Granulosa cell tumor of the ovary with high FDG uptake.

Granulosa cell tumor (GCT) of the ovary is a rare tumor accounting for 2%-5% of ovarian malignancies. Although the usefulness of 18F-FDG PET/CT is well demonstrated in the staging and follow-up of the great majority of ovarian cancers, GCTs are known to cause false-negative results on FDG PET because of very low FDG avidity. We present a case of a GCT in which an 18F-FDG PET/CT proved very useful in the detection of recurrence.

18F-fluoride PET/CT aspect of an unusual case of Erdheim-Chester disease with histologic features of Langerhans cell histiocytosis.

We report the case of a 63-year-old woman with Erdheim-Chester disease (ECD) and histologic features of Langerhans cell histiocytosis, both extremely rare histiocytic proliferations responsible of skeletal and extraskeletal involvement. 18F-Fluoride PET/CT revealed multiple intense focal uptake scattered throughout the skeleton. We also performed an 18F-FDG PET/CT which point out visceral and vascular involvement. This case illustrates the interest of PET/CT in ECD, a rare polymorphus and systemic disease, and in our knowledge, this is the first reported illustration of 18F-fluoride PET/CT findings in this pathology.

Assessment of microcirculatory effects of glycine by intravital microscopy in rats.

Experimental studies using laboratory animal models have shown a potential vasoactive effect of natural metabolites such as glycine. The present study used intravital microscopy in laboratory rat models to study the microcirculation in the brain pial and mesentery vessels. To investigate the pial microvasculature, a stereotaxis-like animal fixing device was used. The intravital microscopy unit consisted of a binocular microscope equipped with a digital photo-video camera, processor, monitor and printer. Using reflected light, a special contact lens with an amplified focus depth provided high-resolution images of nontransparent tissue objects that typically have insufficient light exposure. Glycine had a vasodilatory effect on microvessels in the rat brain and mesenterium. The diameter of pial arterioles increased after glycine application especially markedly (up to 250% of initial size). These changes were not observed when physiological saline was used. Even a very small amount of glycine (a drop on the needle) was sufficient to stop the early stages of histamine-induced blood stasis development in 3-5 s in mesenterial microvessels. The vasodilatory effect of glycine on the pial microcirculation correlates with its reported positive therapeutic effect in cerebral ischemic stroke. The ability of glycine to avoid or prevent histamine-induced microcirculatory alterations in mesenterial microvessels may have potential clinical applications.

Development of multi-compartment model of the liver using image-based meshing software.

Computer simulation of biological systems for in silico validation has the potential of increasing the efficiency of pharmaceutical research and development by expanding the number of parameters tested virtually. Then only the most interesting subset of these has to be probed in vivo. By focusing on variables with the greatest influence on clinical end points, valuable drug targets can be advanced more quickly. A large number of methods have been developed to rebuild a three-dimensional (3D) model of a liver, mostly to prepare a liver surgery. These models are often not accurate and most of the them don't take into account the fluidics inside the vessels. The aim of this work is to provide an accurate computational multi-compartement model of the healthy and the pathological liver with their network of blood vessels (vasculature) using a finite-element-modeling software. Computed tomography (CT) slices, in DICOM format, from two different patients were used to provide the datasets of transverse images for the modeling. Each dataset of images was segmented in order to extract the liver's shape and define the vein and artery networks. On CT images, the contrast between the liver and the nearby organs (background) is very low because all these structures are a similar density. Thus, we used semi-automatic tools to determine liver contours. Manual segmentation was used as a last resort. Then, strong filtering (bilateral filter) and confidence-connected-region-growing algorithm were applied to rebuild from each - healthy and pathological - liver a multicompartment model including parenchyma, arteries and veins. The precision of the obtained vasculature model allowed anatomical classification of hepatic segments and the quantification of their volumes. Although our study demonstrated the difficulties in use of CT images for computational modeling of the liver, it also confirmed that semi-automatic tools can be used to develop anatomically accurate models of hepatic vasculature.