Confocal Optical Coherence Tomography Research Articles

From Clinical Suspicion to Diagnosis: A Review of Diagnostic Approaches and Challenges in Fungal Keratitis.

Fungal keratitis is a relatively rare yet severe ocular infection that can lead to profound vision impairment and even permanent vision loss. Rapid and accurate diagnosis plays a crucial role in the effective management of the disease. A patient's history establishes the initial clinical suspicion since it can provide valuable clues to potential predisposing factors and sources of fungal exposure. Regarding the evaluation of the observed symptoms, they are not exclusive to fungal keratitis, but their timeline can aid in distinguishing fungal keratitis from other conditions. Thorough clinical examination of the affected eye with a slit-lamp microscope guides diagnosis because some clinical features are valuable predictors of fungal keratitis. Definitive diagnosis is established through appropriate microbiological investigations. Direct microscopic examination of corneal scrapings or biopsy specimens can assist in the presumptive diagnosis of fungal keratitis, but culture remains the gold standard for diagnosing fungal keratitis. Advanced molecular techniques such as PCR and MALDI-ToF MS are explored for their rapid and sensitive diagnostic capabilities. Non-invasive techniques like in vivo confocal microscopy (IVCM) and optical coherence tomography (OCT) are useful for real-time imaging. Every diagnostic technique has both advantages and drawbacks. Also, the selection of a diagnostic approach can depend on various factors, including the specific clinical context, the availability of resources, and the proficiency of healthcare personnel.

Fluorescence imaging for the anterior segment of the eye

Diagnostic technologies for the anterior segment of the eye, especially for hard-to-diagnose diseases such as microbial keratitis, are still lacking. Although in vivo confocal microscopy and optical coherence tomography are becoming more widely applicable to a variety of conditions, they are often prohibitively expensive, require specialized training and equipment, and are intrinsically insensitive to chemical changes. Here, ultraviolet-fluorescence imaging is proposed as a new technique to aid in investigation of the anterior segment. In this work, a novel two-color line-of-sight fluorescence imaging technique is described for imaging of the anterior segment. The technique is applied to seven ex vivo porcine eyes to illustrate the utility of the technique. The image data was used to estimate an effective fluorescence quantum yield of each eye at 370 nm. The eyes were then inoculated with bacteria to simulate microbial keratitis, a common sight-threatening infection, and the measurement was repeated. A simplified fluorescence-extinction model was developed to describe and analyze the relative intensities of the eye and biofilm fluorescence. Overall, the technique appears to have utility in clinical practice and with proper development may be suitable for detecting chemical changes in the eye, or the presence of foreign matter; however, further investigation is needed to develop the technique and analysis procedures into a quantitative diagnostic tool.

A-414 - First description of atypical fibroxanthoma in Line-Field Confocal Optical Coherence Tomography and comparison with Reflectance Confocal Microscopy

A-414 - First description of atypical fibroxanthoma in Line-Field Confocal Optical Coherence Tomography and comparison with Reflectance Confocal Microscopy

Line-field confocal optical coherence tomography of eyelid margin growths: A case series.

The clinical differential diagnosis of lesions arising on the eyelid margin may be challenging and an unneeded surgical approach may have serious functional and aesthetic consequences. Nonetheless, early recognition and treatment of malignant tumors of the eyelid margin is mandatory. Line-field confocal optical coherence tomography (LC-OCT) is a novel tool for the in vivo, real-time skin imaging. The aim of the study was to identify and analyze the LC-OCT features of a series of eyelid margin growths and to correlate these features with the histopathological findings. Patients with eyelid margin growths who were scheduled for lesion excision underwent LC-OCT examination. Inclusion criteria were a challenging clinical aspect of the lesions and a clinical history of recent onset (up to 12 months). In all cases, the histopathological examination of the excised lesions was performed for the final diagnosis. A total of 31 lesions located on the upper (13 cases) or lower (18 cases) eyelid margin from 28 consecutive patients (male=15, female=13; mean age: 64.7 years, range: 44-87 years) were evaluated and excised. The histopathologic diagnoses were nodular basal cell carcinoma (BCC) (nine cases), squamous cell carcinoma (SCC) (three cases), compound nevus (four cases), dermal nevus (two cases), seborrheic keratosis (four cases), pyogenic granuloma (one case), trichilemmal cyst (three cases), and hidrocystoma (five cases). LC-OCT allowed the in vivo recognition of the main microscopic features of the examined lesions. LC-OCT represents a promising tool for the evaluation of eyelid margin lesions. Advantages of non-invasive diagnosis particularly relevant in such a sensitive region include a more correct planning of the treatment and, in case of surgery, the most appropriate surgical approach and, importantly, a correct timing of intervention.

A-279 - Assessment of facial pigmented lesions using Line-field Confocal Optical Coherence Tomography and its correlation with Reflectance Confocal Microscopy and histopathology

A-279 - Assessment of facial pigmented lesions using Line-field Confocal Optical Coherence Tomography and its correlation with Reflectance Confocal Microscopy and histopathology

Fungal Keratitis. Part 2. Diagnosis and Treatment

The problem of diagnosis and treatment of fungal keratitis (FK) is very acute. Due to the slow development of clinical features and the absence of clear pathognomonic signs, this disease is characterized by a late start of the introduction of adequate etiotropic therapy. Often this leads to the development of large corneal defects requiring surgical intervention. Diagnostic methods are divided into invasive and non-invasive. Invasive methods include the study of scrapings from the surface of the cornea from the site of ulceration, biopsy of the corneal stroma or moisture of the anterior chamber using microscopic, cultural methods or polymerase chain reaction (PCR). Non-invasive techniques include confocal microscopy and optical coherence tomography of the anterior segment. They allow you to dynamically monitor the course of the pathological process and the response to ongoing therapy. Promising methods are also the detection of (1,3)-β-D-glucans in tears, the detection of the pathogen using MALDI-TOF MS. The gold standard for the treatment of FK in the world is the topical application of 5 % Natamycin (approved by the FDA, but not available in Russia). Fluconazole, Voriconazole and Amphotericin B, available in Russia, are also widely used, but their topical use is possible only in off label format. In the presence of hypopyon or an increase in the size and depth of the infiltrate, despite ongoing treatment, immediate surgical treatment is required in order to preserve the integrity of the eyeball. Such treatments include penetrating keratoplasty, anterior lamellar keratoplasty, amniotic membrane transplantation, conjunctival flaps, corneal collagen cross-linking (with unproven efficacy), and argon laser. A promising method for the treatment of FK can be the use of Ag(10 %):InP/ZnS MPA quantum dots as monotherapy or as a bioconjugate with known antifungal drugs.

Understanding the anatomy of dermoscopy of melanocytic skin tumours: Correlation invivo with line-field optical coherence tomography.

Early melanoma detection is the main factor affecting prognosis and survival. For that reason, non-invasive technologies have been developed to provide a more accurate diagnosis. Recently, line-field confocal optical coherence tomography (LC-OCT) was developed to provide an invivo, imaging device, with deep penetration and cellular resolution in three dimensions. Combining the advantages of conventional OCT and reflectance confocal microscopy, this tool seems to be particularly suitable for melanocytic lesions. The objective of this study was to identify and describe the correlation between specific dermoscopic criteria and LC-OCT features in three dimensions associated with melanocytic lesions. Dermoscopic and LC-OCT images of 126 melanocytic lesions were acquired in three different centres. The following dermoscopic criteria have been considered: reticular pattern, dots and globules, structureless areas, blue-whitish veil, regression structures, negative network, homogeneous pattern, streaks and blotches. 69 (55%) benign and 57 (45%) malignant lesions were analysed. A regular reticular pattern was found associated in the 75% of the cases with the presence of elongated rete ridges with pigmented cells along the basal layer, while atypical reticular pattern showed an irregular organization of rete ridges with melanocytic hyperplasia, broadened and fused ridges and elongated nests. Both typical and atypical dots and globules were found associated with melanocytic nests in the dermis or at the dermoepidermal junction (DEJ), as well as with keratin cysts/pseudocysts. Grey globules corresponded to the presence of melanin-containing dermal inflammatory cells (melanophages) within the papillae. Structureless brown/black areas correlated with alterations of the DEJ. We observed the same DEJ alterations, but with the presence of dermal melanophages, in 36% of the cases of blue/white/grey structureless areas. A description of each LC-OCT/dermoscopy correlation was made. LC-OCT permitted for the first time to perform an invivo, 3D correlation between dermoscopic criteria and pathological-like features of melanocytic lesions.

Line-field confocal optical coherence tomography for in vivo visualization of morphological characteristics of squamous cell carcinoma in a murine model.

Non-invasive imaging with line-field confocal optical coherence tomography (LC-OCT) can support the diagnosis of squamous cell carcinoma (SCC) through visualization of morphological characteristics specific to skin cancer. We aimed to visualize prominent morphological characteristics of SCC using LC-OCT in a well-established murine SCC model. Nine hairless mice were exposed to ultraviolet radiation three times weekly for 9 months to induce SCC development. Visible SCC tumors (n = 9) were imaged with LC-OCT and the presence of 10 well-described morphological characteristics of SCC were evaluated in the scans by two physicians with adjudication by a third. Overall, murine morphological characteristics resembled corresponding features previously reported in human SCCs. Interrupted dermal-epidermal junction occurred in 100% of tumors. In epidermis, the most frequently observed characteristics were severe epidermal dysplasia (100%) and tumor budding (89%). Common dermal characteristics included broad strands (100%) and collagen alterations (78%). LC-OCT imaging can be used to non-invasively visualize morphological characteristics specific to SCC in an in vivo preclinical model.

Line-field confocal optical coherence tomography (LC-OCT) features of a melanotic macule of the lip

Line-field confocal optical coherence tomography (LC-OCT) features of a melanotic macule of the lip

Preoperative evaluation of high-risk basal cell carcinoma with line-field confocal optical coherence tomography (LC-OCT) reduces Mohs micrographic surgery stage number: A case-control study

BackgroundMohs micrographic surgery (MMS) is the preferred surgical approach for high-risk basal cell carcinoma (BCC). Pre-surgical tumor margins delineation with line field confocal optical coherence tomography (LC-OCT) is expected to reduce MMS stages number. Objectiveto investigate the effectiveness of LC-OCT preoperative evaluation of high-risk BCC margins in reducing the number of MMS stages to achieve tumor clearance. Patients and methodshigh-risk BCC patients undergoing MMS at Policlinico A. Gemelli Foundation, IRCCS – Rome during January 2018 – December 2022. The LC-OCT group included patients undergoing preoperative lateral tumor margin demarcation by clinical, dermoscopic, and LC-OCT examination; patients in the control group underwent preoperative lateral tumor margin demarcation by clinical and dermoscopic examination only. LC-OCT imaging was compared to MMS histopathological sections. Results63 facial high-risk BCCs from 60 patients, mean age of 68.3 years (SD 11.9). The LC-OCT and the control group included 22 and 41 BCCs, respectively. LC-OCT imaging showed almost perfect agreement with histopathology for low- versus high-risk of recurrence BCC histopathological subtypes discrimination (Cohen’s kappa 0.88). We reported a significant difference in the mean number of MMS stages between the LC-OCT and the control group (1.23 ± 0.43 SD, and 1.89 ± 1.05 SD, respectively; p-value =0.007). At univariate regression analysis, LC-OCT preoperative mapping of BCC tumor margins significantly reduced patients’ risk of undergoing >1 MMS stage (crude odds ratio [ORc]: 0.3 95% CI 0.1–0.8, p-value =0.032). ConclusionLC-OCT preoperative evaluation of high-risk BCC margins significantly reduced the number of MMS stages to achieve tumor clearance.

Line-Field Confocal Optical Coherence Tomography Evaluation of Eyelid Skin Lesions

Background: Periocular malignancies may be clinically different from the examples arising at other sites, with possible delayed diagnosis and greater challenges for treatment and repair. Line-field confocal optical coherence tomography (LC-OCT) is a recently developed technique characterized by an unprecedented capacity to acquire high-definition images in vertical and horizontal modes. In this study, we aimed to investigate the LC-OCT morphological features of a series of eyelid skin lesions, correlating them to histopathological findings. Methods: Patients with biopsy-proven equivocal skin lesion in the eyelid area, previously investigated by means of LC-OCT, were included in the study. Percentage overall agreement was estimated for LC-OCT and histopathological diagnosis for study cases. Results: A total of 51 patients (28 women, 23 men; mean age 66.4 years old), for a total of 51 skin lesions, were assessed. The histopathological diagnosis consisted of 30 malignant and 21 benign tumors. Different entities were characterized by peculiar findings in LC-OCT, alike to histopathological features, allowing for an accurate “in vivo” classification in almost all cases, with a diagnostic concordance with histopathology of 92.1% (47/51). Conclusions: By integrating this new imaging technique into the assessment of suspicious tumors in this area, diagnostic accuracy may increase, improving strategies adopted in multidisciplinary meetings and patient-centered care.

Development of a sebo-psoriasis-like dermatosis: a newly paradoxical reaction due to ixekizumab described with line-field confocal optical coherence tomography.

Development of a sebo-psoriasis-like dermatosis: a newly paradoxical reaction due to ixekizumab described with line-field confocal optical coherence tomography.

Line-Field Confocal Optical Coherence Tomography (LC-OCT) for Skin Imaging in Dermatology.

Line-field confocal optical coherence tomography (LC-OCT) is a non-invasive optical imaging technique based on a combination of the principles of optical coherence tomography and reflectance confocal microscopy with line-field illumination, which can generate cell-resolved images of the skin in vivo. This article reports on the LC-OCT technique and its application in dermatology. The principle of the technique is described, and the latest technological innovations are presented. The technology has been miniaturized to fit within an ergonomic handheld probe, allowing for the easy access of any skin area on the body. The performance of the LC-OCT device in terms of resolution, field of view, and acquisition speed is reported. The use of LC-OCT in dermatology for the non-invasive detection, characterization, and therapeutic follow-up of various skin pathologies is discussed. Benign and malignant melanocytic lesions, non-melanocytic skin tumors, such as basal cell carcinoma, squamous cell carcinoma and actinic keratosis, and inflammatory and infectious skin conditions are considered. Dedicated deep learning algorithms have been developed for assisting in the analysis of LC-OCT images of skin lesions.

Immediate diagnosis of cutaneous metastases with optical coherence tomography, line‐field confocal optical coherence tomography and dermoscopy: A case series

AbstractBackgroundCutaneous metastases (CM) are a frequent finding in the follow‐up of malignant tumours.ObjectivesCM were examined with dermoscopy, optical coherence tomography (OCT), dynamic OCT and line‐field confocal OCT (LC‐OCT) to describe common findings.MethodsIn the University Hospital Carl Gustav Carus Dresden, Germany, 18 patients with 61 CM were examined with dermoscopy. CM (n = 43, 31 melanoma metastases, two metastases of renal carcinoma, five metastases of cutaneous squamous cell carcinoma and five metastases of pleomorphic dermal sarcoma) were examined with OCT (VivoSight® Michelson Diagnostics). Additional 18 melanoma metastases were examined with LC‐OCT (deepLive™; Damae Medical).ResultsCM were localized on the head, trunk, neck and limbs. Dermoscopy patterns were angioma‐like, nevus‐like nonglobular, nevus‐like globular, blue nevus‐like and unspecific. CM showed an ulceration, hyperkeratosis with increased entrance signal and disturbed architecture of the epidermis in OCT. In deeper metastases, the dermoepidermal junction (DEJ) was normal; in most cases it was disturbed. CM were visible as subepidermal hyporeflective roundish area, with septae, with either clear margin and shadowing or blurred margin. DOCT showed dot, coiled, serpiginous and branched vessels; there was a disarray in size and distribution and vessels were converging on the centre of the metastasis. In LC‐OCT, CM showed enhanced entrance signal and disturbed architecture of a thinned epidermis, ulceration, atypical honeycomb or cobblestone pattern as well as a broken DEJ. In the dermis, a hyporeflective roundish area with clusters of hyporeflective cells with septae, clear margin and clefting or blurred margin was visible; the hyporeflective area was surrounded by bundles of connective tissue. Subepidermal vessels differentiated in size and distribution. Inflammatory, dendritic and pagetoid cells were visible.ConclusionsOCT and LC‐OCT may be useful tools for immediate diagnosis, localization of CM and monitoring under treatment in addition to conventional methods like ultrasound and histopathology.

Line-field confocal optical coherence tomography: New insights for psoriasis treatment monitoring.

Line-field confocal optical coherence tomography (LC-OCT) is a new, valid means for a rapid and non-invasive invivo examination of the epidermis and upper dermis, allowing digital interpretation and measurement of high-resolution images on a cellular level. Given these properties, it may represent a valid tool for monitoring psoriasis during treatment, allowing a new method to set a precise objective severity of the disease. We aimed to investigate the potentialities of LC-OCT in the non-invasive monitoring of microscopical changes associated with moderate-severe plaque psoriasis (PP) during the treatment with the most common biological drugs. We performed LC-OCT imaging of PP lesions from 17 patients before and after 8 weeks of treatment. The clinical severity of the single lesions was evaluated using a lesion score (LS), designed considering three parameters: erythema, desquamation and infiltration. LC-OCT images were segmented by artificial intelligence and evaluated based on three microscopic criteria: the thickness of the stratum corneum, the thickness of the living epidermis and the undulation of the dermo-epidermal junction. Line-field confocal optical coherence tomography digital analysis allowed recognition and quantification of the three microscopic criteria, showing a reduction of all these during the follow-up. Furthermore, a high correlation between change in LS and the thickness of the stratum corneum and the thickness of the living epidermis was found. Line-field confocal optical coherence tomography can non-invasively monitor the response of PP to different treatments. Morphometric changes occurring in the psoriatic lesion during the 8-week treatment period were identified by invivo LC-OCT and measured by using artificial intelligence. Although future studies are required, based on these preliminary results, LC-OCT may represent a valid potential tool for precise monitoring of therapeutic response.

Line-Field Confocal Optical Coherence Tomography for the Diagnosis of Skin Carcinomas: Real-Life Data over Three Years.

Line-field confocal optical coherence tomography (LC-OCT) can help the clinical diagnosis of skin diseases. The present study aimed to evaluate the sensitivity, specificity, and diagnostic accuracy of LC-OCT for the diagnosis of the most frequent non-melanoma skin cancers (NMSCs), i.e., basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Comparing LC-OCT diagnostic performances with those of dermoscopy, histopathological examination was used as a gold standard. For every study endpoint, the diagnostic ability of LC-OCT revealed superiority over the dermoscopic examination. In particular, a significant increase in specificity was observed. Sensitivity, specificity, and diagnostic accuracy of dermoscopy and LC-OCT for the diagnosis of malignancy were, respectively, 0.97 (CI 0.94-0.99), 0.43 (CI 0.36-0.51), and 0.77 (CI 0.72-0.81) for dermoscopy and 0.99 (CI 0.97-1.00), 0.90 (CI 0.84-0.94), and 0.96 (CI 0.93-0.97) for LC-OCT. The positive predictive value (PPV) resulted in 0.74 (CI 0.69-0.78) for dermoscopy and 0.94 (CI 0.91-0.97) for LC-OCT, and the negative predictive value (NPV) was 0.89 (CI 0.81-0.95) for dermoscopy and 0.98 (CI 0.95-1.00) for LC-OCT. Finally, our real-life study showed a potentially important role of LC-OCT in the non-invasive diagnosis of NMSCs, especially BCC. The real-time imaging technique could spare unnecessary biopsies with an increased sensitivity, a much higher specificity, and better accuracy than clinical assessment with dermoscopy alone.

Artificial intelligence-based PRO score assessment in actinic keratoses from LC-OCT imaging using Convolutional Neural Networks.

The histological PRO score (I-III) helps to assess the malignant potential of actinic keratoses (AK) by grading the dermal-epidermal junction (DEJ) undulation. Line-field confocal optical coherence tomography (LC-OCT) provides non-invasive real-time PRO score quantification. From LC-OCT imaging data, training of an artificial intelligence (AI), using Convolutional Neural Networks (CNNs) for automated PRO score quantification of AK in vivo may be achieved. CNNs were trained to segment LC-OCT images of healthy skin and AK. PRO score models were developed in accordance with the histopathological gold standard and trained on a subset of 237 LC-OCT AK images and tested on 76 images, comparing AI-computed PRO score to the imaging experts' visual consensus. Significant agreement was found in 57/76 (75%) cases. AI-automated grading correlated best with the visual score for PROII (84.8%) vs. PROIII (69.2%) vs. PROI (66.6%). Misinterpretation occurred in 25% of the cases mostly due to shadowing of the DEJ and disruptive features such as hair follicles. The findings suggest that CNNs are helpful for automated PRO score quantification in LC-OCT images. This may provide the clinician with a feasible tool for PRO score assessment in the follow-up of AK.

Innovation in Actinic Keratosis Assessment: Artificial Intelligence-Based Approach to LC-OCT PRO Score Evaluation.

Actinic keratosis (AK) is a common skin cancer in situ that can progress to invasive SCC. Line-field confocal optical coherence tomography (LC-OCT) has emerged as a non-invasive imaging technique that can aid in diagnosis. Recently, machine-learning algorithms have been developed that can automatically assess the PRO score of AKs based on the dermo-epidermal junction's (DEJ's) protrusion on LC-OCT images. A dataset of 19.898 LC-OCT images from 80 histologically confirmed AK lesions was used to test the performance of a previous validated artificial intelligence (AI)-based LC-OCT assessment algorithm. AI-based PRO score assessment was compared to the imaging experts' visual score. Additionally, undulation of the DEJ, the number of protrusions detected within the image, and the maximum depth of the protrusions were computed. Our results show that AI-automated PRO grading is highly comparable to the visual score, with an agreement of 71.3% for the lesions evaluated. Furthermore, this AI-based assessment was significantly faster than the regular visual PRO score assessment. The results confirm our previous findings of the pilot study in a larger cohort that the AI-based grading of LC-OCT images is a reliable and fast tool to optimize the efficiency of visual PRO score grading. This technology has the potential to improve the accuracy and speed of AK diagnosis and may lead to better clinical outcomes for patients.

Line-field confocal optical coherence tomography coupled with artificial intelligence algorithms to identify quantitative biomarkers of facial skin ageing

Quantitative biomarkers of facial skin ageing were studied from one hundred healthy Caucasian female volunteers, aged 20–70 years, using in vivo 3D Line-field Confocal Optical Coherence Tomography (LC-OCT) imaging coupled with Artificial Intelligence (AI)-based quantification algorithms. Layer metrics, i.e. stratum corneum thickness (SC), viable epidermal thickness and Dermal–Epidermal Junction (DEJ) undulation, as well as cellular metrics were measured for the temple, cheekbone and mandible. For all three investigated facial areas, minimal age-related variations were observed in the thickness of the SC and viable epidermis layers. A flatter and more homogeneous epidermis (decrease in the standard deviation of the number of layers means), a less dense cellular network with fewer cells per layer (decrease in cell surface density), and larger and more heterogeneous nuclei within each layer (increase in nuclei volume and their standard deviation) were found with significant variations with age. The higher atypia scores further reflected the heterogeneity of nuclei throughout the viable epidermis. The 3D visualisation of fine structures in the skin at the micrometric resolution and the 1200 µm × 500 µm field of view achieved with LC-OCT imaging enabled to compute relevant quantitative biomarkers for a better understanding of skin biology and the ageing process in vivo.

Metabolic changes and retinal remodeling in Heterozygous CRX mutant cats (CRXRDY/+)

CRX is a transcription factor essential for normal photoreceptor development and survival. The CRXRdy cat has a naturally occurring truncating mutation in CRX and is a large animal model for dominant Leber congenital amaurosis. This study investigated retinal remodeling that occurs as photoreceptors degenerate. CRXRdy/+ cats from 6 weeks to 10 years of age were investigated. In vivo structural changes of retinas were analyzed by fundus examination, confocal scanning laser ophthalmoscopy and spectral domain optical coherence tomography. Histologic analyses included immunohistochemistry for computational molecular phenotyping with macromolecules and small molecules. Affected cats had a cone-led photoreceptor degeneration starting in the area centralis. Initially there was preservation of inner retinal cells such as bipolar, amacrine and horizontal cells but with time migration of the deafferented neurons occurred. Early in the process of degeneration glial activation occurs ultimately resulting in formation of a glial seal. With progression the macula-equivalent area centralis developed severe atrophy including loss of retinal pigmentary epithelium. Microneuroma formation occured in advanced stages as more marked retinal remodeling occurred. This study indicates that retinal degeneration in the CrxRdy/+ cat retina follows the progressive, phased revision of retina that have been previously described for retinal remodeling. These findings suggest that therapy dependent on targeting inner retinal cells may be useful in young adults with preserved inner retinas prior to advanced stages of retinal remodeling and neuronal cell loss.