title: Determining the Orientation of Directional Deep Brain Stimulation Electrodes Using 3D Rotational Fluoroscopy.
abstract: OBJECTIVE
  New deep brain stimulation leads with electrode contacts that are split along their circumference allow steering of the electrical field in a predefined direction. However, imaging-assisted directional stimulation requires detailed knowledge of the exact orientation of the electrode array. The purpose of this study was to evaluate whether this information can be obtained by rotational 3D fluoroscopy.
  
  
  METHODS
  Two directional leads were inserted into a 3D-printed plaster skull filled with gelatin. The torsion of the lead tip versus the lead at the burr-hole level was investigated. Then, 3 blinded raters evaluated 12 3D fluoroscopies with random lead orientations. They determined the lead orientation considering the x-ray marker only and considering the overlap of the gaps between the contact segments. Intraclass correlation coefficients and an extended version of the Bland-Altman plot were used to determine interrater reliability and agreement of the measurements of the different raters.
  
  
  RESULTS
  Electrode torsion of up to 35° could be demonstrated. Evaluation of the lead rotation considering the x-ray marker only revealed limits of agreement of ±9.37° and an intraclass correlation coefficient of 0.9975. In addition, taking into account the lines resulting from overlapping of the gaps between the electrode segments, the limits of agreement to the mean were ±2.44° and an intraclass correlation coefficient of 0.9998.
  
  
  CONCLUSIONS
  In directional deep brain stimulation systems, rotational 3D fluoroscopy combined with the described evaluation method allows for determining the exact orientation of the leads, enabling the full potential of imaging-assisted personalized programming.
authors.affiliation: From the Departments of Stereotactic and Functional Neurosurgery (P.C.R., V.A.C.) peter.reinacher@uniklinik-freiburg.de.
authors.forename: P C
authors.identifier: http://orcid.org/0000-0003-1691-546X
authors.initials: PC
authors.lastname: Reinacher
authors.affiliation: Neurosurgery (M.T.K., M.S., R.R.).
authors.forename: M T
authors.identifier: http://orcid.org/0000-0001-6142-5967
authors.initials: MT
authors.lastname: Krüger
authors.affiliation: From the Departments of Stereotactic and Functional Neurosurgery (P.C.R., V.A.C.).
authors.forename: V A
authors.identifier: http://orcid.org/0000-0002-1703-6283
authors.initials: VA
authors.lastname: Coenen
authors.affiliation: Neurosurgery (M.T.K., M.S., R.R.).
authors.forename: M
authors.identifier: http://orcid.org/0000-0002-7224-9185
authors.initials: M
authors.lastname: Shah
authors.affiliation: Neurosurgery (M.T.K., M.S., R.R.).
authors.forename: R
authors.identifier: http://orcid.org/0000-0002-0985-7583
authors.initials: R
authors.lastname: Roelz
authors.affiliation: Clinical Trial Unit (C.J.), Freiburg University Medical Center, Freiburg, Germany.
authors.forename: C
authors.identifier: http://orcid.org/0000-0002-8478-0045
authors.initials: C
authors.lastname: Jenkner
authors.affiliation: Neuroradiology (K.E.).
authors.forename: K
authors.identifier: http://orcid.org/0000-0002-7753-4815
authors.initials: K
authors.lastname: Egger
mesh_terms: D046690:Deep Brain Stimulation / Q000379:methods*; D005471:Fluoroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D059906:Neuroimaging / Q000379:methods*; D019047:Phantoms, Imaging; D011859:Radiography / Q000379:methods; D015203:Reproducibility of Results; D012886:Skull