Purpose: To investigate the nonperfused areas (NPAs) in each subfield segmented by large arterioles on wide-field swept-source optical coherence tomography angiography (SS-OCTA) images in diabetic retinopathy. Methods: We retrospectively reviewed 101 consecutive eyes of 67 patients with severe nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR), for whom 12 × 12-mm SS-OCTA images centered on the optic disc were acquired. Both eyes were included in 34 patients. NPAs in the whole retinal layers were measured in each subfield segmented by large arterioles encompassing both the superficial and deep layers. We compared the percentage of NPAs between individual subfields, considering the overlapping of the feeding arterioles. Results: Extramacular areas had higher rates of NPAs than macular areas in the inner (0.75–3 mm) and outer (3–5.5 mm) rings (P < 0.001 in both comparisons). The arteriolar arcades contacting the NPAs on the extramacular side were significantly longer than those contacting the NPAs on the macular side (P < 0.001). In particular, the extramacular areas between two arteriolar branches had a higher percentage of NPAs than those between two arterioles. The macular NPAs were greater in eyes with PDR than in those with severe NPDR, whereas there were no differences in the NPAs in the outer ring of extramacular areas. Conclusions: Wide-field OCTA images delineated that large arterioles residing in both the superficial and deep layers appear to be the perfusion boundaries, and the overlapping perfusion mediated via collateral vessels may affect the likelihood of diabetic NPAs in each subfield.
Abstract The decorrelation signals in optical coherence tomography angiography (OCTA) are derived from the flow of erythrocytes and concomitantly delineate the retinal vasculature. We compared the structural and functional characteristics of vascular lesions visualized in fluorescein angiography (FA), OCTA and en-face OCT images in 53 eyes (28 patients) with diabetic retinopathy (DR). The foveal avascular zone (FAZ) areas in OCTA images in the superficial layer almost corresponded to those in FA images. The FAZ areas in the en-face OCT images in the superficial layer were smaller than those in the FA images and correlated with each other, which agreed with the finding that en-face OCT images often delineated the vascular structure in the nonperfused areas in FA images. Microaneurysms appeared as fusiform, saccular, or coiled capillaries in OCTA images and ringed, round, or oval hyperreflective lesions in en-face OCT images. OCTA and en-face OCT images detected 41.0 ± 16.1% and 40.1 ± 18.6%, respectively, of microaneurysms in FA images, although both depicted only 13.9 ± 16.4%. The number of microaneurysms in FA images was correlated with that in OCTA and en-face OCT images. Comparisons of these modalities showed the associations and dissociations between blood flow and vascular structures, which improves the understanding of the pathogenesis of DR.
To investigate whether baseline optical coherence tomography (OCT) parameters can predict the treatment frequency of intravitreal ranibizumab (IVR) injections during the first year in patients with diabetic macular edema (DME) treated with pro re nata (PRN) IVR injections.We retrospectively reviewed 68 eyes of 63 patients with center-involved DME who received IVR injections for 12 months or longer according to three monthly IVR injections followed by the PRN dosing. We measured the mean retinal thicknesses in the individual subfields of the Early Treatment Diabetic Retinopathy Study grid and evaluated the qualitative and quantitative parameters on OCT sectional images. We investigated the relationship between these OCT parameters at baseline and the number of IVR injections during the 12-month follow-up.Three loading doses were administered to 10 eyes; four to seven annualized IVR injections were administered to 34 eyes. The number of eyes that received IVR injections decreased gradually until month 6 and was almost constant from months 7 to 11. No relationships were seen between the treatment frequency and baseline systemic factors and the ophthalmic examination findings. Univariate analyses showed that the number of IVR injections during the first year was associated with the mean retinal thickness in the individual subfields and the transverse length of the disrupted external limiting membrane (ELM) and ellipsoid zone of the photoreceptors. Multivariate analysis showed a significant association with the thickness in the inferior subfield alone. The treatment frequency during the 12-month follow-up was not correlated with improved visual acuity but was associated with the decrease in the central subfield thickness and disrupted ELM.The retinal thickness in the inferior subfield predicts the treatment frequency during the first year in eyes with DME treated with PRN IVR injections.
Purpose: To compare the characteristics of macular and extramacular white spots on wide-field swept-source optical coherence tomography angiography (SS-OCTA) and optical coherence tomography (OCT) images in diabetic retinopathy (DR). Methods: We retrospectively reviewed 107 eyes of 64 patients with DR, of whom nominal 12 × 12 mm SS-OCTA images centered on the optic disc and ultrawide field photographs were acquired. White spots on fundus photographs corresponded to hyperreflective lesions in the superficial en-face OCT images, and the characteristics of these white spots were investigated. We compared such OCT findings with the vertical and horizontal extents of nonperfused areas (NPAs) on OCTA images. Results: We observed 136 white spots and corresponding hyperreflective lesions in 49 eyes. The hyperreflective lesions in the extramacular areas had greater areas (P < 0.001) and more frequently spanned from the nerve fiber layer to the outer plexiform layer (P < 0.001), while those in the macula were superficial. All of macular hyperreflective lesions were accompanied with nerve fiber layer defects, whereas only 18 (15.4%) of 117 extramacular lesions had them (P < 0.001). Comparative studies showed that most extramacular hyperreflective lesions corresponded to the NPAs in the whole layers on OCTA images, compared to the lamellar NPAs of the superficial layer in most of the macular lesions (P < 0.001). The NPAs extended to the peripheral side more frequently in the extramacular hyperreflective lesions compared with macular lesions (P < 0.001). Conclusions: This study proposed that most of the extramacular white spots may be discriminated from macular spots with respect to diabetic NPAs on OCTA images.
This paper describes two brachiopod species, Cyrtospirifer cf. procumbens Simorin and Tylothyris sp., from the Upper Devonian Naidaijin Formation of the Chunoboridake area in the Kurosegawa Belt of Kyushu, southwestern Japan. The age of the small brachiopod fauna is assigned to the Late Devonian (probably Famennian). In terms of palaeobiogeography, the Chunoboridake fauna has a certain affinity with the Famennian brachiopod fauna of northwestern China (Xinjiang). Proto-Japan was probably located north of the North China Block during the Late Devonian.
Purpose: To evaluate the relationship between lamellar capillary nonperfusion on optical coherence tomography angiography (OCTA) images and neuroglial changes on structural optical coherence tomography (OCT) images in diabetic retinopathy (DR). Methods: We retrospectively reviewed 101 consecutive eyes of 69 patients with DR. OCTA and OCT images within a 3 × 3-mm square centered on the fovea were acquired simultaneously. The nonperfused areas (NPAs) in the superficial capillary layer (sNPA) (from the nerve fiber layer [NFL] to the inner plexiform layer [IPL]), the deep layer (dNPA) (corresponding mainly to the inner nuclear layer [INL]), or both layers (bNPA) were measured individually along 10 transverse lines. The corresponding lamellar neuroglial changes also were evaluated on OCT images. Results: The transverse lengths of the sNPA, dNPA, and bNPA were 2.34% (interquartile range, 0.81–5.55), 0.61% (0–1.99), and 5.96% (4.02–10.88), respectively. The length of the sNPA was correlated significantly with the lengths of no boundary between the NFL and ganglion cell layer (GCL)/IPL and the spots with inverted OCT reflectivity in the sNPA. The transverse length of the dNPA was associated with the length of cystoid spaces in the INL or Henle's fiber layer (HFL) in the dNPA. There was a significant correlation between the transverse lengths of the bNPA and no boundary between the NFL and GCL/IPL within the bNPA. Conclusions: Systematic evaluation of the OCTA–OCT association showed structural changes in the neuroglial tissues corresponding to the lamellar NPAs and suggested the feasibility of layer-by-layer evaluation of the capillary nonperfusion in DR.
Abstract Anti-VEGF drugs are as the first-line therapies for diabetic macular edema (DME). In this study, we investigated the association between hyperreflective foci in the outer retinal layers and functional efficacy in DME patients who received intravitreal ranibizumab (IVR) injections. We retrospectively reviewed 77 eyes of 71 patients with DME treated with pro re nata IVR injections for at least 12 months. We evaluated how baseline hyperreflective foci in the outer retinal layers on spectral domain optical coherence tomography images were associated with an improvement in logarithm of the minimum angle of resolution visual acuity (logMAR VA) at 12 months. Forty-three eyes with hyperreflective foci in the outer retinal layers had greater VA improvement than 34 eyes without such foci at 12 months. Multivariate analyses demonstrated that both logMAR VA and hyperreflective foci in the outer retinal layers at baseline were associated with VA improvement. Structural analyses revealed that the central subfield thickness was decreased and that the ellipsoid zone of photoreceptors was improved more significantly in eyes with hyperreflective foci in the outer layers than eyes without such lesions. Baseline hyperreflective foci in the outer retinal layers predict the functional efficacy of IVR injections for DME.
