Correlation between morphologic features on spectral-domain optical coherence tomography and angiographic leakage patterns in macular edema

Abstract

Purpose: The purpose of this study was to determine the morphologic patterns of angiographic macular edema using simultaneous colocalization of fluorescein angiography and spectral-domain optical coherence tomography (SD-OCT) images in diabetes, epiretinal membrane, uveitic and pseudophakic cystoid macular edema, and vein occlusion.

Methods: Eighty-seven consecutive patients (107 eyes) with macular edema from 5 different etiologies were imaged by simultaneous scanning laser ophthalmoscopy/OCT to study the morphologic patterns of edema on SD-OCT and then correlated/colocalized with the fluorescein angiographic patterns of leakage. Statistical analysis was done to analyze the differences in the morphologic OCT pattern by different diseases.

Results: Spectral-domain OCT characteristics of macular edema showed a significant difference across different diseases (P = 0.037). Cystic fluid pockets were found to be more commonly seen in patients with diabetic macular edema and retinal vein occlusions, whereas those cases with macular edema secondary to epiretinal membrane showed noncystic changes on OCT. Seventy of the 107 eyes had diffuse angiographic leakage, and the remaining 37 eyes had cystoid leakage on angiography. Of the 70 eyes with diffuse leakage, 24.28% showed microcysts on SD-OCT in the area of edema, and 70% eyes had diffuse thickening or distorted architecture without cyst. All 37 eyes with cystoid leakage showed cysts in the area of edema by SD-OCT. A total of 3.73% of eyes with fluorescein angiographic leakage had no abnormalities on SD-OCT.

Conclusion: Eyes with diabetic macular edema and retinal vein occlusions have a significantly higher incidence of cyst formation on SD-OCT. There was no correlation between visual acuity and cyst formation. Diffuse noncystoid angiographic macular edema may show microcysts on SD-OCT, but diffuse edema is more commonly associated with thickening or distortion of the retinal layers without cyst formation. Cystoid leakage on fluorescein angiography is always associated with cystic changes on SD-OCT.

Figure 1

Idiopathic epiretinal membrane with macular edema in 67 year old male as imaged by simultaneous scanning laser ophthalmoscope/ spectral domain optical coherence tomography.(SLO/ Spectral OCT).Late phase fluorescein angiogram (left image) shows diffuse non cystoid leakage with straightening of retinal vessels. Green line indicates OCT scan location. B-scan OCT (right image) shows thickening of the outer nuclear layer ONL (white star) and inner nuclear layer (INL) layers (white arrow). Note that there are no cystic fluid pockets seen. N-nasal, T- temporal.

Figure 2

Late phase fluorescein angiography (FA) image with a simultaneously acquired Spectral domain optical coherence tomography (Spectral-OCT) scan in a diabetic. FA image (left) shows diffuse non cystoid leakage with few leaking microaneurysms. Parafoveal OCT scan located as indicated in the FA image (green line). Correlation shows diffuse swelling of the retinal layers with distorted architecture of the retinal morphology (Black star).Partial posterior vitreous detachment (PVD) also seen with early hyaloi separation seen superiorly. I-inferior, S-superior

Figure 3

Simultaneous fluorescein angiogram and spectral domain optical coherence tomography (Spectral - OCT) images from a patient with diabetic macula edema. A, Late phase fluorescein angiogram shows ill defined diffuse leakage temporal to the fovea. B, Corresponding OCT image through the area of leakage. B-scan OCT shows normal retinal morphology Central foveal thickness was 275µm. N-nasal, T- temporal.

Figure 4

Simultaneous scanning laser ophthalmoscope /spectral domain optical coherence tomography (SLO- Spectral OCT) in a patient with macular edema secondary to epiretinal membrane. Late phase fluorescein angiogram (left image) shows ill defined diffuse leakage with straightening of the retinal vessels in the perifoveal area. B-scan spectral domain optical coherence tomography (Spectral -OCT) scan through the area of leakage reveals few small microcysts. (As is shown by white arrows)Note: Thin ERM coursing over the retinal surface is also seen in the OCT scan. N-nasal, T- temporal.

Figure 5

Late fluorescein angiogram (left image) reveals late parafoveal diffuse leakage in a patient with an epiretinal membrane. Corresponding horizontal OCT scan passing through the inferior parafoveal region (area of leakage) shows thickening of inner nuclear layer (INL) and outer nuclear layers with faintly Visible cystic spaces in INL layer. (White arrows). N-nasal, T- temporal.

Figure 6

Simultaneously acquired late phase fluorescein angiogram (FA) and spectral domain optical coherence tomography (Spectral- OCT) scan using simultaneous scanning laser ophthalmoscope /spectral domain optical coherence tomography (SLO- Spectral OCT) in a patient with uveitic cystoid macular edema (CME). FA image (left) shows central petalloid and honeycomb pattern of hyperfluorescence corresponding to cystoid spaces in outer nuclear layer/outer plexiform layer(asterix) and inner nuclear layer(white arrows). N-nasal, T- temporal.