Is a prophylactic brain scan indicated for a patient with a strong family history of cerebral aneurysms (cerebral artery aneurysms)?

From the Guidelines

Yes, it would be appropriate to order prophylactic brain imaging for patients with a strong family history of cerebral aneurysms, as they have a significantly increased risk of aneurysms compared to the general population. Screening is typically recommended if two or more first-degree relatives have had intracranial aneurysms or subarachnoid hemorrhages, as stated in the guidelines for the primary prevention of stroke from the American Heart Association/American Stroke Association 1. The preferred imaging modality is magnetic resonance angiography (MRA) without contrast, though CT angiography (CTA) is an acceptable alternative.

Key considerations for screening include:

• Initial screening is usually recommended starting at age 20 or at least 10 years before the earliest age at which a relative was diagnosed with an aneurysm
• If the initial scan is negative, follow-up imaging is typically done every 5-10 years
• The benefits of screening in this high-risk population outweigh the minimal risks associated with non-invasive imaging procedures, as the risk of aneurysms in people with a family history is approximately 4-fold higher compared to the general population 1. The guidelines for the management of patients with unruptured intracranial aneurysms also support considering family history as a factor in the selection of optimal management, highlighting the importance of screening in high-risk populations 1. Early detection allows for monitoring or intervention before a potentially catastrophic rupture occurs, thus prioritizing morbidity, mortality, and quality of life as outcomes.

From the Research

Indications for Prophylactic Brain Scan

A prophylactic brain scan may be indicated for a patient with a strong family history of cerebral aneurysms. The following points support this indication:

• Individuals with two or more first-degree relatives who have had aneurysmal subarachnoid haemorrhage (aSAH) have an increased risk of aneurysms and aSAH 2.
• Screening is recommended in first-degree members of families with familial SAH, as the yield is high 3.
• Independent predictors of aneurysm detection on MR angiography include female sex, pack-years of cigarette smoking, and duration of hypertension 4.

Risk Factors and Screening Recommendations

The following risk factors and screening recommendations are relevant:

• A history of treatment for ruptured or unruptured intracranial aneurysms and having three or more affected relatives are associated with a significantly higher risk of intracranial aneurysms 3.
• Siblings tend to have a higher risk of intracranial aneurysms than children of SAH patients, although the difference is not significant 3.
• Repeated screening should be considered in relatives who have been treated for familial intracranial aneurysms 3.
• Patients with a positive family history of aneurysms who are 30 years of age or younger may benefit from screening 5.

Natural History and Efficacy of Screening

The natural history of aneurysms and the efficacy of screening are important considerations:

• The prevalence of intracranial aneurysms may reach 20% in the subpopulation of patients with a family history of these lesions 5.
• The efficacy of screening depends on the pattern of aneurysm rupture, with screening potentially improving average life expectancy if aneurysms remain at risk for some time after formation 5.
• Long-term serial screening is advocated in individuals with a family history of aSAH, as the yield of long-term screening is substantial even after more than 10 years of follow-up and two initial negative screens 2.