From the Guidelines
For a CT scan of the brain in a patient with head trauma after a fall, it is typically ordered without contrast. A non-contrast CT is the standard initial imaging study for acute head trauma because it can quickly identify acute hemorrhage, fractures, and mass effect that may require urgent intervention 1. According to the American College of Radiology (ACR) Appropriateness Criteria, noncontrast head CT is usually appropriate for the initial imaging of patients with acute head trauma that is mild, moderate, or severe 1.
The use of contrast in the trauma setting could potentially delay critical care and might be contraindicated in patients with unknown renal function or allergies. Contrast-enhanced CT is more appropriate for follow-up imaging when there is concern for vascular injuries, infection, or when trying to differentiate between tumor and edema, but it is not the first-line imaging choice in the acute trauma setting 1.
Some key points to consider when ordering a CT scan for a patient with head trauma include:
- The patient's Glasgow Coma Score (GCS) and the presence of any focal neurologic deficits
- The mechanism of injury and the presence of any other injuries
- The patient's medical history, including any history of coagulopathy or renal disease
- The potential benefits and risks of using contrast in the trauma setting
Overall, a non-contrast CT provides sufficient information for initial management decisions in head trauma cases, and its use is supported by the ACR Appropriateness Criteria and other clinical guidelines 1.
From the Research
CT Scan for Head Trauma
- The initial CT scan for head trauma is usually done without contrast enhancement, as stated in the study 2.
- The value of CT is the demonstration of scalp, bone, extra-axial hematomas, and parenchymal injury, and it is rapid and easily done in the presence of multiple monitors that many trauma patients have in place 2.
- CT is the modality of first choice for evaluating head trauma, as it is quick, safe, and effective in evaluating for life-threatening intracranial hemorrhage and mass effect 3.
Indications for Contrast
- There is no specific mention of the use of contrast in the initial CT scan for head trauma in the provided studies.
- However, it is mentioned that MRI is more sensitive for all posttraumatic lesions other than skull fracture and subarachnoid hemorrhage, and can demonstrate parenchymal spinal cord injury 2.
- MRI will be used increasingly to study early head injury because of its ability to measure cerebral blood flow, cerebral blood volume, and the location and extent of cerebral edema 2.
Imaging Protocols
- A comprehensive "outside-to-inside" approach to head trauma imaging is recommended, discussing not only common findings but also subtle "should not miss" findings and their clinical correlation 3.
- The study 4 describes the indication for imaging, imaging modalities, recommended imaging protocols, and imaging findings of primary and secondary injuries, including pitfalls of each pathology.