Osmotic disruption of the blood brain barrier (BBB) by intraarterial mannitol injection is sometimes the key step for the delivery of chemotherapeutic drugs to brain tissue. BBB disruption (BBBD) with mannitol, however, can be highly variable and could impact local drug deposition. We use optical pharmacokinetics, which is based on diffuse reflectance spectroscopy, to track in vivo brain tissue concentrations of indocyanine green (ICG), an optical reporter used to monitor BBBD, and mitoxantrone (MTX), a chemotherapy agent that does not deposit in brain tissue without BBBD, in anesthetized New Zealand white rabbits. Results show a significant increase in the tissue ICG concentrations with BBBD, and our method is able to track the animal-to-animal variation in tissue ICG and MTX concentrations after BBBD. The tissue concentrations of MTX increase with barrier disruption and are found to be correlated to the degree of disruption, as assessed by the ICG prior to the injection of the drug. These findings should encourage the development of tracers and optical methods capable of quantifying the degree of BBBD, with the goal of improving drug delivery.
The average workload per full-time equivalent (FTE) radiologist increased by 70% from1991-1992 to 2006-
2007. The increase is mainly due to the increase (34%) in the number of procedures, particularly in 3D imaging
procedures. New technologies such as picture archiving and communication systems (PACS) and embodied viewing
capability were accredited for an improved workflow environment leading to the increased productivity. However, the
need for further workflow improvement is still in demand as the number of procedures continues growing. Advanced and
streamlined viewing capability in PACS environment could potentially reduce the reading time, thus further increasing
the productivity. With the increasing number of 3D image procedures, radiographic procedures (excluding
mammography) have remained their critical roles in screening and diagnosis of various diseases. Although radiographic
procedures decreased in shares from 70% to 49.5%, the total number has remained the same from 1991-1992 to 2006-
2007. Inconsistency in image quality for radiographic images has been identified as an area of concern. It affects the
ability of clinicians to interpret images effectively and efficiently in areas where diagnosis, for example, in screening
mammography and portable chest radiography, requires a comparison of current images with priors. These priors can
potentially have different image quality. Variations in image acquisition techniques (x-ray exposure), patient and
apparatus positioning, and image processing are the factors attributed to the inconsistency in image quality. The
inconsistency in image quality, for example, in contrast may require manual image manipulation (i.e., windowing and
leveling) of images to accomplish an optimal comparison to detect the subtle changes. We developed a tone-scale image
rendering technique which improves the image consistency of chest images across time and modality. The rendering
controls both the global and local contrast for a consistent look. We expect the improvement could reduce the window
and level manipulation time required for an optimal comparison of priors and current images, thus improving both the
efficiency and effectiveness of image interpretation. This paper presents a technique for improving the consistency of
portable chest radiographic images. The technique is based on regions-of-interest (ROIs) to control both the local and
global contrast consistency.
We describe an optical tissue phantom that enables the simulation of drug extravasation from microvessels and validates
computational compartmental models of drug delivery. The phantom consists of a microdialysis tubing bundle to
simulate the permeable blood vessels, immersed in either an aqueous suspension of titanium dioxide (TiO2) or a TiO2
mixed agarose scattering medium. Drug administration is represented by a dye circulated through this porous
microdialysis tubing bundle. Optical pharmacokinetic (OP) methods are used to measure changes in the absorption
coefficient of the scattering medium due to the arrival and diffusion of the dye. We have established particle sizedependent
concentration profiles over time of phantom drug delivery by intravenous (IV) and intra-arterial (IA) routes.
Additionally, pharmacokinetic compartmental models are implemented in computer simulations for the conditions
studied within the phantom. The simulated concentration-time profiles agree well with measurements from the phantom.
The results are encouraging for future optical pharmacokinetic method development, both physical and computational, to
understand drug extravasation under various physiological conditions.