Evaluation of Intracranial Aneurysms in Children

Examination

Although ruptured aneurysms are very rare in children, there are some “red flags” that significantly influence diagnostic approach and urgency of treatment:

• Sudden, severe headache (thunderclap headache)
• Signs of elevated ICP: These signs are age-dependent and include impaired consciousness, lethargy, irritability, nausea and vomiting, tense or bulging fontanelle, and gaze abnormality (e.g., Parinaud syndrome). Urgent treatment is required.
• Signs of herniation in comatose patients: These include unilateral or bilateral mydriasis and a Cushing response (i.e., bradycardia and hypertension). Urgent treatment is required.

Laboratory Tests

Standard preoperative blood tests: These should comprise all basic tests, including a coagulation screen, as well as blood typing and crossmatching.

Radiologic Tests

CT scans

• Typically used for initial imaging: CT is the initial radiologic modality, especially in emergency situations. It is equally capable of detecting acute intracranial hemorrhage as MRI (91). Characteristic distribution of subarachnoid, intracerebral, or subdural hemorrhage should raise suspicion of a ruptured aneurysm in patients of all ages.
• CT angiography sensitive and specific: Multidetector row CTA has a high sensitivity and specificity for the detection of intracranial aneurysms (92).
• Consider radiation exposure risk: The risk of radiation exposure in children must be kept in mind. The risk of leukemia was estimated to be 1.9 cases per 10,000 head CT scans performed in children younger than 5 years (93). However, no head CT rules have been validated for vascular conditions in children, unlike in pediatric head trauma.

MRI

• Preferred in nonemergent cases: MRI/MRA should be preferred in nonemergent cases, especially with regard to avoiding radiation exposure in younger children (75).
• FLAIR and T2-weighted sequences: FLAIR and T2-weighted sequences are capable of detecting subarachnoid hemorrhage (94). Moreover, 3D TOF MRA, especially at 3 Tesla, can be used to depict intracranial aneurysms (95).

DSA

• Gold standard: DSA is considered the gold standard in the diagnostic approach to intracranial aneurysms and is used to inform treatment (75). In a large review of 429 diagnostic angiograms, only three (0.7%) complications occurred: two intraprocedural (0.5%) and one postprocedural (0.2%). None of the complications were neurological (96).

MRI/MRA and DSA in the evaluation of a proximal basilar artery aneurysm: (A) Axial 3D TOF MRA demonstrating the fusiform basilar artery aneurysm (yellow arrow). (B) Axial T2 MRI at a similar level showing the aneurysm (yellow arrow). (C) Sagittal postcontrast T1 magnetization-prepared- (MP-)RAGE MRI, revealing the position of the aneurysm (yellow arrow) relative to the ventral pons. (D) Maximum intensity projection (MIP) of TOF MRA demonstrating the aneurysm (yellow arrow). (E) DSA demonstrating the lumen of the aneurysm (yellow arrow) with injection of the left vertebral artery. (F) Rotational angiography allows for the generation of 3D reconstructions. In this case, 3D reconstruction demonstrated a secondary bleb (yellow arrow) from which the left anterior inferior cerebellar artery originates.

Nuclear Medicine Tests

• Not typically indicated: Nuclear medicine tests are generally not used in the evaluation of intracranial aneurysms in children.

Electrodiagnostic Tests

• Electroencephalogram: EEG may be indicated in patients presenting with seizures or symptoms suspicious of seizures.

Neuropsychological Tests

• Neuropsychological assessment: This is not performed on a routine basis, although it might be useful in selected cases or as part of a clinical trial. Neuropsychological testing may be useful when developmental delay and/or brain injury is a concern (42).

Correlation of Tests

The following parameters should be considered when formulating a treatment plan for a child with an intracranial aneurysm:

• Imaging results: The presence of subarachnoid hemorrhage on imaging may indicate rupture of an intracranial aneurysm. Additionally, imaging may reveal the aneurysm size, location, type, and morphology. Emergent intervention may be required to prevent further elevation of ICP, brain herniation, and/or further hemorrhage. Imaging may also reveal the presence of multiple aneurysms and/or additional cerebrovascular lesions in some patients.
• Unruptured aneurysm and presence of neurologic deficits: The presence of focal neurologic deficits may be secondary to mass effect or altered hemodynamics. Symptomatic patients may require more immediate intervention.
• Unruptured aneurysm, consider type, size, and location: Various features of unruptured intracranial aneurysms are associated with an increased risk of rupture in adult patients (97,98). These include large size, presence of lobulation, and location (anterior and posterior communicating arteries, basilar artery bifurcation, and posterior circulation). The presence of one or more of these features may indicate more immediate intervention is required. The type of aneurysm may suggest the etiology and, therefore, may indicate the need for additional treatment (for example, antibiotics for mycotic aneurysms of bacterial origin).
• Ruptured aneurysm on imaging and compromised clinical status: Patients with ruptured intracranial aneurysms require immediate stabilization. Emergent surgical or endovascular treatment may be indicated to prevent brain herniation and/or further hemorrhage. Children with unruptured intracranial aneurysms may be symptomatic or asymptomatic at presentation. Symptomatic patients may require more immediate intervention. The timing of intervention for asymptomatic patients may depend on the presence of high-risk features, as discussed below.
• Presence of red flag signs and symptoms on physical exam and presence of aneurysm: The presence of red flag signs and symptoms (thunderclap headache, signs of elevated ICP, and/or signs of brain herniation) indicates a need for urgent treatment and/or intervention.