Abstract
Purpose: :
Distinction between choroidal nevi and melanoma has long been based on clinical and ultrasonographic evaluation of growth and change in aspect of the lesion over time. Attempts have been made to evaluate choroidal pigmented lesions with optical coherence tomography (OCT), but these efforts are limited by the penetration depth of the light used to acquire the scans. The OCT/SLO provides a simultaneously acquired, combined confocal and coronal OCT image, and the scanning procedure it uses allows for better visualization of the choroid. Patients with choroidal nevi and melanoma were scanned with this technique to evaluate the appearance of both lesions, and to determine if discrimination between the two entities could be made.
Methods: :
Patients with choroidal nevi and melanoma were imaged with a pre–production model of the OCT/SLO (OTI, Canada) providing combined acquisition of confocal and coronal OCT scans. The OCT C–scan images were retrospectively reviewed for characteristics in each entity in both the confocal channel and the coronal OCT channel, and using the longitudinal OCT scans.
Results: :
Choroidal nevi (n=23) showed to be highly reflective in the confocal and coronal OCT images. They showed increased reflectivity in the longitudinal OCT scan either at the level of the RPE/choroicapillaris or as a separate band underneath the RPE together with subsequent shadowing. Choroidal melanoma (n=7) showed to be hyporeflective in the confocal and coronal OCT scan, with destruction of the I/O segment and RPE complex in 85%. No increased reflectivity at the level of the RPE was evident, but only evident optical emptiness at the site of the lesion. Melanoma had significantly more retinal changes (serous retinal detachment, intraretinal cystoid edema) than nevi (57% versus 10%).
Conclusions: :
Using combined confocal and coronal OCT imaging allows for discrimination between choroidal nevi and melanoma. Whether these differences in appearance are mainly due to structural compilation or due to secondary destructive effects to the retina, especially in melanoma, needs further exploration. The OCT/SLO holds the promise of establishing prognostic parameters to discriminate between choroidal nevi and melanoma.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • tumors