Adaptive tracking and MRI-guided catheter and stent placement
A method of automatically adjusting at least one MR image parameter for an interventional procedure includes adaptively tracking an MR micro-coil catheter and automatically updating an imaging scan plane's position and orientation, as well as other features including, but not limited to, field-of-view, resolution, temporal resolution, slice thickness, tip angle, and TE. The disclosed system provides a more natural interface for a physician operating the MR scanner during an interventional procedure. The scanner can react to changes in the clinical environment and automatically adjust a number of image parameters. For example, during catheter insertion, images are acquired at lower resolutions, and possibly larger fields of view, to help facilitate faster updates and tracking. Once the catheter reaches a target area in the tissue and its motion slows, an MR image of higher resolution, and possibly lower field of view, is acquired.
1 . A method of adaptively adjusting at least one MR imaging parameter for an interventional procedure, comprising:
a. adaptively tracking an MR-guided probe inserted into an object by
i. locating the probe by acquiring first probe coordinates with respect to a reference coordinate system; and
ii. calculating a velocity of the probe relative to the object by acquiring second probe coordinates with respect to the reference coordinate system; and
b. based at least partially on the calculated velocity, adjusting a subset of the at least one MR imaging parameter to adaptively perform at least one of tracking of the probe and imaging of a target region of the object.
2 . The method of claim 1 , wherein acquiring the first probe coordinates includes acquiring a plurality of one-dimensional frequency-encoded projections to determine at least one of a three-dimensional position of the probe and an orientation of the probe.
3 . The method of claim 1 , wherein the at least one imaging parameter is selected from the group consisting of: field of view, image spatial resolution, image scan plane position, scan plane orientation, temporal resolution, bandwidth, slice thickness, imaging pulse sequence, image contrast, TR, TE, active receiver channels, k-space trajectory, excitation flip angle, MR scanner table position (e.g., to keep the probe proximal to an isocenter of the table), and a combination thereof.
4 . The method of claim 1 , wherein the adjusting is at least partially based on an auxiliary parameter.
5 . The method of claim 4 , wherein the parameter includes an element selected from the group consisting of: position of the probe relative to a target region of the object, position of the probe relative to the MR imager's receive coils, probe orientation, a physiological parameter associated with the object, and a combination thereof.
6 . The method of claim 1 , wherein adjusting the at least one parameter is at least partially based on a step function of the probe velocity.
7 . The method of claim 6 , wherein the step function includes a binary function of the probe velocity.
8 . The method of claim 1 , wherein adjusting the at least one parameter is at least partially based on a smoothly-varying function of the probe velocity.
9 . The method of claim 8 , wherein the at least one imaging parameter varies between an upper asymptotic value and a lower asymptotic value.
10 . The method of claim 9 , wherein at least one of the upper asymptotic value and the lower asymptotic value is at least partially defined based on a hardware constraint of an MRI machine.
11 . The method of claim 1 , wherein the probe includes a stent.
12 . The method of claim 1 , wherein the probe includes a catheter.
13 . The method of claim 1 , wherein the probe includes a tuned resonant circuit having a resonance frequency substantially the same as a resonance frequency of tissue surrounding the probe.
14 . The method of claim 1 , wherein the object includes an anatomic tissue.
15 . The method of claim 14 , including using the probe to treat at least a portion of the anatomic tissue as part of the interventional procedure.
16 . The method of claim 1 , including providing a user interface to a user so the user can adjust at least one of: the at least one imaging parameter, the lower asymptotic value, the upper asymptotic value, the binary function, the smoothly-varying function, and a combination thereof.
17 . The method of claim 16 , wherein the user interface includes a graphical display for showing the user at least one of the probe and the object.
18 . A method of adaptively adjusting at least one MR imaging parameter for an interventional procedure, comprising:
a. locating an MR-guided probe inserted into an object by acquiring first probe coordinates with respect to a reference coordinate system; and
b. based at least partially on a parameter associated with the located probe, adjusting a subset of the at least one MR imaging parameter to adaptively perform at least one of tracking of the probe and imaging of a target region of the object.
19 . The method of claim 18 , wherein the adjusting is at least partially based on an auxiliary parameter.
20 . The method of claim 19 , wherein the auxiliary parameter includes an element selected from the group consisting of: position of the probe relative to a target region of the object, position of the probe relative to the MR imager's receive coils, probe orientation, a physiological parameter associated with the object, and a combination thereof.
21 . The method of claim 18 , including acquiring second probe coordinates with respect to the reference coordinate system to determine a velocity of the probe.
22 . The method of claim 20 , wherein the adjusting is at least partially based on the determined velocity of the probe.