Preface "MRI in the ER".

D iagnostic imaging now plays an essential role in the care of emergency patients. The catalyst for this reliance on imaging studies has mainly been the exponential increase in computed tomography (CT) utilization over the last couple of decades. CT remains the ‘‘workhorse" imaging modality in the emergency room (ER) as it is familiar to all radiologists. It is an accurate modality that is fast, noninvasive, readily available, easily accessible, and surveys broadly for disease or injury. CT in emergency patients provides many advantages such as increase in the physician’s level of certainty for diagnosing or ruling out pathology and more timely surgical intervention when necessary. The use of CT is also efficient, improving turnaround times and helping to reduce hospital admissions. However, concerns for indiscriminate radiation exposure have made even more important the routine reliance on evidence guidelines for appropriate CT utilization in the ER and the use of alternative imaging modalities when pertinent. The rapid evolution of magnetic resonance (MR) scanners with the increasing availability of rapid sequences easier to use in challenging emergencies with acutely ill patients potentially having a decreased breath-hold capability, neurological impairment, or other difficulties in cooperating with lengthy MR examinations and the obvious advantage of lack of