Considerable progress has been made in the field of in vivo ultrasound imaging equipment driven by a single-element transducer in recent years. The utilization of higher ultrasound operating frequency in such equipment enables the acquisition of high-resolution images, rendering it increasingly prevalent in clinical diagnosis. The front end of such equipment typically comprises a miniature high-frequency ultrasound transducer connected to a wire measuring approximately 1.5–2.5 m in length, forming a catheter for 360° rotational imaging. This structure necessitates specific considerations during electromagnetic compatibility design in contrast to conventional ultrasound equipment. The challenge lies in the significant attenuation of high-frequency ultrasound signals and the low signal-to-noise ratio (SNR). In addition, the structure of the elongated catheter wire facilitates radiated emissions (REs) of electromagnetic noise. This article establishes an equivalent model resembling the emission of a monopole antenna to analyze the electromagnetic radiation for the catheter through simulation. Second, the common-mode (CM) current prediction method is employed to anticipate the radiation of the catheter during operation based on the emission mechanism of a monopole antenna. Finally, a novel combined electromagnetic interference (EMI) suppression method is proposed integrating enhanced CM impedance and suppressed transmitting power. The feasibility and effectiveness of this approach are experimentally verified and discussed.