Evaluation of Contrast Agents for Enhanced Visualization in Optical Coherence Tomography

Cole Eye Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
Investigative ophthalmology & visual science (Impact Factor: 3.4). 11/2010; 51(12):6614-9. DOI: 10.1167/iovs.10-6195
Source: PubMed


To identify and evaluate the use of contrast agents in optical coherence tomography (OCT) for ophthalmic applications.
Three agents-prednisolone acetate (PA), triamcinolone acetonide (TA), and lipid-based artificial tears (LBAT)-were tested in cadaveric porcine eyes imaged with hand-held spectral-domain OCT (SD-OCT). Anterior segment imaging was performed in triplicate with each agent at three sites: corneal epithelial surface, corneal wound interface, and anterior chamber. OCT characteristics of the three agents at each ocular site were analyzed. Quantitative intensity (i.e., brightness) analysis was performed with image analysis software. Institutional review board approval was obtained for imaging in human subjects undergoing cataract surgery. PA was applied to the corneal surface, and SD-OCT imaging was performed of the corneal surface and wound interface immediately after cataract surgery.
All agents provided increased reflectivity. PA and LBAT showed a smooth bright reflectivity profile, whereas TA had a granular profile. Improved visualization of tissue interfaces was noted. Maximum and mean intensity of reflectance were higher for all agents compared with controls (P < 0.05). PA showed topical and wound interface contrast enhancement in human subjects after cataract surgery.
Significant OCT contrast enhancement was achieved with improved visualization of tissue interfaces. Each agent had a unique reflectivity profile. Future applications of OCT contrast agents might include evaluation of wound stability, intraocular fluidics, and ocular surface disease.

Full-text preview

Available from:
  • Source
    • "Specifically, the use of swept-source lasers will permit superior imaging to the deeper regions of the angle, including schlemn's canal. Furthermore, advances in Doppler imaging, such as dual beam Doppler OCT [17], [18], permit Doppler measurements without the dependence on incidence angle of single beam systems. "
    [Show abstract] [Hide abstract]
    ABSTRACT: To investigate gold nanorods (GNRs) as a contrast agent to enhance Doppler optical coherence tomography (OCT) imaging of the intrascleral aqueous humor outflow. A serial dilution of GNRs was scanned with a spectral-domain OCT device (Bioptigen, Durham, NC) to visualize Doppler signal. Doppler measurements using GNRs were validated using a controlled flow system. To demonstrate an application of GNR enhanced Doppler, porcine eyes were perfused at constant pressure with mock aqueous alone or 1.0×1012 GNR/mL mixed with mock aqueous. Twelve Doppler and volumetric SD-OCT scans were obtained from the limbus in a radial fashion incremented by 30°, forming a circular scan pattern. Volumetric flow was computed by integrating flow inside non-connected vessels throughout all 12 scans around the limbus. At the GNR concentration of 0.7×1012 GNRs/mL, Doppler signal was present through the entire depth of the testing tube without substantial attenuation. A well-defined laminar flow profile was observed for Doppler images of GNRs flowing through the glass capillary tube. The Doppler OCT measured flow profile was not statistically different from the expected flow profile based upon an autoregressive moving average model, with an error of -0.025 to 0.037 mm/s (p = 0.6435). Cross-sectional slices demonstrated the ability to view anterior chamber outflow ex-vivo using GNR-enhanced Doppler OCT. Doppler volumetric flow measurements were comparable to flow recorded by the perfusion system. GNRs created a measureable Doppler signal within otherwise silent flow fields in OCT Doppler scans. Practical application of this technique was confirmed in a constant pressure ex-vivo aqueous humor outflow model in porcine eyes.
    Full-text · Article · Mar 2014 · PLoS ONE
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Optical coherence tomography (OCT) has transformed diagnostic ophthalmic imaging but until recently has been limited to the clinic setting. The development of spectral-domain OCT (SD-OCT), with its improved speed and resolution, along with the development of a handheld OCT scanner, enabled portable imaging of patients unable to sit in a conventional tabletop scanner. This handheld SD-OCT unit has proven useful in examinations under anesthesia and, more recently, in intraoperative imaging of preoperative and postoperative manipulations. Recently, several groups have pioneered the development of novel OCT modalities, such as microscope-mounted OCT systems. Although still immature, the development of these systems is directed toward real-time imaging of surgical maneuvers in the intraoperative setting. This article reviews intraoperative imaging of the posterior and anterior segment using the handheld SD-OCT and recent advances toward real-time microscope-mounted intrasurgical imaging.
    Full-text · Article · Jul 2011 · Ophthalmic Surgery Lasers and Imaging
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the use of microscope mounted spectral domain optical coherence tomography (SD-OCT) to detect changes in retinal anatomy during macular surgery. Retrospective, observational case series. We included 25 eyes of 24 consecutive patients who underwent SD-OCT during macular surgery. A retrospective review of operative techniques, outcomes, and imaging for all patients who underwent intraoperative microscope mounted SD-OCT during surgery for macular hole or epiretinal membrane (ERM) from April 2009 to April 2010 was performed. Qualitative and quantitative characteristics of intraoperative and postoperative changes in retinal anatomy were studied. Intraoperative change in macular hole dimensions and retinal thickness in patients with ERM owing to surgical manipulation measured using SD-OCT. Intraoperative SD-OCT from 13 eyes of 13 patients undergoing surgery for macular hole was reviewed. Two cases had images of suboptimal quality and were excluded. The remaining 11 eyes were subjected to quantitative analysis, which revealed stability of macular hole height and central hole diameter after internal limiting membrane (ILM) peeling, but an increase in the diameter of subretinal fluid under the macula in ten of 11 eyes (average 87% wider). Intraoperative imaging from 12 eyes of 11 patients undergoing surgery for ERM was analyzed. Quantitative analysis revealed an average increase of retinal thickness after ILM peel of <2%. Ten of 12 eyes developed a new subretinal hyporeflectance, which likely represents shallow detachment of the macula, after uncomplicated membrane peel. Use of intraoperative SD-OCT has provided new insight into the changes to retinal anatomy during macular surgery and may prove to be a useful tool for vitreoretinal surgery. Further study is warranted to determine whether intraoperative changes such as the creation of shallow retinal detachments during uncomplicated macular surgery affects visual recovery. Proprietary or commercial disclosure may be found after the references.
    No preview · Article · Sep 2011 · Ophthalmology
Show more