Direct Assessment of Wall Shear Stress by Signal Intensity Gradient from Time-of-Flight Magnetic Resonance Angiography

Figure 1

Calculation of TOF-MRA signal intensity gradient (SIG). (a) TOF-MRA axial source image. (b) 3-dimensional gradient vector (red arrow) of the maximum intensity change. (c) Positioning of points ( and ): point is a reference point on the artery wall (contour line) and point is 0.03 mm distant from point .