RU2741365C1 - Method for non-invasive diagnosing of retinal venous occlusion of ischemic type - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention refers to medicine, namely to ophthalmology, and can be used for non-invasive diagnostics of retinal venous occlusion of ischemic type. Retinal vasculature is scanned layer by layer. Before starting the guidance on the optical coherent tomography (OCT) REVO scanning zone, the patient's head is fixed, providing a stable support on the chin and maximum contact with the forehead rest. Hitting zone is determined and a filming program is set in the angio-mosaic mode. Size of the scanning zone is selected for OCT REVO in range from 3 mm to 9 mm, with a fixed resolution of 304 × 304 points, the longitudinal resolution is 10 mcm for scanning 3 mm by 3 mm and 20 mcm for scanning 6 mm by 6 mm. Macula area is successively scanned, retinal segmentation and axial intervals of the vascular plexus separation and the avascular area are segmented. Optic nerve disc zone is scanned (NDZ). After the scanning, the primary treatment is performed with reconstruction of the eye ground surface to assess the presence of scanning artefacts. Mosaic elements are combined to visualize a common pattern of retinal lesion. Visual fundus visualization is used to determine a capillary perfusion area. In the absence of capillary perfusion over the area of more than 5 NDZ in the retinal vein of the retinal vein and more than 10 NDZ in the retinal occlusion of the retinal vein, retinal venous ischemia of the ischemic type is diagnosed.EFFECT: method provides non-invasive diagnosis of ischemic retinal venous occlusion by determining the area of capillary perfusion.3 cl, 12 dwg, 2 ex

Description

The invention relates to medicine, and specifically to ophthalmology, and is intended for the diagnosis of the type of retinal venous occlusions (ischemic or non-ischemic).

Occlusion of the central retinal vein (RCVO) and its branches (RCVO) ranks second among acquired vascular ocular diseases after diabetic retinopathy. According to pooled demographic data, in the general population, the prevalence of retinal vein occlusion is 1% to 2% of people over 40 years of age and occurs in approximately 16 million people worldwide. The outcomes of the postponed occlusion of the retinal veins lead to permanent disability in about 15% of cases. This indicates the great medico-social significance of this pathology and the need for further study of issues of etiology, pathogenesis, prevention and treatment of this disease.

Retinal venous occlusion (VVO) is a multifactorial disease, its pathogenesis is still not fully understood. Among the factors involved in the formation of occlusions are mechanical, hemodynamic, hemorheological, coagulation, biochemical, immunological. In recent years, two theories predominate in the concept of the pathogenesis of RVR: the mechanical theory and the theory of coagulopathy. According to Rudolf Virchow's triad, formulated more than 150 years ago, the pathophysiology of thrombosis includes three interrelated factors: changes in the vascular wall, changes in blood flow, changes in blood coagulation. The severity of postocclusive changes directly depends on the degree of ischemic damage to the retina, which is expressed in the area of its lesion. In this regard, various authors have developed clinical classifications, the essence of which was not only the division of occlusions of the retinal veins by anatomical localization, but also in the division into ischemic and non-ischemic types. By anatomical localization there are: 1. Occlusion of the central retinal vein (PCV) 2. Occlusion of the hemicentral branch of the PCV. 3. Occlusion of the branch of the central branch of the retina (VTSVS). By the type of occlusion they are divided into: 1. non-ischemic type; 2. Ischemic type (absence of capillary perfusion over an area of more than 5 diameters of the optic nerve head (optic nerve disc) with occlusion of CVV and more than 10 diameters of the optic disc with occlusion of PCV) Non-ischemic type, which in the literature is also referred to as incomplete thrombosis, perfusion occlusion or retinopathy of venous stasis - the form is characterized by intact capillary perfusion and a significantly better prognosis in terms of preservation of vision.

The most severe form is called ischemic or complete, nonperfusional or hemorrhagic retinopathy. With this form, the spread of capillary nonperfusion zones and cell death lead to a significant decrease in vision with a poor prognosis. Areas of retinal ischemia do not recover over time and tend to increase.

Fluorescence angiography (FA), which has its advantages and disadvantages, remains the gold standard for the diagnosis of retinal perfusion. Fluorescence angiography (FAG) is the main method of examining a patient with damage to the vascular bed of the retina. The data obtained with PAH help the ophthalmologist to determine the type of retinal vein thrombosis and to differentiate it in doubtful cases from other diseases. With the help of FAG, you can get information about: the age of retinal vein occlusion; localization of the occlusion site; the degree of occlusion (complete or partial); the condition of the venous wall; state of capillary perfusion; pathological changes in the arterial bed; the presence or absence of anastomoses (veno-venous, arteriovenous, arterio-arterial); the presence of neovascularization; the state of the macular zone (assessment of the degree of preservation of the peripheral veolar capillary network); condition of the optic nerve disc; blood circulation in the vessels of the choroid. The advantages of this method include: it provides a two-dimensional image with wide-field visualization of blood flow, the patterns of PAH are dye leakage, its accumulation and tissue staining. However, this method for diagnosing retinal perfusion has disadvantages: it requires intravenous administration of a fluorescent dye, is contraindicated in pregnant women, lactating women, children, patients with renal and heart failure, and the impossibility of separate visualization of intraretinal vascular plexuses. Intraretinal hemorrhages block the excitation and emission of photons with the appearance of hypofluorescence zones, shielding the underlying structures.

A known method for predicting occlusion of retinal veins (patent No. 2484791, IPC A61F 9/00 (2006.01), publ. 20.06.2013 bull. No. 17). The invention relates to medicine, in particular to ophthalmology, and is intended to predict the occlusion of the retinal veins in venous occlusion of the paired eye. Photographic registration of the fundus of a "healthy" eye is carried out using an adaptive multispectral fundus camera. Determine the arterio-venous coefficient (AVK) at the site after the second bifurcation. If the AVK value is below 0.73, occlusion of the retinal veins in the “healthy” eye is predicted. The method provides the possibility of predicting patients without concomitant vascular pathology and taking timely preventive therapeutic measures with constant monitoring of the healthy eye in the presence of venous thrombosis in the other eye.

A non-invasive method of optical coherence tomography is known (https://gsproekt.ru/diagnostika/opticheskaya-kogerentnaya-fotografiya - OCT (optical coherence tomography, OCT), taken as a prototype that allows you to image optical sections of the retina using a scanning laser beam. transpupillary; the light source is an infrared laser.The resolution of the method, depending on the type of device used, reaches from 10-15 to 1-3 microns, which allows you to obtain optical sections comparable in information content with histological ones. The "mapping" mode allows you to assess the thickness of the sensorineural retina macular The method is used for diagnostics, dynamic observation and evaluation of the effectiveness of treatment of diseases of the retina.In case of retinal vein occlusion, OCT allows: to determine the height and area of macular edema; to determine the structural characteristics of edema (cystic changes, neuroepithelial detachment); to reveal the presence of vitreoretinal traction; identify the presence of epiretinal fibrosis; determine the position of the posterior hyaloid membrane of the vitreous body; monitor the effectiveness of macular edema treatment.

However, the known method is insufficiently informative in assessing microcirculation, which does not always allow determining the area of capillary nonperfusion of the retina and identifying the type of occlusion.

The technical problem to be solved by the present invention is the creation of an effective method for the diagnosis of non-ischemic and existing type of occlusion, which will allow to choose an adequate treatment tactics. The technical result to which the present invention is aimed is to improve the accuracy of determining the area of capillary nonperfusion of the retina, which will allow identify the type of retinal venous occlusion in the patient and improve the quality of treatment.

The technical result is achieved by the fact that in the method of non-invasive diagnostics of retinal venous occlusions, including layer-by-layer scanning of the retinal vasculature, before the start of aiming at the scanning area of the REVO optical coherence tomograph, the patient's head is fixed, providing stable support on the chin and maximum contact with the forehead support, optimizing the working the distance between the patient's eye and the tomograph and compensate for the patient's refraction in the C-gate mode, the lesion zone is determined in the longitudinal scanning window of the Revo optical coherence tomograph, the shooting program is set in angio-mosaic mode, the size of the scanning zone for the REVO optical coherence tomograph is selected in the range from 3 mm up to 6 mm, at a fixed resolution of 304 by 304 points, the longitudinal resolution is ~ 10 μm for scanning 3 mm by 3 mm and 20 μm for scanning 6 mm by 6 mm, then the macular zone, the optic nerve disc (optic nerve disc) zone are sequentially scanned, define segmentation layers of the retina and the main axial intervals of separation of the vascular plexus and the avascular zone, then scan the remaining areas of retinal lesion, depending on the occlusion of the branch or trunk of the central retinal vein. After scanning, primary processing with reconstruction of the fundus surface is carried out to assess the presence of scanning artifacts, mosaic elements are combined to visualize the overall picture of retinal damage. According to the results of retinal imaging, the area of capillary perfusion is determined, according to which venous occlusions of the ischemic type or non-ischemic type are diagnosed, the ischemic type is determined by the absence of capillary perfusion over an area of more than 5 optic nerve discs with occlusion of the branch of the central retinal vein and more than 10 optic discs with occlusion of the ventral retinal vein.

If there are several scans in one area in the results viewing mode, the Motion correction artifact elimination technology is used.

If necessary, after the completion of automatic guidance, manual adjustment of the scanning window, the position of the scan within the window, focusing optimization is carried out; to switch to the manual angio-mosaic mode, an appropriate mark is placed in the fundus reconstruction preview window after the first scan.

The proposed non-invasive method of opic coherence tomography in angio-mode (OCTA) for determining retinal perfusion has the following advantages: non-invasiveness, safety, an informative method for assessing microcirculation, which makes it possible to determine the localization, shape, structure and area of pathological vascular changes, visualizes four capillary and capillary plexuses ( retinal plexus, outer layers of the retina and choriocapillaries), allows for a quantitative analysis of microcirculation with the calculation of the density of the capillary network, areas of absence of capillary perfusion. This diagnostic method (OCTA), thanks to the angio mosaic mode, allows to determine the area of capillary nonperfusion of the retina, to identify the type of occlusion and, accordingly, to choose an adequate treatment tactics.

Figure 1 shows an optical coherence tomograph in SOCT Copernicus angio mode (REVO / REVO NX), on which the studies were carried out.

FIG. 2 - picture of the fundus (patient 1).

FIG. 3 - optical coherence tomography (patient 1).

FIG. 4 - fluorescence angiography (patient 1).

FIG. 5 - optical coherence tomography in angio mosaic mode (patient 1).

FIG. 6 - optical coherence tomography after laser treatment VIS OD 0.5 sph 2.75 = 0.7. (patient 1).

FIG. 7 - optical coherence tomography in angio mosaic mode (patient 2).

FIG. 8 - picture of the fundus (patient 2).

FIG. 9 - optical coherence tomography (patient 2).

FIG. 10 - optical coherence tomography in angio mosaic mode, (patient 2).

FIG. 11 - optical coherence tomography after anti-VGF therapy VIS OD 0.5 ns. (patient 2).

FIG. 12 - optical coherence tomography in angio mosaic mode, (patient 2).

Optical coherence tomography in angio-mode (OCTA) is performed in the following way. Before starting to aim at the scan area, the patient's head should have a stable support on the chin and maximum contact with the forehead support. Correct fixation of the head will exclude some of the movements during scanning, which will be reflected in the study result in the form of artifacts. The working distance between the patient's eye and the tomograph is optimized, the patient's refraction is compensated in the C-gate mode, the affected area is determined in the longitudinal scanning window of the tomograph. The choice of scanning program will determine the location and the possibility of shooting in the angio-mosaic mode. A scan of the macular area will determine the segmentation of the 8 retinal layers and the main axial spaces of the choroid plexus / complex separation and the avascular zone. The scanning of the optic disc includes 3 main axial spaces of the choroid plexus separation. Depending on the required level of detail for small-caliber vessels, it is necessary to select the size of the scanning zone (for REVO 80k, the range is from 3 mm to 6 mm / for REVO NX, the range is from 3 mm to 6 mm). With a fixed resolution of 304 x 304 dots, the longitudinal resolution is ~ 10 μm for a 3 mm x 3 mm scan and 20 μm for a 6 mm x 6 mm scan.

After scanning, fast primary processing takes place with the reconstruction of the fundus surface to assess the presence of scanning artifacts. If there are several scans in one area in the results viewing mode, you can apply the Motion correction technology for eliminating artifacts.

If necessary, after completion of automatic guidance, it is possible to manually adjust the scanning window, scan position inside the window, and optimize focus. To switch to the manual angio-mosaic mode, check the corresponding box in the fundus reconstruction preview window after the first angio-scan.

To ensure the correct alignment of the mosaic elements, the intersection area of the subsequent scanned area with the already scanned area is set at least 25% of the area of a single scan.

The proposed method for the diagnosis of angio-OCT in mosaic mode makes it possible to accurately map the entire affected area and determine the area of capillary perfusion in a non-invasive way without administering a contrast agent, in contrast to fluorescent angiography. And with angio-OCT in mosaic mode, it is possible to accurately determine the depth of the lesion in the form of layers of capillary plexuses (superficial and deep capillary plexuses of the retina, outer layers of the retina and choriocapillaries).

So, using the example of Fig. 5, the affected area is clearly visualized in the form of the absence of small capillaries (capillary perfusion) along the superior temporal branch of the central retinal vein, the boundaries of the lesion and the area of the modified retina are accurately determined, the size of which is more than 5 times the area of the optic nerve head. The dimensions of the optic nerve head diameter are personal for each individual patient, therefore, there is a definition of the accommodability of the optic nerve head area in the affected area on the retina and is determined by the number of optic nerve head diameters of more than five or more than ten in the area of the altered retina.

Accurate determination of the boundaries of the retinal lesion zone and its depth allows further laser treatment of this zone without affecting healthy retinal tissues, which is impossible according to the results of the PAH study. Also, this diagnostic method allows you to take control pictures after the treatment.

FIG. 6 shows the result of the laser treatment performed in the form of the sufficiency and accuracy of laser coagulation application to the affected area of the retina (the area of absence of capillary perfusion) without affecting healthy tissue.

REVO is the name of the optical coherence tomograph shown in FIG. one.

REVO scan area - the area that the REVO optical coherence tomograph selects for scanning in automatic mode.

Angio - mosaic - assembly of images of retinal fragments in manual mode according to the vascular pattern.

The working areas of retinal scanning from 3 mm to 6 mm are determined by the technical characteristics of the REVO optical coherence tomograph.

C-gate mode - autofocusing of the REVO optical coherence tomograph.

Segmentation of the retinal layers and its spaces is the capabilities of the REVO optical coherence tomograph, which makes it possible to determine not only the lesion area, but also the depth of retinal changes by layers, prescribed by the software of the optical coherence tomograph.

Vascular complex (synonym for choroid plexus) - a layer of the retina with vessels

Motion correction mode - capabilities of a specific optical coherence tomograph, allowing to perform the technology of eliminating artifacts in automatic mode

Choroid plexus / complex separation spacing - distance between retinal layers

Characteristics of the SOCT Copernicus (REVO / REVO NX) optical coherence tomograph in angio mode, on which the studies were carried out.

The central wavelength of the SLD is 830 nm.

The half width of the spectral band is 50 nm.

Axial optical resolution 5 µm.

Axial digital resolution 2.6 microns.

Scanning speed 80,000 A-scans / sec.

The length of the scan on the retina is from 3 to 12 mm.

Scanning depth 2.4 mm. Correction of ametropia from -25 D to +25 D.

Patient 1

VIS OD 0.3 sph 2.75 = 0.5

Diagnosis: Occlusion of the superior temporal branch of the central retinal vein, ischemic type. Fundus picture (Fig. 2). Optical coherence tomography (Fig. 3). Fluorescence angiography (Fig. 4). Mosaic angiooptic coherence tomography (Fig. 5).

Optical coherence tomography after laser treatment VIS OD 0.5 sph 2.75 = 0.7 (Fig. 6). Optical coherence tomography in angiomosaic mode (Fig. 7).

Patient 2

VIS OD 0.05 n.s.

Diagnosis: Occlusion of the superior temporal branch of the central retinal vein with macular edema, non-ischemic type. Fundus picture (Fig. 8).

Optical coherence tomography (Fig. 9).

Mosaic angiooptic coherence tomography (Fig. 10).

After anti VGF therapy, VIS OD 0.5 n.s.

Optical coherence tomography (Fig. 11).

Optical coherence tomography in angiomosaic mode (Fig. 12).

OCTA is the only method of layer-by-layer assessment of capillary plexuses with a possible quantitative assessment of blood flow in them, it allows to identify the initial signs of ischemic maculopathy (I degree of macular perfusion disturbance) before their visualization during PAH or screening of these changes by hemorrhages.

By the absence of capillary perfusion over an area of more than 5 optic discs with occlusion of the branch of the central retinal vein and more than 10 optic discs with occlusion of the ventral retinal vein, the ischemic type of retinal venous occlusions is determined

Thanks to the mosaic mode, it becomes possible to differentiate ischemic from non-ischemic type of EVR and, accordingly, to choose a treatment strategy. OCTA can be used as a diagnostic standard for retinal perfusion.

Thus, the use of optical coherence tomography of the retina in the angiography mode makes it possible to visualize the vascular bed of the retina and choroid, to assess the degree and nature of structural changes, taking into account hemodynamic disorders in the diagnosis of various forms of CSHR, significantly expanding the possibilities of diagnosis, understanding the pathogenesis of the disease from the standpoint of anatomy and physiology.

An important advantage of this diagnostic method is the possibility of layer-by-layer visualization of the entire retinal vascular network, which makes it possible to conduct a quantitative analysis of microcirculation with the calculation of the density of the capillary network, zones of absence of capillary perfusion, which was previously impossible, because traditional angiography with fluorescein and indocyanine green provides information only about the surface layers.

Claims (3)

1. A method for non-invasive diagnostics of retinal venous occlusion of the ischemic type, including layer-by-layer scanning of the retinal vasculature, characterized in that before the start of pointing to the scanning area of the REVO optical coherence tomograph (OCT), the patient's head is fixed, providing stable support on the chin and maximum contact with the support for forehead, determine the affected area and set the shooting program in angio-mosaic mode, select the scan area size for REVO OCT in the range from 3 mm to 9 mm, at a fixed resolution of 304 by 304 points, the longitudinal resolution is 10 μm for scanning 3 mm by 3 mm and 20 μm for scanning 6 mm by 6 mm, sequentially scan the macular area, determine the segmentation of the retina and the axial separations of the vascular plexuses and the avascular zone, scan the optic nerve head (optic nerve disc) area, after the scan, perform primary processing with reconstruction of the fundus surface to assess the presence of an artifact in scanning, mosaic elements are combined to visualize the general picture of retinal damage, according to the results of visualization of the fundus, the area of capillary perfusion is determined, in the absence of capillary perfusion over an area of more than 5 optic discs with occlusion of the branch of the central retinal vein and more than 10 optic discs with occlusion of the ventral retinal vein, retinal venous is diagnosed ischemic occlusion. 2. The method according to claim 1, characterized in that in the presence of several angio-scans in one area in the results viewing mode, the Motion correction artifact elimination technology is used. 3. The method according to claim 1, characterized in that after the completion of automatic guidance, the scanning window, the position of the scan inside the window, focusing are manually corrected; to switch to the manual angio-mosaic mode, a mark is placed in the fundus reconstruction preview window after the first angio- scanning.

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