Role of wide-field autofluorescence imaging and scanning laser ophthalmoscopy in differentiation of choroidal pigmented lesions

Abstract

Aim: To evaluate the diagnostic properties of wide-field fundus autofluorescence (FAF) scanning laser ophthalmoscope (SLO) imaging for differentiating choroidal pigmented lesions.

Methods: A consecutive series of 139 patients were included, 101 had established choroidal melanoma with 13 untreated lesions and 98 treated with radiotherapy. Thirty-eight had choroidal nevi. All patients underwent a full ophthalmological examination, undilated wide-field imaging, FAF and standardized US examination. FAF images and imaging characteristics from SLO were correlated with the structural findings in the two patient groups.

Results: Mean FAF intensity of melanomas was significantly lower than the FAF of choroidal nevi. Only 1 out of 38 included eyes with nevi touched the optic disc compared to 31 out of 101 eyes with melanomas. In 18 out of 101 melanomas subretinal fluid was seen at the pigmented lesion compared to none seen in eyes with confirmed choroidal nevi. In "green laser separation", a trend towards more mixed FAF appearance of melanomas compared to nevi was observed. The mean maximal and minimal transverse and longitudinal diameters of melanomas were significantly higher than those of nevi.

Conclusion: Wide-field SLO and FAF imaging may be an appropriate non-invasive diagnostic screening tool to differentiate benign from malign pigmented choroidal lesions.

Keywords: autofluorescence; choroidal lesion; imaging; melanoma; scanning laser ophthalmoscopy.

Figure 1. Optomap composite color (A), green laser separation (B), red laser separation (C) and fundus autofluorescence image (D) of a 72-year-old female patient with a choroidal melanoma of her right eye after radiation therapy. Lesion appears dark in red laser separation image compared to a mixed appearance in green laser separation image.

Figure 2. Optomap composite color (A), green laser separation (B), red laser separation (C) and fundus autofluorescence image (D) of a 45 year-old female patient with a CN in the macular area of her left eye. Lesion appears dark in red laser separation image compared to a mixed appearance in green laser separation image.

Figure 3. Mean fundus autofluorescence intensity (see method section) of established choroidal melanomas was 14.24±7.89 and significantly (P<0.001) lower than of confirmed choroidal nevi with 22.22±20.75.

The autofluorescence patterns seem to subdivide the melanoma group into two subgroups: one group with predominantly decreased autofluorescence intensity and one group with increased autofluorescence intensity.

Figure 4. Lesion appearance in “green laser separation” images in “melanoma” vs “nevus” group in %.

Figure 5. Maximal transverse and longitudinal diameters measured in individual optic disc size between the “melanoma” and “nevus” group with significantly higher mean maximal transverse as well as longitudinal diameters found in eyes with melanomas.