The Nakagami parameter associated with the Nakagami distribution estimated from ultrasonic backscattered signals reflects the scatterer concentration in a tissue. A nonfocused transducer does not allow tissue characterization based on the Nakagami parameter. This paper proposes a new method called the noise-assisted Nakagami parameter based on empirical mode decomposition of noisy backscattered echoes to allow quantification of the scatterer concentration based on data obtained using a nonfocused transducer. To explore the practical feasibility of the proposed method, the current study performed experiments on phantoms and measurements on rat livers
in vitro with and without fibrosis induction. The results show that using a nonfocused transducer makes it possible to use the noise-assisted Nakagami parameter to classify phantoms with different scatterer concentrations and different stages of liver fibrosis in rats more accurately than when using techniques based on the echo intensity and the conventional Nakagami parameter. However, the conventional Nakagami parameter and the noise-assisted Nakagami parameter have different meanings: the former represents the statistics of signals backscattered from unresolvable scatterers, whereas the latter is associated with stronger resolvable scatterers or local inhomogeneity caused by scatterer aggregation. (E-mail:
mechang@gate.sinica.edu.tw;
mcho1215@ntu.edu.tw)
- Use of Nakagami Statistics and Empirical Mode Decomposition for Ultrasound Tissue Characterization by a Nonfocused Transducer
- Po-Hsiang Tsui - Academia SinicaChien-Cheng Chang - National Taiwan UniversityMing-Chih Ho - National Taiwan University HospitalYu-Hsin Lee - National Taiwan University HospitalYung-Sheng Chen - National Central UniversityChien-Chung Chang - National Central UniversityNorden E. Huang - National Central UniversityZhao-Hua Wu - Department of Meteorology, Florida State University, Tallahassee, FL, USAKing-Jen Chang - National Taiwan University Hospital
- Elsevier Inc
- 14
- Academia Sinica: AS-98-TP-A02 National Science Council of the Republic of China (Taiwan): NSC95-2119-M-008-031-MY3, NSC98-2627-B-008-004
This work was supported by Academia Sinica under Grant No. AS-98-TP-A02 and the National Science Council of the Republic of China (Taiwan) under Grant Nos. NSC95-2119-M-008-031-MY3 and NSC98-2627-B-008-004. The authors would like to acknowledge the reviewers for their valuable comments.
- Journal article
- 01/12/2009
- Ultrasound in medicine & biology, Vol.35(12), pp.2055-2068
- English