Mechanical imaging in medical applications

Phantom Study of Arterial Localization using Tactile Sensor Array and a Normal Vs. Shear Pulse Pressure Propagation Method

OBJECTIVE

Locating the radial artery reliably is a key challenge in reducing patient risks from complications in Trans-Radial Access, which is an important clinical method for catheterization, cardiac monitoring, and neuroendovascular procedures. New tactile sensing technology is being developed to bridge the skill, cost, and performance gap between ultrasonic needle guidance, and manual palpation, for use in developing countries. This paper further develops tactile artery localization with a novel algorithm for arterial localization based on the properties of a curved tactile sensor array.

METHODS

Using tactile sensor insensitivity to shear loading, coupled with a radial pulse wave propagation path, the position of the artery can be found at the intersection of a normal and tangential vector from the array corresponding to maximum and minimum pulse pressure measurement locations respectively. This was validated in a simple silicone phantom study Results: The proposed method measured with MAE= 0.58±0.25mm whilst the artery is within range of the tactile array, compared with 0.81±0.57mm for a comparative method of simple pulse localization. This showed improvement in arterial localization and repeatability, and was within 1 arterial radius, expected to reduce the risk of missing the artery, or perforating the side wall.Clinical Relevance- Robust and repeatable arterial localization is important for reducing the failure rate of trans-radial (and other arterial) procedures, and thus reducing the risk of harmful complications.

Reviewing the technological challenges associated with the development of a laparoscopic palpation device

Minimally invasive surgery (MIS) has heralded a revolution in surgical practice, with numerous advantages over open surgery. Nevertheless, it prevents the surgeon from directly touching and manipulating tissue and therefore severely restricts the use of valuable techniques such as palpation. Accordingly a key challenge in MIS is to restore haptic feedback to the surgeon. This paper reviews the state-of-the-art in laparoscopic palpation devices (LPDs) with particular focus on device mechanisms, sensors and data analysis. It concludes by examining the challenges that must be overcome to create effective LPD systems that measure and display haptic information to the surgeon for improved intraoperative assessment.