Ultrasonography and the more recently developed technique of computerized tomography (see the preceding chapter) should be used concurrently in the evaluation and diagnosis of suspected orbital pathology. Ultrasonography is easily performed and safe; it has no known complications or contraindications. Unique information concerning the position and acoustical quality of tumors can be obtained. However, the interpretation of the ultrasonogram can be quite difficult; highly sophisticated equipment is needed to obtain the finer resolution required to make tissue diagnosis.