Noncontrast CT scans are often employed in emergency situations (to quickly rule out most acute abnormalities), to evaluate bone in great detail, or as a screening test. It excels in demonstrating acute blood (EDH, SDH, IPH, SAH), fractures, foreign bodies, pneumocephalus, and hydrocephalus. It is weak in demonstrating acute stroke (DWI MRI is preferred), and often has poor signal quality in the posterior fossa (due to bone artifact).
IV enhanced CT scans are used primarily for imaging neoplasms or vascular malformations, especially in patients with contraindications to MRI. All CT contrast agents contain iodine. A typical IV dose of contrast: 60–65 ml o fe.g.Isovue3 00® which delivers 18–19.5 grams of iodine.
Cranial CT (CCT) scans and hospital admission are increasingly performed to rule out intracranial hemorrhage in patients after minor head injury (MHI), particularly in older patients and in those receiving antiplatelet therapy. This leads to high radiation exposure and a growing financial burden
After mTBI, worsening of repeat head CT finding is seen in a third of patients and is associated with worse outcomes. A substantial fraction of patients who require operative intervention will have no clinical changes in the first 8 hours, supporting the value of repeat head CT within this time frame 1).
Neurologic examination can be trusted and is reliable in pediatric blunt TBI patients in determining when an RHCT scan is necessary. Aziz et al. recommend that RHCT is required routinely in patients with intracranial hemorrhage with GCS score of 8 or less and in patients with GCS greater than 8 and that RHCT be performed only when there are clinical indications 2).
Routine repeat head CT scan is not warranted in patients with normal neurologic examination. Routine repeat head CT scan does not supplement the need for neurologic examination for determining management in patients with traumatic brain injury 3).
Since 2000, The Department of Emergency Medicine, University of Cincinnati, Cincinnati, OH, standard practice has been to obtain a repeat head computed tomography (CT) at least 6 hours after initial imaging. Patients are eligible for discharge if clinical and CT findings are stable. Whether this practice is safe is unknown.
Discharge after a repeat head CT and brief period of observation in the ED allowed early discharge of a cohort of mild TBI patients with traumatic ICH without delayed adverse outcomes. Whether this justifies the cost and radiation exposure involved with this pattern of practice requires further study 4).
High rates of head CT use for patients with hemorrhagic stroke are frequently observed, without an association with decreased mortality. A higher number of physicians consulted was associated with high-intensity use of head CT 5).