Hemodynamic Analysis of Cerebral AVMs with 3D Phase-Contrast MR Imaging

BACKGROUND AND PURPOSE

The hemodynamics associated with cerebral AVMs have a significant impact on their clinical presentation. This study aimed to evaluate the hemodynamic features of AVMs using 3D phase-contrast MR imaging with dual velocity-encodings.

MATERIALS AND METHODS

Thirty-two patients with supratentorial AVMs who had not received any previous treatment and had undergone 3D phase-contrast MR imaging were included in this study. The nidus diameter and volume were measured for classification of AVMs (small, medium, or large). Flow parameters measured included apparent AVM inflow, AVM inflow index, apparent AVM outflow, AVM outflow index, and the apparent AVM inflow-to-outflow ratio. Correlation coefficients between the nidus volume and each flow were calculated. The flow parameters between small and other AVMs as well as between nonhemorrhagic and hemorrhagic AVMs were compared.

RESULTS

Patients were divided into hemorrhagic (n = 8) and nonhemorrhagic (n = 24) groups. The correlation coefficient between the nidus volume and the apparent AVM inflow and outflow was .83. The apparent AVM inflow and outflow in small AVMs were significantly smaller than in medium AVMs (P < .001 for both groups). The apparent AVM inflow-to-outflow ratio was significantly larger in the hemorrhagic AVMs than in the nonhemorrhagic AVMs (P = .02).

CONCLUSIONS

The apparent AVM inflow-to-outflow ratio was the only significant parameter that differed between nonhemorrhagic and hemorrhagic AVMs, suggesting that a poor drainage system may increase AVM pressure, potentially causing cerebral hemorrhage.

A high-performance and simplified quasi-elastic laser scattering method using homodyne detection in beam divergence

We devise the new principle of the quasi-elastic laser scattering (QELS) method using a homodyne detection technique in a beam divergence and successfully facilitate the equipment The QELS method is a unique technique for the noncontact and time-resolved study of surface tension at liquid surfaces and liquid/liquid interfaces. The conventional QELS method requires a precise optical alignment using a local oscillator such as a diffraction grating, and the determination of the surface tension accompanies much difficulty because of the low S/N ratio of the power spectra. Our new principle allows high-performance QELS measurements by only a simple alignment of a downsized experimental setup. The power spectra are obtained with 50-100 times higher S/N ratios than the conventional ones. The power spectra are analyzed by a new theory, and the calculated surface tensions agree with the literature values. The accuracy of the surface tension measurements using the QELS method is substantially improved.

Partial color constancy of isolated surface colors examined by a color-naming method

Color samples selected from the OSA Uniform Color Scales set were viewed without any surround. Separate light sources were used to illuminate the samples and to control the state of adaptation of the subject, thereby separating two factors that are normally confounded. A color-naming procedure was used to assess shifts in color appearance produced by altering the spectral distributions of one or both light sources. The results confirm that chromatic adaptation, when it is the only factor operating, can mediate partial color constancy.

Influence of achromatic surrounds on categorical perception of surface colors

Color samples selected from the OSA Uniform Color Scales set were seen isolated in a dark field, illuminated by hidden projectors. These appeared as self-luminous aperture colors when thus isolated. We employed a categorical color-naming procedure to assess color appearance. Achromatic surrounds of 33 min width, if adjacent to samples subtending about 2.2 deg, were sufficient to render normal categorical surface-color perception. As the size of surrounds decreased, color naming shifted from that normally observed in the surface-color mode to that appropriate to the aperture-color mode. For isolated samples, brown was almost never seen, being most often replaced by orange; a white border less than one-sixtieth the width of the color samples was sufficient to restore its perception in an otherwise dark field. The reflectance of the surround and the gap between test and surround stimuli were also examined and found to be important factors in surface color perception, whereas the overall luminance level was not.

Two-site column enzyme immunoassay for neuron-specific enolase (NSE) in human serum using monoclonal antibodies

A new method for the rapid determination of neuron-specific gamma-enolase (NSE), gamma-subunit of alpha gamma- and gamma gamma-enolase in human serum was developed by employing monoclonal antibodies for the separation method. The assay system consists of 0.1 ml Sepharose 4B column with immobilized rabbit anti-mouse IgG antibodies for the separation of bound label, Fab' fragments of rabbit anti-bovine gamma gamma-enolase IgG labeled with beta-D-galactosidase from Escherichia coli, and F(ab')2 fragments of two mouse monoclonal antibodies to gamma gamma-enolase. Serum samples or standard NSE solutions were incubated at 30 degrees C with the monoclonal antibody fragments. 10 min later, the galactosidase-labeled antibody fragments were added to the mixture, and incubated at 30 degrees C for 30 min. Then the reaction mixture was applied to a micro-column of Sepharose 4B with immobilized anti-mouse IgG antibodies. From the galactosidase activity bound in the column, NSE concentration in the samples could be estimated within 2 h. The minimum detection limit of the assay system was 30 pg/tube, being sufficiently sensitive for the assay of serum NSE with a satisfactory precision. Serum concentrations of NSE determined by the present method correlated well with that by the colorimetric solid-phase immunoassay method.

Practicable enzyme immunoassay for neuron-specific enolase in human serum

A practicable sandwich-type enzyme immunoassay for neuron-specific enolase (NSE) in human serum was established by the use of purified antibodies to bovine neuron-specific gamma gamma-enolase. The assay system consisted of polystyrene balls (6.5 mm in diameter) with immobilized antibody F(ab')2 fragments and the same antibody Fab' fragments labeled with beta-D-galactosidase from Escherichia coli. The assay could be performed within a working day. The assay system had a minimum detectable sensitivity of 50 pg per assay tube or 1 microgram per liter of NSE in human serum. The assay did not cross-react with nonspecific alpha alpha-enolase and muscle-specific beta beta-enolase. Coefficients of variation in within-assay and between-assay of serum NSE were less than 10%. Serum NSE values (n = 79) determined with the present method correlated well with those obtained by the previously developed method (correlation coefficient r = 0.96, y = 0.92x - 0.83). Serum NSE concentrations of healthy subjects were less than 5 micrograms per liter and those in sera of patients with small-cell carcinoma of the lung were enhanced.

Equating colors for saturation and brightness: the relationship to luminance

With a modified step-by-step brightness-matching procedure, a series of colors, with dominant wavelengths from 400 to 670 nm, was adjusted so that the saturations and brightnesses of the colors appeared equal to those of the reference, which was a mixture of 570-nm and white light. The results show that equally bright and equally saturated colors are not equal in luminance. We also report a saturation function of spectral lights derived by utilizing these equally bright and equally saturated colors. Finally, our equally saturated colors do not plot as a circle in the 1976 CIE u', v' space, which indicates some limitations of this uniform chromaticity diagram.