Comprehensive volumetric optical microscopy in vivo

Abstract

Comprehensive volumetric microscopy of epithelial, mucosal and endothelial tissues in living human patients would have a profound impact in medicine by enabling diagnostic imaging at the cellular level over large surface areas. Considering the vast area of these tissues with respect to the desired sampling interval, achieving this goal requires rapid sampling. Although noninvasive diagnostic technologies are preferred, many applications could be served by minimally invasive instruments capable of accessing remote locations within the body. We have developed a fiber-optic imaging technique termed optical frequency-domain imaging (OFDI) that satisfies these requirements by rapidly acquiring high-resolution, cross-sectional images through flexible, narrow-diameter catheters. Using a prototype system, we show comprehensive microscopy of esophageal mucosa and of coronary arteries in vivo. Our pilot study results suggest that this technology may be a useful clinical tool for comprehensive diagnostic imaging for epithelial disease and for evaluating coronary pathology and iatrogenic effects.

Label-free optical-resolution photoacoustic endomicroscopy in vivo

“…57 and 58 demonstrated 19.6 µm and 15.7 µm transverse resolutions, respectively), and an SNR of 29 dB from a 3-µm diameter microsphere illuminated by a pulse energy of 500-nJ in a 9.2 µm beam diameter. As shown in the in vivo and ex vivo image demonstrations, the major benefit of the OR-PAEM over existing IVM techniques [44][45][46][47][48][49][50][51][52][53][54][55][56] lies in its label-free angiographic imaging capability, which provides critical image in experimental biology and clinical medicine. Although other groups [57,58] developed endoscopic devices with optical focusing and achieved an even smaller probe diameter (i.e., ~1.1 mm in the case of ref.…”

“…OR-PAM realizes the key benefits of PAT in biological experimentation through its high-resolution imaging capability; further, its unique optical absorption-based contrast mechanism enables it to complement conventional highresolution microscopy tools, such as confocal microscopy [44][45][46][47][48][49], two-photon microscopy [44][45][46][50][51][52][53], and optical coherence tomography [44][45][46][53][54][55][56]. So far, considerable efforts have been made to improve the spatial resolution [15], scanning speed [7,12], and functional imaging capability [4][5][6][7][8][9] of OR-PAM.…”

Optical coherence tomography—current technology and applications in clinical and biomedical research

“…Nevertheless, research continues to eliminate the risk of ischemia completely, for instance by matching the refractive index of the blood serum with that of the red blood cells [199] or by using oxygen-carrying flushing liquids [200,201]. An important step was the introduction of high-speed FD-OCT systems, since it enabled the acquisition of large sampling volumes during relatively short flushing periods [36,195].…”

Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter

“…The development of Fourier domain detection techniques and high speed, wavelength swept light sources has greatly improved the imaging speed and detection sensitivity of OCT systems, enabling volumetric endoscopic OCT imaging [10,11]. Using a high speed, wavelength swept light source based on a polygon mirror filter [12], early studies demonstrated volumetric endoscopic OCT of the esophagus and coronary arteries in living swine at an A-scan rate of 64 kHz [10]. In parallel, studies also demonstrated volumetric imaging in the rabbit GI tract using a high speed endoscopic OCT system with a Fourier domain mode-locked (FDML) laser at an A-scan rate of 100 kHz [11].…”