Vascular Motion on B-scan Ultrasound Cannot Rule out Choroidal Nevi

Distinguishing benign choroidal nevi from small choroidal melanomas can be challenging due to their overlapping clinical features. Multimodal imaging techniques are vital to help differentiate between the two lesion types. A recent study focused on one imaging modality—B-scan ultrasonography—to compare the intrinsic vascularity of choroidal nevi, suspicious choroidal nevi and choroidal melanoma. Contrasting with prior research, the authors found that choroidal nevi can have moderate to high intrinsic vascularity detectable during B-scan ultrasound exams; therefore, observing vascular motion on these scans cannot exclude a choroidal nevus diagnosis, they argued.To conduct the study, the authors examined 43 eyes with choroidal nevi, 49 with suspicious choroidal nevi and 45 with choroidal melanomas. At a tertiary ocular oncology service, all patients underwent ultrasound exams using 10- or 15-MHz B-scan probes.After evaluating the areas of flickering motion inside the lesions on B-scan ultrasonography videos, the researchers detected intrinsic vascularity in 86% of choroidal nevi, 88% of suspected nevi and 100% of choroidal melanomas. Moderate intrinsic vascularity was observed in 58% of choroidal nevi, while high vascularity was present in 45% of suspected nevi and 73% of melanomas. Across the combined group of nevi and melanomas, the intensity of intrinsic vascularity showed a positive correlation with subretinal fluid, lesion height and lesion basal diameter. Conversely, a negative correlation was found between vascularity intensity and both internal reflectivity and the presence of overlying drusen. Using B-scan ultrasonography, this study identified moderate to high intrinsic vascularity in 58% and 28% of eyes with choroidal nevi, respectively. The authors believe some of these cases “may actually represent small choroidal melanomas that have not yet entered a phase of rapid growth.” These images from the study show the following: - A-D: Pigmented choroidal nevus with overlying drusen (A), without orange pigment on FAF (B), without associated subretinal fluid on OCT (C), medium internal reflectivity on B-scan (D).  - E-H: Pigmented suspicious choroidal nevus with overlying orange pigment (E), orange pigment is more prominent on FAF (F), associated shallow subretinal fluid on OCT (G), low-to-medium- internal reflectivity on B-scan (H).  - I-L: Pigmented choroidal melanoma (I), FAF shows areas of hyper and hypoautofluorescence(J), OCT demonstrates bilobulated choroidal mass (K), mushroom-shaped lesion associated with extensive retinal detachment shows low internal reflectivity on B-scan (L). Photo: Beser BG, et al. Ophthalmol Sci. May 6, 2025. Click image to enlarge. “Traditionally, choroidal nevus has been typically described as a lesion with high internal reflectivity and lack of intrinsic vascularity on A-scan or B-scan ultrasonography,” the researchers explained in their paper for Ophthalmology Science. “However, advances in ultrasound technology that allow better resolution of anatomic detail can challenge this assumption, as shown in this study.”The team also observed that “some choroidal nevi showing intrinsic vascularity may actually represent small choroidal melanomas that have not yet entered a phase of rapid growth.” Supporting this hypothesis, they found that 10 of 49 patients initially monitored due to a suspected nevi showed lesion growth within two years following the initial ultrasonographic exam, though 23 patients in this group showed no growth during the same timeframe. The authors relayed in their paper that there was “[no] statistically significant difference in the degree of intensity of vascularity between the patients who showed growth or no growth in the suspected nevi group.”Given that this study revealed nonsuspicious choroidal nevi can have moderate (58%) or high (28%) intrinsic vascularity, the authors conclude that “identifying vascular motion on B-scan ultrasonography cannot be used to exclude the diagnosis of choroidal nevus” and argue instead that “serial multimodal imaging along with a clinical follow-up is necessary for the differentiation of choroidal nevi and melanomas.”Click here for the journal source. Beser BG, McClendon T, Ayres B, Demirci H. Ultrasonographic assessment of intrinsic vascularity in choroidal nevus, suspicious choroidal nevus and choroidal melanoma. Ophthalmol Sci. May 6, 2025. [Epub ahead of print].