Transcranial Holter and Carotid Stenosis

The Atys Medical TCDx Transcranial Holter is a unique transcranial Doppler with an innovative motorised 1.5MHz Doppler probe. Traditional transcranial Doppler (TCD) requires the patient to be stationary during the recording period with a bulky and uncomfortable headframe that is prone to movement artefacts and loss of signal. The TCDx recorder is small, lightweight and battery operated allowing high resolution digital recording of up to 5 hours duration. Because of the temporal variability in embolization the longer monitoring length is preferable to ensure embolic episodes are not missed.

As the TCDx is portable the patient can engage in normal daily activities and the product can be used in an outpatient setting. An auto search algorithm and automatic self-adjusting probe restores vessel insonation if the signal quality gets weak. Post processing of the recorded TCD signal is automatic and fast using software for emboli detection. Each embolic event is tagged and the operator has full access to both the Doppler spectral signal and audiogram. The Doppler spectral signal is a representation of the Doppler signal in the frequency domain. The Audiogram is the representation of the same Doppler signal but in the time domain.

During set up real time display of the Doppler spectrum and the motorised probe ensures optimum signal quality and positioning on the acoustic window. In symptomatic carotid stenosis, the presence of emboli predicts future transient ischemic attack and stroke risk. Whether they have a similar predictive role in asymptomatic stenosis is under investigations and the TCD-x has been designed to help answer this question.

The applications of the TCD-x are not restricted to carotid plaques. They also include all unstable wall diseases, endocarditis and decompression illness. The TCD-x is also suitable for physiological studies as the time evolution of blood velocity can be analysed.