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 SPELT 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. SPELT 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 hypoperfusionj 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 (beta=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.