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The Ambulatory TCD  -- click to enlarge

The TC-Pilot Ambulatory System - click on image to enlarge


The Urdoppler -- click to enlarge

The 'UrDoppler' in 1983

New: Accurate Noninvasive Recording of the Arterial Blood Pressure Wave: Read more ..

Latest TCD News: the first study (3) using ambulatory transcranial Doppler monitoring equipment was reported in the January 2004 issue of Stroke. (The link should take you ot the abstract of the article)

New from Hemodynamics AG: Ambulatory TCD Monitoring using Microrobotic technology - The problem of probe fixation and maintaining Doppler signal has hampered the more general use of TCD for monitoring purposes, even with the use of dedicated TCD probe headgear. At the 7th Meeting of the ESNCH, in Bern, May 26 - 28, 2002 we first demonstrated a possible way to solve these problems.

This consists of a very compact instrument with matching headgear. Not only is it so small and uses so little power that it can be carried like a Holter ECG; in addition, its microrobotic probe automatically locks on to the Doppler signals. The same unit, when connected to a laptop, can perform like a 'high-end' investigative TCD unit, recording the full Doppler data for later scientific analysis. The first study using the ambulatory TCD monitoring equipment was recently reported in Stroke.

History: the 'UrDoppler' -- the first dedicated Transcranial Doppler instrument (1) was designed and constructed by Dr. Rune Aaslid in 1981- 82 at the then new Vascular Laboratory of the Neurosurgical Department of Inselspital in Bern, Switzerland. It is still going strong and is in daily routine use.

Later, in 1989 - 91, it was complemented by the first dual-channel TCD instrument (2) which was used extensively for scientific work, and monitoring in the ICU.

However, we're definitely not at the end of the road for dedicated TCD machines -- in spite of the recent development of Imaging and Power TCCD. For embolus monitoring, and for functional, autoregulatory and other cerebral hemodynamic studies, dedicated TCD instruments are still superior to their larger (and more expensive) TCCD counterparts.

 

 


1. Aaslid R, Markwalder T-M, Nornes H: Noninvasive transcranial Doppler ultrasound recording of flow velocity in basal cerebral arteries. J Neurosurg 1982; 57:769-774
2. Aaslid R, Newell DW, Stooss R, Sorteberg W, Lindegaard K-F: Assessment of cerebral autoregulation dynamics from simultaneous arterial and venous transcranial Doppler recordings in humans. Stroke 1991;22:1148-1154
3. Mackinnon AD, Aaslid R, Markus HS. Long-Term Ambulatory Monitoring for Cerebral Emboli Using Transcranial Doppler Ultrasound. Stroke. 2004;35:73-78


Updated May 20, 2004

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