Dynamic Myocardial Ultrasound Localization Angiography (MULA) is an
ultrasound-based imaging modality destined to enhance the diagnosis and
treatment monitoring of coronary pathologies. Current diagnosis methods
of coronary artery disease focus on the observation of vessel narrowing
in the coronary vasculature to assess the organ’s condition. However, we
would strongly benefit from mapping and measuring flow from
intramyocardial arterioles and capillaries as they are the direct
vehicle of the myocardium blood income. With the advent of ultrafast
ultrasound scanners, imaging modalities based on the localization and
tracking of injected microbubbles allow for the subwavelength resolution
imaging of an organ’s vasculature. Yet, the application of these
vascular imaging modalities relies on an accumulation of cine loops of a
region of interest undergoing no or minimal tissue motion. This work
introduces the MULA framework that combines 1) the mapping of the
dynamics of the microvascular flow using an ultrasound sequence
triggered by the electrocardiogram with a 2) novel Lagrangian beamformer
based on non-rigid motion registration algorithm to form images
directly in the myocardium’s material coordinates and thus correcting
for the large myocardial motion and deformation. Specifically, we show
that this framework enables the non-invasive imaging of the
angioarchitecture and dynamics of intramyocardial flow in vessels as
small as a few tens of microns in the rat’s beating heart in vivo.
