Contact position analysis of deep brain stimulation electrodes on post-operative CT images.
OBJECTIVE
Groups performing deep brain stimulation advocate post-operative imaging [magnetic resonance imaging (MRI) or computer tomography (CT)] to analyse the position of each electrode contact. The artefact of the Activa 3389 electrode had been described for MRI but not for CT. We undertook an electrode artefact analysis for CT imaging to obtain information on the artefact dimensions and related electrode contact positions.


METHODS
The electrode was fixed on a phantom in a set position and six acquisitions were run (in-vitro study). The artefacts were compared with the real electrode position. Ten post-operative acquisitions were analysed (in-vivo analysis). We measured: H (height of the lateral black artefact), D (distance between the beginning of the white and the lateral black artefacts) and W (maximal artefact width), representing respectively the lengths of the four contacts and the electrode tip and width of the contact zone. A Student t-test compared the results: in vivo vs in vitro and coronal vs sagittal reconstructions along the electrode.


RESULTS
The limits of the lateral black artefact around the electrode contacts corresponded to the final electrode position. There was no significant difference for D (in vivo, 1.1 +/- 0.1 mm; in vitro, 1.2 +/- 0.2 mm; p = 0.213), while W and H differed slightly (in vivo, W = 3.3 +/- 0.2 mm, H = 7.7 +/- 0.2 mm; in vitro, W = 3.1 +/- 0.1 mm, H = 7.5 +/- 0.2 mm). Results obtained with sagittal and coronal reconstructions were similar (p > 0.6).


CONCLUSIONS
Precise three-dimensional (3D) localisation of the four-contact zone of the electrode can be obtained by CT identification of the limits of the lateral black artefact. The relative position of the four contacts is deduced from the size of the contacts and the inter-contact distance. Sagittal and coronal reconstructions along the electrode direction should be considered for the identification of the four electrode contacts. CT offers a useful alternative to post-operative MRI.
Hemm
Simone
S
Inserm, ERI 14, Equipe de Recherche en Imagerie Médicale, Clermont-Ferrand 63001, France.
Coste
Jérôme
J
Gabrillargues
Jean
J
Ouchchane
Lemlih
L
Sarry
Laurent
L
Caire
François
F
Vassal
François
F
Nuti
Christophe
C
Derost
Philippe
P
Durif
Franck
F
Lemaire
Jean-Jacques
JJ
D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology / Q000601:surgery*; D001927:Brain Diseases / Q000628:therapy; D001931:Brain Mapping / Q000379:methods; D046690:Deep Brain Stimulation / Q000295:instrumentation* / Q000379:methods*; D004567:Electrodes, Implanted / Q000592:standards; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D011182:Postoperative Care / Q000379:methods* / Q000592:standards; D011183:Postoperative Complications / Q000517:prevention & control; D015203:Reproducibility of Results; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards