Stepped 2D array needle transducer for 4D ultrasound imaging-guided spinal puncture

Ultrasound imaging-guided spinal puncture is highly desirable for the treatment of degenerative diseases of the spine, cerebrospinal fluid sampling, and spinal anesthesia administration due to its real-time and portable nature. However, conventional ultrasound imaging guidance methods image the target area from outside the body and obtain only two-dimensional (2D) images, making it very difficult to identify the puncture needle and understand the situation behind the vertebrae during the puncture process. Here, we present a new method for placing a 2D ultrasound array transducer into the needle tip. The array has a stepped shape that fits well with the puncture needle, and real-time three-dimensional (3D) volumetric images can be obtained in the body in front of the needle as guidance during the puncture procedure. Our innovative transducer design and fabrication method enable the integration of a 10-MHz, 256-element 2D array transducer in the needle tip, leading to superior imaging resolution. The results of in vitro and in vivo pig experiments demonstrate that the needle position can be clearly identified and guided during the puncture process. This technology can improve the guidance accuracy and greatly reduce unexpected risks during puncture procedures, which has great potential in spinal punctures in clinical settings.