Measuring tissue mobility
View Patent ↗A method of measuring tissue mobility includes applying an oscillatory force to a region of tissue and measuring the velocity with which the tissue moves in response to the applied force. Tissue mobility is then determined by a ratio of the tissue velocity to the applied force.
1. A method of measuring tissue mobility comprising the steps of:
(a) applying an oscillatory force to a region of tissue using a vibrating mass having an oscillatory velocity u m ; and
(b) determining an oscillatory velocity u t with which the tissue moves in response to the applied force;
wherein tissue mobility is determined by a ratio of the tissue velocity u t to the velocity of the vibrating mass, u m .
2. A method of measuring tissue mobility according to claim 1 wherein the frequency of the oscillatory force is varied over a period of time.
3. A method of measuring tissue mobility according to claim 1 wherein the oscillatory force corresponds to pseudo-random noise or white noise.
4. A method of measuring tissue mobility according to claim 1 wherein the force is applied using a vibrating mass which is set in motion, with oscillatory velocity u m , using an electromagnetic driver which is coupled to the tissue via a coupling device.
5. A method of measuring tissue mobility according to claim 4 , wherein the mobility of the tissue, z t (ƒ) is given by:
z
t
(
f
)
=
1
2
π
f
{
u
m
u
t
m
v
+
m
f
}
where m ν is the mass of the vibrating mass; and
m ƒ is the mass of the coupling device.
6. A method of measuring tissue mobility according to claim 1 wherein the velocity at which the tissue moves in response to the applied force is determined at a location which is spatially distinct from the region of tissue to which the force is applied.
7. A method of measuring tissue mobility according to claim 1 comprising the additional step of providing a visual representation of the velocity at which the tissue moves in response to the applied force.
8. Apparatus for measuring mobility of a region of tissue comprising:
(a) a force generator driving a vibrating mass with an oscillating velocity u t for application of an oscillatory force to a region of tissue;
(b) a tissue velocity determiner producing a tissue velocity signal u t which corresponds to the velocity with which the tissue moves in response to the applied oscillatory force; and
(c) a processor processing the tissue velocity signal u t and the vibrating mass velocity signal u m ;
wherein the tissue's mobility is determined using a ratio of the tissue velocity u t to the velocity of the vibrating mass, u m .
9. Apparatus for measuring tissue mobility according to claim 8 wherein the force generator is a vibrating mass which is set in motion with an oscillatory velocity u m , using an electromagnetic driver which is coupled to the tissue via a coupling device.
10. Apparatus for measuring tissue mobility according to claim 9 , wherein the mobility of the tissue, z t (ƒ) at a frequency ƒ is given by:
z
t
(
f
)
=
1
2
π
f
{
u
m
u
t
m
v
+
m
f
}
where:
m ν is the mass of the vibrating mass; and
m ƒ is the mass of the coupling device.
11. Apparatus for measuring tissue mobility according to claim 8 wherein the force generator applies an oscillatory force to a region of tissue which is spatially distinct from the location of the tissue velocity determining means.
12. Apparatus for measuring tissue mobility according to claim 10 further comprising a display device for displaying a representation of mobility of the region of tissue, wherein the representation of mobility includes a graph of mobility versus frequency.