There are few reports regarding brain imaging in patients with SAE. Two recent small prospective studies of SAE reported abnormal imaging findings in the majority of patients.46,47 Lesions in the subcortical white matter, with imaging appearance consistent with vasogenic edema (e.g., increased signal on T2-weighted imaging, decreased signal on diffusion-weighted imaging, increased apparent diffusion constant), was the most common presentation (Figure 2). Size and number of lesions varied considerably across patients. In one study, all patients who eventually died had abnormal imaging.46 Imaging in related conditions may also be informative. Posterior reversible encephalopathy syndrome (PRES) is a clinical radiographic syndrome characterized by headache, confusion, seizures, and visual loss.48 It is associated with white-matter edema primarily affecting the posterior occipital and parietal lobes in a variety of conditions, including hypertension and immunosuppression. PRES was associated with infection or sepsis in 7%–24% of patients in two recent retrospective studies.49,50 A neuroimaging case series of eight ICU patients who were diagnosed with delirium (no focal neurological findings) found white-matter hyperintensities in six and mild atrophy in one.17 No patient had ischemic/hemorrhagic lesions, and neuroimaging in this small case series did not lead to new diagnoses or immediate changes in therapy. A retrospective study of ICU patients who underwent neuroimaging because of neurological changes such as alteration in mental status, confusion, delirium, or coma, reported imaging abnormalities in 64% (41/64), including seven in which the initial neuroimaging examination was normal.51 The most common abnormalities were atrophy and white-matter hyperintensities. Patients with and without neuroimaging findings did not differ in age, length of hospitalization, time in ICU, or outcome. Risks and benefits must be weighed before obtaining any brain imaging. The use of MRI in comparison with CT affords a more detailed illustration of the brain, more specifically, the white matter. Its use is limited in the unstable patient, given the duration to complete the study, and a head CT offers a better alternative in these cases.