Which imaging technique uses two pulses per scan line, with the second pulse inverse of the first, to improve axial resolution?

• A. Pulse Inversion
• B. PRF
• C. PRP
• D. ROM Read Only Memory

Answer: (A)

Two opposite-phase pulses per scan line form the basis of pulse inversion imaging. The idea is to transmit a standard pulse and then an inverted one. In linear tissue, the echoes from those two pulses cancel when added, so you don’t see much signal. But nonlinear scatterers, such as microbubble contrast agents, respond differently to the two pulses, so the combined signal retains the nonlinear content, especially harmonics. Those higher-frequency harmonics improve axial resolution because they occupy a broader, higher-frequency portion of the spectrum. This approach also enhances image contrast by highlighting nonlinear responses. So the technique described is pulse inversion. The other terms refer to timing or memory and don’t describe this imaging method.