Evaluation of spectral domain and time domain optical coherence tomography findings in toxoplasmic retinochoroiditis

Abstract

Purpose: To investigate spectral domain optical coherence tomography (SD-OCT) findings and compare them with time domain (TD)-OCT imaging of macula and retinochoroiditis lesions of patients with toxoplasmosis.

Design: Prospective cross-sectional study.

Methods: Ten eyes of 10 patients with active toxoplasmic retinochoroiditis were included. Morphologic features from the macula and retinochoroiditis lesions were obtained at baseline and at 6-week follow up. Scan acquisition protocols for TD-OCT included raster and radial lines through the retinochoroiditis lesion, fast macular, and a linear scan from the lesion to the fovea, whereas the acquisition protocols for SD-OCT also included horizontal volume scans at the lesion site and at the macula. Thickness measurements obtained by SD-OCT were analyzed.

Results: At baseline, macular serous retinal detachment was observed in five patients; two of them only seen by SD-OCT. Retinochoroidal lesions were 4260 μm distant from the fovea on average (R = 681-7130) and this distance had an indirect correlation to the presence of macular detachment. Epiretinal membrane and vitreo-macular traction were also observed. The posterior hyaloid was not identified in four patients by TD-OCT and only in one by SD-OCT at baseline. Perilesional subretinal fluid was observed in two patients. The median retinal thickness significantly decreased at the retinochoroiditis lesion (P = 0.0004), and all the patients remained with disorganized retinal layers reflectivity at follow up.

Conclusion: SD-OCT is a useful tool in the diagnosis of macular changes related with toxoplasmic retinochoroiditis. SD-OCT is superior in evaluating retinal changes associated with ocular toxoplasmosis.

Keywords: optical coherence tomography; retinochoroiditis; toxoplasmosis.

Figure 1

Fundus photography and radial scans at baseline by SD-OCT A) and TD-OCT C). Increased thickness and disorganization of the retinal layers at the lesion site at A and C (asterisk). Subretinal fluid at the foveal area. Small RPE detachments (arrowhead) only in A. Six-week follow up images by SD-OCT B) and TD-OCT D) show resolution of the subretinal fluid and decrease of the retinal thickness at the lesion site. Abbreviations: OCT, optical coherence tomography; SD, spectral domain; TD, time domain.

Figure 2

Fundus photography at baseline. Radial scans at baseline by SD-OCT A) and TD-OCT C) shows increased thickness at the lesion site and foveal subretinal fluid. At follow up, residual fluid (arrowhead) both by SD-OCT B) and TD-OCT D). Partial detachment of the posterior hyaloid and adhesion to the fovea only seen by SD-OCT (asterisk). Abbreviations: OCT, optical coherence tomography; SD, spectral domain; TD, time domain.

Figure 3

Baseline fundus photography. Green arrows show the scan acquisition protocol used by spectral domain optical coherence tomography. A, C, and E are from the volume scans at baseline, and G, a linear scan from the fovea to the lesion. B, D, F, and H correspond to the same points at follow up. Vitreoschisis (asterisk) can be noticed at baseline A) and after 6 weeks B). Note the expanded vitreous detachment at follow up. Subretinal fluid at the lesion site (arrowhead) is seen at baseline E) with resolution after 6 weeks F). The triangle shows the retinochoroidal lesion increased thickness at baseline (C, G) and atrophy at follow up (D, H).

Figure 4

Baseline fundus photography. Radial scans at baseline (A, B) and after six weeks (C, D). Increased thickness at the perifoveal lesion both by SD-OCT and TD-OCT. Hyper-reflective vitreous dots (asterisk) better seen in A. Decrease of the retinal thickness and disorganization of the layers are seen at follow up. Interruption of the IS/OS junction of the photoreceptor band: arrowhead C, C1. Abbreviations: IS/OS, inner/outer segment; OCT, optical coherence tomography; SD, spectral domain; TD, time domain.