3D Shear Wave Imaging

Rotational 3D-SWE:

in vivo  shear wave propagation in 3D in the rectus femoris muscle, demonstrating transverse isotropy

Rectus Femoris Shear Wave in 3D

This video shows the particle velocity of a shear wave produced in the rectus femoris muscle in vivo, with a Verasonics L7-4 transdcuer rotating around the z axis in 5 degree increments, and acquiring 36 SWEI acquistions over ~2 minutes. Although care was taken to align the transducer start position with the fiber direction as seen on B-mode, the maximum shear wave speed was found, using ellipse fitting of the SWS in all directions, to be actually 8.3 degrees rotation from the X axis. As such, the ~XZ and ~YZ planes shown here are rotated 8.3 degrees around the Z axis, to show the most accurate along and across the fibers shear wave propagation. 

in vivo shear wave propagation in 3D in the vastus lateralis muscle, with an added imaging plane to demonstrate the presence of shear splitting

Vastus Lateralis Shear Wave in 3-space

This video shows the particle velocity of a shear wave produced in the rectus femoris muscle in vivo, with a Verasonics L7-4 transdcuer rotating around the z axis in 5 degree increments, and acquiring 36 SWEI acquistions over ~2 minutes. Although care was taken to align the transducer start position with the fiber direction as seen on B-mode, the maximum shear wave speed was found, using ellipse fitting of the SWS in all directions, to be actually 6.2 degrees rotation from the X axis. As such, the ~XZ and ~YZ planes shown here are rotated 6.2 degrees around the Z axis, to show the most accurate along and across the fibers shear wave propagation. Additionally, a fourth plane, is shown between the XZ and YZ plane here, (intersecting approximately with the -10 mm mark on the lat axis). This was included so as to show the shear splitting behavior present. As the wave propagates along this plane, there are two different shear wave fronts present, representing shear splitting.

 

TI Elastic Material 45 degree tilt simulation

Orthotropic Simulation with 45 degree "fiber' tilt

This video shows Simulated 3D-SWE data in a TI elastic material with fibers oriented at a 45 degree tilt relative to the push (axial) direction. The shear moduli were 25 kPa (along) and 9 kPa (across) with the ratio of ET/EL=0.36

TI Elastic Material 0 degree tilt simulation

Orthotropic Simulation with 0 degree fiber tilt 

This video shows Simulated 3D-SWE data in a TI elastic material with fibers oriented at a 0 degree tilt relative to the push (axial) direction. The shear moduli were 25 kPa (along) and 9 kPa (across) with the ratio of ET/EL=0.36