Effectiveness of transcranial Doppler ultrasonography for the detection of vasospasm in the anterior cerebral arteries

The anterior cerebral arteries are often affected by vasospasm secondary to subarachnoid haemorrhage. The effectiveness of transcranial Doppler ultrasonography to detect this complication has still not been accurately determined. AIM. To assess the usefulness of transcranial Doppler ultrasonography for diagnosing vasospasm of the anterior cerebral arteries in patients with subarachnoid haemorrhage. We studied 56 patients between the 4th and 14th days of their subarachnoid haemorrhage; all of them were submitted to a contrast-enhanced neurovascular study and daily monitoring with transcranial Doppler ultrasonography. All the patients had a clinical degree of between 1 and 3 on the World Federation of Neurological Surgeons scale, 46 of them had aneurysms, and bleeding was intense in 20 cases (degree 3-4 on the Fisher scale). The frequency of angiographic vasospasm was 41% in the anterior cerebral arteries. The mean flow velocities in patients with vasospasm were 84.5 cm/s. The maximum peaks of mean blood flow rate were obtained on the tenth day. Sensitivity was 57.9% for flow rates equal to or above 87.5 cm/s, and the predictive positive value was 66.6%. No significant relation was found between the findings of the transcranial Doppler ultrasonography scan, the degree of clinical symptoms and the intensity of bleeding in the computerised axial tomography scan. The overall precision of the test was good, the specificity and predictive negative value were excellent, but sensitivity was low.