Diagnostic posture control system for seated-style echocardiography robot

Abstract

Purpose: Conventional robotic ultrasound systems were utilized with patients in supine positions. Meanwhile, the limitation of the systems is that it is difficult to evacuate the patients in case of emergency (e.g., patient discomfort and system failure) because the patients are restricted between the robot system and bed. Therefore, we validated a feasibility study of seated-style echocardiography using a robot.

Method: Preliminary experiments were conducted to verify the following two points: (1) diagnostic image quality due to the sitting posture angle and (2) physical load due to the sitting posture angle. For reducing the physical burden, two unique mechanisms were incorporated into the system: (1) a leg pendulum base mechanism to reduce the load on the legs when the lateral bending angle increases, and (2) a roll angle division by a lumbar lateral bending and thoracic rotation mechanisms.

Results: Preliminary results demonstrated that adjusting the diagnostic posture angle allowed to obtain the views, including cardiac disease features, as in the conventional examination. The results also demonstrated that the body load reduction mechanism incorporated in the results could reduce the physical load in the seated echocardiography. Furthermore, this system was shown to provide greater safety and shorter evacuation times than conventional systems.

Conclusion: These results indicate that diagnostic echocardiographic images can be obtained by seated-style echocardiography. It was also suggested that the proposed system can reduce the physical load and guarantee a sense of safety and emergency evacuation. These results demonstrated the possibility of the usage of the seated-style echocardiography robot.

Keywords: Echocardiography; Human–robot interaction; Medical robots; Robotic ultrasound.

Fig. 1

Echocardiography robot and subject placement a supine, b seated

Fig. 2

Marker tracking calibration. a Probe travel path and plane approximation; b calculation of θ_roll, θ_pitch

Fig. 3

Ultrasound images in sitting posture; a clear parasternal long-axis view; b unclear parasternal long-axis view; c clear apical four-chamber view; d unclear apical four-chamber view

Fig. 4

Relationship between the number of diagnosable features and sitting posture angles. a The number of diagnosable features and posture angles in the parasternal long-axis view; b the number of diagnosable features and posture angles in the apical four-chamber view

Fig. 5

Change of heart position during body posture change; a roll; b pitch

Fig. 6

a Posture support mechanism for verification of body load in sitting test, b relationship between subjective assessment of physical load and posture angles

Fig. 7

Seated posture angle control system

Fig. 8

a Lumbar flexion mechanism, b lumbar lateral bending mechanism. Note that red and blue arrows indicate each figure’s active and passive motion parts

Fig. 9

Thoracic rotation mechanism. Note that red and blue arrows indicate each figure’s active and passive motion parts

Fig. 10

Leg pendulum base mechanism; a mechanism operation; b mechanism details. Note that red and blue arrows indicate each figure’s active and passive motion parts

Fig. 11

The experiment setup of supine-style configuration [16]

Fig. 12

Ratio of leg/abdominal load for each condition; a comparison of the use of leg pendulum base mechanism (conditions A vs. B); b comparison of lumbar lateral bending mechanism only and a roll angle division by lumbar lateral bending mechanism and thoracic rotation mechanisms (conditions B vs. D); c comparison of thoracic rotation mechanisms only and a roll angle division by lumbar lateral bending mechanism and thoracic rotation mechanisms (conditions C vs. D); d comparison of the use of two body load reduction mechanisms (conditions A vs. D)

Fig. 13

Comparison of subjective evaluation between the spine-style and seated-style configurations in terms of a comfortability, b safety, and c evacuation time