Phase-to-amplitude/slope mapping

• US 9,265,452 B2
• Filed: 04/27/2011
• Issued: 02/23/2016
• Est. Priority Date: 06/04/2010
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Covitch, Adam Jacob, Klahr, Paul
• Primary Examiner(s): TSAI, CAROL S W
• Application Number:
  US13/700,161
• Publication Number:
  US 20130073262A1
• Time in Patent Office: 1,763 Days
• Field of Search: 702/189, 600/463, 600/322, 600/324, 600/336, 600/407, 600/484
• US Class Current: 1/1
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: A61B 6/527 using data from a motion artifact sensor
• CPC Class Codes: A61B 6/5288 involving retrospective matching to a physiological signal
• CPC Class Codes: A61B 6/541 involving acquisition triggered by a physiological signal
• CPC Class Codes: G06F 17/00 Digital computing or data processing equipment or methods, specially adapted for specific functions information retrieval, database structures or file system structures therefor G06F16/00
• CPC Class Codes: G06F 2218/10 by analysing the shape of a waveform, e.g. extracting parameters relating to peaks

Abstract

A method includes obtaining a signal that includes a plurality of cycles and generating a map that maps motion phases to the signal based on both an amplitude and a slope of the signal. A system includes a processor that identifies a set of motion signal timestamps, for a plurality of motion cycles in a motion signal indicative of cyclic motion of a moving object, based on a predetermined motion phase of interest and a phase-to-amplitude/slope mapping, wherein the set of motion signal timestamps correspond to a common signal amplitude. A method include identifying a peak of a plurality of peaks in a motion cycle of a noisy cyclic signal having irregular periodicity, wherein the peak corresponds to a point lying between two points with amplitudes below a predetermined threshold, comparing points before and after the peak with the peak, and identifying the peak as a local maximum when the peak is greater than the points.

Claims

1. A method, comprising:

obtaining a signal that includes a plurality of cycles;

generating a map that maps motion phases to the signal based on both an amplitude and a slope of the signal, wherein the map divides each cycle into a descending region and an ascending region, and the descending region includes a portion of the signal with a negative slope between a lesser of a cycle maximum and a mean of signal maxima of the plurality of cycles and a greater of a cycle minimum and a mean of signal minima of the plurality of cycles, and the ascending region includes a second portion of the signal with a positive slope between the lesser of the cycle maximum and the mean of the signal maxima and the greater of the cycle minimum and the mean of the signal minima; and

generating volumetric image data based on data acquired by a scanner and the mapped motions phases.

2. The method of claim 1, further comprising:

identifying a set of timestamps for the plurality of cycles for a predetermined phase of interest based on the map, wherein identified set of timestamps corresponds to a common signal amplitude; and

generating a signal indicative thereof.

3. The method of claim 1, wherein the signal is detected while imaging a moving object having recurring cyclic motion and a plurality of cycles corresponding to the recurring cyclic motion having irregular periodicity.

4. The method of claim 1, wherein the object is a subject and the signal is indicative of multiple breathing or cardiac cycles of the subject.

5. The method of claim 1, wherein the scanner includes at least one of a CT scanner, an X-ray scanner, a Positron Emission Tomography (PET) scanner, a Single Photon Emission Computed Tomography (SPECT) scanner, a Magnetic Resonance Imaging (MRI) scanner, or an Ultrasound (US) scanner;

and

wherein generating volumetric image data includes;

selecting at least one mapped phase;

selecting data acquired by the scanner according to the at least one selected phase; and

reconstructing selected data in he volumetric image data.

6. The method of claim 1, wherein the descending amplitude region corresponds to one of contraction or expansion of the object and the ascending amplitude region corresponds to the other of expansion or contraction of the object.

7. The method of claim 1, wherein the phases span from 0% to 99% over the cycle, and one set of phases ranges from 0% to 49% and correspond to at least one of the ascending region or the descending region and another set of phases ranges from 50% to 99% and correspond to the other of the least one of the ascending region or the descending region.

8. The method of claim 1, further comprising:

identifying the signal maxima and minima for the plurality of cycles;

determining the mean signal maximum and the mean signal minimum respectively based on the identified signal maxima and minima; and

mapping the phases to the amplitude of each cycle in a range spanning from the lesser of the mean signal maximum and the cycle maximum to the greater of the mean signal minimum and the cycle minimum.

9. The method of claim 1, further comprising:

identifying a maximum for an evaluation range within a cycle, wherein the maximum corresponds to a point lying between two points with amplitudes below a predetermined threshold;

comparing points in the evaluation range before and after the maximum with the maximum;

identifying the maximum as a local maximum for the evaluation range when the maximum is greater than the points; and

determining that the maximum is not the local maximum when the maximum is less than at least one of the points in the evaluation range.

10. The method of claim 9, further comprising:

de-identifying a maximum identified as a local maximum when the maxima are closer together than a predetermined remove maximum threshold; and

adding a maximum to the local maxima when the maxima are farther apart than a predetermined add maximum threshold.

11. A method, comprising:

mapping a first set of motion phases to a descending amplitude region of at least one motion cycle of a motion signal including a plurality of motion cycles, and the descending amplitude region includes the signal between the lesser of the cycle maximum and a mean signal maxima and a greater of a cycle minimum and a mean signal minima;

mapping a second set of motion phases to an ascending region of the at least one motion cycle, and the ascending region of the at least one motion cycle includes the signal between the greater of the cycle minimum and the mean signal minima and the lesser of the cycle maximum and the mean signal maxima; and

reconstructing data acquired from a scanner according to at least one of the first set of motion phases or the second set of motion phases.