Wednesday, October 27, 2010
My bad for being a couple of months late is posting this: Congratulations to Amir Manbachi on the successful defense of his Master's thesis, "Characterization of common carotid artery geometry and its impact on velocity profile shape". Amir is now doing a PhD on the topic of ultrasound-guided therapy, and is also patiently waiting for me to get my act together so we can submit a paper on his Master's work!
Labels: BSL members
In 2008 we demonstrated a significant correlation between certain geometric variables and the amount of disturbed flow at the carotid bifurcation. Now working with Qi Zhang and Mort Friedman -- yes, that Mort Friedman, the father of the geometric risk hypothesis -- we extended and improved these correlations in "Use of factor analysis to characterize arterial geometry and predict hemodynamic risk: application to the human carotid bifurcation." To me the strength of factor analysis is not just its ability to rationally combine variables to create factors that improve correlations, but also the ability to identify why certain variables (in the present case, bifurcation angle) are not correlated with disturbed flow. Less directly, the debates we had about why certain geometric factors are better correlated with disturbed flow helped inspire us to identify better geometric variables (to be presented at SPIE Medical Imaging 2011), which can only lead to better factors, etc. And in case you didn't notice the subtle use of bold text, yes there is an issue of terminology that I'm still trying to get used to!
Tuesday, October 19, 2010
In 2005 we showed how Doppler ultrasound spectra could be synthesized in real-time from CFD data, provided that simplistic assumptions were made about the sample volume (SV) power distribution and intrinsic spectral broadening (ISB). In the first paper arising from Luis Aguilar's doctoral thesis work, "On the Synthesis of Sample Volumes for Real-Time Spectral Doppler Ultrasound Simulation", we show how acoustic monopoles can be used to overcome the SV assumption. For Luis' next trick, he will show how this approach can also be used to overcome the ISB assumption, and probably much, much more...