Orbital tissue differentiation with standardized echography.

The standardized A-scan (Kretztechnik 7200 MA) supplemented by contact B-scan and Doppler ultrasound is a time-tested, highly reliable, and noninvasive tool for the evaluation of patients presenting with signs or symptoms suggesting an orbital lesion. Diseases of the orbital adipose tissue, extraocular muscles, optic nerves and periorbital sinuses are detectable within minutes by the experienced examiner. More than 60 types of orbital lesions can then be differentiated, localized, measured, and schematized. While the value of orbital CT scanning has been widely accepted, standardized echography is now also being recognized as an important modality in the diagnosis and management of orbital and periorbital disease. The use of standardized echography results in more frequent and more accurate tissue differentiation, specifically: (1) standardized tumor patterns closely correlate with histologic diagnoses, (2) vascular flow detection and compression testing (hard or soft), (3) detection and diagnosis of optic nerve sheath distention due to increased subarachnoid fluid (eg, benign intracranial hypertension), and (4) greater sensitivity in detecting mild extraocular muscle thickening (eg, Graves' disease). Additional advantages are the noninvasive nature of the procedure (no radiation) and portability of the equipment.