Measurement of the Active Toxoplasma Retinochoroiditis Lesion Size During the Disease Course With Swept Source Optical Coherence Tomography Angiography: A Retrospective Image Analysis
Abstract Purpose To measure the lesion size reduction in eyes with active toxoplasma retinochoroiditis during the disease course with swept- source optical coherence tomography angiography (SS-OCTA). Methods We retrospectively analyzed the chorioretinal lesion size in a group of 14 eyes with a single active toxoplasma retinochoroiditis lesion.SS-OCTA was performed at the baseline and follow -up in all eyes. The 6x6 mm choriocapillaris slab images were evaluated with an image analysis (Matlab). The number of black and white pixels in a 1500µm-diameter circle centered on each active lesion was counted at the time of baseline examination and at the first follow-up visit when the chorioretinal scar formation was noticed. Results Fourteen eyes with a single active toxoplasmosis retinochoroiditis lesion were included. Ten patients were female and three,male. Mean age was 29.1 ± 14.9 years. Active lesions were at the macula in five eyes, at the periphery in six eyes and juxtapapillary in three eyes. At the initial examination lesion area was observed as an area with a decreased flow signal on SS-OCTA.There was perilesional capillary disruption in superficial and deep capillary plexi together with a diffuse capillary network attenuation and non-detectable flow signal zones in the choriocapillaris slabs. In addition to sulfamethoxazole-trimethoprim and azithromycine combination oral corticosteroids were only co-administered in five (35%) eyes with macular involvement. The chorioretinal scar formation was observed in four to 16 weeks. At the time of inactivity, original lesion was diminished in size when compared to its baseline in all study eyes (p = 0.001) with a mean black pixel reduction percentage of 21.8%. The reduction was 15.4% in eyes with macular lesion, 31.6% with peripheral lesions and 18.1% with juxtapapillary lesions (p = 0.001, p = 0.032, p = 0.028, p = 0.043, respectively). Visual acuity was correlated with black pixel reduction percentage in eyes with macular lesion (r = 0.56, p < 0.001). Conclusion Active toxoplasma retinochoroiditis lesion size diminished with the healing process as expected and this could be monitorized with an OCTA based image analysis technique. Macular lesions showed less reduction in lesion size despite the addition of oral corticosteroids in contrast to peripheral and juxtapapillary lesions.