Capillary contrast enhancement

Time-resolved CTA could improve visualization of currently difticult-to-detect lesions, such as cavernous sinus aneurysms and small arterial venous malfor-mations/fistulae, as these could be visuahzed with greater temporal resolution during arterial, capillary, and venous phases of contrast enhancement. In fact, dedicated studies could display a temporally parsed image, which could mirror the temporal resolution of the conventional cerebral catheter angiogram. 

The dynamic first pass approach to CTP measnrement involves the IV administration of an intravascnlar contrast agent, which is tracked with serial imaging dnring its first circnlation throngh the brain tissne capillary bed. The main assnmption of dynamic first pass contrast-enhanced CTP models is that the perfnsion tracer is not diffnsible, neither metabolized nor absorbed by the tissue through which it traverses. This is certainly the case in a healthy hnman brain, however, breakdown of the blood-brain barrier (BBB) in infection, inflammation, or tnmor adds an additional level of complexity. When extensive BBB breakdown exists, leakage of... 

Ishizuka N., Nakanishi K., Hirao K. Preparaion and chromatographic application of macroporous silicate in a capillary. J. Sol-Gel Sci. Technol. 2000 19 371-375 Ismail M.G.M.U., Nakai Z., Somiya S. Microstructure and mechanical properties ofmullite prepared by the sol-gel method. I. Am. Ceram. Soc. 1987 70 C7-C8 Ito T. Selectively absorbing filter films for color Braun tube. Indust. Mater. 1998 46 52-56 Ito T., Sol-Gel products news sol-gel coating for contrast enhancement of color cathode-ray tubes. J. Sol-Gel Sci. Technol. 2000 18 287... 

Dynamic contrast-enhanced MRI has been used as an additional imaging technique in various clinical applications, such as differentiation of benign from malignant lesions, tissue characterization by narrowing down the differential diagnosis, identification of areas of viable tumour before biopsy and detection of recurrent tumour tissue after therapy. This technique provides information on tissue vascularization, perfusion, capillary permeability and composition of the interstitial space. 

The opposite behavior as sketched before was detected for solutions of PS in DOP [112], Again, the critical temperature (an UCST at Tc = 12 °C in the quiescent state) turned out to be a function of the shear rate to which the solution is subjected. But, in contrast to solutions of PS and PB in DOP, here enhancements of the UCST as large as 28 °C were recorded at a shear rate of 220 s-1. Similar results have been found for PS solutions in di(2-ethyl hexyl)phthalate or in a mixture of cis- and frans-decalin [113], The solutions demixed in a converging flow from a reservoir into a capillary tube. It has been observed that an increase in the deformation rate raised the UCST or reduced the region of miscibility. In both of these studies an increase of the cloud point temperature of the polymer solutions was used as an indication of phase separation. 

In the heart, the lead salt has been found to be deposited along the plasma membrane and sarcotubular system of muscle cells, and precipitation was enhanced by adrenaline, glucagon and F. In contrast, histamine caused particularly intense staining at the plasma membrane and the membrane of the pinocytotic vesicles of endothelial cell capillaries. This raises the possibility that cyclic AMP formed in endothelial cells of the coronary capillaries under the influence of histamine may affect cardiac cells, thereby acting as a local hormone. 

The ideal contrast agent for enhancing ultrasound images and Doppler signals would be non-toxic, injectable intravenously, capable of crossing the pulmonary capillary bed, stable for the duration of the ultrasound examination, and useful for both Doppler and grey scale enhancement. 

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