Reproducibility of repeated mountings of a noninvasive CT/MRI stereoadapter.

The reproducibility of a noninvasive computed tomography (CT)/magnetic resonance imaging stereoadapter was tested on 12 healthy volunteers. The adapter was easy to mount and detach without discomfort. Two repeated mountings of the adapter showed a good reproducibility in relation to the scalp. When extrapolated to a hypothetical target in the right thalamus, the mean differences between the two mountings were 0.07 mm in the lateral, 0.16 mm in the anteroposterior and 0.17 mm in the height coordinates. This high degree of reproducibility seems to permit a safe CT-guided functional stereotaxis, where the preoperative CT scanning can take place on one day and the surgery may be performed on any other suitable day.