Transcranial Doppler assessment of cerebral vasospasm.

This review summarizes the use of transcranial Doppler (TCD) for assessment of cerebral vasospasm. The basic hemodynamic principles are presented, and used as a basis for discussing findings and interpretation methods. The need for additional information and measurements to correctly interpret TCD velocities is analyzed, and the use of a special extracranial Doppler technique is recommended. The advantages and limitations of the 'Lindegaard Index' (LI) are discussed. The recent advances in the use of TCD for cerebral autoregulation testing are opening up a new and promising avenue in diagnosis, monitoring and treatment of cerebral vasospasm.