Methods of using high intensity focused ultrasound to form an ablated tissue area containing a plurality of lesions

Abstract

A device and method for ablating tissue is disclosed comprising the steps of acquiring an anatomical image of a patient, correlating the image to the patient, guiding an ablating member within the patient while tracking the position of the ablating member in the patient, positioning the ablating member in a desired position to ablate tissue, emitting ablating energy from the ablating member to form an ablated tissue area and removing the ablating member from the patient.

1 . A method of performing an ablation procedure within a patient, the method comprising: acquiring an image of an anatomy of interest of the patient; 
 correlating the image with the patient's anatomy using an image guidance system;    guiding an ablation device to an energy delivery location within the patient, the ablation device comprising a high intensity focused ultrasound (HIFU) emitting member and one or more image guidance sensors for tracking a position of the ablation device within the patient;    emitting ultrasound energy from the HIFU emitting member into a target area of tissue disposed a distance from the energy delivery location, the ultrasound energy being focused into one or more focusing zones within the target area of tissue; and    heating the target area of tissue generally within the focusing zones to form ablation lesions in the target area of tissue.    
   
   
       2 . The method of  claim 1  further comprising removing the ablation device from the patient.  
   
   
       3 . The method of  claim 1  wherein the image is acquired using an imaging device.  
   
   
       4 . The method of  claim 3  wherein the imaging device is based on one or more of ultrasound imaging, CT, MRI, PET, fluoroscopy, and echocardiography.  
   
   
       5 . The method of  claim 3  wherein the imaging device is adapted to be positioned on the skin of the patient for acquiring the image.  
   
   
       6 . The method of  claim 3  wherein the imaging device is adapted to be positioned through one or more body cavity openings of the patient for acquiring the image.  
   
   
       7 . The method of  claim 3  wherein the imaging device is adapted to be positioned within one or more of an esophagus, a trachea, and bronchi of lungs of the patient.  
   
   
       8 . The method of  claim 1  wherein the ablation device includes an imaging device for acquiring the image.  
   
   
       9 . The method of  claim 8  wherein the imaging device is an ultrasound imaging device coupled to the ablation device.  
   
   
       10 . The method of  claim 9  further comprising alternately emitting ultrasound energy from the HIFU emitting member and the ultrasound imaging device.  
   
   
       11 . The method of  claim 1  wherein acquiring the image is performed substantially while guiding the ablation device.  
   
   
       12 . The method of  claim 1  wherein acquiring the image is performed substantially while forming the ablation lesions.  
   
   
       13 . The method of  claim 1  wherein the step of acquiring the image is performed prior to the guiding and emitting steps.  
   
   
       14 . The method of  claim 1  wherein the image guidance sensor comprises at least one sensor coil.  
   
   
       15 . The method of  claim 1  wherein the target area of tissue includes cardiac tissue.  
   
   
       16 . The method of  claim 15  wherein the ablation lesions formed block the propagation of cardiac action potentials.  
   
   
       17 . The method of  claim 16  wherein the ablation lesions are formed as part a Maze procedure for treating atrial fibrillation.  
   
   
       18 . The method of  claim 16  wherein the ablation lesions are electrically isolating lesions which at least partially encircle one or more pulmonary veins of the patient.  
   
   
       19 . The method of  claim 15  wherein the energy delivery location is selected from the group consisting of an esophagus, a trachea, and bronchi of lungs of the patient.  
   
   
       20 . The method of  claim 1  wherein the image guidance system for correlating the acquired image with the patient's anatomy comprises reference markers.  
   
   
       21 . The method of  claim 1  wherein the energy delivery location to which the ablation device is guided is selected from the group consisting of an esophagus, a trachea, and bronchi of lungs of the patient.  
   
   
       22 . The method of  claim 21  wherein the HIFU emitting member of the ablation device is guided to the esophagus of the patient.  
   
   
       23 . The method of  claim 22  wherein the ablation device is guided using transesophageal echocardiography (TEE).  
   
   
       24 . The method of  claim 1  wherein the HIFU emitting member of the ablation device comprises a phased array.  
   
   
       25 . The method of  claim 24  further comprising electronically controlling the phased array to steer the one or more focusing zones.  
   
   
       26 . The method of  claim 25  wherein the one or more focusing zones are steered to form a plurality of substantially contiguous ablation lesions for blocking electrical conduction pathways in cardiac tissue.  
   
   
       27 . The method of  claim 1  wherein the HIFU emitting member of the ablation device comprises an annular array.  
   
   
       28 . The method of  claim 1  wherein the ablation device is adapted to focus ultrasound energy from the HIFU emitting member into the one or more focusing zones.  
   
   
       29 . The method of  claim 1  further comprising positioning an organ using a tissue-engaging device.  
   
   
       30 . The method of  claim 29  wherein the tissue-engaging device is used to engage and position a heart of the patient during a cardiac ablation procedure.  
   
   
       31 . The method of  claim 29  wherein the tissue-engaging device uses suction to engage and position an organ of the patient.  
   
   
       32 . The method of  claim 1  further comprising creating a display that shows a position of the ablation device superimposed on an acquired image of the patient.  
   
   
       33 . The method of  claim 32  further comprising marking the display to show locations of the ablation lesions.  
   
   
       34 . The method of  claim 1  further comprising repositioning the HIFU emitting member to focus ultrasound energy into the one or more focusing zones.  
   
   
       35 . An ablation device for performing an ablation procedure within a patient, the ablation device comprising: 
 an flexible, elongate portion adapted for guiding the ablation device within the patient;    an image guidance sensor for tracking a position of the ablation device within the patient;    an imaging device coupled to the ablation device, the imaging device adapted to acquire one or more images of an anatomy of interest of the patient; and    an ultrasound emitting member coupled to the elongate portion and adapted for emitting high intensity focused ultrasound (HIFU) energy to a focusing zone within the patient.    
   
   
       36 . The device of  claim 35  wherein the image guidance sensor is coupled to the ultrasound-emitting member of the ablation device.  
   
   
       37 . The device of  claim 35  wherein the ultrasound-emitting member comprises a phased array of transducer elements adapted to electronically steer HIFU energy to one or more focusing zones in a target area of tissue within the patient  
   
   
       38 . The device of  claim 37  wherein the phased array of transducer elements comprises a rectangular array of transducer elements.  
   
   
       39 . The device of  claim 38  wherein the array of transducer elements comprises  64  active elements sampled from  195  rectangular elements.  
   
   
       40 . The device of  claim 38  wherein the array of transducer elements comprises  64  active elements operating at a frequency of approximately 1.6 MHz.  
   
   
       41 . The device of  claim 37  wherein the ultrasound-emitting member further comprises a housing, an acoustic membrane, and one or more pipes adapted to provide fluid around the transducer elements, the fluid adapted to acoustically couple the ultrasound-emitting member to an energy delivery location within the patient.  
   
   
       42 . The device of  claim 35  wherein an array of ultrasound transducer elements are adapted to function as both the imaging device and the ultrasound emitting member of the ablation device.  
   
   
       43 . The device of  claim 42  further comprising a controller adapted to multiplex between operation of the imaging device and the ultrasound emitting member.  
   
   
       44 . The device of  claim 43  wherein the controller multiplexes between wide area/low power operation of the imaging device and focused/high power operation of the ultrasound emitting member.  
   
   
       45 . A system for performing an ablation procedure within a patient, the system comprising: an ablation device comprising 
 an ultrasound-emitting member adapted to deliver high intensity focused ultrasound (HIFU) into a target area of tissue of the patient, and    at least one image guidance sensor coupled to the ablation device;    an imaging device adapted to acquire anatomical images of the patient;    a processor adapted to correlate images acquired by the imaging device with the patient's anatomy; and    a display adapted to facilitate performing the ablation procedure by showing a location of the ablation device within the patient.    
   
   
       46 . The system of  claim 45  wherein the ultrasound-emitting member comprises a phased array of transducers adapted to electronically steer ultrasound energy to one or more focusing zones in a target area of tissue within the patient.  
   
   
       47 . A system for performing high intensity focused ultrasound (HIFU) ablation of cardiac tissue within a patient, the system comprising: 
 a power source for supplying ultrasound energy;    an ablation device having a flexible elongate portion, a HIFU emitting portion, and one or more image guidance sensors, the flexible elongate portion adapted for placing the HIFU emitting portion in an energy delivery location within an esophagus of the patient, the HIFU emitting portion being adapted to direct HIFU energy from the power source to one or more focusing zones within a target area of cardiac tissue within the patient, and the image guidance sensors adapted for tracking a position of the ablation device within the patient;    an imaging device adapted to acquire one or more images of an anatomical area of interest of the patient including the target area of cardiac tissue within the patient; and    an image guidance system for tracking a position of the ablation device within the patient, the image guidance system comprising one or more reference devices disposed in known locations in the anatomical area of interest, and a processor adapted to receive the one or more images from the imaging device, the image guidance system adapted to correlate the one or more images with an anatomy of the patient based on the one or more reference devices.    
   
   
       48 . The system of  claim 47  wherein the imaging device is mechanically coupled to the flexible elongate portion of the ablation device.  
   
   
       49 . The system of  claim 48  wherein the ablation device further comprises a controller adapted to multiplex between delivery of HIFU energy to the ablation device and a lower level of ultrasound energy to the imaging device.  
   
   
       50 . The system of  claim 47  wherein the HIFU emitting portion comprises a phased array of ultrasound transducers, the transducers of the phased array being selectively actuatable to allow electronic steering of the one or more focusing zones.