title: Redundant system of passive markers for ultrasound scanhead tracking.
abstract: Scanhead tracking by opto-electronic (OE) systems allows high accuracy in three-dimensional (3-D) freehand ultrasound imaging. In this paper, a new set of methods is proposed and compared with the standard approach [Gram-Schmidt method (GS)]. Three redundancy-based algorithms are introduced to compensate for possible loss of markers during data acquisition: regression plane (RP), multiple Gram-Schmidt (MGS), and center of mass least square (CMLS). When combined with the ultrasound instrument, the root-mean-squared (RMS) uncertainty in locating target points, over a working volume of 420 mm x 490 mm x 100 mm, improved by 7% and 24% using MGS and CMLS method respectively, compared to GS. A lower improvement was obtained with RP methods (5%), using the best marker configuration. In conclusion, CMLS method provides a robust and accurate procedure for 3-D freehand ultrasound scanhead tracking, able to manage possible loss of markers, with interesting perspectives for image fusion and body referenced 3-D ultrasound.
authors.affiliation: Laboratorio di Tecnologie Biomediche, Dipartimento di Bioingegneria, Politecnico di Milano University, via Garofalo 39, Milan 20133, Italy. francesca.patruno@polimi.it
authors.forename: Francesca
authors.initials: F
authors.lastname: Patruno
authors.forename: Andrea
authors.initials: A
authors.lastname: Aliverti
authors.forename: Raffaele L
authors.initials: RL
authors.lastname: Dellacà
authors.forename: David
authors.initials: D
authors.lastname: Burns
authors.forename: Antonio
authors.initials: A
authors.lastname: Pedotti
mesh_terms: D000465:Algorithms; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods*