CT angiography for evaluation of cerebral vasospasm following acute subarachnoid haemorrhage.

INTRODUCTION: Cerebral vasospasm (CV) is one of the most dreaded complications in patients who survive acute subarachnoid haemorrhage (SAH), and conventional cerebral angiography (DSA) is the gold standard for its diagnosis. We evaluated CT angiography (CTA) as a non-invasive alternative for diagnosis of CV and assessed if CTA could have a role in choosing appropriate treatment.
METHODS: Consecutive patients with SAH and suspected vasospasm were included when DSA was performed within 24 h from CTA. Two neuro-radiologists retrospectively analysed CTA and DSA studies independently. Assessment included presence of central and peripheral vasospasm and grading of severity of central CV. A treatment recommendation based on CTA was compared to actual treatment received.
RESULTS: Final analysis included 34 patients. CTA was more accurate for diagnosis of central then for peripheral CV with high sensitivity (reader 1, 91%; reader 2, 92%), specificity (reader 1, 73%; reader 2, 90%), accuracy, positive predictive value and negative predictive value for central vasospasm. For grading the severity of CV CTA's sensitivity, specificity and accuracy were high for most central arteries. The reader's recommendation of angioplasty according to CTA was significantly predictive of actual receipt of angioplasty but overestimated actual receipt of triple H treatment.
CONCLUSION: CTA is adequate for detecting central vasospasm in symptomatic SAH patients. A negative result should not prevent further investigation especially when evaluating arterial segments adjacent to metal artefacts from coils or clips. CTA is helpful in treatment decision making specifically regarding the need for balloon angioplasty.