Purpose: Epidural anesthesia under real-time ultrasound guidance has been studied to enhance puncture safety. However, in the thoracic spine, where the anatomy is complex and the interlaminar space is narrow, improved image quality is necessary. Because imaging quality is degraded in bones that are greatly tilted relative to the probe, we aimed to improve the imaging quality by steering the transmitted ultrasonic beam.
Methods: We investigated a method to improve bone visibility by selecting appropriate transmit steering angles and receiving aperture ranges for each of the two bones forming the interlaminar space, and by compensating for the directivity of the receiving elements.
Results: The proposed method emphasized the delineation of a bone phantom near the gap corresponding to the puncture site. Furthermore, when comparing the contrast ratio in the region of interest of the bone and gap areas, the proposed method showed an improvement of 24.2 dB on the left side and 4.2 dB on the right side compared to the conventional B-mode image.
Conclusion: The proposed method was confirmed to emphasize the bones and is expected to improve the image quality of the thoracic spine gap.
Keywords: Beam forming; Beam steering; Element factor; Epidural anesthesia; Thoracic spine; Ultrasound imaging.
© 2026. The Author(s), under exclusive licence to The Japan Society of Ultrasonics in Medicine.