Noninvasive imaging of heart chamber in Drosophila with dual-beam optical coherence tomography

Authors

  • Meng-Tsan Tsai,

    Corresponding author
    1. Department of Electrical Engineering, Chang Gung University, 259, Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 33302 Taiwan
    2. Graduate Institute of Medical Mechatronics, Chang Gung University, Tao-Yuan, 33302 Taiwan
    • Department of Electrical Engineering, Chang Gung University, 259, Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 33302 Taiwan
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  • Cheng-Kuang Lee,

    1. Department of Electrical Engineering, Chang Gung University, 259, Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 33302 Taiwan
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  • Feng-Yu Chang,

    1. Department of Electrical Engineering, Chang Gung University, 259, Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 33302 Taiwan
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  • June-Tai Wu,

    Corresponding author
    1. Graduate Institute of Molecular Medicine, National Taiwan University, 1, Chang-Te St., Taipei, 10048 Taiwan
    2. Department of Medical Research, National Taiwan University Hospital, Taipei, 10048 Taiwan
    • Graduate Institute of Molecular Medicine, National Taiwan University, 1, Chang-Te St., Taipei, 10048 Taiwan
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  • Chung-Pu Wu,

    1. Department of Physiology and Pharmacology, Chang Gung University, 259, Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 33302 Taiwan
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  • Ting-Ta Chi,

    1. Institute of Photonics and Optoelectronics, National Taiwan University, 1, Roosevelt Road, Section 4, Taipei, 10617 Taiwan
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  • C. C. Yang

    Corresponding author
    1. Institute of Photonics and Optoelectronics, National Taiwan University, 1, Roosevelt Road, Section 4, Taipei, 10617 Taiwan
    2. Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road, Section 4, Taipei, 10617 Taiwan
    • Institute of Photonics and Optoelectronics, National Taiwan University, 1, Roosevelt Road, Section 4, Taipei, 10617 Taiwan
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Abstract

The heart chamber of an adult Drosophila is approximately 2 mm long and 0.5 mm wide, and the interwall separation of different heart portions during systole and diastole range from tens of micrometers to hundreds of micrometers. Furthermore, the heart chamber has a curved structure, which results in the larger differences in depth between the different heart portions. However, applying the wavelength calibration process before Fourier transform in an optical coherence tomography (OCT) system may cause degradation in system sensitivity and longitudinal resolution when the optical path difference between the reference and sample arms increases, which makes imaging the entire heart chamber difficult with OCT system. Additionally, since the heartbeat rate of Drosophila is approximately 6 beats/s, a high-speed OCT system is necessary to record the dynamics of the heat beats. In this study, we propose a new approach to visualize the entire heart chamber including the conical chamber and four ostia portions, and to observe the retrograde and anterograde beats. A buffered Fourier-domain mode-locked (FDML) laser is implemented to provide a high imaging speed. Two output ports of the buffered FDML laser are used simultaneously to scan the different heart portions of Drosophila, and the effective A-scan rate of the OCT system can be doubled. Then, the two scanned images are merged into a single B-mode scan. Furthermore, with dual-beam OCT system, the beating behaviors of the different heart portions from 7-day-old and 21-day-old flies are compared. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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