A blood flow measurement robotic system: Ultrasound visual servoing algorithms under pulsation and displacement of an artery

The purpose of this paper is to propose blood flow measurement algorithms during nonperiodic displacement of an artery by controlling an ultrasound (US) probe. Detecting the position and speed of the bleeding source is required as the first step in treating internal bleeding in emergency medicine. Current methods for detecting a bleeding source, however, involve an invasive approach and cannot quantitatively estimate bleeding speed. Current emergencymedical care therefore requires an alternative system for addressing these problems. In this study, we aim to develop a blood flow measurement system for detecting a bleeding source by using a noninvasive modality, such as a US imaging device. Some problems related to the measurement error still need to be addressed before we can create this system. Specifically, blood flow measurement error in the abdominal area is typically large because the displacement of the artery is large and nonperiodic to adequately control the probe. As the first step in solving these problems, we focused on the displacement of the artery toward the out-ofplane state of the US image and developed measurement algorithms to control the probe, based on respiratory information, during artery displacement. We conducted experimentsmeasuring cross-sectional area and flow rate using an ultrasound phantom containing an artery model and a manipulator equipped with a US probe, BASIS-1. As of this writing, results represent the first experimental validation of the proposed algorithms.