Indocyanine Green Angiography Features in Toxoplasmic Retinochoroiditis

Abstract

Indocyanine green angiography showed that toxoplasmic retinochoroiditis is a more widespread process than is clinically suspected because it extends beyond the visible lesions. Indocyanine green angiography appears useful in assessing the extent of choroidal involvement and the evolution of lesions. It might become an important follow-up parameter and also may give new insights into the pathophysiology of this disease. Based on the findings gathered so far, ICG angiography appears indicated in the workup and management of toxoplasmic retinochoroiditis.

Fluorescein and indocyanine green angiography in ocular toxoplasmosis

“…Auer et al [2] showed marked choroidal involvement in toxoplasmic retinochoroiditis using ICGA, and found multiple hypofluorescent SDD in 75% of patients with acute toxoplasmic retinochoroiditis which disappeared after treatment. In our study, multiple SDDs were more common (92%) in eyes with active toxoplasmic retinochoroiditis, and in addition, they were observed in eyes with inactive lesions.…”

“…The latter contain the toxoplasma organisms and may represent an immunological defense reaction to antigenic stimuli [9,10]. The resolution of SDDs after treatment may suggest an infectious component [2,3]; however, SDDs have also been reported to resolve spontaneously [4]. Animal studies provided more evidence to suggest that the proliferating parasites are responsible for tissue destruction, whereas hypersensitivity reactions to the parasite are responsible for associated inflammatory signs [8].…”

“…Fluorescein angiography (FA) does not usually contribute significantly to the diagnosis in typical cases; however, it is helpful in demonstrating associated features such as vasculitis, vascular occlusion, arteriovenous shunt within the retina, retinachoroidal shunts, macular edema and choroidal neovascular membranes, as well as optic nerve and neuroretinal involvement. On the other hand, indocyanine green angiography (ICGA) has been shown to be of value in assessing the extent of choroidal involvement and the evolution of the lesions [1][2][3][4][5]. Herbort and colleagues have previously reported the ICGA findings of ocular toxoplasmosis, namely satellite dark dots (SDD) and hypofluorescence of the active retinochoroiditis lesion [1][2][3].…”

Immunopathogenesis of toxoplasmosis

“…This indicates that the active lesion is more widespread than is clinically suspected. It also indicates ICG is important in follow-up [285].…”

Scoring of dual fluorescein and ICG inflammatory angiographic signs for the grading of posterior segment inflammation (dual fluorescein and ICG angiographic scoring system for uveitis)

“…Several reports have shown that ICGA revealed choroidal lesions that were not detected by ophthalmoscopy or FA in patients with a variety of chorioretinal inflammatory disorders, including ocular sarcoidosis [4,5], ocular tuberculosis [6], ocular syphilis [7], ocular toxoplasmosis [8][9][10], sympathetic ophthalmia [11], Vogt-Koyanagi-Harada (VKH) disease [12], multifocal choroiditis [13][14][15], acute posterior multifocal placoid pigment epitheliopathy (APMPPE) [13,16], multiple evanescent white dot syndrome (MEWDS) [13,17,18], serpiginous choroiditis [19,20], the choroidal involvement in birdshot chorioretinopathy [21], and lupus choroidopathy [22][23][24]. The use of ICGA has also made it possible to better understand the pathogenesis of several choroidal inflammatory disorders and to classify these entities based on either predominant inflammation of the choriocapillaris or predominant inflammation of the stromal choroidal vessels with or without secondary choriocapillaritis [25].…”