PROCEDURES FOR AN ULTRASONIC ARC SCANNING APPARATUS

• US 20100004537A1
• Filed: 04/03/2009
• Published: 01/07/2010
• Est. Priority Date: 04/03/2008
• Status: Active Grant

• Current Assignee: ArcScan, Inc.
• Original Assignee: ArcScan, Inc.
• Inventors: Medvedeva, Olga, Rasmussen, Randy, McGregor, Paul, Osmann, Eric, Stienmier, J. David, Eilers, George J., Weber, Wes
• Granted Patent: US 8,496,588 B2
• Time in Patent Office: Days
• US Class Current: 600/443
• CPC Class Codes: A61B 8/0858 involving measuring tissue layers, e.g. skin, interfaces
• CPC Class Codes: A61B 8/10 Eye inspection
• CPC Class Codes: A61B 8/4245 involving determining the position of the probe, e.g. with respect to an external reference frame or to the patient
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe

Abstract

Embodiments of the present invention are directed to methods of rapidly obtaining ultrasonic images of the eye using a set of procedural options that can be automated by a positioning mechanism that can be controlled by software.

Claims

1. An ocular imaging method, comprising:

(a) receiving, from an operator, a selection of at least one feature of a patient'"'"'s eye, a set of scan meridians comprising a prime scan meridian and one or more secondary scan meridians, and a set of scan analysis instructions;

(b) receiving, from an operator, a selection of an approximate center location of an ultrasonic transducer relative to at least one selected feature of the patient'"'"'s eye;

(c) determining, by a processor, a first approximate range of an ultrasonic transducer aperture respecting the at least one selected feature of the patient'"'"'s eye;

(d) altering a position at least one of an ultrasonic transducer and arcuate guide relative to the at least one selected feature of the patient'"'"'s eye;

(e) determining, by a processor, a predetermined range of the at least one of an ultrasonic transducer and arcuate guide respecting the at least one selected feature of the patient'"'"'s eye;

(f) executing, based on the set of scan meridians, a series of ultrasonic scans of the patient'"'"'s eye; and

(g) executing, based on the set of scan analysis instructions, at least one of a set of acoustic images for each selected scan meridian, a set of eye component thickness maps, and major dimensions of the selected eye components.

2. The method of claim 1, wherein step (c) comprises the sub-steps:

(C1) performing a series of ultrasonic A-scans;

(C2) determining an A-scan representation of the selected feature of the patient'"'"'s eye; and

(C3) setting a focal plane of the ultrasonic transducer aperture on the A-scan representation.

3. The method of claim 1, wherein step (d) comprises the sub-steps:

(D1) executing a series of B-scans along the prime meridian;

(D2) determining from a selected B-scan whether or not the arcuate guide is centered laterally by applying the following rules;

(i) when the selected B-scan is substantially horizontal, the arcuate guide is properly centered laterally; and

(ii) when the selected B-scan is not substantially horizontal, the arcuate guide is not centered properly and the processor causes movement of the arcuate guide laterally until the B-scan is substantially horizontal;

(D3) determining from a selected B-scan whether or not the arcuate guide is centered vertically by applying the following rules;

(i) when the selected B-scan is not substantially curved, the arcuate guide is properly centered vertically;

(ii) when the selected B-scan is substantially curved, the arcuate guide is not centered vertically and the processor causes movement of the arcuate guide vertically until the selected B-scan is substantially uncurved; and

(D4) rotating the arcuate guide through a substantial angle from the prime meridian to a second meridian; and

(D5) repeating steps (D1)-(D3) with respect to the second meridian and then returning the arcuate guide to the prime meridian.

4. The method of claim 1, wherein, in step (a), a type of scan to be performed is received from an operator and further comprising:

(h) selecting a scan configuration from a plurality of scan configurations associated with differing types of scans, the various scan configurations comprising differing configuration parameters.

5. The method of claim 1, further comprising:

(h) determining a distance from the ultrasonic transducer aperture to a selected surface of the patient'"'"'s eye by performing the following substeps;

(H1) at a first aperture position and using a first gain, taking a first scan along a first vector;

(H2) receiving a reflected ultrasonic wave; and

(H3) forming a first waveform from the reflected ultrasonic wave;

(H4) repositioning the aperture to a second aperture position and repeating steps (H1)-(H3) with respect to the second aperture position and using a second gain; and

(G5) combining the waveforms to form a composite waveform.

6. The method of claim 1, wherein step (g) comprises:

(G1) receiving reflected waves from a scan;

(G2) splitting the reflected waves into first and second waves;

(G3) applying a first gain to the first wave; and

(G4) applying a second gain to the second wave.

7. The method of claim 1, further comprising:

(h) generating, from the ultrasonic scans, distances between the selected features of the patient'"'"'s eye, the distances being determined by the time interval between the peak-to-peak amplitudes of the selected features converted to distances by multiplying the time intervals by a local acoustic velocity between the selected features.

8. The method of claim 1, wherein the selected feature is at least one of a cornea, a natural lens, an artificial lens, an iris, a retina, diseased ocular tissue, damaged ocular tissue and injured ocular tissue, and further comprising:

moving a fixation light to change a degree of focus of the patient'"'"'s eye.

9. A computer readable medium comprising processor-executable instructions to perform the steps (c) through (g) of claim 1.

10. An ocular imaging system, comprising:

an ultrasound transducer;

an arcuate guide for the ultrasound transducer;

a plurality of positional displacement devices to displace the arcuate guide and the transducer to a selected position and orientation;

an input operable to receive, from an operator, at least one of a selection of at least one feature of a patient'"'"'s eye, a set of scan meridians comprising a prime scan meridian and a plurality of secondary scan meridians, and a set of scan analysis instructions; and

a processor operable to perform the following operations;

(a) determine a first range of an ultrasonic transducer aperture respecting the selected feature of the patient'"'"'s eye;

(b) center the ultrasonic transducer and arcuate guide relative to the selected feature of the patient'"'"'s eye;

(d) determine a predetermined range of the ultrasonic transducer aperture respecting the selected feature of the patient'"'"'s eye;

(e) execute, based on the set of scan meridians, a series of ultrasonic scans of the patient'"'"'s eye; and

(f) execute, based on the set of scan analysis instructions, at least one of a set of acoustic images for each selected scan meridian, a set of eye component thickness maps, and major dimensions of the selected eye components.

11. The system of claim 10, wherein operation (b) comprises the sub-operations:

(B1) perform a series of ultrasonic A-scans;

(B2) determine an A-scan representation of the selected feature of the patient'"'"'s eye; and

(B3) set a focal plane of the ultrasonic transducer aperture on the A-scan representation.

12. The system of claim 10, wherein operation (c) comprises the sub-operations:

(C1) execute a series of B-scans along the prime meridian;

(C2) determine from a selected B-scan whether or not the arcuate guide is centered laterally by applying the following rules;

(i) when the selected B-scan is substantially horizontal, the arcuate guide is properly centered laterally; and

(ii) when the selected B-scan is not substantially horizontal, the arcuate guide is not centered properly and the processor causes movement of the arcuate guide laterally until the B-scan is substantially horizontal;

(C3) determine from a selected B-scan whether or not the arcuate guide is centered vertically by applying the following rules;

(i) when the selected B-scan is not substantially curved, the arcuate guide is properly centered vertically;

(ii) when the selected B-scan is substantially curved, the arcuate guide is not centered vertically and the processor causes movement of the arcuate guide vertically until the selected B-scan is substantially uncurved; and

(C4) rotate the arcuate guide through a substantial angle from the prime meridian to a second meridian; and

(C5) repeating operations (C1)-(C3) with respect to the second meridian and then returning the arcuate guide to the prime meridian.

13. The system of claim 10, wherein a type of scan to be performed is received from an operator and wherein the processor further:

(f) selects a scan configuration from a plurality of scan configurations associated with differing types of scans, the various scan configurations comprising differing configuration parameters.

14. The system of claim 10, wherein the processor further:

(f) determines a distance from the ultrasonic transducer aperture to a selected surface of the patient'"'"'s eye by performing the following sub-operations;

(G1) at a first aperture position and using a first gain, take a first scan along a first vector;

(G2) receive a reflected ultrasonic wave; and

(G3) form a first waveform from the reflected ultrasonic wave;

(G4) reposition the aperture to a second aperture position and repeat steps (G1)-(G3) with respect to the second aperture position and using a second gain; and

(G5) combine the waveforms to form a composite waveform.

15. The system of claim 10, further comprising:

a splitter adapted to receive, at an input, reflected waves from a scan and split the reflected waves into first and second waves; and

first and second gain amplifiers adapted to apply, respectively, a first gain to the first wave and a second gain to the second wave.

16. The system of claim 10, wherein the processor generates, from the ultrasonic scans, distances between the selected features of the patient'"'"'s eye, the distances being determined by the time interval between the peak-to-peak amplitudes of the selected features converted to distances by multiplying the time intervals by a local acoustic velocity between the selected features.

17. The system of claim 10, wherein the selected feature is at least one of a cornea, a natural lens, an artificial lens, an iris, a retina, diseased ocular tissue, damaged ocular tissue and injured ocular tissue, and further comprising:

a movable fixation light to change a degree of focus of the patient'"'"'s eye.