Intraoperative 4-Dimensional Microscope-Integrated Optical Coherence Tomography-Guided 27-Gauge Transvitreal Choroidal Biopsy for Choroidal Melanoma

Visualization of Cataract Surgery Steps With 4D Microscope-Integrated Swept-Source Optical Coherence Tomography in Ex Vivo Porcine Eyes

Purpose

To investigate the visualization capabilities of high-speed swept-source optical coherence tomography (SS-OCT) in cataract surgery.

Methods

Cataract surgery was simulated in wet labs with ex vivo porcine eyes. Each phase of the surgery was visualized with a novel surgical microscope-integrated SS-OCT with a variable imaging speed of over 1 million A-scans per second. It was designed to provide four-dimensional (4D) live-volumetric videos, live B-scans, and volume capture scans.

Results

Four-dimensional videos, B-scans, and volume capture scans of corneal incision, ophthalmic viscosurgical device injection, capsulorrhexis, phacoemulsification, intraocular lens (IOL) injection, and position of unfolded IOL in the capsular bag were recorded. The flexibility of the SS-OCT system allowed us to tailor the scanning parameters to meet the specific demands of dynamic surgical steps and static pauses. The entire length of the eye was recorded in a single scan, and unfolding of the IOL was visualized dynamically.

Conclusions

The presented novel visualization method for fast ophthalmic surgical microscope-integrated intraoperative OCT imaging in cataract surgery allowed the visualization of all major steps of the procedure by achieving large imaging depths covering the entire eye and high acquisition speeds enabling live volumetric 4D-OCT imaging. This promising technology may become an integral part of routine and advanced robotic-assisted cataract surgery in the future.

Translational Relevance

We demonstrate the visualization capabilities of a cutting edge swept-source OCT system integrated into an ophthalmic surgical microscope during cataract surgery.

Methods for real-time feature-guided image fusion of intrasurgical volumetric optical coherence tomography with digital microscopy

4D-microscope-integrated optical coherence tomography (4D-MIOCT) is an emergent multimodal imaging technology in which live volumetric OCT (4D-OCT) is implemented in tandem with standard stereo color microscopy. 4D-OCT provides ophthalmic surgeons with many useful visual cues not available in standard microscopy; however it is challenging for the surgeon to effectively integrate cues from simultaneous-but-separate imaging in real-time. In this work, we demonstrate progress towards solving this challenge via the fusion of data from each modality guided by segmented 3D features. In this way, a more readily interpretable visualization that combines and registers important cues from both modalities is presented to the surgeon.

Evaluation of optical coherence tomography (OCT) changes following transretinal tumour biopsy for choroidal melanoma

AIM

This study uses OCT imaging to examine morphological changes at the chorioretinal interface of the choroidal melanoma biopsy site over time.

SETTING

Liverpool Ocular Oncology Centre (LOOC), St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom.

METHODOLOGY

Retrospective analysis of all patients who underwent 25G vitrector-assisted transretinal biopsy for choroidal melanoma between 1st Jan 2017 and 31st Dec 2019. The biopsy procedure does not involve full vitrectomy, treatment of the retinal hole or tamponade. Patients routinely undergo OCT imaging over the tumour site at each follow up. Cases required a minimum of a baseline OCT and two consecutive post-operative OCT scans of adequate quality, overlying the biopsy site. All images were reviewed and graded by an ophthalmic specialist.

RESULTS

Fifty-one patients met the criteria for inclusion. OCT analysis identified 2 characteristic morphologies following transretinal biopsy -a choroidal plugging of biopsy site (47.0%), or a flat retinal hole (53.0%). Choroidal plugging morphologies tend to remain unchanged over time, whereas flat holes demonstrate greater variability and would more commonly seal over with atrophic retina (Fisher Exact Value = <0.01). 60.8% demonstrated vitreous plugging of the biopsy site.

CONCLUSION

OCT analysis has identified key morphological changes following transretinal choroidal melanoma biopsy. The morphologies identified may provide dynamic protective effects against vitreous flow into the subretinal space, accounting for low rates of retinal detachment despite the presence of an untreated iatrogenic retinal hole following transretinal biopsy.

Importance of Optical Coherence Tomography and Optical Coherence Tomography Angiography in the Imaging and Differentiation of Choroidal Melanoma: A Review

Simple Summary

Choroidal melanoma is a highly malignant intraocular neoplasm. It is the most prevalent intraocular tumor in adults and it derives from melanocytes; the liver is the most common site of its metastases. An early and noninvasive diagnosis is essential to enhance patients’ chances for early treatment. The OCT and OCTA-A are a noninvasive and noncontact methods used in the diagnostic process and support therapeutic decisions during control visits. These devices allow for detection and the real-time imaging of choroidal melanoma and its differentiation from metastasis and choroidal nevi. In addition to analyzing the currently utilized OCT and OCT-A methods, this review describes also the anatomy and imaging of specific vascular layers of the eye.

Abstract

Choroidal melanoma requires reliable and precise clinical examination and diagnosis to differentiate it from benign choroidal nevi. To achieve accurate diagnosis, as well as monitoring the progression of disease, various imaging modalities are used, including non-invasive optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). This review begins with a historical account of the development of OCT and OCTA and the methods of generation of images. This outlines the understanding of what OCT/OCTA images show, as well as how image artifacts arise. The anatomy and imaging of specific vascular layers of the eye are introduced. Then, anatomical aspects of choroidal melanoma, its diagnosis and differentiation from metastasis, and choroidal nevi are presented. The purpose of this review is to critically evaluate application of OCT and OCTA in the diagnosis of choroidal melanoma.

A Review of Robotic and OCT-Aided Systems for Vitreoretinal Surgery

The introduction of the intraocular vitrectomy instrument by Machemer et al. has led to remarkable advancements in vitreoretinal surgery enabling the limitations of human physiologic capabilities to be reached. To overcome the barriers of perception, tremor, and dexterity, robotic technologies have been investigated with current advancements nearing the feasibility for clinical use. There are four categories of robotic systems that have emerged through the research: (1) handheld instruments with intrinsic robotic assistance, (2) hand-on-hand robotic systems, (3) teleoperated robotic systems, and (4) magnetic guidance robots. This review covers the improvements and the remaining needs for safe, cost-effective clinical deployment of robotic systems in vitreoretinal surgery.

Intraoperative Optical Coherence Tomography Guided Ocular Surgeries: Critical Analysis of Clinical Role and Future Perspectives

Intraoperative imaging of ocular tissues for diagnostic and therapeutic applications has gained immense admiration in recent years. The real time cross-sectional imaging, as well as three and four dimensional reconstruction abilities of intraoperative optical coherence tomography (iOCT), has enhanced our knowledge on many fronts in surgical maneuvers. In this review, we discuss the iOCT discovered constructive knowledge in the cornea, cataract, refractive, glaucoma, pediatric ocular, and various retinal conditions. The practical utility with decision modifying aspects along the specified ocular tissues and with respect to specific ocular entities have been narrated. Moreover, limitations and future directions have also been emphasized to make ophthalmic care more comprehensive in the future.

What Is the Impact of Intraoperative Microscope-Integrated OCT in Ophthalmic Surgery? Relevant Applications and Outcomes. A Systematic Review

Background: Optical coherence tomography (OCT) has recently been introduced in the operating theatre. The aim of this review is to present the actual role of microscope-integrated optical coherence tomography (MI-OCT) in ophthalmology. Method: A total of 314 studies were identified, following a literature search adhering to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. After full-text evaluation, 81 studies discussing MI-OCT applications in ophthalmology were included. Results: At present, three microscope-integrated optical coherence tomography systems are commercially available. MI-OCT can help anterior and posterior segment surgeons in the decision-making process, providing direct visualization of anatomic planes before and after surgical manoeuvres, assisting in complex cases, and detecting or confirming intraoperative complications. Applications range from corneal transplant to macular surgery, including cataract surgery, glaucoma surgery, paediatric examination, proliferative diabetic retinopathy surgery, and retinal detachment surgery. Conclusion: The use of MI-OCT in ophthalmic surgery is becoming increasingly prevalent and has been applied in almost all procedures. However, there are still limitations to be overcome and the technology involved remains difficult to access and use.

Multi-center analysis of intraocular biopsy technique and outcomes for uveal melanoma: Ocular Oncology Study Consortium report 4

PURPOSE

To investigate the relationship between surgical approach for intraocular tumor biopsy of uveal melanoma and tumor morphologic features such as size and intraocular location and the effect of these variables on diagnostic yield and biopsy outcome.

METHODS

Consecutive patients from nine Ocular Oncology centers with uveal melanoma (UM) undergoing tumor biopsy immediately preceding I125 plaque brachytherapy with tissue sent for gene expression profiling (GEP) testing were reviewed retrospectively.

RESULTS

Three hundred sixty patients were included (50% men, mean age 60.2 years). Overall biopsy yield was 99% and 83% for GEP and cytopathology, respectively. Surgeon choice of biopsy approach (trans-vitreal vs. trans-scleral) was found to associate with both tumor location and tumor thickness. A trans-scleral rather than trans-vitreal approach was used more commonly for anteriorly located tumors (92% vs. 38% of posterior tumors, p < 0.001) and thicker tumors (86% vs. 55% of thin tumors, p < 0.001). When performing trans-vitreal biopsies, ocular oncologists with previous vitreoretinal surgery fellowship training were more likely to use wide-field surgical viewing systems, compared with indirect ophthalmoscopy (82.6% vs. 20.6%, p < 0.001). Surgical complications were rare and occurred more frequently with trans-vitreal biopsies (3.6% vs. 0.46%, p = 0.046).

CONCLUSIONS

In this multi-center analysis of UM tumor biopsy, surgical yield was high for obtaining tumor tissue for GEP and cytopathology analysis with both trans-scleral and trans-vitreal techniques. Fellowship-trained ocular oncologists' preferred intraocular biopsy techniques associated strongly with tumor location, tumor thickness, and fellowship training of the surgeon. Short-term complication rates were low.

Updates in imaging in ocular oncology

Innovations in ophthalmic imaging have made a profound impact on the diagnosis and treatment of ophthalmic disease. In ocular oncology, the development of optical coherence tomography with enhanced depth imaging and swept source technologies has made it possible to visualize the anatomical characteristics of retinoblastoma and uveal melanoma with a level of detail previously unobtainable on clinical exam alone. As a result, our understanding of the pathophysiology of vision loss in choroidal melanoma in particular has improved. These modalities have also helped identify fundoscopically “invisible” tumors and risk stratify pre-malignant choroidal lesions, making a strong case for their inclusion in all screening evaluations. Optical coherence tomography angiography, on the other hand, has allowed non-invasive imaging of the retinal and uveal vasculatures, providing insight into vascular changes associated with malignant transformation and vision loss following exposure to radiation. While the impact of new imaging technologies on clinical outcomes and overall survival in ocular oncology has yet to be determined, several reports cited herein offer promising results.

Outcomes of 27-Gauge Vitrectomy-Assisted Choroidal and Subretinal Biopsy

BACKGROUND AND OBJECTIVE

To report the initial experience of 27-gauge vitrectomy-assisted choroidal and subretinal biopsy PATIENTS AND METHODS: Retrospective, interventional case series. Eighteen eyes of 18 patients undergoing 27-gauge vitrectomy-assisted choroidal (n = 16) or subretinal biopsy (n = 2). Clinical and lesion characteristics, cytopathology, histology, gene expression profiling (GEP), visual acuity (VA), complications including vitreous hemorrhage (VH), development of rhegmatogenous retinal detachment (RD), and need for additional surgeries were analyzed.

RESULTS

Indications were choroidal melanoma (n = 10), indeterminate choroidal (n = 5), and subretinal lesions (n = 3). Mean lesion height was 3.33 mm ± 1.55 mm (range: 0.80 mm to 6.75 mm) and largest diameter was 8.63 mm ± 4.14 mm (range: 3 mm to 15.5 mm). Mean number of intralesional biopsy passes required was 1.76 ± 0.83 (range: one to four). During a mean follow-up of 7.4 months ± 2.7 months (range: 4 months to 14 months), VA was unchanged (0.5 logMAR ± 0.6 logMAR vs. 0.7 logMAR ± 0.84 logMAR; P = .07). Pathologic diagnosis was obtained in 16 of 18 eyes (88.9%), and GEP data were collected for all 11 choroidal melanomas. Post-biopsy VH occurred in 13 of 18 eyes (72.2%) and was severe enough to require a concurrent limited vitrectomy in six eyes (33.3%). These eyes had a greater lesion height compared to eyes not requiring a vitrectomy (4.08 mm ± 1.68 mm vs. 2.76 mm ± 1.43 mm; P = .04). A rhegmatogenous RD requiring repeat surgery developed in two of 18 eyes (11.1%).

CONCLUSION

The authors concluded that 27-gauge vitrectomy-assisted choroidal and subretinal biopsy established a diagnosis in 88.9% of eyes in lesions 0.8 mm or larger. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:406-415.].

Review of intraoperative optical coherence tomography: technology and applications [Invited]

During microsurgery, en face imaging of the surgical field through the operating microscope limits the surgeon's depth perception and visualization of instruments and sub-surface anatomy. Surgical procedures outside microsurgery, such as breast tumor resections, may also benefit from visualization of the sub-surface tissue structures. The widespread clinical adoption of optical coherence tomography (OCT) in ophthalmology and its growing prominence in other fields, such as cancer imaging, has motivated the development of intraoperative OCT for real-time tomographic visualization of surgical interventions. This article reviews key technological developments in intraoperative OCT and their applications in human surgery. We focus on handheld OCT probes, microscope-integrated OCT systems, and OCT-guided laser treatment platforms designed for intraoperative use. Moreover, we discuss intraoperative OCT adjuncts and processing techniques currently under development to optimize the surgical feedback derivable from OCT data. Lastly, we survey salient clinical studies of intraoperative OCT for human surgery.