Serial single-photon emission computed tomographic and transcranial Doppler measurements for evaluation of vasospasm after aneurysmal subarachnoid hemorrhage

OBJECTIVE: To assess the clinical value of serial single photon-emission computed tomographic (SPECT) measurements after aneurysmal subarachnoid hemorrhage (SAH). METHODS: Thirty-two patients were studied prospectively during the first 26 days after SAH with repeated SPECT measurements, clinical examinations, and transcranial Doppler recordings. Time trends were analyzed with a general linear model. A final SPECT measurement was performed after 1 year. RESULTS: A mean of 2.6 (range, 1-5) SPECT measurements revealed a significant (P = 0.001) quadratic curve consistent with initial hypoperfusion and then with hyperperfusion during the acute stage. SPECT findings were significantly associated with transcranial Doppler recordings (P = 0.016) and clinical assessments (P = 0.008). Patients fulfilling clinical and transcranial Doppler criteria for vasospasm demonstrated a more pronounced relative hypoperfusion-hyperperfusion time course. A multivariate logistic regression analysis identified SPECT measurements obtained during Days 7 to 14 after the SAH as the only independent predictor (β = 0.042, P = 0.02) for impaired perfusion after 1 year. CONCLUSION: Serial SPECT measurements after aneurysmal SAH demonstrate that regional changes in cerebral perfusion follow a nonlinear time trend, and repeated measurements are necessary. This observation, as well as the low feasibility of SPECT, restricts the clinical value of such measurements.