On the reproducibility of expert-operated and robotic ultrasound acquisitions.
OBJECTIVE
We present the evaluation of the reproducibility of measurements performed using robotic ultrasound imaging in comparison with expert-operated sonography. Robotic imaging for interventional procedures may be a valuable contribution, but requires reproducibility for its acceptance in clinical routine. We study this by comparing repeated measurements based on robotic and expert-operated ultrasound imaging.


METHODS
Robotic ultrasound acquisition is performed in three steps under user guidance: First, the patient is observed using a 3D camera on the robot end effector, and the user selects the region of interest. This allows for automatic planning of the robot trajectory. Next, the robot executes a sweeping motion following the planned trajectory, during which the ultrasound images and tracking data are recorded. As the robot is compliant, deviations from the path are possible, for instance due to patient motion. Finally, the ultrasound slices are compounded to create a volume. Repeated acquisitions can be performed automatically by comparing the previous and current patient surface.


RESULTS
After repeated image acquisitions, the measurements based on acquisitions performed by the robotic system and expert are compared. Within our case series, the expert measured the anterior-posterior, longitudinal, transversal lengths of both of the left and right thyroid lobes on each of the 4 healthy volunteers 3 times, providing 72 measurements. Subsequently, the same procedure was performed using the robotic system resulting in a cumulative total of 144 clinically relevant measurements. Our results clearly indicated that robotic ultrasound enables more repeatable measurements.


CONCLUSIONS
A robotic ultrasound platform leads to more reproducible data, which is of crucial importance for planning and executing interventions.
Computer Aided Medical Procedures, Johns Hopkins University, Baltimore, MD, USA.|Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera, Italy.
Risto
R
Kojcev
Computer Aided Medical Procedures, Johns Hopkins University, Baltimore, MD, USA. camp@jhu.edu.|Computer Aided Medical Procedures, Technische Universität München, Munich, Germany. camp@jhu.edu.
Ashkan
A
Khakzar
Computer Aided Medical Procedures, Johns Hopkins University, Baltimore, MD, USA.
Bernhard
B
Fuerst
Computer Aided Medical Procedures, Technische Universität München, Munich, Germany.
Oliver
O
Zettinig
Otolaryngology, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
Carole
C
Fahkry
Otolaryngology, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
Robert
R
DeJong
Division of Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, USA.
Jeremy
J
Richmon
Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD, USA.
Russell
R
Taylor
Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera, Italy.
Edoardo
E
Sinibaldi
Computer Aided Medical Procedures, Johns Hopkins University, Baltimore, MD, USA.|Computer Aided Medical Procedures, Technische Universität München, Munich, Germany.
Nassir
N
Navab
D006801:Humans; D015203:Reproducibility of Results; D065287:Robotic Surgical Procedures; D012371:Robotics / Q000379:methods*; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D014463:Ultrasonography / Q000379:methods*
Autonomous acquisition; Reproducibility; Robotic ultrasound; Thyroid; Ultrasound acquisition