Imaging Cerebral Blood Vessels Using Near-Infrared Optical Tomography: A Simulation Study

Cerebral veins have received increasing attention due to their importance in preoperational planning and the brain oxygenation measurement. There are different modalities to image those vessels, such as magnetic resonance angiography (MRA) and recently, contrast-enhanced (CE) 3D gradient-echo sequences. However, the current techniques have certain disadvantages, i.e., the long examination time, the requirement of contrast agents or inability to measure oxygenation. Near-infrared optical tomography (NIROT) is emerging as a viable new biomedical imaging modality that employs near infrared light (650-950 nm) to image biological tissue. It was proven to easily penetrate the skull and therefore enables the brain vessels to be assessed. NIROT utilizes safe non-ionizing radiation and can be applied in e.g., early detection of neonatal brain injury and ischemic strokes. The aim is to develop non-invasive label-free dynamic time domain (TD) NIROT to image the brain vessels. A simulation study was performed with the software (NIRFAST) which models light propagation in tissue with the finite element method (FEM). Both a simple shape mesh and a real head mesh including all the segmented vessels from MRI images were simulated using both FEM and a hybrid FEM-U-Net network, we were able to visualize the superficial vessels with NIROT with a Root Mean Square Error (RMSE) lower than 0.079.

[Markers of viral hepatitis B. Diagnostic, prognostic and therapeutic relevance]

Analysis of the behaviour and chronological development of B virus markers (including those most recently identified) in acute and chronic hepatitis gives rise to a diagnostic hypothesis about their presence and association. The prognostic and therapeutic significance of the markers is also emphasised with particular reference to fulminating and chronic active HBSAg and D positive hepatitis and the early diagnosis of liver cell carcinoma.

[Benign monoclonal gammopathies: probable antibody specificity of monoclonal immunoglobulins]

40 patients with benign paraproteinemia have been studied in relation to their age and associated diseases. Significantly high frequency of liver diseases (CALD, cirrhosis, hepatoma, metastases) has been found (12 over 40 people) and increased incidence of idiopathic paraproteinaemia in the old age has been confirmed. 9 patients have been followed for 5 years, so that one could be sure that they had really benign paraproteinaemia: these patients have been then studied from an immunological point of view, in vivo by means of skin tests (PPD, Candida, Trichophyton, DNCB) and in vitro by searching for circulating immune complexes (using a new highly specific immuno-enzymatic method), and compared to controls without paraproteinaemia. Highly positive skin tests have been found only in 7 over 9 patients (even in old subjects) and 6 of them had circulating immune complexes (C.I.C.) in their sera; all the controls were negative both for skin tests and for C.I.C. Immune complexes have been found also in some cases of idiopathic paraproteinaemia, so that they do not seem to be in relation to the associated diseases. The Authors suggest that a genetically determined defect in regulator/suppressor T lymphocyte activity may cause the growth of a benign B cell neoplasm; and that monoclonal immunoglobulins most probably have antibody specificity and are directed against target antigens.