Welcome to Jonathan Mynard

I've been a bit distracted lately, so was remiss in not announcing the addition of Jonathan Mynard from the University of Melbourne.  Jonathan is a NHMRC postdoctoral fellow, who will be investigating the role of imaging and full- and reduced-order models for studying congenital cardiovascular disease.

Editorial in AJNR

Earlier this year Juan Cebral's group published an interesting paper suggested that rare cases of aneurysm rupture following treatment by flow diverters might be due to treatment-induced pressure increases.  Barry Lieber and colleagues subsequently questioned these CFD-based results, which brought a strong response from Cebral and colleagues.  I was then asked by AJNR's Charlie Strother to help explain the controversy for the AJNR readership.

Who is right?  This remains to be seen, but I see it as a terrific opportunity for our community to demonstrate the clinical value (or lack thereof) of image-based CFD.

Paper Published: Hemodynamics of the Mouse Aorta

Congratulations to BSL postdoc Yiemeng Hoi, whose paper "Correlation between local hemodynamics and lesion distribution in a novel aortic regurgitation murine model of atherosclerosis" has been published by the Annals of Biomedical Engineering. (And kudos to Springer: two weeks from acceptance to online-first publication!)

Our co-authors had previously demonstrated that the induction of aortic regurgitation accelerates the formation of atherosclerotic lesions in Ldlr-/- mice -- lesions whose distinct and consistent spatial localization suggested a strong local hemodynamic influence. Building upon this work, and with painstaking care, Yiemeng reconstructed the geometry of the mouse aorta from micro-CT of a cast vessel; derived the necessary flow rate boundary conditions from Doppler ultrasound measurements and literature values; and ensured that the process of mapping the CFD predictions for comparison with en face plaque stainings was fair and unbiased.

Our main result, summarized in the figure above, shows that the distinctive distributions of plaque can indeed be explained by the patterns of high oscillatory shear index (OSI) and/or long relative residence times (RRT).  Control CFD studies using normal flow rates and straightened geometry confirm that these focal hotspots arise from the combination of the anatomical curvatures of the mouse aorta and the strong retrograde flow rates of the AR mice. On the other hand, time-averaged shear magnitude (TAWSS), the usual suspect, does not explain the plaque distributions, showing that, when it comes to "disturbed" flow, "low and oscillatory" need not always go hand in hand. (I know, I know, that's a lot of hands.)

Paper Published: Scan-Rescan Reproducibility of Carotid Geometry

Congratulations to PhD student Payam Bijari, whose first BSL paper, "Scan-rescan reproducibility of carotid bifurcation geometry from routine contrast-enhanced MR angiography", was recently published in the Journal of Magnetic Resonance Imaging.

As suggested by the figure, this paper demonstrates that lumen geometry can be rapidly and reliably segmented from not-always-optimal MR angiograms, in our case from 60 participants in the ARIC Carotid MRI study, each scanned twice on separate occasions. This now sets the stage for our analysis of the full cohort, which seeks to identify whether the geometry of the carotid bifurcation can be considered a "missing" local risk factor for atherosclerosis.

Journal of Universal Rejection

A new and prestigious journal (100% rejection rate, talk about selective!). Got me thinking about starting a Journal of Universal Acceptance, which would guarantee a 100% acceptance rate* so you can pad your CV with "Accepted" submissions from the moment you submit them. Even better, maybe a Journal of Anticipated Submissions, so you can focus on padding your CV without wasting precious time actually writing manuscripts. Oooh, the possibilities are endless...

*guaranteed to be accepted before the end of the universe, or around the same time that the editor will reply to author queries regarding the status of their manuscripts.

Update: Starting from an NPR blog entry about the JUR, I came across a brief interview with the editor, which refers to a Journal of Are You Fucking Kidding, which has an entry about the seemingly "legitimate" journal Nature and Science (as in "I've had my work published in Nature and Science"). Indeed, there is a fine line between stupid and clever...

Welcome to Diego Gallo

The BSL welcomes Diego Gallo, PhD student from the group of Morbiducci and Montevecchi at the Politecnico di Torino, who will be spending the next six months at the BSL. (Sorry about the extreme cold alert, Diego! :-)

A Theory of Everything in Venn Diagram Form

An exceptionally clever visualization of a grand unifying theory (not mine :-). Eat that, Lie Group E₈! (In case there was any doubt, I'm a nerd.)