When should a CT brain scan be repeated in a patient with an intracranial (IC) bleed?

When to Repeat CT Brain for Intracranial Bleed

Immediate Repeat CT: Clinical Deterioration Mandates Imaging

Any neurological deterioration whatsoever requires immediate repeat CT regardless of scheduled protocol or time since initial scan. 1, 2 This is the single most important principle—do not delay imaging when the patient worsens clinically.

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Evidence-Based Timing Protocol for Spontaneous Intracerebral Hemorrhage

For patients with spontaneous ICH (non-traumatic):

• Obtain repeat CT at 6 hours after symptom onset for all patients with stable neurological examination 1

  • This captures the critical window when most hematoma expansion occurs (26% within first hour, additional 12% by 20 hours) 1
  • Anticoagulated patients have 3-fold increased risk of progression (26% vs 9%) and require this scan regardless of stability 1, 2

• Obtain final CT at 24 hours to document final hematoma volume and exclude delayed intraventricular hemorrhage 1

  • Delayed IVH occurs in 21% of patients with no initial IVH, sometimes beyond 24 hours 1
  • Hematoma expansion after 24 hours is extremely rare (0%) 1

• For epidural hematoma managed conservatively: Obtain repeat CT at 6 hours, then again at 24 hours if stable, then consider stopping at 36 hours if GCS remains 15 with stable imaging 3

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Traumatic Brain Injury: Severity-Based Approach

Mild TBI (GCS 13-15) with Initial ICH

For patients NOT on anticoagulation:

• Do not routinely repeat CT if neurologically stable with normal examination 1, 2, 4
• The negative predictive value of a normal neurologic examination is 100% 5
• Only 1% require neurosurgical intervention, and these patients show clinical deterioration first 5, 4

Exception—High-risk ICH patterns requiring repeat imaging even if stable:

• Subfrontal/temporal intraparenchymal contusion (53% progression rate) 4
• ICH volume >10 mL 4
• Age >65 years 4

Mild TBI on Anticoagulation with NEGATIVE Initial CT

For patients on warfarin, heparin, or NOACs with normal initial CT:

• Discharge without repeat imaging or observation if neurologically intact at baseline 6, 2
• Delayed ICH rate is only 1.4-2% in observed patients, with <1% requiring intervention 6, 7
• The largest study of 916 NOAC patients found 1.5% delayed ICH on repeat scan, but zero deaths or neurosurgical interventions 6
• Exception: Consider 24-hour observation with repeat CT for patients >80 years with loss of consciousness or GCS <15 2

Mild TBI on Anticoagulation with POSITIVE Initial CT

• Obtain repeat CT at 6-24 hours regardless of clinical stability due to 3-fold increased progression risk 1, 2, 3
• Hold anticoagulation and consult neurosurgery 2

Moderate to Severe TBI (GCS ≤12)

• Routine repeat CT is indicated regardless of neurological status 2
• These patients are at high risk for progression requiring intervention even without clinical change 2

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Algorithm for Implementation

1. Obtain baseline non-contrast CT and document GCS, neurological exam, anticoagulation status 1

2. Determine bleed type:

   • Spontaneous ICH: Follow 6-hour and 24-hour protocol 1
   • Traumatic ICH: Use severity-based approach above

3. Assess anticoagulation status:

   • On anticoagulation + positive CT: Repeat at 6-24 hours regardless of stability 1, 2
   • On anticoagulation + negative CT: Discharge without repeat imaging if neurologically intact 6, 2
   • Not anticoagulated + mild TBI: No routine repeat imaging unless high-risk pattern 4, 8

4. Perform hourly neurological assessments between scheduled scans 1

5. Obtain immediate unscheduled CT for any deterioration: decreased GCS, new focal deficit, worsening headache, vomiting, pupillary changes 1, 2, 3

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Critical Pitfalls to Avoid

• Delaying repeat imaging when neurological deterioration occurs—this is the most dangerous error; obtain immediate CT regardless of scheduled protocol 1, 2

• Performing routine repeat CT in mild TBI patients with stable exam and no anticoagulation—this leads to overutilization without changing management, with intervention rates of only 0.6% based on imaging alone vs 2.7% based on clinical change 8

• Underestimating hemorrhage progression risk in anticoagulated patients—these patients require more vigilant monitoring and scheduled repeat imaging even when stable 1, 2

• Discontinuing anticoagulation unnecessarily after negative initial CT—thromboembolic risk may outweigh the small risk of delayed hemorrhage (<1%) 2

• Failing to recognize high-risk ICH patterns (subfrontal/temporal contusion, volume >10 mL) that warrant repeat imaging despite mild TBI and clinical stability 4