Dynamic optical contrast imaging as a novel modality for rapidly distinguishing head and neck squamous cell carcinoma from surrounding normal tissue.

BACKGROUND: Head and neck squamous cell carcinomas (HNSCCs) are debilitating diseases for which a patient's prognosis depends heavily on complete tumor resection. Currently, the surgeon's fingers determine the location of tissue margins. This study evaluated the diagnostic utility of a novel imaging modality, dynamic optical contrast imaging (DOCI), in the detection of HNSCC. This system generates contrast by illuminating the tissue with pulsed light and detecting variations in endogenous fluorophore lifetimes. METHODS: A total of 47 fresh ex vivo samples from 15 patients were imaged with the DOCI system immediately after surgical resection. DOCI maps were analyzed to determine the statistical significance of contrast between tumors and adjacent nonmalignant tissue. Pilot intraoperative clinical data were also acquired. RESULTS: Statistical significance (P < .05) between muscle and tumor was established for 10 of 10 emission wavelengths, between collagen and tumor for 8 of 10 emission wavelengths, and between fat and tumor for 2 of 10 wavelengths. The system extracted relative fluorescence decay information in a surgically relevant field of view in <2 minutes. CONCLUSIONS: This study demonstrates the feasibility of using DOCI to rapidly and accurately distinguish HNSCC from surrounding normal tissue. An analysis of DOCI images revealed microscopic characterization sufficient for tissue-type identification consistent with histology. Such an intraoperative tool would be transformative by allowing the rapid delineation of tumor tissue from nontumor tissue and thus maximizing the efficacy of resection and improving patient outcomes. Cancer 2017;123:879-86. © 2016 American Cancer Society.

Hypersonic vitrectomy in intraoperative posterior capsular rupture with retained nuclear fragments.

In our report, we present the hypersonic vitrectomy (Vitesse, Bausch and Lomb) being employed for anterior vitreous liquefaction and removal in posterior capsular rupture. The capsular tear with nucleus drop during conventional phacoemulsification was managed by vitrectomy using the hypersonic vitrector after posterior-assisted levitation followed by intraocular lens (IOL) implantation. The minimal cortical and epinuclear lens particles in the anterior chamber and vitreous were also liquefied with a stoke length of 30 to 40 µm and aspirated via the Vitesse vitrectomy system. The same probe performs the vitrectomy and the nucleus removal. The postoperative period was uneventful with clear cornea, normal fundus, and 20/20 best-corrected visual acuity (BCVA). The hypersonic vitrectomy utilizes the ultrasound power of 29.5 kHz and a stoke length of 0 to 60 µm for liquefaction of the vitreous. It can be a safe alternative for vitrectomy and lens removal in a single setting.

Ultrasonic Vitrectomy Performance Assessment Using Micro-Extensional Rheology.

Purpose: The purpose of this study was to assess the performance of ultrasonic (US) vitrectomy devices by quantifying and comparing its impact on extracted vitreous properties to conventional pneumatic blade (PB) cutters using micro-extensional rheology. US vitrectomy is a new technology that offers an alternative to PB cutters used in vitreo-retinal surgeries. Methods: Thirty-six porcine vitreous samples were extracted using US and PB cutters. Each sample was kept at 4°C and tested within 24 hours postmortem and 4 hours post-vitrectomy. A recently developed micro-extensional rheology technique is used to infer the relative protein fragment size of extracted vitreous by quantifying the extensional relaxation time. Results: US-extracted vitreous exhibited extensional relaxation times orders of magnitude lower than PB-extracted vitreous (0.37 ms and 27.25 ms, respectively). Relaxation time is directly correlated to the fragment size of the collagen fibers in the vitreous. The formation of beads-on-a-string droplets within the PB samples indicates the presence of larger collagen fragments. These droplets were not seen on US samples. Conclusions: This new micro-extensional rheology technique can identify significant differences in physical properties of extracted vitreous. Long relaxation times and beads-on-a-string droplets within the PB vitreous samples indicate larger protein fragments compared to the US samples. Translational Relevance: Higher fragmentation of vitreous and lower extensional relaxation times may improve retina safety due to a reduction in vitreo-retinal traction resulting from the continuous shear action and aspiration applied by ultrasonic vitrectomy technology.

[Pars plana vitrectomy-from suction cutting systems to ultrasound technology : Vitesse-a new form of vitrectomy based on ultrasound technology]. / Pars-plana-Vitrektomie ­ von Saug-Schneide-Systemen bis hin zur Ultraschalltechnik : Vitesse ­ eine neuartige Form der Vitrektomie mittels einer Ultraschalltechnik.

In the 1970s a cutting device into which an infusion and an aspiration channels were integrated, the so-called vitreous infusion suction cutter (V.I.S.C), was used for the first time for the removal of the vitreous body. These cutting systems have continued to constantly evolve since then; however, sonic energy remained reserved for anterior segment surgery for a long time. In 2020, this form of energy could also be used for the posterior segment in form of Vitesse™. In this liquification technique, ultrasonic energy is transferred to a single, large inner lumen design that mechanically vibrates the needle's port. These high-speed vibrations shear the vitreous body at the port edges before it enters the needle. This mechanism reduces traction to a minimal level and enables faster aspiration at lower vacuum levels compared to conventional cutters. These advantages can promote a safer and more efficient vitreoretinal surgery.

Imaging autofluorescence temporal signatures of the human ocular fundus in vivo.

We demonstrate real-time in vivo fundus imaging capabilities of our fluorescence lifetime imaging technology for the first time. This implementation of lifetime imaging uses light emitting diodes to capture full-field images capable of showing direct tissue contrast without executing curve fitting or lifetime calculations. Preliminary results of fundus images are presented, investigating autofluorescence imaging potential of various retina biomarkers for early detection of macular diseases.

Wide-field Raman imaging for bone detection in tissue.

Inappropriate bone growth in soft tissue can occur after trauma to a limb and can cause a disruption to the healing process. This is known as Heterotopic Ossification (HO) in which regions in the tissue start to mineralize and form microscopic bone-like structures. These structures continue to calcify and develop into large, non-functional bony masses that cause pain, limit limb movement, and expose the tissue to reoccurring infections; in the case of open wounds this can lead to amputation as a result of a failed wound. Both Magnetic Resonance Imaging (MRI) and X-ray imaging have poor sensitivity and specificity for the detection of HO, thus delaying therapy and leading to poor patient outcomes. We present a low-power, fast (1 frame per second) optical Raman imaging system with a large field of view (1 cm(2)) that can differentiate bone tissue from soft tissue without spectroscopy, this in contrast to conventional Raman microscopy systems. This capability may allow for the development of instrumentation which permits bedside diagnosis of HO.

Optical imaging for brain tissue characterization using relative fluorescence lifetime imaging.

An autofluorescence lifetime wide-field imaging system that can generate contrast in underlying tissue structures of normal and malignant brain tissue samples with video rate acquisition and processing time is presented. Images of the investigated tissues were acquired with high resolution (∼35 µm) using an algorithm to produce contrast based on differences in relative lifetimes. Sufficient contrast for delineation was produced without the computation of fluorescence decay times or Laguerre coefficients. The imaged tissues were sent for histological analysis that confirmed the detected imaged tissues morphological findings and correlations between relative lifetime maps and histology identified.