Contrast-enhanced ultrasound study of Internal Jugular vein blood flow in Multiple Sclerosis patients. Imaging study of cerebral venous system in mouse.

The underlying mechanism of the widespread axonal degeneration in Multiple Sclerosis (MS) is not yet fully understood. The patterns of demyelination are different between different subgroups of patients with MS, suggesting that the disease is heterogeneous. It is known that the development of a chronic inflammatory reaction in the brain requires additional factors and that the impairment associated with relapsing-remitting clinical form is primarily caused by inflammation and demyelination, whereas the accumulation of irreversible neurological deficit, typical of the progressive forms, is caused mainly by axonal destruction and neuronal loss. Other mechanisms may contribute in determining brain damage during the course of the disease. One hypothesis is that immune factors interacting with the vascular system may secondarily induce changes in cerebral perfusion that are detectable in both early stage of disease and advanced disease and that may cause neuronal damage. The higher frequency of ischemic stroke in patients with MS may be due to several factors such as inflammation, oxidative stress, and increase of thrombophilic factors such as homocysteine. Recently it has been suggested that alterations of cerebral venous outflow in MS patients could determine perivenular extravasations of erythrocytes, iron overload and activation of the immune response. Vascular dysfunction could be one of the factors involved in the complex pathogenesis of MS. However, available data to support the presence and importance of vascular dysfunction are still insufficient to draw definitive conclusions. A first part of research project was to study the Internal Jugular Veins dynamics in MS patients compared with healthy controls using contrast-enhanced ultrasonography. The patients with MS showed a significantly reduction of wash-out rate compared to healthy controls [22.2% (2.7%-65.9%) vs. 33.4% (16.2%-76.8%); P<0.005]. Then we decided to explore the effect of cerebral outflow reduction on cerebral nervous system in experimental animal model. Therefore, the second part of research project was dedicated to the characterization the anatomy of the cerebral veins of the mouse brain using different imaging techniques. This work was preliminary to the development of a mice model of cerebral outflow occlusion to assess the correlations between venous stasis and the development of neurological disease

Evaluation of a Trustees Leadership Academy at the Medical University of South Carolina

Developing leaders in academic medicine has become a priority for many academic health science centers. The increased need for these leaders as well as the desire of individuals on such campuses to enhance their skills in teaching, research and leadership is driving the increase in faculty development programs

Head and Neck Veins of the Mouse. A Magnetic Resonance, Micro Computed Tomography and High Frequency Color Doppler Ultrasound Study.

To characterize the anatomy of the venous outflow of the mouse brain using different imaging techniques. Ten C57/black male mice (age range: 7-8 weeks) were imaged with high-frequency Ultrasound, Magnetic Resonance Angiography and ex-vivo Microcomputed tomography of the head and neck. Under general anesthesia, Ultrasound of neck veins was performed with a 20MHz transducer; head and neck Magnetic Resonance Angiography data were collected on 9.4T or 7T scanners, and ex-vivo Microcomputed tomography angiography was obtained by filling the vessels with a radiopaque inert silicone rubber compound. All procedures were approved by the local ethical committee. The dorsal intracranial venous system is quite similar in mice and humans. Instead, the mouse Internal Jugular Veins are tiny vessels receiving the sigmoid sinuses and tributaries from cerebellum, occipital lobe and midbrain, while the majority of the cerebral blood, i.e. from the olfactory bulbs and fronto-parietal lobes, is apparently drained through skull base connections into the External Jugular Vein. Three main intra-extracranial anastomoses, absent in humans, are: 1) the petrosquamous sinus, draining into the posterior facial vein, 2) the veins of the olfactory bulb, draining into the superficial temporal vein through a foramen of the frontal bone 3) the cavernous sinus, draining in the External Jugular Vein through a foramen of the sphenoid bone. The anatomical structure of the mouse cranial venous outflow as depicted by Ultrasound, Microcomputed tomography and Magnetic Resonance Angiography is different from humans, with multiple connections between intra- and extra- cranial veins

Pancreatoblastoma with Metastatic Retroperitoneal Lymph Node and PET/CT

A previously healthy 4-year-old girl presented with petechial rash and low platelet count. There were no other symptoms. On abdominal ultrasound, a 4.7-cm heterogeneous mass was demonstrated anterior to the left kidney. An abdominal MRI subsequently performed demonstrated a heterogeneously enhancing mass at the same location extending to the pancreas and spleen. A surgical biopsy of the mass was obtained. Pathology reported a malignant epithelioid neoplasm consistent with pancreatoblastoma. The mass demonstrated intense FDG uptake on PET and an FDG avid retrocaval lymph node

Optimization of tagged MRI for quantification of liver stiffness using computer simulated data.

The heartbeat has been proposed as an intrinsic source of motion that can be used in combination with tagged Magnetic Resonance Imaging (MRI) to measure displacements induced in the liver as an index of liver stiffness. Optimizing a tagged MRI acquisition protocol in terms of sensitivity to these displacements, which are in the order of pixel size, is necessary to develop the method as a quantification tool for staging fibrosis. We reproduced a study of cardiac-induced strain in the liver at 3T and simulated tagged MR images with different grid tag patterns to evaluate the performance of the Harmonic Phase (HARP) image analysis method and its dependence on the parameters of tag spacing and grid angle. The Partial Volume Effect (PVE), T1 relaxation, and different levels of noise were taken into account. Four displacement fields of increasing intensity were created and applied to the tagged MR images of the liver. These fields simulated the deformation at different liver stiffnesses. An Error Index (EI) was calculated to evaluate the estimation accuracy for various parameter values. In the absence of noise, the estimation accuracy of the displacement fields increased as tag spacings decreased. EIs for each of the four displacement fields were lower at 0° and the local minima of the EI were found to correspond to multiples of pixel size. The accuracy of the estimation decreased for increasing levels of added noise; as the level increased, the improved estimation caused by decreasing the tag spacing tended to zero. The optimal tag spacing turned out to be a compromise between the smallest tag period that is a multiple of the pixel size and is achievable in a real acquisition and the tag spacing that guarantees an accurate liver displacement measure in the presence of realistic levels of noise

Simulation algorithm.

<p>Schematic representation of data generation and data processing steps.</p

EI in the presence of noise.

<p>Plot of EI for tag spacings varying from 4.0 to 7.0 pixels, a grid angle of 0°, and different noise levels for (a) Dg₁, (b) Dg₂, (c) Dg₃, and (d) Dg₄.</p