This paper presents dynamic flow experiments with fluorescently labeled platelets to allow for spatial observation of wall attachment in inter-strut spacings, to investigate their relationship to flow patterns. Human blood with fluorescently labeled platelets was circulated through an in vitro system that produced physiologic pulsatile flow in a parallel plate flow chamber that contained three different stent designs that feature completely recirculating flow, partially recirculating flow (intermediate strut spacing), and completely reattached flow. Highly resolved spatial distribution of platelets was obtained by imaging fluorescently labeled platelets between the struts. Platelet deposition was higher in areas where flow is directed towards the wall, and lower in areas where flow is directed away from the wall. Flow detachment and reattachment points exhibited very low platelet deposition. Platelet deposition within intermediate strut spacing continued to increase throughout the experimental period, indicating that the deposition rate had not plateaued unlike other strut spacings. The spatial uniformity and temporal increase in platelet deposition for the intermediate strut spacing confirms and helps explain our previous finding that platelet deposition was highest with this strut spacing. Further experimental investigations will include more complex three-dimensional geometries.

Near-infrared optical imaging is an emerging noninvasive technology toward breast cancer diagnosis. The optical imaging systems available to date are limited either by flexibility to image any given breast volume, patient comfort, or instrument portability. Here, a hand-held optical probe is designed and developed, 1. employing a unique measurement scheme of simultaneous multiple point illumination and collection for rapid data acquisition and minimal patient discomfort, and 2. employing a curved probe head such that it allows flexible imaging of tissue curvatures. Simulation studies are carried out on homogeneous slab phantoms (5x10x8 cc) to determine an appropriate source-detector configuration for the probe head. These design features are implemented in the development of the probe, which consisted of six simultaneous illuminating and 165 simultaneous collecting fibers, spaced 0.5 cm apart on a 5x10 sq-cm probe head. Simulation studies on 3-D slab and curved phantoms demonstrate an increase in the total area of predicted fluorescence amplitude and overall signal strength on using simultaneous multiple point sources over a single point source. The probe is designed and developed such that on coupling with a detection system in the future, the hand-held probe based imager can be clinically assessed toward cancer diagnostic imaging.

Additional knowledge of the role of mechanical factors in stent restenosis will aid in designing stents that minimize intimal hyperplasia and restenosis. The results of this study demonstrate the importance of stent design-mediated blood flow patterns, with smaller strut spacings minimizing platelet adhesion per unit strut area.

Additional knowledge of the role of mechanical factors in stent restenosis will aid in designing stents that minimize intimal hyperplasia and restenosis. The results of this study demonstrate the importance of stent design-mediated blood flow patterns, with smaller strut spacings minimizing platelet adhesion per unit strut area.

Purpose: To design and develop a portable optical imager for early‐stage breast cancer diagnostics, providing great depth information, enhanced data acquisition rates, and minimal patient discomfort. Method and Materials: A unique measurement geometry of simultaneous multiple point source illumination was implemented in the design and development of the hand‐held based optical probe. Simultaneous multiple point detection was carried out using an intensified charge‐coupled camera (ICCD) that can be operated in the continuous wave and frequency domain measurement approaches. The hand‐held based imaging probe has been coupled to the ICCD detection system and the performance characteristics (in terms of measurement accuracy and precision) of the imager is characterized through initial phantom studies under homogeneous conditions. Results: Preliminary simulated studies using simultaneous multiple point illumination measurement geometry over the universally used single point illumination geometry demonstrated an increase in the detected signal strength as well as total interrogated tissue volumes. An optimal number of source and detector fibers used to develop the probe head, minimized the dead volume and improved the data acquisition times. Conclusion: A novel fluorescence‐enhanced imaging system was developed using a hand‐held probe and an ICCD camera, enabling the flexible and rapid imaging of any given tissue volume. Further work involves phantom based experimental studies towards 3D optical imaging and tomographic analysis. The final goal is to translate the current laboratory‐based techniques into routine clinical use.