CN101438955A - Automatic guidance method of catheter - Google Patents

Abstract

The invention provides an automatic navigation method for a catheter. The invention relates to the automatic navigation method for the catheter, which is applied to a minimally-invasive intervention surgery for guiding the catheter to reach a lesion part automatically, so as to overcome the defect that the previous technology totally depends on vision and decision of doctors. A front end and a back end of a steering section at the distal end of an active catheter are respectively integrated into a position sensor. The method comprises the following steps: 1. a skeleton of a blood vessel is used for generating a navigation path, and a plurality of guiding planes are arranged along the navigation path, wherein, the guiding planes are a serial of discrete round planes which take points on the navigation path as circle centers and are vertical to the navigation path; 2. during the blood vessel intervention process of the catheter, the catheter is controlled to sequentially pass the guiding planes arranged in the first step to a target location. The movement of the catheter comprises two alternate operations of propulsion and direction selection. During the propulsion, the position sensor continuously collects the position of the endpoint of the distal end of the catheter, so that the direction vectors of the steering section point to the inside of the guiding planes and are intersected in the circle centers.

Description

A kind of automatic navigation method of conduit

Technical field

The present invention relates to a kind of automatic navigation method of conduit, be used for Wicresoft's intervene operation guide catheter and arrive diseased region automatically.

Background technology

Wicresoft's intervene operation with its go out insufficiency of blood, advantage such as wound is little, complication is few, safe and reliable and post-operative recovery is fast, worldwide obtained extensive use.Its development trend is operated from a distance, and promptly the doctor breaks away from operative site, and by means of the guiding of navigation picture, the special conduit conveyer device of remote control carries out interventional therapy in the control room.

Conduit is as the topmost instrument of intervene operation, and it can handlingly constantly improve.Multiple active catheter (Active catheter) occurred, driven conduit and hydraulic-driven conduit such as marmem (SMA, Shape memory alloy).They are in a plurality of drivers of distal end of catheter circumferential directions, cause the driver action by thermoelectricity or hydraulic method, make conduit to carry out bending and deflection at 3d space, initiatively choice direction has strengthened the ability that conduit enters target vessel to a certain extent.

Along with 3D-X ray, computerized tomography (Computed Tomography, CT), nuclear magnetic resonance (Magnetic Resonance Imaging, MRI), ultrasonic (Ultrasonography, US) etc. image technology is ripe gradually, can obtain human body and internal's thereof two-dimensional digital tomographic sequence, carry out three-dimensional visualization, the auxiliary doctor operation that undergos surgery.In order to reduce radiation and better assisted surgery, having occurred is the system of purpose with utensil location and navigation in a large number, can position with certain precision in its specific surgical environments, and show on medical image.

The skeleton technology is the one-dimensional representation to 3-D view, and the anatomical structure medically expressing human body organ or tissue is used to virtual navigation more, and auxiliary doctor diagnoses human lesion by image.

At present, the conveying of active catheter doctor's vision and the decision-making that still place one's entire reliance upon.Navigational figure only provides the image of three-dimensional visualization for the doctor, the bulk information that wherein comprises is not fully utilized, and the effect of alignment sensor only rests on positional information to be provided and to be shown on the navigational figure for the operator and carries out reference.Every key technology of Wicresoft's conduit interventional technique does not fully combine, particularly between navigational figure and active catheter.

Doctor's vision and decision-making because the conveying of conduit still places one's entire reliance upon, safety and efficient that fatigue factor and difference of technology level can cause conduit to be got involved are affected.

Summary of the invention

The automatic navigation method that the purpose of this invention is to provide a kind of conduit, make conduit in the blood vessel of human body, bronchus etc. have the human body pipe-line system of arborizations structure, arrive lesion locations automatically according to the strategy that is provided, to overcome existing conduit conveying technology place one's entire reliance upon doctor's vision and decision-making, safety and the affected defective of efficient that fatigue factor and difference of technology level can cause conduit to get involved.

The present invention adopts following technical proposals to solve its technical problem:

A kind of automatic navigation method of conduit, each integrated position sensor in the front and back end of active catheter far-end guide section, the step of its method is as follows:

One, utilize the skeleton of blood vessel to generate guidance path, along guidance path a plurality of guide surfaces are set, described guide surface is to be the center of circle with the point on the guidance path, and perpendicular to the circular flat of the series of discrete of guidance path, the setting of guide surface meets following principle:

(a) spacing of guide surface changes setting according to the curvature of guidance path, and curvature changes greatly then guide surfaces that are provided with more;

(b) the entrance and exit place of single vessel section is provided with guide surface;

(c) in the single vessel section, the radius of guide surface is set to the center of circle to 2/3 of vessel borders beeline, and in stub area, the radius of guide surface is set to the center of circle to 1/3 of vessel borders beeline;

Two, get involved in the blood vessel process at conduit, the control conduit passes the set a series of guide surfaces of first step successively, until moving to objective; The conveying of conduit comprises propelling and two alternative operations of direction selection; When forward operation, the position of the continuous collection tube far-end of position sensor end points just obtains the track of above-mentioned end points, in real time according to current position

Position with a last sampling period correspondence

Obtain a vector $q=\stackrel{\→}{m_n^1{m}_{n-1}^1}$ The current direction of motion of end of conduit is described; Be obstructed and enter guide surface for fear of front end, when direction is selected the direction vector q of guide section is adjusted to and points to guide surface inside and q and guide surface and meet at its center of circle c.

The invention has the beneficial effects as follows, can realize guiding automatically active catheter to arrive target vessel, can avoid end of conduit to contact and be hindered or the injured blood vessel wall with blood vessel wall along guidance path; Utilize the skeleton of blood vessel to generate guidance path, extract the crucial geological information of decision navigation, formulate the self-navigation strategy.Method of the present invention does not rely on doctor's vision and decision-making, is not subjected to the influence of doctor's fatigue factor and difference of technology level, so safety and efficient that conduit is got involved all can be improved.

Description of drawings

Fig. 1 is the structure chart that the used SMA of the present invention drives conduit; Fig. 2 is the C-C cutaway view of Fig. 1, and Fig. 3 is the B-B cutaway view of Fig. 1, and Fig. 4 is the A-A cutaway view of Fig. 1, among Fig. 1 to Fig. 4, Reference numeral: 1-guide section, 3-pick off I, 4-pick off II, 101-silica gel, 102-connector I, 103-SMA driver I, 104-SMA driver II, 105-SMA driver III, 106-connector II, the working chamber of 108-active catheter, 109-wire guide I, 110-wire guide II, 111-silica gel tube chamber I, 112-silica gel tube chamber II, 113-silica gel tube chamber III, 114-flexible member.

Fig. 5 is the sketch map of connector 102 and 106; Symbol among the figure: the fixing hole of 1021-SMA driver I, the fixing hole of 1022-SMA driver II, the fixing hole of 1023-SMA driver III, 1024-wire guide, 1025-wire guide, 1026-flexible member fixing hole.

Fig. 6 is the structure chart of the used hydraulic-driven conduit of the present invention; Fig. 7 is the C-C cutaway view of Fig. 6, and Fig. 8 is the B-B cutaway view of Fig. 6, and Fig. 9 is the A-A cutaway view of Fig. 6, symbol among Fig. 6 to Fig. 9: 2-guide section, 3-pick off I, 4-pick off II, 201-silica gel, 202-connector I, 203-hydraulic-driven chamber I, 204-hydraulic-driven chamber II, 205-hydraulic-driven chamber III, 206-connector II, the working chamber of 208-active catheter, the 209-wire guide, 210-wire guide, 211-flexible member.

Figure 10 is the sketch map of connector 202 and 206; Symbol among the figure: 2021-hydraulic-driven chamber I, 2022-hydraulic-driven chamber II, 2023-hydraulic-driven chamber III, 2024-wire guide, 2025-wire guide, 2026-flexible member fixing hole.

Figure 11 is the generation of guidance path and guide surface; Symbol among the figure: 5-blood vessel, 6-vascular skeleton, 7-guidance path, 8-guide surface, the starting point of 701-guidance path, the terminal point of 702-guidance path, 703-single vessel section, 704-vessel branch area I, 705-vessel branch area I I.

Figure 12 is that the direction of active catheter far-end is selected sketch map; Symbol among the figure: 1-guide section (also can be 2), 3-pick off I, 4-pick off II, 8-guide surface.

The specific embodiment

The specific embodiment one: present embodiment adopts following technical proposals: a kind of automatic navigation method of conduit, each integrated position sensor of front and back end at the guide section of active catheter far-end, its step is as follows: one, utilize the skeleton of blood vessel to generate guidance path, along guidance path a plurality of guide surfaces are set, described guide surface is to be the center of circle with the point on the guidance path, perpendicular to the circular flat of the series of discrete of guidance path, the setting of guide surface meets following principle:

(a) spacing of guide surface changes setting according to the curvature of guidance path, and curvature changes greatly then guide surfaces that are provided with more;

(b) the entrance and exit place of single vessel section is provided with guide surface;

(c) in the single vessel section, the radius of guide surface is set to the center of circle to 2/3 of vessel borders beeline, and in stub area, the radius of guide surface is set to the center of circle to 1/3 of vessel borders beeline;

Two, get involved in the blood vessel process at conduit, the control conduit passes the set a series of guide surfaces of first step successively, until moving to objective; The motion of conduit comprises propelling and two alternative operations of direction selection; When forward operation, the position of the continuous collection tube far-end of position sensor end points just obtains the track of above-mentioned end points, in real time according to current position

Position with a last sampling period correspondence

Obtain a vector $q=\stackrel{\→}{m_n^1{m}_{n-1}^1}$ The current direction of motion of end of conduit is described; Be obstructed and enter guide surface for fear of front end, when direction is selected the direction vector q of guide section is adjusted to and points to guide surface inside and q and guide surface and meet at its center of circle c.

When first step generated guidance path, the skeleton 6 of blood vessel 5 shown in Figure 11 can adopt the method in topological refinement, range conversion or the virtual field of force to extract.Owing to be the arborizations structure, the path that arrives another point of a bit setting out arbitrarily on it has only one.Can on above-mentioned skeleton, generate guidance path 7 by the following method: at first on skeleton, select starting point 701 and impact point 702 by hand, inquire about the vessel segment at starting point and impact point place then according on position and lesion locations.Grade according to impact point is upwards searched, up to the vessel segment that finds the starting point place.The vessel segment that is experienced is connected, promptly form guidance path 7.Conduit can fast speeds advance in the single vessel section, to improve the efficient of intubate; And, then need slow-down in the zone that has vessel branch, avoid being strayed into non-target vessel, and need have higher stepping accuracy.End of conduit contacts with blood vessel wall, blocks easily on the one hand, makes conduit get involved and is obstructed, and can increase the mechanical damage to blood vessel wall on the other hand.Therefore wish that catheter proximal end can keep breaking away from the state of blood vessel wall, the skeleton of blood vessel is extraordinary reference.But, because guidance path is irregular space curve, if the information and the guidance path of pick off compared, can be very consuming time, and be not easy to realize.Therefore along the guidance path direction, the guide surface of series of discrete is set.After setting up guide surface, according to getting involved direction they are numbered, and distinguish corresponding to single vessel section or stub area.

In the progradation of second step because the flexibility of end of conduit, conduit in intervention procedure with blood vessel between contact and relative position all has randomness, so catheter proximal end pushes motion and the uninevitable corresponding relation of the motion of distal end of catheter.This provides difficulty for the automatization of intubate.But position sensor just obtains the track of above-mentioned end points in real time in the position of the distal end of catheter end points of continuous collection tube.As shown in figure 12, current end points is positioned at The position of a last sampling period correspondence is

Like this, can obtain a new vector $q=\stackrel{\→}{m_n^1{m}_{n-1}^1}$ The current direction of motion of end of conduit is described, and this vector as expection to the conduit direction of advance.Q can reflect the movement tendency of end of conduit more accurately.

The coaxial respectively integrated six-degree of freedom position pick off that has central through hole in the front-end and back-end of the guide section of conduit is to obtain position, attitude and the shape of distal end of catheter.The coordinate system ∑ OUVW of active catheter sets up according to the coordinate system of pick off 4.

The location tables of pick off is shown

Direction vector is

I (i=1,2) represents pick off 3 or 4, j (j=1 ..., n) the expression sampling time.The work space of end of conduit can followingly be expressed:

$U=(\frac{L}{\mathrm{\θ}}(1-\cos \mathrm{\θ})+l_s\sin \mathrm{\θ})\cos \mathrm{\ω}$

$V=(\frac{L}{\mathrm{\θ}}(1-\cos \mathrm{\θ})+l_s\sin \mathrm{\θ})\sin \mathrm{\ω}---\left(1\right)$

$W=\frac{L}{\mathrm{\θ}}\sin \mathrm{\θ}+l_s\cos \mathrm{\θ}$

(U, V W) are 3 coordinate components of active catheter end among the coordinate system ∑ OUVW, and L is the length of guide section, l _sBe the length of pick off 3, θ (θ ∈ [0 θ to end of conduit _Max]) be angle of bend, ω (ω ∈ [0 2 π]) is a deflection angle.

In the direction selection course of second step, to be obstructed and to enter guide surface smoothly for fear of front end, direction is selected the direction vector q of distal end of catheter to be adjusted to and is pointed to guide surface inside.In the restriction of this strictness, q and guide surface meet at its center of circle c.Rule of judgment is converted in ∑ OUVW, seeks straight line

Intersection point with work space.If intersection point exists, think that then pick off 3 approach axis select in the zone.

Can utilize the transition matrix between ∑ OUVW and the ∑ OXYZ in ∑ OUVW, to be expressed as

$\frac{u-u_{\mathrm{<figure-callout\; id="1"\; label="c\; q"\; filenames="A200810209793E00132.png"\; state="\{\{state\}\}">c</figure-callout>}}}{q_{}}=\frac{v-v_c}{q_2}=\frac{w-w_c}{q_3}---\left(2\right)$

(u _c, v _c, w _c) be the coordinate of c at ∑ OUVW, (q ₁, q ₂, q ₃) be the expression of direction vector in ∑ OUVW.Simultaneous equations (1) and (2) can obtain following equation:

${(L(1-\cos \mathrm{\&theta;})+l_s\mathrm{\&theta;}\sin \mathrm{\&theta;})}^2-{(\frac{q_1}{q_3}(L\sin \mathrm{\&theta;}+l_s\mathrm{\&theta;}\cos \mathrm{\&theta;})+u_c\mathrm{\&theta;}-\frac{q_1}{q_3}{w}_c\mathrm{\&theta;})}^2$

(3)

$-{(\frac{q_2}{q_3}(L\sin \mathrm{\&theta;}+l_s\mathrm{\&theta;}\cos \mathrm{\&theta;})+v_c\mathrm{\&theta;}-\frac{q_2}{q_3}{w}_c\mathrm{\&theta;})}^2=0$

Make the equation left side be f (θ), [0, θ _Max] adopt on the interval two way classification iterative computation to seek separating of above-mentioned equation, if in limited iterations, $\left|f\left(\widetilde{\mathrm{\&theta;}}\right)\right|<\mathrm{\&epsiv;}$ (ε is predefined error) then will

As approximate solution, and then obtain On this basis conduit is adjusted.

Comprehensive propelling and direction are selected this two operations, and navigation strategy can be expressed as

(1) conduit inserts human vas, reads the information of first guide surface;

(2) near-end pushes 3 step pitches and obtains direction vector;

(3) travel direction is selected, and makes pick off 3 point to the center of circle of guide surface;

(4) near-end pushes a step pitch, judges whether guide section 1 deflects away from guide surface, if then go to (2), if otherwise carry out next step;

(5) continue to push, judge whether pick off 3 passes guide surface, if then read in next guide surface, if otherwise go to (4).

Repeat said process, pass the pelvic inlet plane of target vessel, go deep into certain distance then and arrive target spot until pick off 3.

The specific embodiment two: present embodiment with the difference of embodiment one is: the forward operation position sensor of second step gather guide section on a corresponding position of sampling period

The time, for fear of the shake of double sampling, four adjacent points are obtained this vector as least square linear fit.So be provided with, q can reflect the movement tendency of end of conduit more accurately.

The specific embodiment three: the difference of present embodiment and embodiment one is: in the direction selection course of second step, do not need each step to advance, all want travel direction to select.After selecting, judge whether the intersection point of q and pelvic inlet plane is positioned at guide surface inside in the process first power.If then continue to push, otherwise travel direction is selected.

The specific embodiment four: Fig. 1 is to a specific embodiment that Figure 5 shows that integrated position sensor on the active catheter.The guide section of active catheter far-end (1) adopts marmem to drive, its concrete structure is as follows: 3 sma actuators 103,104 and 105 pass circumferentially equally distributed 3 eccentric cavitys 111,112 and 113 respectively, are connected with 3 eccentric orfices 1021,1022 and 1023 of connector 102 and connector 106.The flexible member 114 that is positioned at the center can be a spring or hyperelastic NiTi pipe, and two ends are connected with 2 centre bores 1026 of connector 102 and connector 106 respectively.The 6DOF electromagnetic transducer 3 and 4 that the hole is opened at 2 centers is imbedded in the silica gel tube 101, and is coaxial with active catheter.The rear end of electromagnetic transducer 3 and connector 102 are connected, and the front end of electromagnetic transducer 4 and connector 106 are connected.The working chamber 108 of conduit passes the centre bore of pick off 3, connector 102, flexible member 114, connector 106 and pick off 4 successively.Distal end of catheter begins to have wire guide to proximal direction from connector 102.

The specific embodiment five: Fig. 6 is to another specific embodiment that Figure 10 shows that integrated position sensor on the active catheter.The guide section 2 of active catheter far-end adopts hydraulic-driven, its concrete circumferentially equally distributed 3 eccentric cavity 203,204 and 205, these cavitys from guide section one through to catheter proximal end.The flexible member 211 that is positioned at the center can be a spring or hyperelastic NiTi pipe, and two ends are connected with 2 centre bores 2026 of connector 202 and connector 206 respectively.The 6DOF electromagnetic transducer 3 and 4 that the hole is opened at 2 centers is imbedded in the silica gel tube 201, and is coaxial with active catheter.3 rear end and connector 202 are connected, and the front end of electromagnetic transducer 4 and connector 206 are connected.The working chamber 108 of conduit passes the centre bore of pick off 3, connector 202, flexible member 211, connector 206 and pick off 4 successively.Distal end of catheter begins to have wire guide to proximal direction from connector 202.

Above-mentioned connected mode can adopt bonding, does not rupture in order to guarantee to be subjected to the load effect, is just drawing adhesive strength to need greater than 20MPa, and shear bond strength needs greater than 10MPa.

Claims (4)

1, a kind of automatic navigation method of conduit is characterized in that, at each integrated position sensor of front and back end of the guide section of active catheter far-end, the step of its method is as follows:

One, utilize the skeleton of blood vessel to generate guidance path, along guidance path a plurality of guide surfaces are set, described guide surface is to be the center of circle with the point on the guidance path, and perpendicular to the circular flat of the series of discrete of guidance path, the setting of guide surface meets following principle:

(a) spacing of guide surface changes setting according to the curvature of guidance path, and curvature changes greatly then guide surfaces that are provided with more;

(b) the entrance and exit place of single vessel section is provided with guide surface;

(c) in the single vessel section, the radius of guide surface is set to the center of circle to 2/3 of vessel borders beeline, and in stub area, the radius of guide surface is set to the center of circle to 1/3 of vessel borders beeline;

Two, get involved in the blood vessel process at conduit, the control conduit passes the set a series of guide surfaces of first step successively, until moving to objective; The conveying of conduit comprises propelling and two alternative operations of direction selection; When forward operation, the pose of the continuous collection tube far-end of position sensor end points just obtains the track of above-mentioned end points, in real time according to current position Position with a last sampling period correspondence Thereby, obtain a vector $q=\stackrel{\&RightArrow;}{m_n^1{m}_{n-1}^1}$ The direction of motion of end of conduit is described; Be obstructed and enter guide surface for fear of front end, when direction is selected the direction vector q of guide section is adjusted to and points to guide surface inside and q and guide surface and meet at its center of circle (c).

2, the automatic navigation method of a kind of conduit according to claim 1 is characterized in that the position of a sampling period correspondence on the forward operation position sensor collection tube far-end end points of second step

The time, for fear of the shake of double sampling, four adjacent points are obtained this vector as least square linear fit.

3, the automatic navigation method of a kind of conduit according to claim 1, the coaxial respectively integrated six-degree of freedom position pick off that has central through hole in front-end and back-end that it is characterized in that the guide section of conduit is to obtain position, attitude and the shape of distal end of catheter.

4, the automatic navigation method of a kind of conduit according to claim 1 is characterized in that in the direction selection course of second step, after selecting, judges whether the intersection point of q and pelvic inlet plane is positioned at guide surface inside in the process first power; If then continue to push, otherwise travel direction is selected.

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