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M Balzarini

Publications and source records attributed to M Balzarini.

5 recordsLinked to original sources
PubMed1999

An overview of cerebral aneurysms. Which factors affect the outcome of microsurgical treatment.

There is a higher incidence of subarachnoid hemorrhage (SAH) with advancing age. Considerable controversy exists as to whether aggressive therapy is indicated in the elderly. With increased life expectancy, a greater number of elderly patients with SAH will require treatment in the future. This study was undertaken to evaluate the effect of age, aneurysm characteristics, Hunt-Hess grade on admission, race, and smoking status to the eventual outcome. The results of 76 consecutive aneurysms clipped in 67 patients by a single surgeon (B.B.) were analyzed. Among the variables, Hunt-Hess grade at admission seemed to be the only significant factor influencing the outcome in this series (X2MH = 17.136, p < 0.001). Advancing age did not worsen the prognosis after SAH and therefore age should not be a contraindication for aggressive management.

Aged↗
PubMed1996

NMR study of the diffusion processes in gels.

Stimulated spin-echo and Carr-Purcell pulse sequences, with pulsed magnetic field gradients, have been used to study the self-diffusion processes of the water in swollen and in supercoiled polyacrylamide gels and in polysaccharides agarose gels, for different polymer concentrations. Restricted diffusion effects are evidenced in both types of gels through the time dependence of the diffusion constant. The results can be interpreted in the framework of diffusion model through permeable walls.

Acrylic Resins↗
PubMedDate not supplied

Quantification and description of fracture network by MRI image analysis.

The contribution of fractures to total porosity and their geometrical descriptions have been studied by Image Analysis applied to 1H Magnetic Resonance Imaging (MRI). Reservoirs of different lithology were acquired with MSME 2D quantitative and 3D sequences. An image analysis procedure, developed ad hoc, was then applied to these acquisitions and the petrophysical parameters computed. These parameters range from fracture porosity to fracture density.

Magnetic Resonance Imaging↗
PubMedDate not supplied

Permeability estimation from NMR diffusion measurements in reservoir rocks.

It is well known that in restricted geometries, such as in porous media, the apparent diffusion coefficient (D) of the fluid depends on the observation time. From the time dependence of D, interesting information can be derived to characterise geometrical features of the porous media that are relevant in oil industry applications. In particular, the permeability can be related to the surface-to-volume ratio (S/V), estimated from the short time behaviour of D(t), and to the connectivity of the pore space, which is probed by the long time behaviour of D(t). The stimulated spin-echo pulse sequence, with pulsed magnetic field gradients, has been used to measure the diffusion coefficients on various homogeneous and heterogeneous sandstone samples. It is shown that the petrophysical parameters obtained by our measurements are in good agreement with those yielded by conventional laboratory techniques (gas permeability and electrical conductivity). Although the diffusing time is limited by T1, eventually preventing an observation of the real asymptotic behaviour, and the surface-to-volume ratio measured by nuclear magnetic resonance is different from the value obtained by BET because of the different length scales probed, the measurement remains reliable and low-time consuming.

Diffusion↗