Biomedical Engineering Reference
In-Depth Information
Figure 3.19:
Two-dimensional phase contrast localizer as guide image to apply
multiple velocities in a short period of time (left panel on top row). Sagittal 2D
phase contrast angiogram images are shown at VENC 20
◦
to highlight drain-
ing veins of AVM (panel in center) and VENC 80
◦
to highlight arterial supply
(right panel on top row). Axial collapsed image from 3D TOF angiogram shows
clear delineated AVM nidus (left on bottom row). Axial collapsed images from
3D phase contrast angiogram is shown with greater signal intensity in the left
hemisphere arterial structures (right panel on bottom row).
angiography is that, by varying the VENC, the user can generate images of the
arteries or the veins. Vascular occlusions can also be confirmed by imaging at
slower flow rates. However, 2D techniques are faster than 3D techniques while
3D PC MRA generates better SNR.
3.2.3.1.1 Image Acquisition.
Here bipolar phase-encoding gradients are
used in a fashion analogous to 3D PC techniques. Instead of 3D volume, however,
