Understanding of delirium pathogenesis remains limited despite improved diagnosis, and elucidation of risk factors and prognosis. Major advances in neuroimaging offer the possibility of probing the mechanisms and networks involved in delirium and hence improving understanding of this often devastating syndrome. This review describes the current literature of imaging studies in delirium and related conditions, introduces some of the newer capabilities of neuroimaging with magnetic resonance imaging, positron emission tomography, and single photon emission computed tomography, and discusses how these techniques may be applied to the study of delirium. Despite considerable challenges in patient recruitment, study design, intersubject variability, and scanner and contrast agent availability, imaging offers great potential for the identification and clarification of pathogenic mechanisms of delirium and its long-term sequelae.T HE rapid advancement of neuroimaging methods over the last few decades has made available a wide array of tools for research and clinical management of brain disorders. Imaging can be used to quantify normal or pathologic physiology and to localize abnormalities to specific regions of the brain. In clinical studies, imaging results can also help to control for intersubject variation due to varying severity of related or comorbid pathologies. These capabilities of imaging could prove highly valuable in the study of delirium, an important and highly prevalent syndrome in elderly people, but one for which understanding of pathophysiology remains limited.In this review article, we discuss the shortcomings of our current understanding of delirium and distill from this a series of target questions about the pathophysiology of delirium that might be addressable by neuroimaging studies and whose answers would provide a major advance in the understanding of delirium. We survey the existing literature on imaging studies in delirium and highlight the gaps that remain. Subsequently, we introduce a number of newer neuroimaging techniques and describe how some of these methods might be used to answer our target questions about delirium. Finally, we consider the obstacles to performing such neuroimaging studies and discuss potential solutions. This article may provide a useful framework to guide future neuroimaging studies investigating the pathophysiology of delirium.