### Abstract

Elastography, computation of elasticity modulus of tissue is one of medical imaging methods with applications such as tumor detection and ablation therapy. Phase-based time delay estimation methods exploit the frequency information of the RF data to obtain strain estimates [1]. Although iterative Phase zero estimation is more computationally efficient in comparison to methods that seek for the absolute maximum cross-correlation between precompression and postcompression echo signals, it is quite sensitive to noise. The reason for this sensitivity is that for this iterative method an initial guess for the time shift is needed for each pixel. To estimate time shifts for the sample k, the time shift resulted from iterative phase zero method applied on sample k-1 is used as an initial value. This makes the method sensitive to noise because the error is propagating sample by sample and if the method gets unstable for any pixel, it will give unstable result for the following pixels in image line. Proposed strategy in this work to overcome this problem is to first estimate the displacement using Dynamic Programming [2] and use the results from DP as an initial guess of displacement for each pixel in iterative Phase zero method. Recently, regularized methods that incorporate the prior of tissue continuity in time delay estimation have been shown to produce low-noise and high contrast strain images [3,5]. In this work, we also incorporate the prior of tissue motion continuity in the phase zero method to make the zero-phase method more robust to signal decorrelation.

Original language | English (US) |
---|---|

Title of host publication | Progress in Biomedical Optics and Imaging - Proceedings of SPIE |

Volume | 7968 |

DOIs | |

State | Published - 2011 |

Event | Medical Imaging 2011: Ultrasonic Imaging, Tomography, and Therapy - Lake Buena Vista, FL, United States Duration: Feb 13 2011 → Feb 14 2011 |

### Other

Other | Medical Imaging 2011: Ultrasonic Imaging, Tomography, and Therapy |
---|---|

Country | United States |

City | Lake Buena Vista, FL |

Period | 2/13/11 → 2/14/11 |

### Fingerprint

### Keywords

- Dynamic Programming
- Phase Phase-zero
- Ultrasound Elastography

### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Radiology Nuclear Medicine and imaging

### Cite this

*Progress in Biomedical Optics and Imaging - Proceedings of SPIE*(Vol. 7968). [79681D] https://doi.org/10.1117/12.878247

**Ultrasound elastography using regularized phase-zero cost function initialized with dynamic programming.** / Sefati, Shahin; Rivaz, Hassan; Boctor, Emad; Hager, Gregory.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Progress in Biomedical Optics and Imaging - Proceedings of SPIE.*vol. 7968, 79681D, Medical Imaging 2011: Ultrasonic Imaging, Tomography, and Therapy, Lake Buena Vista, FL, United States, 2/13/11. https://doi.org/10.1117/12.878247

}

TY - GEN

T1 - Ultrasound elastography using regularized phase-zero cost function initialized with dynamic programming

AU - Sefati, Shahin

AU - Rivaz, Hassan

AU - Boctor, Emad

AU - Hager, Gregory

PY - 2011

Y1 - 2011

N2 - Elastography, computation of elasticity modulus of tissue is one of medical imaging methods with applications such as tumor detection and ablation therapy. Phase-based time delay estimation methods exploit the frequency information of the RF data to obtain strain estimates [1]. Although iterative Phase zero estimation is more computationally efficient in comparison to methods that seek for the absolute maximum cross-correlation between precompression and postcompression echo signals, it is quite sensitive to noise. The reason for this sensitivity is that for this iterative method an initial guess for the time shift is needed for each pixel. To estimate time shifts for the sample k, the time shift resulted from iterative phase zero method applied on sample k-1 is used as an initial value. This makes the method sensitive to noise because the error is propagating sample by sample and if the method gets unstable for any pixel, it will give unstable result for the following pixels in image line. Proposed strategy in this work to overcome this problem is to first estimate the displacement using Dynamic Programming [2] and use the results from DP as an initial guess of displacement for each pixel in iterative Phase zero method. Recently, regularized methods that incorporate the prior of tissue continuity in time delay estimation have been shown to produce low-noise and high contrast strain images [3,5]. In this work, we also incorporate the prior of tissue motion continuity in the phase zero method to make the zero-phase method more robust to signal decorrelation.

AB - Elastography, computation of elasticity modulus of tissue is one of medical imaging methods with applications such as tumor detection and ablation therapy. Phase-based time delay estimation methods exploit the frequency information of the RF data to obtain strain estimates [1]. Although iterative Phase zero estimation is more computationally efficient in comparison to methods that seek for the absolute maximum cross-correlation between precompression and postcompression echo signals, it is quite sensitive to noise. The reason for this sensitivity is that for this iterative method an initial guess for the time shift is needed for each pixel. To estimate time shifts for the sample k, the time shift resulted from iterative phase zero method applied on sample k-1 is used as an initial value. This makes the method sensitive to noise because the error is propagating sample by sample and if the method gets unstable for any pixel, it will give unstable result for the following pixels in image line. Proposed strategy in this work to overcome this problem is to first estimate the displacement using Dynamic Programming [2] and use the results from DP as an initial guess of displacement for each pixel in iterative Phase zero method. Recently, regularized methods that incorporate the prior of tissue continuity in time delay estimation have been shown to produce low-noise and high contrast strain images [3,5]. In this work, we also incorporate the prior of tissue motion continuity in the phase zero method to make the zero-phase method more robust to signal decorrelation.

KW - Dynamic Programming

KW - Phase Phase-zero

KW - Ultrasound Elastography

UR - http://www.scopus.com/inward/record.url?scp=79957970145&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79957970145&partnerID=8YFLogxK

U2 - 10.1117/12.878247

DO - 10.1117/12.878247

M3 - Conference contribution

AN - SCOPUS:79957970145

SN - 9780819485106

VL - 7968

BT - Progress in Biomedical Optics and Imaging - Proceedings of SPIE

ER -