Transvaginal sonographic orientation detection system using ceramic gyroscopes.

Use of three-dimensional ultrasonograms in daily clinical medicine requires the development of data accumulation techniques and image reconstruction techniques . We describe an image position and orientation detection technique using small piezoelectric vibratory gyroscopes. Such gyroscopes, of the same type that is used in an automobile navigation system, produce angular velocity by Coriolis force. After attaching three gyroscopes to an ordinary transvaginal probe, we attempted to detect image orientation to assist transvaginal scanning and to reconstruct three-dimensional projection images. Three-dimensional images were reconstructed by simple white and black inversion thresholding technique. Using free hand transvaginal scanning, the direction of the transvaginal ultrasound beam was displayed with B-mode ultrasonography. Using a personal computer, three-dimensional images of follicles and fetuses were successfully reconstructed within a few minutes. Our system provides easy understanding of transvaginal sonographic images and potentially might allow ordinary ultrasound machines to handle three-dimensional images in a day-to-day clinical practice.