Method and program for navigating TMS stimulation
Disclosed is a transcranial magnetic stimulation (TMS) stimulation navigation method comprising the steps of: acquiring a stimulation target point in the brain of a subject to which an electrical stimulus is to be applied; acquiring data on the spatial distribution of a magnetic vector potential of a coil for a TMS procedure; acquiring, from the spatial distribution, at least one parameter for acquiring an optimal stimulation condition for the stimulation target point; and by using the acquired parameter, calculating a position and direction of the coil satisfying the optimal stimulation condition for the stimulation target point.
1. A transcranial magnetic stimulation (TMS) stimulation navigation method, comprising:
acquiring a stimulation target point to apply electrical stimulation on a brain of an object;
acquiring information about a spatial distribution of a magnetic vector potential of a coil for TMS procedure;
acquiring an optimal point, which has the highest magnetic vector potential in the spatial distribution, and an optimal vector, which is a normal vector where multiplication with a gradient at the optimal point becomes minimum among normal vectors where the optimal point is a start point;
acquiring, based on the optimal point and the optimal vector, from the spatial distribution, an optimal stimulation condition for the stimulation target point, wherein the optimal stimulation condition is a condition where an intensity of a magnetic field applied to the stimulation target point by the coil for TMS procedure becomes maximum; and
calculating, using the optimal point and the optimal vector, a position and direction of the coil, which satisfy the optimal stimulation condition for the stimulation target point, wherein according to the calculated position and direction of the coil, the coil is being placed on a particular position on a scalp of the object, and the particular position is the closest position among other positions on the scalp, from the stimulation target point, in the direction of the optimal vector from the optimal point,
wherein the optimal point that is a position (x, y, z) having the highest value in a magnetic vector potential map, is calculated by Equation 1 below:
max
x
,
y
,
z
f
(
x
,
y
,
z
)
,
[
Equation
1
]
where f denotes the magnetic vector potential map, and
wherein the optimal vector that is a vector v, is calculated by Equation 2 below:
min
x
,
y
,
z
∇
f
(
x
_
,
y
_
,
z
_
)
T
v
(
x
,
y
,
z
)
,
[
Equation
2
]
where ∇f( x , y , z ) denotes a value acquired by differentiating f used when defining the optimal point at the optimal point x , y , z , and v(x, y, z) denotes the normal vector in a direction of (x, y, z).
2. A transcranial magnetic stimulation (TMS) stimulation navigation method, comprising:
acquiring a stimulation target point to apply electrical stimulation on a brain of an object;
acquiring information about a spatial distribution of a magnetic vector potential of a coil for TMS procedure;
acquiring an optimal point, which has the highest magnetic vector potential in the spatial distribution, and an optimal vector, which is a normal vector where multiplication with a gradient at the optimal point becomes minimum among normal vectors where the optimal point is a start point;
acquiring, based on the optimal point and the optimal vector, from the spatial distribution, an optimal stimulation condition for the stimulation target point, wherein the optimal stimulation condition is a condition where an intensity of a magnetic field applied to the stimulation target point by the coil for TMS procedure becomes maximum; and
calculating, using the optimal point and the optimal vector, a position and direction of the coil, which satisfy the optimal stimulation condition for the stimulation target point, wherein according to the calculated position and direction of the coil, the coil is being placed on a particular position on a scalp of the object, and the particular position is the closest position among other positions on the scalp, from the stimulation target point, in the direction of the optimal vector from the optimal point,
generating and applying a matrix, shown in Equation 3 below, that is arranging a vector K and the optimal vector of the coil,
R
x
(
θ
)
=
[
1
0
0
0
cosθ
-
sin
θ
0
sin
θ
cos
θ
]
[
Equation
3
]
R
y
(
θ
)
=
[
cos
θ
0
sin
θ
0
1
0
-
sin
θ
0
cos
θ
]
R
z
(
θ
)
=
[
cos
θ
-
sin
θ
0
sin
θ
cos
θ
0
0
0
1
]
;
and
calculating a location of the coil by using Equation 4:
Locdipole= S+K *( D+P ), [Equation 4]
where Locdipole denotes the location of the coil, S denotes the stimulation target point, K denotes the vector K, D denotes a distance between the stimulation target point and the closest position on the scalp from the stimulation target point, and P denotes a half of a thickness of the coil.
3. The TMS stimulation navigation method of claim 1 , wherein the acquiring of the information about the spatial distribution includes:
acquiring information by visualizing the magnetic vector potential using a magnetic dipole according to a shape of the coil for TMS procedure.
4. The TMS stimulation navigation method of claim 1 , further comprising:
simulating a state where electrical stimulation induced from the magnetic field of the coil for TMS procedure is propagated in the brain of the object, when the coil for TMS procedure is located at the calculated position in the calculated direction.
5. The TMS stimulation navigation method of claim 4 , wherein the simulating includes:
acquiring a brain magnetic resonance imaging (MRI) image of the object;
generating a three-dimensional brain map of the object, the three-dimensional brain map being capable of simulating a process of delivering electrical stimulation to the brain of the object, based on properties of each of a plurality of regions included in the brain MRI image; and
simulating a state where the electrical stimulation is propagated in the brain of the object, using the generated three-dimensional brain map.
6. The TMS stimulation navigation method of claim 5 , wherein the generating of the three-dimensional brain map includes:
generating a three-dimensional stereoscopic image composed of a plurality of meshes, the three-dimensional stereoscopic image being capable of simulating a process of delivering electrical stimulation to the brain of the object.
7. The TMS stimulation navigation method of claim 6 , wherein the simulating includes:
visualizing a state where electrical stimulation induced from the magnetic field of the coil for TMS procedure is propagated in the brain of the object, using the three-dimensional stereoscopic image.
8. A non-transitory computer-readable recording medium storing a computer program configured to be coupled with a computer hardware, and the program includes instructions to perform the method of claim 1 .
9. The TMS stimulation navigation method of claim 2 , wherein the acquiring of the information about the spatial distribution includes:
acquiring information by visualizing the magnetic vector potential using a magnetic dipole according to a shape of the coil for TMS procedure.
10. The TMS stimulation navigation method of claim 2 , further comprising:
simulating a state where electrical stimulation induced from the magnetic field of the coil for TMS procedure is propagated in the brain of the object, when the coil for TMS procedure is located at the calculated position in the calculated direction.
11. The TMS stimulation navigation method of claim 10 , wherein the simulating includes:
acquiring a brain magnetic resonance imaging (MRI) image of the object;
generating a three-dimensional brain map of the object, the three-dimensional brain map being capable of simulating a process of delivering electrical stimulation to the brain of the object, based on properties of each of a plurality of regions included in the brain MRI image; and
simulating a state where the electrical stimulation is propagated in the brain of the object, using the generated three-dimensional brain map.
12. The TMS stimulation navigation method of claim 11 , wherein the generating of the three-dimensional brain map includes:
generating a three-dimensional stereoscopic image composed of a plurality of meshes, the three-dimensional stereoscopic image being capable of simulating a process of delivering electrical stimulation to the brain of the object.
13. The TMS stimulation navigation method of claim 12 , wherein the simulating includes:
visualizing a state where electrical stimulation induced from the magnetic field of the coil for TMS procedure is propagated in the brain of the object, using the three-dimensional stereoscopic image.
14. A non-transitory computer-readable recording medium storing a computer program configured to be coupled with a computer hardware, and the program includes instructions to perform the method of claim 2 .