Diagnostic imaging techniques are becoming increasingly valuable in the evaluation of ophthalmologic patients. Recent advances in technology have greatly improved resolution and now provide physiologic as well as anatomic information. Although plain film radiology, computed tomography, and, more recently, magnetic resonance imaging are important modalities, other noninvasive techniques have important new applications. In this chapter we examine ultrasound, positron emission tomography, and nuclear medicine as they are currently used in evaluation of the patient with neuro-ophthalmologic symptoms.