Reflector-based Transrectal 3D Ultrasound Imaging System for Transperineal Needle Intervention

The conventional transrectal ultrasound (TRUS) probe for transperineal needle insertion is typically a sagittal viewing linear array or combined with another transverse curvilinear array. Physicians are required to manually move and rotate the probe back and forth to determine the needle trajectory or to render 3D volume. For the hands-free 3D imaging guidance of transperineal needle insertion, this paper proposes a reflector-based 3D TRUS imaging probe. The proposed probe is enabled by motorizing rotation of a forward-viewing array transducer and bending the ultrasound beam to cover whole prostate utilizing an acoustic mirror as reflector. The proposed device is capable of providing an arbitrary angled B-mode slice with respect to prostate based on the motorized probe rotation angle adjustment, and enables to render 3D images with volume-based reconstruction. In the experimental validation with the cyst phantom, the contrast-noise ratios in the 0 and 90-degree of rotation angle were 4.36 and 4.05 dB in the image acquisition with reflector, and 4.26 and 5.07 dB in that without reflector, respectively. Also, the 3D appearance of cyst can be rendered with maximum intensity projection. These results demonstrated the limited image quality deterioration by adding reflector, and indicate the reflector-based TRUS probe has a potential to improve the guidance of transperineal needle insertion.