Surgical targeting accuracy analysis of six methods for subthalamic nucleus deep brain stimulation

Figures & data

Table I.  Imaging parameters of DESPOT1 and DESPOT2.

Imaging modality	TR (ms)	TE (ms)	Flip angle (°)	BW (kHz)	Voxel size (mm^3)	Sequence
DESPOT1	11.4	2.9	4, 16	±7.81	0.34	SPGR
DESPOT2	4.2	2.1	15, 55	±62.5	0.34	SSFP

Figure 1. Scatter plot displaying the absolute difference between the actual surgical target for each of the 55 procedures and that estimated with each of the six targeting approaches. [Color version available online.]

Table II.  Absolute differences between actual surgical targets and targets estimated with each targeting method.

	Mean (mm)	Max (mm)	Min (mm)	SD (mm)
T2-weighted MRI	3.0	5.5	1.2	1.3
Brain atlas	3.0	6.2	1.2	1.3
T1 and T2 maps	3.0	5.7	1.0	1.0
EP database	2.6	5.8	1.4	1.1
Previous targets	2.5	4.5	1.1	0.9
Combination	1.7	3.6	0.4	0.7

Figure 2. T₂-weighted MR image of a patient demonstrating direct visualization of STN: (a) axial slice; (b) coronal slice. The contour of the segmented STN based on T₁ and T₂ maps is marked in yellow; that based on the digitized Schaltenbrand atlas is marked in blue. The small white sphere is the actual surgical target. The digitized atlas and T₁ and T₂ maps were registered to the patient brain image space. [Color version available online.]

Figure 3. Positions of surgical targets estimated with each targeting approach. Yellow sphere: target based on the T2-weighted MR image. Green sphere: target based on the Schaltenbrand atlas. Magenta sphere: target based on T1 and T2 maps. Blue sphere: target based on the electrophysiological database. Cyan sphere: target based on previous surgical targets. Red sphere: target based on combined functional and anatomical data. White sphere: “gold standard” actual surgical target. [Color version available online.]