Ocular ultrasonography focused on the posterior eye segment: what radiologists should know

Abstract

Ocular B-mode ultrasonography (US) is an important adjuvant for the clinical assessment of a variety of ocular diseases. When ophthalmoscopy is not possible, mainly due to opacification of the transparent media (e.g., mature cataract or vitreous haemorrhage), US can guide the ophthalmologist in diagnosing disease and choosing treatment. The superficial location and cystic structure of the eye make US ideal for imaging of the eye. Moreover, dynamic study helps distinguish between various conditions that would otherwise be difficult to differentiate in some clinical setting, such as vitreous, retinal, and choroidal detachment. US is also good technique for detecting other pathologic conditions such as lens dislocation, vitreous haemorrhage, asteroid hyalosis, optic disc drusen, and tumors (e.g., choroidal melanoma, metastases, hemangioma). An understanding of the basic anatomy of the eye, the US technique, and common entities that affect the ocular globe will allow radiologists to offer this valuable imaging modality to patients and referring clinicians. This article focuses on the US anatomy and pathologic conditions that affect the posterior ocular segment.Teaching points• US is specially indicated when ocular fundus cannot be assessed on ophthalmoscopy.• Multipurpose equipment with high-frequency transducers is optimal for imaging the eye.• Ultrasound can reliably depict ocular anatomy and pathology as detachments and tumours.• Dynamic examination is vital for distinguishing certain pathologic conditions as detachments.Electronic supplementary materialThe online version of this article (doi:10.1007/s13244-016-0471-z) contains supplementary material, which is available to authorized users.

Correlation of B-scan, CT scan and biopsy findings in orbital masses (space occupying lesions)

“…Ultrasound is an easily available initial imaging modality which can be performed for the evaluation of these cases. The superficial location and cystic structure of globe render themselves for characterization of these lesions [6].…”

Ultrasonographic assessment of the lens

“…[1][2][3] On placing the probe along the lateral longitudinal axis, the nasal aspect of the retina, ciliary body, the lens in its entirety, iris, angle and peripheral cornea can be appreciated easily. Using this technique, the anatomy of the lens can be studied in terms of its width along the horizontal and anteroposterior extent; similarly, by placing the probe along the inferior longitudinal axis, the vertical width of the lens can be defined, along with the anteroposterior thickness.…”

Simple way to optimise ultrasonographic visualisation of the retinal periphery and anterior segment structures

“…On B-scan, the normal spikes correspond to anterior lens capsule, posterior capsule, hypoechoic vitreous followed by the first high spike of the retina followed by the sclera. The retrobulbar fat is echogenic, and between this, the optic nerve can be seen as a tube-like hypoechoic channel extending from the sclera posteriorly towards the apex 1 2…”