In vivo assessment of the mechanical properties of crystalline lenses in a rabbit model using ultrasound elastography

Effects of ultrasound frequency and age

Qingmin Wang, Ying Zhu, Meng Shao, Haoming Lin, Siping Chen, Xin Chen, Azra Alizad, Mostafa Fatemi, Xinyu Zhang

Research output: Contribution to journalArticle

Abstract

Purpose: The occurrence of presbyopia and cataract is closely related to changes in the mechanical properties of the crystalline lens. There are no established methods so far for in vivo assessment. By introducing ultrasound elastography, we proposed group velocity (V g )of an induced shear wave as a new biomarker to characterize the mechanical properties of the lens in our previous study. Here, we investigated the effect of the ultrasound frequency on measurement accuracy and validated the results with a conventional ex vivo compression testing. We also demonstrated a change trend in V g and its correlation with age in a rabbit model. Methods: Eight New Zealand white rabbits were fed normally from the fourth to seventh month. An ultrasound elastography system was developed to measure V g in vivo on every eye once per month. The performances when using a high-frequency (L22-11v)and low-frequency (L11-4v)probe were compared. Rabbits were sacrificed after in vivo measurements by the end of the seventh month and this was followed by ex vivo ultrasound measurements and conventional compression tests on the extracted lenses. Results: The results demonstrated that there were no significance differences in V g between measurements with high-frequency (USE-HF)and low-frequency (USE-LF)probes in the same month-age group. The mean V g and the standard deviation of four rabbits that were 7 months old were 2.37 ± 0.24 m/s, 2.36 ± 0.25 m/s, 2.43 ± 0.26 m/s and 2.44 ± 0.38 m/s, with USE-HF for ex vivo and in vivo measurements and USE-LF for ex vivo and in vivo measurements, respectively. There were no significant differences (p > 0.05)and they were all in agreement with the results of compression tests, which was 16.16 ± 1.84 kPa in Young's modulus. The results also showed that V g increased with age. In combination with the results of our previous study, V g showed a relatively sharp increase from 2 to 5 months, while it had a slight increase from 5 to 7 months. Conclusions: The USE-HF and USE-LF has comparable accuracy in V g measurements while USE-HF had an advantage regarding better spatial resolution. The change trend of V g was in accord with the growth phase of New Zealand white rabbits, which usually results in sexual maturity at 5 months old. This implies that V g can be used as a biomarker parameter for evaluating the mechanical properties of the lens undergoing physiological changes.

Original languageEnglish (US)
Pages (from-to)258-265
Number of pages8
JournalExperimental Eye Research
Volume184
DOIs
StatePublished - Jul 1 2019

Fingerprint

Elasticity Imaging Techniques
Crystalline Lens
Rabbits
Lenses
Biomarkers
Presbyopia
Elastic Modulus
Cataract
Age Groups
Growth

Keywords

  • Acoustic radiation force
  • Age
  • Crystalline lens
  • Frequency
  • Mechanical properties
  • Shear wave
  • Ultrasound elastography

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

In vivo assessment of the mechanical properties of crystalline lenses in a rabbit model using ultrasound elastography : Effects of ultrasound frequency and age. / Wang, Qingmin; Zhu, Ying; Shao, Meng; Lin, Haoming; Chen, Siping; Chen, Xin; Alizad, Azra; Fatemi, Mostafa; Zhang, Xinyu.

In: Experimental Eye Research, Vol. 184, 01.07.2019, p. 258-265.

Research output: Contribution to journalArticle

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abstract = "Purpose: The occurrence of presbyopia and cataract is closely related to changes in the mechanical properties of the crystalline lens. There are no established methods so far for in vivo assessment. By introducing ultrasound elastography, we proposed group velocity (V g )of an induced shear wave as a new biomarker to characterize the mechanical properties of the lens in our previous study. Here, we investigated the effect of the ultrasound frequency on measurement accuracy and validated the results with a conventional ex vivo compression testing. We also demonstrated a change trend in V g and its correlation with age in a rabbit model. Methods: Eight New Zealand white rabbits were fed normally from the fourth to seventh month. An ultrasound elastography system was developed to measure V g in vivo on every eye once per month. The performances when using a high-frequency (L22-11v)and low-frequency (L11-4v)probe were compared. Rabbits were sacrificed after in vivo measurements by the end of the seventh month and this was followed by ex vivo ultrasound measurements and conventional compression tests on the extracted lenses. Results: The results demonstrated that there were no significance differences in V g between measurements with high-frequency (USE-HF)and low-frequency (USE-LF)probes in the same month-age group. The mean V g and the standard deviation of four rabbits that were 7 months old were 2.37 ± 0.24 m/s, 2.36 ± 0.25 m/s, 2.43 ± 0.26 m/s and 2.44 ± 0.38 m/s, with USE-HF for ex vivo and in vivo measurements and USE-LF for ex vivo and in vivo measurements, respectively. There were no significant differences (p > 0.05)and they were all in agreement with the results of compression tests, which was 16.16 ± 1.84 kPa in Young's modulus. The results also showed that V g increased with age. In combination with the results of our previous study, V g showed a relatively sharp increase from 2 to 5 months, while it had a slight increase from 5 to 7 months. Conclusions: The USE-HF and USE-LF has comparable accuracy in V g measurements while USE-HF had an advantage regarding better spatial resolution. The change trend of V g was in accord with the growth phase of New Zealand white rabbits, which usually results in sexual maturity at 5 months old. This implies that V g can be used as a biomarker parameter for evaluating the mechanical properties of the lens undergoing physiological changes.",
keywords = "Acoustic radiation force, Age, Crystalline lens, Frequency, Mechanical properties, Shear wave, Ultrasound elastography",
author = "Qingmin Wang and Ying Zhu and Meng Shao and Haoming Lin and Siping Chen and Xin Chen and Azra Alizad and Mostafa Fatemi and Xinyu Zhang",
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T2 - Effects of ultrasound frequency and age

AU - Wang, Qingmin

AU - Zhu, Ying

AU - Shao, Meng

AU - Lin, Haoming

AU - Chen, Siping

AU - Chen, Xin

AU - Alizad, Azra

AU - Fatemi, Mostafa

AU - Zhang, Xinyu

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