Chapter VI-3. How to Read a Head CT in a Patient with Head Trauma

CT interpretation is most efficient when specific findings related to the patient’s clinical presentation are sought. In patients with head trauma, first, look for large subdural, epidural, or intracerebral hematomas that require emergency surgical treatment.

Second, using a targeted approach, review each slice for intra and extra-axial blood collections, midline shift, ventricular compression or enlargement (hydrocephalus), and fractures (Table 1). Examine the brain adjacent to the site of impact (evident by scalp swelling or fracture) for coup injures, as well as opposite the site of impact for contra-coup injuries. Examine brain, subdural, and bone windows.

Table 1 Targeted Approach to Head CT Interpretation in Patients with Head Trauma

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Table 1 Targeted Approach to Head CT Interpretation in Patients with Head Trauma

Examine each slice for:

1. Extra-axial blood—SDH, EDH, traumatic SAH (Figures 1, 2, 3, and 4)

2. Intraparenchymal blood—Hemorrhagic contusion and hematoma (Figure 5)

3. Midline shift—May be greater than the width of a SDH due to underlying cerebral edema (Figure 3)

4. Ventricles:

Compressed (unilateral or bilateral)—Mass effect of hematoma or cerebral edema (Figure 6)

Enlarged (usually asymmetrical)—Obstruction to CSF flow (hydrocephalus) (see Introduction to Head CT, Figure 2 in Section VI: Head CT, and Patient 2, Figure 11 in Basilar Skull Fracture, Pneumocephalus)

5. Scalp swelling—Indicates site of impact to the head (Figure 2)

6. Fractures—Examine bone windows and “scout” lateral skull view (Figures 2B, 9, and 10)

7. Pneumocephalus (intracranial air)—A sign of open skull fracture (seen best on bone windows) (see Patient 2)

8. Craniofacial sinuses—Blood or air/fluid level; examine bone windows (Figures 2B, 9, and 10)

Figure 5

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Intracerebral hematomas.

Hemorrhagic contusions (intra-axial blood) involving the frontal lobes.

Figure 6

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Diffuse axonal injury.

Slit-like lateral ventricles due to diffuse cerebral edema. A small (petechial) hemorrhage is caused by shear forces at the gray/white interface when the brain is subjected to a forceful impact.