title: Accuracy of an electromagnetic three-dimensional ultrasound system for carotid artery imaging.
abstract: Freehand, three-dimensional (3-D) ultrasound (US) systems, which incorporate an electromagnetic tracking device to register the 3-D spatial location of images acquired using a standard linear array scan-probe, are a flexible and cost-effective solution for many clinical applications. The reconstruction accuracy of one such system was investigated by using a precision-made phantom. The error in 3-D distance measurements, under conditions appropriate to US investigations of the carotid arteries, was found to be -0.45 +/- 1.30 mm, equivalent to -0.53 +/- 3.39% (mean +/- SD). The results are relevant to data acquired using a single sweep scan and for distances in the range 25.00 to 79.06 mm. Both the overall accuracy and precision in point-target location were found to be relatively unaffected by scan depth, and the precision of point-target location was found to be poorest in the elevational direction. In conclusion, the system tested in our laboratory performed with high accuracy, adopting a setup and scan-sweep identical to that used for imaging of the carotid arteries in 3-D.
authors.affiliation: Department of Clinical Pharmacology & Therapeutics, School of Medicine, Imperial College of Science, Technology & Medicine, Paddington, London W2 1NY, UK. d.barratt@ic.ac.uk
authors.forename: D C
authors.initials: DC
authors.lastname: Barratt
authors.forename: A H
authors.initials: AH
authors.lastname: Davies
authors.forename: A D
authors.initials: AD
authors.lastname: Hughes
authors.forename: S A
authors.initials: SA
authors.lastname: Thom
authors.forename: K N
authors.initials: KN
authors.lastname: Humphries
mesh_terms: D002138:Calibration; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D055590:Electromagnetic Phenomena; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D019047:Phantoms, Imaging; D014463:Ultrasonography / Q000295:instrumentation*