Title :
A new ultrasound-based approach to visualize target specific polymeric contrast agent
Author :
Larsson, Malin ; Bjällmark, Anna ; Larsson, Matilda ; Caidahl, Kenneth ; Winter, Reidar ; Brodin, Lars-Åke
Author_Institution :
Dept. of Med. Eng., R. Inst. of Technol., Stockholm, Sweden
Abstract :
There are advantages of using a polymeric shelled contrast agent (CA) during ultrasound imaging instead of lipid shelled CA, e.g. particles can be attached to the surface, which enables an introduction of antibodies to the surface making the CA target specific. For this application it is essential to have a sensitive imaging technique suitable for polymeric CA. However, previously presented results have indicated difficulties in visualizing polymeric CA with commercially available contrast algorithms. Therefore a new subtraction algorithm (SA), was developed that define the difference between contrast and reference images. The aim of this study was to evaluate the response from a polymeric CA, when using the SA and compare it with existing contrast algorithms. Moreover, the possibility to detect a thin layer of CA was tested using the SA. Ultrasound short-axis images of a tissue-mimicking vessel phantom with a pulsating flow were obtained using a GE Vivid7 system (M12L) and a Philips iE33 system (S5-1). Repeated (n=91) contrast to tissue ratios (CTR) calculated at various mechanical index (MI) using the contrast algorithms pulse inversion (PI), power modulation (PM) and SA at a concentration of 105 microbubbles/ml. The developed SA showed improvements in CTR compared to existing contrast algorithms. The CTRs were -0.99 dB ± 0.67 (MI 0.2), 9.46 dB ± 0.77 (MI 0.4) and 2.98 dB ± 0.60 (MI 0.8) with PI, 8.17 dB ± 1.15 (MI 0.2), 15.60 dB ± 1.29 (MI 0.4) and 11.60 dB ± 0.73 (MI 0.8) with PM and 14.97 dB ± 3.97 (MI 0.2), 20.89 dB ± 3.54 (MI 0.4) and 21.93 dB ± 4.37 (MI 0.8) with the SA. In addition to this, the layer detection, when using the SA was successful.
Keywords :
biological tissues; biomedical ultrasonics; haemodynamics; phantoms; polymers; pulsatile flow; GE vivid7 system; antibodies; contrast algorithms pulse inversion; contrast-tissue ratios; layer detection; lipid shelled CA; mechanical index; microbubbles; philips iE33 system; polymeric shelled contrast agent; power modulation; pulsating flow; sensitive imaging technique; subtraction algorithm; surface making; target specific polymeric contrast agent; tissue-mimicking vessel phantom; ultrasound imaging; ultrasound short-axis images; ultrasound-based approach; Blood; Imaging phantoms; Phantoms; Polymers; Ultrasonic imaging; Visualization; Contrast to tissue ratio; Target specific Ultrasound contrast agent; Vessel mimicking phantom;
Conference_Titel :
Ultrasonics Symposium (IUS), 2011 IEEE International
Conference_Location :
Orlando, FL
Print_ISBN :
978-1-4577-1253-1
DOI :
10.1109/ULTSYM.2011.0404