Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technique for microvasculature imaging at high spatial resolution and contrast. In this work, we present a practical visible laser-diode-based OR-PAM (LD-OR-PAM) prototype for vasculature imaging, which has the desirable properties of being portable, low-cost, and label-free. The prototype employs a 300 mW pulsed laser diode in a 3.8 mm diameter package, emitting 174 ns pulses at 405 ± 5 nm wavelength and a pulse energy of 52 nJ. An aspheric objective with a numerical aperture of 0.60 is used to achieve microscope optical illumination. The laser diode excitation has a compact size of 4.5 × 1.8 × 1.8 cm3 assembled with a cooling block. The lateral resolution was tested to be 0.95 μm on ~7 μm carbon fibers. The subcutaneous microvasculature on a mouse back was label-free imaged ex vivo, which demonstrates the potential of the LD-OR-PAM prototype for in vivo imaging skin chromosphores such as hemoglobin. Our ultimate aim is to provide a practical and affordable OR-PAM system as a routine instrument for standard clinical applications.
Optical coherence tomography (OCT) is a noninvasive method for retinal imaging. In this work, we present an in vivo
human retinal microvascular network measurement by an intensity-based Doppler variance (IBDV) based on sweptsource
OCT. In addition, an automatic three-dimensional (3-D) segmentation method was used for segmenting
intraretinal layers. The microvascular networks were divided into six layers by visualizing of each individual layer with
enhanced imaging contrast. This method has potential for earlier diagnosis and precise monitoring in retinal vascular
diseases.
We present an automatic segmentation method for delineation and quantitative thickness measurement of multiple layers in endoscopic airway optical coherence tomography (OCT) images. The boundaries of the mucosa and the sub-mucosa layers were extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested with pig airway OCT images acquired with a custom built long range endoscopic OCT system. The performance of the algorithm was demonstrated by cross-validation between auto and manual segmentation experiments. Quantitative thicknesses changes in the mucosal layers are obtained automatically for smoke inhalation injury experiments.
In this study, we have developed an acoustic radiation force orthogonal excitation optical coherence elastography
(ARFOE-OCE) method for the visualization of the shear wave and the calculation of the shear modulus based on the OCT
Doppler variance method. The vibration perpendicular to the OCT detection direction is induced by the remote acoustic
radiation force (ARF) and the shear wave propagating along the OCT beam is visualized by the OCT M-scan. The
homogeneous agar phantom and two-layer agar phantom are measured using the ARFOE-OCE system. The results show
that the ARFOE-OCE system has the ability to measure the shear modulus beyond the OCT imaging depth. The OCT
Doppler variance method, instead of the OCT Doppler phase method, is used for vibration detection without the need of
high phase stability and phase wrapping correction. An M-scan instead of the B-scan for the visualization of the shear
wave also simplifies the data processing.
Microvascular network of the retina plays an important role in diagnosis and monitoring of various retinal diseases. We propose a three-dimensional (3-D) segmentation method with intensity-based Doppler variance (IBDV) based on swept-source optical coherence tomography. The automatic 3-D segmentation method is used to obtain seven surfaces of intraretinal layers. The microvascular network of the retina, which is acquired by the IBDV method, can be divided into six layers. The microvascular network of the six individual layers is visualized, and the morphology and contrast images can be improved by using the segmentation method. This method has potential for earlier diagnosis and precise monitoring in retinal vascular diseases.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.