Transcranial Doppler series part II: performing a transcranial Doppler.

Because of its portability, low cost, and quick, noninvasive nature, transcranial Doppler (TCD) has become a widely utilized exam to evaluate the basal cerebral arteries for various disease processes. The test is considered a "blind" and very difficult study by most vascular labs. Neurologists commonly order TCD, so the performance of it is slowly being adopted by neurodiagnostic labs. To perform a quality TCD, the technologist must be extremely skilled. The technologist must know where to place and how to angle the probe in order to insonate the vessels and must be familiar with the TCD equipment. The technologist should also have an understanding of what each vessel's waveform should look like under normal circumstances.