Method and apparatus for evaluating subject with excitation time map
View Patent ↗There is provided an analysis device for generating an excitation time map, which includes an interface device configured to receive time-series medical images of a subject and a computing device configured to generate an excitation time map by solving a diffusion reaction of electrical signals calculated from the time-series medical images using a solution of an ordinary differential equation. The excitation time map indicates excitation times at grid points of the time-series medical image.
1 . An analysis device for generating an excitation time map, comprising:
an interface device configured to receive time-series medical images of a subject; and
a computing device configured to generate an excitation time map by solving a diffusion reaction of electrical signals calculated from the time-series medical images using a solution of an ordinary differential equation,
wherein the ordinary differential equation comprises (i) a function of the time of maximum membrane potential and (ii) a reaction function for a membrane potential and ion channels, and
wherein the excitation time map is a scalar map including excitation times at all grid points of the time-series medical images,
wherein the excitation time at each grid point is directly determined as a cell-specific time at which the membrane potential at the grid point reaches a maximum value, and
wherein the excitation time map is generated based on the determined excitation times determined independently for each grid point.
2 . The analysis device of claim 1 , wherein the time-series medical images include magnetic resonance imaging (MRI) or diffusion tensor imaging (DTI) images.
3 . The analysis device of claim 1 , wherein the computing device generates the excitation time map using the following expression,
𝒯
(
x
i
)
=
∑
j
t
j
∇
u
(
x
i
,
t
j
)
∑
j
∇
u
(
x
i
,
t
j
)
-
T
0
,
for
all
t
=
t
j
satisfying
du
dt
>
0
,
(u denotes the membrane potential, x i denotes an i th grid point among the grid points, and t j denotes a time in the time-series medical image).
4 . The analysis device of claim 1 , wherein the ordinary differential equation is expressed as the following expression for cell B,
du
(
x
B
)
dt
=
I
app
δ
T
T
B
+
R
(
u
(
x
B
)
,
…
)
,
(x B denotes cell B, R(u, . . . ) denotes the reaction function for the membrane potential u and the ion channels, I app denotes a magnitude of a current transmitted from the outside with respect to cell B, T B denotes a period of time for cell B to reach a maximum membrane potential,
δ
T
T
B
denotes a Kronecker delta function for T and T B , and T denotes a specific time).
5 . A method of evaluating a subject using an excitation time map, comprising:
receiving, by an analysis device, time-series medical images of a subject;
generating, by the analysis device, an excitation time map by solving a diffusion reaction of electrical signals calculated from the time-series medical images using a solution of an ordinary differential equation; and
comparing, by the analysis device, the excitation time map for the subject with a pre-built reference excitation time map and evaluating a condition of the subject,
wherein the ordinary differential equation comprises (i) a function of the time of maximum membrane potential and (ii) a reaction function for a membrane potential and ion channels, and
wherein the excitation time map is a scalar map including excitation times at all grid points of the time-series medical images,
wherein the excitation time at each grid point is directly determined as a cell-specific time at which the membrane potential at the grid point reaches a maximum value, and
wherein the excitation time map is generated based on the determined excitation times determined independently for each grid point.
6 . The method of claim 5 , wherein the time-series medical images include magnetic resonance imaging (MRI) or diffusion tensor imaging (DTI) images.
7 . The method of claim 5 , wherein the analysis device generates the excitation time map using the following expression,
𝒯
(
x
i
)
=
∑
j
t
j
∇
u
(
x
i
,
t
j
)
∑
j
∇
u
(
x
i
,
t
j
)
-
T
0
,
for
all
t
=
t
j
satisfying
du
dt
>
0
,
(u denotes the membrane potential, x i denotes an i th grid point among the grid points, and t j denotes a time in the time-series medical image).
8 . The method of claim 5 , wherein the ordinary differential equation is expressed as the following expression for cell B,
du
(
x
B
)
dt
=
I
app
δ
T
T
B
+
R
(
u
(
x
B
)
,
…
)
,
(x B denotes the cell B, R(u, . . . ) denotes the reaction function for the membrane potential u and the ion channels, Lapp denotes a magnitude of a current transmitted from the outside with respect to cell B, T B denotes a period of time for cell B to reach a maximum membrane potential,
δ
T
T
B
denotes a Kronecker delta function for T and T B , and T denotes a specific time).