Figure 3.
The (a) fundamental, (b) subharmonic, (c) ultraharmonic, and (d) combined-mode CE-IVUS images acquired at 30 MHz transmit frequency. The fundamental and nonlinear CE-IVUS images are displayed at dynamic ranges of 60 dB and 25 dB, respectively to aid visualization. The combined imaging mode improved imaging performance relative to subharmonic and ultraharmonic imaging.