# US 2014/0194738 A1 · Method for Focused Acoustic Computed Tomography (FACT) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194738 A1 - Document ID: US20140194738A1 - Status: Published application - Kind: A1 - Application number: 14/149,569 - Filed: 2014-01-07 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: Volcano Corporation - Applicants: Volcano Corporation - Inventors: Cheryl Rice; David Sheehan - Web page: https://patentgrep.com/patent/US20140194738A1 ## CPC - A61B 8/14: Echotomography - A61B 8/0891: {for diagnosis of blood vessels} - A61B 8/12: in body cavities or body tracts, e.g. by using catheters - A61B 8/5207: {involving processing of raw data to produce diagnostic data, e.g. for generating an image} - A61B 8/54: {Control of the diagnostic device} - A61B 8/06: Measuring blood flow - A61B 8/085: {for locating body or organic structures, e.g. tumours, calculi, blood vessels, nodules} - A61B 8/445: {Details of catheter construction} - A61B 8/4461: {Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe} - A61B 8/483: {involving the acquisition of a 3D volume of data} - A61B 8/488: {involving Doppler signals} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A method for acoustic tomography within a patient may include generating a focused ultrasonic signal using a transducer is provided; the ultrasonic signal forming a path within the patient. The method includes directing the ultrasonic signal on a spot within the patient; scanning the spot in a predetermined pattern about a volume within the patient; receiving an ultrasonic echo in the transducer; converting the ultrasonic echo into a voltage; selecting a frequency band from the voltage; amplifying the voltage in the selected frequency band with a processing circuit; and generating an image of the volume within the patient structure utilizing the amplified voltage. A method for recanalization of a blood vessel including the above acoustic tomography steps is also provided. ## Claims ### Claim 1 A method for acoustic tomography within a patient, the method comprising: generating a focused ultrasonic signal using a transducer, the ultrasonic signal forming a path within the patient; directing the ultrasonic signal on a spot within the patient; scanning the spot in a predetermined pattern about a volume within the patient; receiving an ultrasonic echo in the transducer; converting the ultrasonic echo into a voltage; selecting a frequency band from the voltage; amplifying the voltage in the selected frequency band with a processing circuit; and generating an image of the volume within the patient structure utilizing the amplified voltage. ### Claim 2 (depends on 1) The method of claim 1 wherein the converting the ultrasonic echo into a voltage includes using an Application Specific Integrated Circuit (ASIC) proximal to the transducer. ### Claim 3 (depends on 2) The method of claim 2 wherein the ASIC and the transducer are positioned in a distal end of a catheter. ### Claim 4 (depends on 3) The method of claim 3 wherein the scanning the spot in a predetermined pattern about a volume comprises rotating an imaging core about a longitudinal axis inside the catheter. ### Claim 5 (depends on 4) The method of claim 4 wherein the rotating an imaging core comprises rotating a reflective element about a longitudinal axis of the catheter. ### Claim 6 (depends on 1) The method of claim 1 wherein generating a focused ultrasonic beam comprises generating a focused beam having a bandwidth that is more than 70% of the center frequency. ### Claim 7 Wherein the generating a focused ultrasonic signal comprises using a piezoelectric polymeric transducer. ### Claim 8 (depends on 1) The method of claim 1 wherein scanning the spot in a predetermined pattern includes forming a helical pattern. ### Claim 9 (depends on 1) The method of claim 1, wherein the volume within a patient comprises a wall of a blood vessel; and the providing an image from the echo signal includes providing a cross section of the blood vessel. ### Claim 10 (depends on 10) The method of claim 10, further comprising classifying a plaque within the wall of the blood vessel. ### Claim 11 (depends on 11) The method of claim 11 wherein classifying the plaque within the wall of the blood vessel comprises rendering a characterized tissue component map. ### Claim 12 (depends on 11) The method of claim 11 wherein rendering the characterized tissue component map comprises: spectrally analyzing the ultrasonic echo; distinguishing different plaque components in the characterized tissue component map; assigning identifying values to the different plaque components; applying a classification criterion to spatially arranged data of the characterized tissue map; and rendering a plaque classification associated with the cross section of the blood vessel. ### Claim 13 (depends on 1) The method of claim 1, wherein the ultrasonic signal has a frequency in the range from 5 MHz to 135 MHz. ### Claim 14 (depends on 1) The method of claim 1 wherein the generating an image of the volume within the patient includes reconstructing a three-dimensional (3D) image using two-dimensional data. ### Claim 15 (depends on 1) The method of claim 1, wherein the generating the ultrasonic signal comprises directing the ultrasonic signal along a direction substantially parallel to a longitudinal axis of the volume within the patient, and further comprising deflecting the ultrasonic signal transversally with respect to the longitudinal axis by a rotating reflective element. ### Claim 16 (depends on 1) The method of claim 1, wherein the generating the ultrasonic signal comprises directing the ultrasonic signal transversally with respect to a longitudinal axis of the volume within the patient by a rotating transducer. ### Claim 17 (depends on 1) The method of claim 1, wherein the spot within the patient has a diameter of less than 50 μm. ### Claim 18 (depends on 1) The method of claim 1 wherein the spot within the patient is located at a depth of about 10 mm, or less from a surface of a tissue structure within the patient. ### Claim 19 (depends on 1) The method of claim 1, wherein the generating the ultrasonic signal comprises directing the ultrasonic signal at an angle from about 0° to about 180° relative to a longitudinal axis of the volume within the patient. ### Claim 20 (depends on 19) The method of claim 19 further comprising: measuring a frequency shift in the ultrasonic echo signal relative to the generated focused ultrasonic signal; and determining a flow rate of a fluid in a lumen of the volume within the patient using the measured frequency shift. ### Claim 21 (depends on 1) The method of claim 1 further comprising: displacing the ultrasonic transducer along a longitudinal axis of the volume within the patient; and providing a plurality of cross-sectional images of the volume within the patient collected along the longitudinal axis. ### Claim 22 (depends on 21) The method of claim 21 wherein displacing the ultrasonic transducer comprises at least one of the steps selected from the group consisting of manually displacing the transducer and automatically displacing the transducer. ### Claim 23 (depends on 21) The method of claim 21 wherein displacing the ultrasonic transducer comprises at least one of the steps selected from the group consisting of retracting the transducer and advancing the transducer. ### Claim 24 A method for recanalization of a blood vessel, the method comprising: positioning a flexible member within the blood vessel proximal to a pre-selected area of interest; generating a focused ultrasonic signal using a transducer, the ultrasonic signal forming a path within the blood vessel; directing the ultrasonic signal on a spot within the blood vessel; scanning the spot in a predetermined pattern about a volume within the patient; receiving an ultrasonic echo in the transducer; converting the ultrasonic echo into a voltage; selecting a frequency band from the voltage; amplifying the voltage in the selected frequency band with a processing circuit; and recanalizing a lumen in the blood vessel based on the image. ### Claim 25 (depends on 24) The method of claim 24 wherein the pre-selected area of interest comprises a stenosed segment of the blood vessel; and the predetermined pattern comprises the stenosed segment of the blood vessel. ### Claim 26 (depends on 25) The method of claim 25 wherein the recanalizing the lumen in the blood vessel based on the image comprises at least one of the steps in the group consisting of: directing an ablation laser to a point of interest; removing a portion of the stenosed segment of the blood vessel with an abrasive surface; and delivering a drug to the point of interest. ### Claim 27 (depends on 24) The method of claim 24, further comprising classifying a plaque within the wall of the blood vessel. ### Claim 28 (depends on 27) The method of claim 27 wherein the recanalizing the lumen in the blood vessel is performed when the classifying a plaque indicates that the plaque is a vulnerable plaque.