The retina is limited anteriorly by the ora serrata and posteriorly by the optic disk. In case of retinal detachment, the retina is visible within the vitreum as a mobile membrane. In case of complete detachment, anatomic limits of the retina allow a differential diagnosis with vitreal membranes, that are not attached to the ora serrata nor to the optic disk, and are more mobile compared to the retina. However, vitreal membranes related to clots or haemovitreum are usually associated with partial retinal detachments. These lesions are not easily detectable. In addition, vitreal membranes could even be randomly attached to the retina, next to its insertion on the ora serrata or the optic disk, being cause of diagnostic misleading. In a preliminary study, Wong et al. demonstrated that the rate of diagnostic errors between vitreal membranes and retinal detachment was about 17%. More recently, Han et al. showed a rate of diagnostic misleading of 22%. In case of hemovitreous associated to vitreal membranes and retinal detachment, color Doppler improved the differential diagnosis, showing high vascularity inside the retina and lack of vascularity inside the membranes. With color Doppler, Han demonstrated a sensitivity of 57% in the detection of retinal vascularity, definitely inferior than that reported by Wong (100%). This difference can be partially justified with the different size of patients’ sample and with different selection criteria for them. On the contrary, power Doppler was rather helpless, due to high amount of artefact produced by the membranes.
In conclusion, Han reported a diagnostic accuracy of B-mode ultrasound of 78%, color Doppler 81%, and power Doppler 59% in differentiating vitreal membranes from retinal detachment. The use of first generation ultrasound contrast agents improved the sensitivity in the detection of retinal detachments from 57% to 93%.
In our experience, the use of second generation ultrasound contrast agents in association with dedicate imaging algorithms allowed identifying retinal detachments in 100% of cases.
Globe tumors
Ultrasound can be considered the first imaging technique in the assessment of globe tumors. Color Doppler was used in the differential diagnosis among choroid melanoma, choroid nevi, and haemorrhage. Melanoma is richly vascular if compared to other lesions of globe wall, with exception for metastases. In our limited experience, CEUS demonstrated a high vascularity of choroid melanoma. In addition, CEUS was helpful during radiotherapy of the melanoma, showing a progressive decrease of vascularity.
Orbit tumors
Primitive malignancies of the orbit include vascular lesions, such as hemangioma cavernosum, lymphangioma, and hemangiopericytoma. In these vascular neoplasms, color Doppler can be helpless due to slow blood stream inside the lesion. Meningiomas of the optic nerve and lymphomas are more vascular. In these lesions, CEUS showed an intense vascularity, allowing a differential diagnosis with other type of lesions.