When to Repeat CT Scan in Hemorrhagic Stroke
Obtain routine repeat CT scans at 6 hours and 24 hours after symptom onset for all patients with spontaneous intracerebral hemorrhage, and perform immediate repeat CT for any neurological deterioration regardless of timing. 1
Standard Timing Protocol for Stable Patients
The American Heart Association provides clear guidance on serial imaging for hemorrhagic stroke:
Perform the first repeat CT at approximately 6 hours after symptom onset to capture the critical window when most hematoma expansion occurs—26% of patients show substantial expansion within the first hour, with an additional 12% by 20 hours. 1, 2
Obtain a second repeat CT at 24 hours after symptom onset to document final ICH volume and exclude delayed complications, as hematoma expansion after 24 hours is extremely rare (0%). 1, 2
Serial head CT within the first 24 hours is useful to evaluate for hemorrhage expansion in all patients with spontaneous ICH and/or intraventricular hemorrhage (IVH). 1
High-Risk Patients Requiring Closer Monitoring
Patients with low Glasgow Coma Scale (GCS) scores or neurological deterioration require more frequent serial CT scans to evaluate for hemorrhage expansion, hydrocephalus, brain swelling, or herniation. 1
Key clinical scenarios demanding heightened surveillance:
Impaired level of consciousness limits neurological examination reliability, making imaging essential for detecting complications. 1
Anticoagulated patients have a 3-fold increased risk of hemorrhage progression (26% vs 9%) and warrant closer monitoring with potentially more frequent imaging. 2, 3
Delayed intraventricular hemorrhage occurs in 21% of patients with no initial IVH, sometimes beyond 24 hours, and is independently associated with mortality and poor outcomes. 1, 2
Immediate Repeat CT Indications
Any neurological deterioration mandates immediate repeat CT regardless of the scheduled protocol. 1, 2
Specific triggers for urgent imaging include:
- Decline in level of consciousness or drowsiness 1
- Change in Canadian Neurological Scale score ≥1 point 1
- Change in NIHSS score ≥4 points 1
- New or worsening focal neurological deficits 1
- Signs of elevated intracranial pressure 1
Clinical Monitoring Between Scans
Perform hourly neurological assessments including level of consciousness, symptom severity, and blood pressure between scheduled CT scans. 1, 2
More frequent assessments are required as individual patient condition dictates, particularly for those with:
- GCS scores declining from baseline 1
- Anticoagulation therapy requiring reversal 2, 3
- Large initial hemorrhage volume 1
Risk Stratification Using Initial CT
CT angiography (CTA) within the first few hours may be reasonable to identify patients at risk for subsequent hematoma expansion through detection of the "spot sign." 1
Non-contrast CT markers predicting expansion risk include:
- Heterogeneous densities within the hematoma 1
- Irregularities at hematoma margins 1
- Presence of IVH on initial scan 1
These markers influence triage decisions, monitoring intensity, and outcome prognostication. 1
Critical Pitfalls to Avoid
Do not delay repeat imaging when neurological deterioration occurs—obtain immediate CT regardless of whether the patient is within or beyond the scheduled 6-hour or 24-hour timepoints. 1, 2
Do not assume stability based solely on time elapsed—delayed IVH can occur beyond 24 hours and requires emergency intervention. 1, 2
Do not underestimate hemorrhage progression risk in anticoagulated patients—they require more vigilant monitoring due to 3-fold higher progression rates. 2, 3
Do not skip the 24-hour scan in stable patients—this documents final hematoma volume and is essential before initiating anticoagulation or antiplatelet therapy for secondary prevention. 1, 2