Ultrasound and Orbital Disorders

This represents an introduction to all the 11 chapters dedicated to the orbit. The role of ultrasound versus MRI and CT scan is developed, mainly useful for detection, localization, and characterization, but of little help to study the extension of an orbital lesion. A diagnostic algorithm is proposed in case of exophthalmos with or without dystopia. Also, special cases are discussed, such as the anterior palpable masses in children, lesions of the lacrimal fossa, and vascular exophthalmos (orbital varix and arteriovenous fistulae) for which color Doppler imaging plays a major role. Finally, fine-needle biopsy under ultrasound control is presented, mainly useful for posteriorly located malignant lesions (and hence treatable with chemo- or radiotherapy).