title: Quantitative error analysis for computer assisted navigation: a feasibility study.
abstract: OBJECTIVE
  The benefit of computer-assisted navigation depends on the registration process, at which patient features are correlated to some preoperative imagery. The operator-induced uncertainty in localizing patient features-the user localization error (ULE)-is unknown and most likely dominating the application accuracy. This initial feasibility study aims at providing first data for ULE with a research navigation system.
  
  
  METHODS
  Active optical navigation was done in CT-images of a plastic skull, an anatomic specimen (both with implanted fiducials), and a volunteer with anatomical landmarks exclusively. Each object was registered ten times with 3, 5, 7, and 9 registration points. Measurements were taken at 10 (anatomic specimen and volunteer) and 11 targets (plastic skull). The active NDI Polaris system was used under ideal working conditions (tracking accuracy 0.23 mm root-mean-square, RMS; probe tip calibration was 0.18 mm RMS). Variances of tracking along the principal directions were measured as 0.18 mm(2), 0.32 mm(2), and 0.42 mm(2). ULE was calculated from predicted application accuracy with isotropic and anisotropic models and from experimental variances, respectively.
  
  
  RESULTS
  The ULE was determined from the variances as 0.45 mm (plastic skull), 0.60 mm (anatomic specimen), and 4.96 mm (volunteer). The predicted application accuracy did not yield consistent values for the ULE.
  
  
  CONCLUSIONS
  Quantitative data of application accuracy could be tested against prediction models with iso- and anisotropic noise models and revealed some discrepancies. This could potentially be due to the facts that navigation and one prediction model wrongly assume isotropic noise (tracking is anisotropic), while the anisotropic noise prediction model assumes an anisotropic registration strategy (registration is isotropic in typical navigation systems). The ULE data are presumably the first quantitative values for the precision of localizing anatomical landmarks and implanted fiducials. Submillimetric localization is possible for implanted screws; anatomic landmarks are not suitable for high-precision clinical navigation.
authors: Childrens' National Medical Center, Washington, DC 20010, USA.
authors: Ö
authors: Ö
authors: Güler
authors: M
authors: M
authors: Perwög
authors: F
authors: F
authors: Kral
authors: F
authors: F
authors: Schwarm
authors: Z R
authors: ZR
authors: Bárdosi
authors: G
authors: G
authors: Göbel
authors: W
authors: W
authors: Freysinger
mesh_terms: D000704:Analysis of Variance; D005240:Feasibility Studies; D006801:Humans; D015203:Reproducibility of Results; D012107:Research Design; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed
references: Med Image Anal. 1998 Mar;2(1):1-36
references: 10638851
references: J Neurosurg. 2007 Jun;106(6):1012-6
references: 17564173
references: Comput Aided Surg. 2001;6(1):1-13
references: 11335954
references: Comput Aided Surg. 2000;5(2):98-107
references: 10862132
references: Laryngoscope. 2011 Oct;121(10):2060-4
references: 21898439
references: Med Image Comput Comput Assist Interv. 2007;10(Pt 1):442-9
references: 18051089
references: IEEE Trans Med Imaging. 2012 Mar;31(3):725-37
references: 22156977
references: Laryngoscope. 1999 Nov;109(11):1793-9
references: 10569409
references: Med Image Comput Comput Assist Interv. 2008;11(Pt 2):1032-40
references: 18982706
references: IEEE Trans Med Imaging. 2009 Nov;28(11):1791-801
references: 19884067
references: Laryngoscope. 1997 May;107(5):594-601
references: 9149159
references: Radiology. 1993 Sep;188(3):735-42
references: 8351341
references: Radiat Oncol. 2010 May 26;5:42
references: 20504338
references: IEEE Trans Med Imaging. 1998 Oct;17(5):694-702
references: 9874293
references: Comput Aided Surg. 2010;15(1-3):1-12
references: 20233129
references: Proc Inst Mech Eng H. 2010;224(5):607-22
references: 20718266
references: Otolaryngol Head Neck Surg. 2005 Mar;132(3):435-42
references: 15746858
references: Neurosurgery. 2008 Oct;63(4 Suppl 2):326-32; discussion 332-3
references: 18981839
references: Int J Med Robot. 2007 Jun;3(2):91-6
references: 17619240
references: IEEE Trans Med Imaging. 2011 Mar;30(3):679-93
references: 21075718
references: IEEE Trans Med Imaging. 2008 Mar;27(3):378-90
references: 18334433
references: IEEE Trans Med Imaging. 2009 Jun;28(6):799-813
references: 19423435
references: Neurosurgery. 2000 Jan;46(1):118-35; discussion 135-7
references: 10626943
references: J Neurosurg. 1993 Nov;79(5):667-73
references: 8410245
references: Arch Otolaryngol Head Neck Surg. 2011 Feb;137(2):144-50
references: 21339400
references: HNO. 1997 Feb;45(2):74-80
references: 9173073
references: Surg Neurol. 1987 Jun;27(6):543-7
references: 3554569
references: J Neurosurg. 1999 Jan;90(1):160-8
references: 10413173
references: IEEE Trans Med Imaging. 2010 Mar;29(3):708-23
references: 20199909
references: Phys Med Biol. 2008 Aug 21;53(16):4355-68
references: 18660560
references: Neurosurgery. 1997 Apr;40(4):755-63; discussion 763-4
references: 9092849
references: Ann Otol Rhinol Laryngol. 2003 Aug;112(8):689-92
references: 12940666
references: IEEE Trans Med Imaging. 1997 Aug;16(4):447-62
references: 9263002
references: Neurosurgery. 1996 Jul;39(1):194-202; discussion 202-4
references: 8805161
references: IEEE Trans Med Imaging. 2004 May;23(5):533-45
references: 15147007
references: Neurosurgery. 2006 Jul;59(1 Suppl 1):ONS146-56; discussion ONS146-56
references: 16888546
references: Med Image Comput Comput Assist Interv. 2007;10(Pt 2):628-35
references: 18044621
references: Int J Comput Assist Radiol Surg. 2009 Jan;4(1):45-52
references: 20033601
references: Neurosurg Rev. 1988;11(3-4):245-7
references: 3251168
references: IEEE Trans Pattern Anal Mach Intell. 1987 May;9(5):698-700
references: 21869429
references: Otol Neurotol. 2008 Dec;29(8):1050-5
references: 18836389