An apparatus for minimally-invasive in vivo measurements of the ciliary beat frequency (CBF) has been developed. The instrument is based on speckle interferometry technique. To be able to distinguish speckle fluctuations caused by motion of the detection probe with respect to the epithelium from the oscillations due to ciliary beat, an image fiber bundle with a position sensitive CCD detector is used. A fast CCD camera taking images with a frame rate of 500 fps provides position and timing resolution to simultaneously detect the CBF and the probe displacement. The probe can be inserted into the working channel of a standard bronchoscope. Two prototypes with different observation angles (straight and 90 degree) were constructed and are now subject to testing. First results of CBF measurements in a human nose are presented.
An apparatus for minimally-invasive in vivo measurements of the ciliary beat frequency (CBF) has been developed. The instrument is based on speckle interferometry technique. Since the diagnostic standard is still based on ex vivo motility analysis of cilia, a less invasive analytical technique for in vivo measurement of the CBF are thus eagerly awaited since a long time. The contrast and the resolution of conventional endoscopy are entirely insufficient for direct observation of the ciliary activity. Because of it we exploited the formation of speckle pattern. Until now, all attempts to measure CBF in vivo by laser light scattering employed a single detector, selecting an area of roughly one speckle from the speckle field. With such a detector there is no way to distinguish fluctuations on the basis of translation from the oscillations due to ciliary beat. We employed image fiber bundle with a position sensitive CCD detector, which allows detecting the motion and correcting for the motion artifacts. The biggest challenge was to combine dynamic speckle interferometry with endoscopic imaging techniques. Two approaches for merging speckle interferometry with fiber-optic endoscopy are presented. In a first, incoherent approach, the speckle image is formed on the front face of the image bundle. In a second, coherent approach, the speckles are formed after the fiber transmission by superposing the light-fields from a number of fibers by image defocusing.