Role of single photon emission computed tomography and transcranial Doppler ultrasonography in clinical vasospasm

This report presents our experience with Transcranial Doppler (TCD) ultrasonography and Single Photon Emission Computed Tomography (SPECT) in the assessment of patients with aneurysmal subarachnoid haemorrhage (SAH). It was designed to evaluate clinical vasospasm with both TCD and SPECT and determine their diagnostic value. Twenty-eight consecutive patients were examined with both TCD and SPECT, performed within 24 hours of each other. They had a total of 45 TCDs and 46 SPECT scans. Eight patients (29%) developed clinical vasospasm, noted from day 2 to day 11 post subarachnoid haemorrhage; these patients underwent TCDs and SPECT scans when the diagnosis of vasospasm was made. Twenty patients (71%) did not demonstrate clinical vasospasm throughout their hospital stay and underwent TCDs and SPECT scans within the first 2 weeks of their SAH, mostly between day 2 and day 10, the period of greatest risk for vasospasm. TCD and SPECT sensitivity for clinical vasospasm was 100% and 50% respectively, their specificity was only 20% and 60%. TCD sensitivity for symptomatic vasospasm was found to be excellent, whereas SPECT was not found to be as useful. We conclude that TCD is the preferred method in the evaluation of patients with subarachnoid haemorrhage.