Novel application of anterior segment optical coherence tomography for periocular imaging

ObjectiveThis study aims to assess the use of optical coherence tomography (OCT) imaging for periocular skin lesions and to determine which characteristic features of these images can be correlated to histopathology.DesignThis is an ongoing prospective study with Research Ethics Board approval.ParticipantsFifty patients over 18 years old with lesions clinically suspicious of nonmelanoma skin cancer on the periocular region were included in this study.MethodsAfter consent was obtained, clinical photographs and dermatoscopic images were obtained (DermLite II Hybrid M) from the lesion and its contralateral side. Subsequently, the patient was subjected to OCT imaging using the anterior segment module of a spectral domain OCT (Optovue Avanti) and images of the contralateral skin were also obtained. Surgical excision of the lesion was performed and sent for histopathological examination as per routine treatment. OCT images were then correlated to their matching digitalized histopathology section (Philips Ultra Fast Scanner 1.6 RA).ResultsBased on the OCT images acquired from 50 patients, 8 predominant architectural features have been correlated to histopathology: hyperkeratosis, acanthosis, loss of dermal-epidermal junction delineation, hyporeflective tumour nests, cystic structures, “bunch of grapes” nodules, hyperreflective nests, and ulcerations. Results observed from 45 malignant lesions (basal cell carcinoma, squamous cell carcinoma, and sebaceous gland carcinoma) suggest that groups of features and their layout within the same OCT image may be associated to specific tumour characteristics.ConclusionsCurrent data suggest that anterior-segment OCT imaging is a noninvasive imaging modality for periocular lesions and may be a valuable tool to help differentiate between some tumour types before a biopsy is performed.     

Spectral optical coherence tomography: a novel technique for cornea imaging

PURPOSE: Spectral optical coherence tomography (SOCT) is a new, noninvasive, noncontact, high-resolution technique that provides cross-sectional images of the objects that weakly absorb and scatter light. SOCT, because of very short acquisition time and high sensitivity, is capable of providing tomograms of substantially better quality than the conventional OCT. The aim of this paper is to show the application of the SOCT to cross-sectional imaging of the cornea and its pathologies. METHODS: Eleven eyes with different corneal pathologies were examined with a slit lamp and the use of a prototype SOCT instrument constructed in the Institute of Physics, Nicolaus Copernicus University, Toruń, Poland. RESULTS: Our SOCT system provides high-resolution (4 microm axial, 10 microm transversal) tomograms composed of 3000-5000 A-scans with an acquisition time of 120-200 ms. The quality of the images is adequate for detailed cross-sectional evaluation of various corneal pathologies. Objective assessment of the localization, size, shape, and light-scattering properties of the changed tissue is possible. Corneal and epithelial thickness and the depth and width of lesions can be estimated. CONCLUSION: SOCT technique allows acquiring clinically valuable cross-sectional optical biopsy of the cornea and its pathologies.     

Limitations of imaging choroidal tumors in vivo by optical coherence tomography

· Background: Optical coherence tomography (OCT) produces two-dimensional cross-sectional images with a longitudinal resolution of 10 μm. Its capacity for imaging retinal structure has been shown in a variety of diseases. There are no reports on its capacity and limitations in imaging choriocapillary and choroidal structures. · Methods: Twenty-two patients with the diagnosis of malignant melanoma of the choroid were submitted to OCT. We used a prototype and a commercial device, both with an 850-nm superluminescent diode with a bandwidth of 30 nm (reported longitudinal resolution 10 μm). The images were evaluated for retinal thickness, changes in retinal pigment epithelium, subretinal fluid accumulation and changes in choriocapillary or choroidal reflectivity. · Results: Retinal edema and detachment found on biomicroscopic examination for fluorescein angiography was detected by OCT in all such cases. In 2 of 22 cases small retinal detachments were detected only by OCT. Tumor extension through the retinal pigment epithelium was not seen in this series, either by biomicroscopy or by OCT. The pattern of choroidal or choriocapillary reflectivity was nonspecifically lower than that of normal choroid, but did not yield any additional information about tumor histology. When normal retina was present, the OCT appearance of a malignant melanoma resembled that of normal choroid. · Conclusion: OCT may provide information about the retinal structure overlying prominent tumors and the extent of adjacent retinal detachment. In its present state of development, OCT is of little value in the differential diagnosis of choroidal tumors. Its potential value for the follow-up of shallow tumors needs further investigation. Received: 19 March 1997 Revised version received: 18 August 1997 Accepted: 1 October 1997     

In vivo quantification of human aqueous veins by enhanced depth imaging optical coherence tomography and optical coherence tomography angiography images

AIM: To investigate the aqueous vein in vivo by using enhanced depth imaging optical coherence tomography (EDI-OCT) and optical coherence tomography angiography (OCTA). METHODS: In this cross-sectional comparative study, 30 healthy participants were enrolled. Images of the aqueous and conjunctival veins were captured by EDI-OCT and OCTA before and after water loading. The area, height, width, location depth and blood flow of the aqueous vein and conjunctival vein were measured by Image J software. RESULTS: In the static state, the area of the aqueous vein was 8166.7±3272.7 μm2, which was smaller than that of the conjunctival vein (13 690±7457 μm2, P<0.001). The mean blood flow density of the aqueous vein was 35.3%±12.6%, which was significantly less than that of the conjunctival vein (51.5%±10.6%, P<0.001). After water loading, the area of the aqueous vein decreased significantly from 8725.8±779.4 μm2 (baseline) to 7005.2±566.2 μm2 at 45min but rose to 7863.0±703.2 μm2 at 60min (P=0.032). The blood flow density of the aqueous vein decreased significantly from 41.2%±4.5% (baseline) to 35.4%±3.2% at 30min but returned to 45.6%±3.6% at 60min (P=0.021). CONCLUSION: The structure and blood flow density of the aqueous vein can be effectively evaluated by OCT and OCTA. These may become biological indicators to evaluate aqueous vein changes and aqueous outflow resistance under different interventions in glaucoma patients.     

'Fast-tracking' cancer referrals: application for periocular basal cell carcinoma

AIM: To study the feasibility of a modified fast-track protocol for periocular basal cell carcinoma (BCC). METHODS: A modified protocol was set up with an aim to examine all periocular BCCs within 6 weeks of referral to our oculoplastic clinic. An audit of this protocol was performed over a 2-year period. RESULTS: A total of 65 patients were referred as a 'possible BCC' over the 2-year period. In all, 32 of these patients were referred by dermatologists (49%), followed by fellow consultant ophthalmologists (20 patients, 31%) and general practitioners (11 patients, 17%). The clinical suspicion in the oculoplastic clinic agreed with the referral diagnosis in 71% (46 of the 65) of patients. This figure was particularly high for referrals from dermatologists (84%). In all, 44 out of the 46 'clinically suspected BCC' underwent surgical excision. Histopathology confirmed BCC in 39 of these 44 patients, a diagnostic accuracy of 89%. Among the subgroup of patients referred by the dermatologists, the largest source of referrals, 24 out of 30 patients that underwent surgical excision had histologically proven BCC; a diagnostic accuracy of 80%. CONCLUSION: Our study shows that the modified fast-track protocol for periocular BCCs is practical and feasible. Such a practice is highly desirable since it prevents a long wait for patients who are aware of a possible malignant periocular lesion.     

Three dimensional optical coherence tomography imaging: Advantages and advances

Three dimensional (3D) ophthalmic imaging using optical coherence tomography (OCT) has revolutionized assessment of the eye, the retina in particular. Recent technological improvements have made the acquisition of 3D-OCT datasets feasible. However, while volumetric data can improve disease diagnosis and follow-up, novel image analysis techniques are now necessary in order to process the dense 3D-OCT dataset. Fundamental software improvements include methods for correcting subject eye motion, segmenting structures or volumes of interest, extracting relevant data post hoc and signal averaging to improve delineation of retinal layers. In addition, innovative methods for image display, such as C-mode sectioning, provide a unique viewing perspective and may improve interpretation of OCT images of pathologic structures. While all of these methods are being developed, most remain in an immature state. This review describes the current status of 3D-OCT scanning and interpretation, and discusses the need for standardization of clinical protocols as well as the potential benefits of 3D-OCT scanning that could come when software methods for fully exploiting these rich datasets are available clinically. The implications of new image analysis approaches include improved reproducibility of measurements garnered from 3D-OCT, which may then help improve disease discrimination and progression detection. In addition, 3D-OCT offers the potential for preoperative surgical planning and intraoperative surgical guidance.     

Imaging the vitreous: optical coherence tomography and ultrasound imaging

Imaging the vitreous in optically transparent and translucent ocular media using OCT and in optically opaque ocular media using ultrasound is discussed.Optical coherence tomography and colour flow mapping are briefly described. Images of tomograms, B-mode sections, and colour flow maps illustrate the use of these techniques in imaging the vitreous.     

眼周基底细胞癌治疗方法研究进展

基底细胞癌（basal cell carcinoma,BCC）是眼睑最常见的恶性肿瘤,占所有眼睑恶性上皮肿瘤的90%,以下睑多见（50%）。BCC远处转移非常罕见,但易复发。虽然BCC死亡率低,如未及时诊治,可广泛破坏周围组织并向眶内浸润,甚至失明、容貌改变,影响患者的身心健康及生活质量。目前BCC的主要治疗方式包括手术治疗和非手术治疗,本文就目前常用的治疗方法做一综述。     

Extremely advanced basal cell carcinoma in periocular region: a case report

A case of extreme basal cell carcinoma affecting eyelids region in a 66-year old man is presented. Long time duration, large destruction of the face tissues and histopathological type of metatypic basal cell carcinoma (bcc) eliminated any way of therapy (surgery, radiotherapy, chemotherapy). We present this case because bcc as localy invasive tumor with low growth, diagnosed and treated at early stage can lead to complete recovery.     

In vivo three-dimensional high-resolution imaging of rodent retina with spectral-domain optical coherence tomography

PURPOSE: To demonstrate the application of high-resolution spectral-domain optical coherence tomography (SD-OCT) for three-dimensional (3D) retinal imaging of small animals and quantitative retinal information extraction using 3D segmentation of the OCT images. METHODS: A high-resolution SD-OCT system was built for in vivo imaging of rodent retina. OCT fundus images similar to those acquired with a scanning laser ophthalmoscope (SLO) were constructed from the measured OCT data, which provided precise spatial registration of the OCT cross-sectional images on the fundus. A 3D segmentation algorithm was developed for calculation of the retinal thickness map. OCT images were compared by histologic examination. RESULTS: High-quality OCT images of the retinas of mice (B6/SJLF2 for normal retina, rhodopsin-deficient Rho(-/-) for photoreceptor degeneration, and LH(BETA)T(AG) for retinoblastoma) and rat (Wistar) were acquired. The OCT images compared well with histology. Not only was a 3D image of the tumor in a retinoblastoma mouse model successfully imaged in vivo but the tumor volume was extracted from the 3D image. Retinal thickness maps were calculated that enabled successful quantitative comparison of the retinal thickness distribution between the normal (202.3 +/- 9.3 microm) and the degenerative (102.7 +/- 12.6 microm) mouse retina. CONCLUSIONS: High-resolution spectral-domain OCT provides unprecedented high-quality 2D and 3D in vivo visualization of retinal structures of mouse and rat models of retinal diseases. With the capability of 3D quantitative information extraction and precise spatial registration, the OCT system made possible longitudinal study of ocular diseases that has been impossible to conduct.     

Foveal hypoplasia demonstrated in vivo with optical coherence tomography

PURPOSE: We demonstrate foveal hypoplasia by optical coherence tomography (OCT). DESIGN: Observational case report. METHODS: Foveal hypoplasia was demonstrated in a 79-year-old man with decreased vision since childhood using fundus photography, fluorescein angiography, and OCT scans through four meridians of the central foveal. RESULTS: The OCT showed extension of all neurosensory retinal layers through the area in which the fovea would normally be located. CONCLUSION: Optical coherence tomography can be used to demonstrate foveal hypoplasia.     

Small margin excision of periocular basal cell carcinoma: 5 year results

BACKGROUND: The traditional surgical management of nodular adnexal basal cell carcinomas (BCC) involves excision with 3-4 mm margins and primary repair. This may remove a significant area of healthy tissue, often necessitating a complicated reconstruction, without the confirmation that tumour excision is complete. METHODS: Nodular adnexal BCCs were excised with 2 mm margins, and the repair delayed for 2 days, providing time for histological confirmation of complete excision with formal paraffin sections. Any incompletely excised tumours underwent further resection, which was facilitated by the undisturbed wound edges. Repair was again delayed until further histological examination had confirmed complete excision. RESULTS: 5 year follow up data were available for 55 patients who had undergone small margin BCC excision with delayed repair. 10 patients required more than one excision to achieve clear margins. There were no recurrences. CONCLUSION: Small margin excision of nodular adnexal BCCs with delayed repair is a safe and efficient method. Delayed repair allows histological confirmation of complete excision and assists further resection if required. Preservation of healthy tissue is maximised allowing less radical reconstructive surgery without resorting to Mohs' labour intensive technique.