Evaluation of retained products of conception using pulsed continuous arterial spin-labeling MRI: clinical feasibility and initial results

Objectives

We evaluated the vascularity of retained products of conception (RPOC) using arterial spin-labeling magnetic resonance imaging (ASL-MRI) to clarify the clinical feasibility of this approach.

Materials and methods

A pulsed-continuous ASL sequence with echo-planar imaging (EPI) acquisitions was used. Ten consecutive patients with RPOC were enrolled. All ASL images were evaluated visually and semiquantitatively and compared with the findings of Doppler ultrasound (US) and dynamic contrast-enhanced MRI (DCE-MRI).

Results

The technical success rate was 93.7% (15/16 scans). One failed case was excluded from the analysis. Six patients showed quite high signals over RPOC, while three patients showed no abnormal signals. Doppler US alone failed to detect the hypervascular area in two cases, and ASL-MRI alone failed in three. A significant linear correlation was found between semiquantitative values of ASL-MRI and DCE-MRI. All six patients showing high signals on ASL-MRI underwent follow-up MRI after therapy. High signals in five patients decreased visually and semiquantitatively, while one patient showed signal increases.

Conclusion

Evaluation of RPOC using ASL-MRI was clinically feasible and response to therapy could be evaluated. However, the clinical advantages over conventional imaging remain unclear and need to be evaluated.

     

Quantitative analysis of deuterium using laser-induced plasma at low pressure of helium

It was proved that the analysis of deuterium can be conducted using laser-induced plasma spectroscopy. By selecting the appropriate surrounding gas, its pressure, and gating time of the detection system, it was shown that the emission lines of both hydrogen (H(alpha)) and deuterium (D(alpha)), separated by only 0.179 nm, can be fully resolved. A linear calibration curve was also obtained, indicating that this technique has the potential for quantitative analysis of deuterium. The minimum detection limit achieved in this stage of research was estimated to be 50 ppm. We have also shown that this technique can be used as a simple and rapid method for D and H analysis in solid samples.     

Regional difference of water content in human skin studied by diffuse-reflectance near-infrared spectroscopy: consideration of measurement depth

Diffuse reflectance (DF) spectra in the 1250-2500 nm region were measured in vivo for the skin of the forehead, cheek, jaw, elbow, volar forearm, palm, knee, and heel of seven healthy volunteers, using a Fourier transform near-infrared (FT-NIR) spectrophotometer with a fiber-optic probe. Apparent regional differences of water content in the skin, as estimated from the diffuse reflectance NIR spectra, are discussed in relation to the influence of measurement depth. The NIR spectra were collected with or without a 300 microm gap between the fiber-optic probe and the skin surface. For comparison, in vitro NIR spectra of stratum corneum sheets equilibrated at 41, 50, 63, and 81% relative humidity, at 25 degrees C, were also obtained. There was a difference in the ratio of the two water bands centered near 1450 nm and 1900 nm between the contact and non-contact measurements. In addition, regional differences of water content calculated from the peak height of the 1900 nm water band, which was normalized to the peak height of the 2175 nm amide band, were compared. The results of Monte Carlo simulation indicated that the apparent regional differences arise at least in part from differences in the measurement depth due to differences in specular reflection at the skin surface and in the thickness of the stratum corneum.     

Stabilization analysis of commercial‐scale subsonic diagonal‐type MHD generator considering loading conditions

In previous research on subsonic diagonal‐type MHD generators, the authors have proposed a conceptual design with relatively low Mach number in order to stabilize the MHD generator of commercial scale and have shown that the MHD generator works stably under constant‐current loading condition. In the present paper, effects of loading conditions on stability of the MHD generator are examined. A channel‐length scale linear stability analysis and time‐dependent calculations are carried out, where both gasdynamical boundary conditions and loading condition are taken into account. These analyses show that the MHD generator behaves stably under various loading conditions such as constant‐voltage loading condition and ohmic loading condition. Then the stability of the MHD generator connected with an ac power system is also analyzed by time‐dependent calculations. The analysis shows that the MHD generator stably provides the rated power to the ac power line. © 1999 Scripta Technica, Electr Eng Jpn, 128(4): 16–24, 1999     

SOLVENT EXTRACTION OF COPPER (II) WITH AN ALDOXIME FROM HYDROCHLORIC AND HYDROBROMIC ACIDS

2-ethylhexanal oxime was synthesized to examine the selectivities for various metals in the extractions from hydrochloric acid. It was found to be highly selective for palladium(II) over platinum(II and IV) and other base metals including copper(II), zinc and aluminum, especially in the low concentration region of chloride ions.