What is the preferred imaging study for a patient with a history (hx) of intracranial bleed presenting with symptoms of occipital headache radiating to the frontal area?

Preferred Imaging for Patient with History of Intracranial Bleed and Recurrent Headache Symptoms

For a patient with a history of intracranial hemorrhage presenting with recurrent occipital headache radiating frontally, non-contrast CT head is the preferred initial imaging study, followed by CT angiography (CTA) or MRI with contrast if the clinical picture suggests underlying vascular pathology or if non-contrast CT is negative but suspicion remains high. 1

Initial Imaging Approach

Non-contrast CT head (rating 9/9 "usually appropriate") is the gold standard for detecting acute or recurrent parenchymal hemorrhage and should be performed first in any patient with prior intracranial bleed presenting with similar symptoms. 1 This modality:

• Rapidly identifies acute hemorrhage, hematoma expansion, or new bleeding with 98% sensitivity 2
• Detects complications such as hydrocephalus or mass effect requiring urgent intervention 2
• Provides immediate availability in emergency settings 2
• Serves as the baseline for determining whether additional vascular imaging is needed 1

Subsequent Vascular Imaging

If non-contrast CT shows hemorrhage or if clinical suspicion remains high despite negative CT, proceed immediately to CTA head (rating 8/9) while the patient is still on the CT scanner. 1 The rationale includes:

• CTA detects underlying vascular malformations, aneurysms, or arteriovenous malformations with >90% sensitivity and specificity 3, 4
• In patients with proven hemorrhage, 42-46% will have vascular abnormalities detected on CTA (28% aneurysms, 11% AVMs) 4
• CTA can be obtained immediately following non-contrast CT without moving the patient 1
• The sensation of headache recurrence in a patient with prior bleed raises concern for re-bleeding from an underlying vascular lesion 3

Alternative: MRI-Based Approach

MRI head without and with IV contrast (rating 9/9) is preferred over CT when the clinical presentation is subacute or when superior soft-tissue characterization is needed. 1 Consider MRI when:

• The patient is stable and there is time for a longer study 1
• You need to evaluate for underlying enhancing mass or vascular malformation with greater anatomic detail 1
• Assessing the age of hemorrhage is clinically important, as MRI is superior to CT for dating blood products 5, 6
• MRA can be added to evaluate for vascular malformations without additional contrast 1

Venous Imaging Considerations

If there is any concern for cerebral venous sinus thrombosis (which can cause hemorrhage and headache), add CT venography (rating 7/9) or MR venography (rating 7/9) to the initial evaluation. 1, 7 This is critical because:

• Venous thrombosis can present identically with headache and intracranial hemorrhage 7
• Missing this diagnosis has catastrophic consequences including stroke and death 7
• Venography should be performed within 24 hours when clinically suspected 7

Clinical Decision Algorithm

1. Perform non-contrast CT head immediately to detect acute hemorrhage 1
2. If hemorrhage is present OR if CT is negative but clinical suspicion is high (prior bleed history, severe headache, neurological changes): proceed to CTA head 1, 3
3. If venous pathology is suspected (progressive headache, papilledema, atypical features): add CT or MR venography 1, 7
4. If initial CT and CTA are negative but symptoms persist: consider MRI with contrast and MRA for superior detection of small vascular lesions or underlying masses 1

Critical Pitfalls to Avoid

• Do not rely solely on non-contrast CT in a patient with prior hemorrhage and recurrent symptoms, as 42% of hemorrhage patients have underlying vascular abnormalities that require CTA for detection 4
• Do not delay vascular imaging if the clinical picture suggests vascular pathology, as the number needed to scan to find a clinically significant abnormality (other than incidental aneurysm) is only 61 patients 8
• Do not use MRI as the initial study in acute presentations, as CT is faster, more available, and superior for detecting acute hemorrhage 2
• Do not forget venous imaging if the headache pattern suggests elevated intracranial pressure (progressive, positional, associated with visual changes), as cerebral venous thrombosis can mimic arterial pathology 7

The radiation exposure and contrast risks of CTA are justified given the 42-46% yield of detecting vascular abnormalities in patients with intracranial hemorrhage, particularly when the patient has a history of prior bleed. 4