What is the recommended follow-up computed tomography (CT) head timing post cerebellar stroke?

Follow-Up CT Head After Cerebellar Stroke

Noncontrast CT head should be performed when clinically indicated to evaluate for life-threatening complications such as hemorrhagic conversion, mass effect, brainstem compression, and obstructive hydrocephalus, rather than on a routine fixed schedule. 1

Clinical Monitoring Framework

The decision for follow-up imaging in cerebellar stroke is driven by clinical deterioration rather than routine protocols. Serial CT findings in the first 2 days are useful to identify patients at high risk for developing symptomatic swelling. 1

High-Risk Features Requiring Close Monitoring

Patients with cerebellar infarction should be monitored for specific clinical and radiological predictors of space-occupying edema 1:

Clinical predictors:

• Progressive impairment of consciousness 1
• Diplopia or other cranial nerve palsies 1
• Progressive ataxia with pyramidal signs 1
• Signs of brainstem compression (hypertension, bradycardia) 1
• Nausea, vomiting, and progressive headaches 1

Radiological predictors on initial imaging:

• Hypodensity affecting ≥2/3 of the cerebellar hemisphere 1
• Compression or displacement of the 4th ventricle 1
• Obstructive hydrocephalus 1
• Displacement of the brainstem 1
• Compression of the basal cisternae 1
• Hemorrhagic transformation of the cerebellar infarction 1

Imaging Recommendations

When to Obtain Follow-Up CT

Immediate repeat CT is indicated for:

• Any neurological deterioration (declining consciousness, new focal deficits, signs of herniation) 1
• Clinical signs suggesting hemorrhagic conversion (seizures, severe headache, novel acute deficits) 2
• Patients with high-risk radiological features on initial imaging who remain in intensive care 1

Routine 24-hour CT is NOT recommended for:

• Clinically stable or improving patients with cerebellar stroke 3, 2
• Patients without high-risk features on initial imaging 4

Optimal Imaging Modality

Noncontrast CT head is the preferred modality for surveillance because of its quick repeatability, ease of comparison to prior examinations, and superior sensitivity for detecting hemorrhagic conversion and mass effect. 1

Avoid contrast-enhanced CT as it can paradoxically cause confusion with hemorrhagic conversion or other aggressive lesions. 1

Triage and Management Algorithm

Initial Assessment (First 24-48 Hours)

1. Admit all cerebellar stroke patients with high-risk features to intensive care or stroke unit with neuromonitoring capabilities 1

2. Obtain early neurosurgical consultation to facilitate planning for potential decompressive suboccipital craniectomy or ventriculostomy if deterioration occurs 1, 5

3. Perform baseline noncontrast CT to establish extent of infarction and identify early complications 1

Surveillance Strategy

For high-risk patients (those with ≥2/3 cerebellar hemisphere involvement or mass effect):

• Clinical neurological assessments every 1-2 hours 1
• Repeat CT immediately if any clinical deterioration 1
• Consider repeat imaging within 24-48 hours even if stable, given approximately 20% of cerebellar infarction patients develop radiographic signs of mass effect with neurological deterioration 5

For low-risk patients (small infarcts, no mass effect, clinically stable):

• Clinical monitoring with examination-based approach 3, 2
• CT only if neurological deterioration occurs 1, 2
• No routine 24-hour imaging required 3, 4, 2

Critical Pitfalls to Avoid

Do not delay imaging when clinical deterioration occurs. Signs of impending brainstem compression appear late before herniation and can lead to sudden respiratory arrest. 1

Do not perform routine 24-hour CT in stable patients. Recent evidence shows routine follow-up imaging rarely changes management in clinically stable patients (only 12.5% show clinically relevant findings, and most are in high-risk groups). 4

Do not rely solely on initial CT. Cerebellar strokes are notoriously difficult to diagnose on early CT, which can be normal despite significant infarction. 6 Clinical examination of cerebellar function is essential and often omitted. 6

Do not use contrast-enhanced studies for routine surveillance as contrast enhancement can mimic hemorrhagic conversion or other pathology. 1

Special Considerations

Approximately 20% of cerebellar infarction patients develop mass effect requiring potential surgical intervention (decompressive suboccipital craniotomy). 5 Therefore, all patients with cerebellar stroke should have early neurosurgical consultation and be managed in centers capable of providing timely surgical decompression. 1

For patients who underwent thrombolysis or thrombectomy, the same principles apply: imaging should be driven by clinical status rather than routine protocols, though these patients may warrant closer monitoring given higher hemorrhagic transformation risk. 3, 2