What Is the Best Timing of Repeated CT Scan in Mild Head Trauma with an Initially Positive CT Scan?

Background: Mild traumatic brain injury (MTBI) is among the most common causes of emergency admission. Current guidelines have clearly evidenced risk factors and neurologic signs that should suggest computed tomography (CT) of the head at admission and indications for the first repeated CT scan. However, the role and frequency of further repeated CT scans after an initially positive scan are still unclear. Methods: We retrospectively analyzed 222 patients admitted in our hospital for clinical observation after an MTBI and a positive initial scan. Repeated CT scans were categorized according to timing from the first scan. All the scans were evaluated for the presence of posttraumatic lesions. We classified the data in 3 groups according to the timing of CT scans: A (CT scans at t0-t12-t24), B (t0-t12-t48), and C (t0-t24-t48). Differences in worsening or stability of posttraumatic lesions were compared by the χ2 test. Results: 146 CT scans were performed at t12, 81 at t24, and 143 at t48. The initial CT scan was positive for epidural hematoma in 17 cases, subdural hematoma in 106, subdural hygroma in 10, intracerebral contusion in 110, subarachnoid hemorrhage in 109, and intraventricular hemorrhage in 12. None of the posttraumatic lesions showed significant worsening or at the first or second CT scan in any of the 3 groups. Conclusions: The treatment of patients in clinically stable condition with an MTBI and posttraumatic intracranial lesions at initial CT scan has been shown to minimally benefit from repeated CT scans. Given neurologic stability, a control scan can be safely delayed up to 48 hours to avoid unnecessary scans.