Biomedical subjects
Publications and source records attributed to Katherine Ferrara.
We present an overview of graduate programs in biomedical imaging that are currently available in the US. Special attention is given to the emerging technologies of molecular imaging and biophotonics. Discussions from the workshop on Graduate Imaging at the 2005 Whitaker Educational Summit meeting are summarized.
We sought to use ultrasonography to quantify renal size and echogenicity in a mouse model of polycystic kidney disease. We imaged 36 wild-type (WT) and juvenile cystic kidney (jck) mice by using a standard ultrasound unit and 10-5 MHz linear transducer. Mice were imaged at 3 (6 WT, 7 jck), 6 (7 WT, 5 jck), and 9 (6 WT, 5 jck) wk of age. Kidney length, width, and height were recorded for volume calculation. Sagittal images of both kidneys were recorded for assessment of intensity. Quantitative values were obtained from areas of similar depth and gain settings. Kidney and liver intensities were determined for calculation of their ratio. Representative histologic kidney sections were stained with hematoxylin and eosin and digitized for calculation of cyst number, mean cyst area, and percentage cystic area. We found that renal volume was greater in jck than WT mice at 3 (P < 0.0001), 6 (P < 0.0001), and 9 (P < 0.0001) wk of age. In addition, kidney intensity and kidney:liver ratio were higher in jck than WT mice at 3 (P < 0.002 for both parameters), 6 (P < 0.04), and 9 wk (P < 0.008). Kidneys with smaller mean cyst size and less percentage cystic space had higher intensity values. We therefore conclude that ultrasound measures of renal volume and intensity can noninvasively identify jck-affected mice as early as 3 wk of age. Cortical intensity is greater in jck versus WT mice and appears affected by percentage cyst area and mean cyst size.
Explore the source record for details and available documents.
Ultrasound contrast agent microbubbles are intravascular agents that can be used to estimate blood perfusion. Blood perfusion may be estimated by destroying the bubbles in a vascular bed and observing the refresh of contrast agents back into the vascular bed. Contrast agents can be readily destroyed by traditional imaging techniques. The design of a nondestructive imaging technique is necessary for the accurate quantification of contrast agent refresh. In this work, subharmonic imaging is investigated as a method for nondestructive imaging with the contrast agent microbubble MP1950 (Mallinckrodt, Inc., St. Louis, MO). Optical observation during insonation, in conjunction with a modified Rayleigh-Plesset (R-P) analysis, provides insight into the mechanisms of and parameters required for subharmonic frequency generation. Subharmonic imaging with a transmission frequency that is the same as the resonant frequency of the bubble is shown to require a minimum pressure of insonation that is greater than the experimentally-observed bubble destruction threshold. Subharmonic imaging with a transmission frequency that is twice the resonant frequency of the bubble produces a subharmonic frequency response while minimizing bubble instability. Optimization is performed using optical experimental analysis and R-P analysis.