with reduced basis for the velocity, the density and the adjoint method. The effectiveness of the reconstruction method is shown with simulated realistic stationary and non-stationary blood flows in a vessel.

X-ray in-line phase contrast imaging relies on the measurement of Fresnel diffraction intensity patterns due to the phase shift and the attenuation induced by the object. The recovery of phase and attenuation from one or several diffraction patterns is a nonlinear ill-posed inverse problem. In this work, we propose supervised learning approaches using mixed scale dense (MS-D) convolutional neural networks to simultaneously retrieve the phase and the attenuation from x-ray phase contrast images. This network architecture uses dilated convolutions to capture features at different image scales and densely connects all feature maps. The long range information in images becomes quickly available, and greater receptive field size can be obtained without losing resolution. This network architecture seems to account for the effect of the Fresnel operator very efficiently. We train the networks using simulated data of objects consisting of either homogeneous components, characterized by a fixed ratio of the induced refractive phase shifts and attenuation, or heterogeneous components, consisting of various materials. We also train the networks in the image domain by applying a simple initial reconstruction using the adjoint of the Fréchet derivative. We compare the results obtained with the MS-D network to reconstructions using U-Net, another popular network architecture, as well as to reconstructions using the contrast transfer function method, a direct phase and attenuation retrieval method based on linearization of the direct problem. The networks are evaluated using simulated noisy data as well as images acquired at NanoMAX (MAX IV, Lund, Sweden). In all cases, large improvements of the reconstruction errors are obtained on simulated data compared to the linearized method. Moreover, on experimental data, the networks improve the reconstruction quantitatively, improving the low-frequency behavior and the resolution.

High resolution peripheral quantitative CT (HR-pQCT) permits to investigate bone micro-architecture in vivo. While it is a considerable progress over standard CT for this specific application, the spatial resolution remains so far limited for the investigation of bone topology. In this paper, we investigate super resolution techniques to improve 3-D HR-pQCT images via semi-coupled dictionary learning based on the knowledge of high resolution micro-CT images. We propose a method to select the number of atoms and study the impact of patch sizes. To handle the anisotropy of the 3-D bone structure, we propose a 2.5-D strategy learning low and high resolution dictionaries in a semi-coupled way on the three different directions. The results show that this strategy is superior to the application of the method in 2-D. The bone volume fraction is successfully recovered and the estimation of the connectivity is improved in most test samples. The images have a better quality compared with previously studied methods based on total variation (TV) regularization or a combination of TV and a double-well potential. In the future, we expect to further evaluate the method on a larger data set.

New markers are needed to improve diagnosis and to personalize treatments for patients with breast cancer (BC). Receptor-interacting protein of 140 kDa (RIP140) and ligand-dependent corepressor (LCoR), two transcriptional co-regulators of estrogen receptors, strongly interact in BC cells. Although their role in cancer progression has been outlined in the last few years, their function in BC has not been elucidated yet. In this study, we investigated RIP140 and LCoR localization (cytoplasm vsnucleus) in BC samples from a well-characterized cohort of patients (n = 320). RIP140 and LCoR were expressed in more than 80% of tumors, (predominantly in the cytoplasm), and the two markers were highly correlated. Expression of RIP140 and LCoR in the nucleus was negatively correlated with tumor size. Conversely, RIP140 and LCoR cytoplasmic expression strongly correlated with expression of two tumor aggressiveness markers: N-cadherin and CD133 (epithelial mesenchymal transition and cancer stem cell markers, respectively). Finally, high RIP140 nuclear expression was significantly correlated with longer overall survival, whereas high total or cytoplasmic expression of RIP140 was associated with shorter disease-free survival. Our study strongly suggests that the role of RIP140 and LCoR in BC progression could vary according to their prevalent sub-cellular localization, with opposite prognostic values for nuclear and cytoplasmic expression. The involvement in BC progression/invasiveness of cytoplasmic RIP140 could be balanced by the anti-tumor action of nuclear RIP140, thus explaining the previous contradictory findings about its role in BC.

Introduction : Le présent rapport de cas confirme l’hypothèse selon laquelle l’embryogenèse et la croissance maxillo-faciale sont sous l’influence du système nerveux périphérique et notamment du nerf trijumeau (V). Il devient intéressant d’utiliser les stigmates du nerf trijumeau comme référentiel pour analyser tridimensionnellement le volume maxillo-facial et comprendre sa croissance. L’objectif est d’évaluer la validité de l’analyse céphalométrique tridimensionnelle d’essence trigéminale de Treil. Présentation des cas : Le premier cas est un enfant caucasien de sexe féminin atteint du syndrome de Goldenhar. Le deuxième cas est un adulte caucasien de sexe masculin atteint du même syndrome. Dans les deux cas, l’IRM cérébrale montre une atteinte trigéminale unilatérale, homolatérale à l’atteinte faciale. Conclusion : Les résultats de l’étude radiologique de ces cas de syndrome de Goldenhar tendent à prouver le rôle matriciel du nerf trijumeau dans la croissance cranio-faciale. Ces cas mettent en évidence la validité de la conception de la croissance neuro-matricielle de Moss. Ils sont une des justifications anatomo-fonctionnelles de la biométrie tridimensionnelle de Treil d’essence trigéminale.

Les kératokystes ou tumeurs odontogéniques kératokystiques représentent 7 % de tous les kystes odontogéniques et se développent de manière asymptomatique dans la plupart des cas. Bien que l’énucléation soit la solution thérapeutique princeps, d’autres alternatives chirurgicales telles que la marsupialisation ou la décompression s’imposent dans certaines indications. Essentiellement lorsque la tumeur odontogénique kératokystique est de gros volume avec un risque fracturaire associé élevé ou lorsqu’elle présente une inclusion de structures nobles comme le nerf alvéolaire inférieur ou des dents avec comme conséquence un défaut de croissance de l’os alvéolaire. Les auteurs présentent le cas d’une enfant de 9 ans prise en charge pour un volumineux kératokyste secteur 4 incluant la canine et les deux prémolaires. La mise en place d’une décompression associée à un traitement orthodontique multibague a permis de tracter puis de mettre en occlusion sur l’arcade les 3 dents initialement incluses. Avec un recul de 7 ans depuis la première intervention chirurgicale et de 3 ans depuis la fin de traitement orthodontique, cette coordination orthodonticochirurgicale est une réussite aussi bien sur le plan fonctionnel qu’esthétique.

Keratocysts, also known as keratocystic odontogenic tumors (KCOT), make up 7% of all odontogenic cysts and develop asymptomatically in most cases. Enucleation is the benchmark treatment. However, there are surgical alternatives. Marsupialization and decompression are necessary in some cases, mainly when the KCOT is large, thus causing an increased risk of bone fracture, or if it has engulfed important elements such as the inferior alveolar nerve or teeth, consequently causing alveolar bone growth failure. The authors describe the case of a nine-year-old child treated for a large keratocyst situated in sector 4 (lower right jaw), impacting both premolars and the canine (45, 44 and 43). Surgical decompression associated with orthodontic multiband treatment were delivered to pull, and then place the three teeth in occlusion on the dental arch. With seven years hindsight since the first surgical procedure and three years since finishing orthodontic treatment, the cooperation between orthodontists and surgeons can be considered a success, from both the functional and esthetic points of view.