small hemorrhage may not be detected by CT, and in such cases, blood in the cerebrospinal fluid (CSF) is the only diagnostic finding However, this is an uncommon situation in the pediatric population As with laboratory testing, few children with headaches who come to the ED will require an emergent imaging study A child with a ventricular shunt may require a shunt series in addition to CT or MRI Likewise, sinus radiographs are rarely indicated in pediatric patients because the diagnosis is almost always made on clinical grounds Occasionally, a child with multiple episodes of an apparent sinus infection will require a CT scan of the sinuses, but this is normally done as an outpatient However, it should be noted that the Image Gently campaign has changed the landscape of pediatric imaging Utilizing radiation-free imaging modalities, such as ultrasound and MRI, is encouraged when possible As a result, MRI usage in the pediatric population has increased Scheinfeld et al looked at MRI usage trends over a 5-year period and found an increased utilization rate This was especially true for neuroimaging, particularly children with headaches The two imaging modalities that are most widely used clinically to obtain detailed information about intracranial abnormalities are CT and MRI, each of which has advantages and disadvantages CT is more readily available on an emergent basis (many EDs have a dedicated scanner) Scanning time is also much shorter for CT, and the potentially unstable patient can be more easily observed and monitored These characteristics make CT the test of choice to evaluate patients at risk for problems such as intracranial hemorrhage, head trauma, cerebral edema, hydrocephalus, and herniation syndrome Recent advances in MRI approaches have reduced the time needed for some MRI scans For example, 1-minute ultrafast brain MRI technology is now being developed and utilized Researchers are also looking at using MRI to replace CT as a screening tool, including those with traumatic brain injury, stroke, and identification of skull fractures in cases of potential abusive head trauma It is possible, and highly probable, that within the next decade MRI will replace CT as a screening tool for brain imaging in children CT does not offer the quality of image resolution provided by MRI Smaller lesions, particularly those of the posterior fossa and brainstem, are more reliably detected by MRI This is true even when the CT scan is performed using contrast material Consequently, MRI is superior for children suspected of having a brain tumor who have a normal neurologic examination and no signs of elevated ICP If these patients have a normal head CT scan in the ED, they will likely also require an outpatient MRI Such duplication of testing is costly, time consuming, and usually unwarranted While the use of MRI in the acute management of stroke has led to a substantial increase in overall scanning