In addition to the patented PaR-technology, which is convenient when both flow velocity and arterial blood pressure signals are available, a new technique for the analysis of flow velocity alone was published in 2012. This technique proposes the use of new parameters for the numerical representation of pulsatile signals in order to better represent it's hemodynamic properties.
- Schaafsma A. Improved Parameterization of the Transcranial Doppler Signal. Ultrasound in Medicine and Biology 2012; 38(8): 1451–1459.
These parameters are based upon the Theory of Arterial Acceleration.
- Schaafsma A. Harvey with a modern twist: How and why conducting arteries amplify the pressure wave originating from the heart. Medical Hypotheses 2014; 82(5): 589–594.
The first clinical study making use of these new parameters was published in 2017
- de Goede A.A., Loef B.G., Reidinga A.C. and Schaafsma A. Fluid resuscitation in septic patients improves systolic but not diastolic middle cerebral artery flow velocity. Ultrasound in Medicine and Biology 201; 43: 2591-2600).
A new method for age correction and graphical representation of the new parameters was published in 2018
- A. Schaafsma, A new method for correcting middle cerebral artery flow velocity for age by calculating Z-scores. Journal of Neuroscience Methods. 307, 1–7 (2018).1.
Applying age corrected Z-scores for the analysis of changes in middle cerebral artery flow velocity after carotid endarterectomy was published in 2021
- M. Schaafsma, G.J. Glade, B.J.A.M. Keller, A. Schaafsma, Age corrected changes in intracranial haemodynamics after carotid endarterectomy. J. Cardiovascular Surgery. Aug 2021; 62(4):354-363.
Applying PaR ratio for the detection of increased intracranial pressure in patients with traumatic brain injury
- Brasil S, Romeijn H, Haspels EK, Paiva W, Schaafsma A. Improved Transcranial Doppler Waveform Analysis for Intracranial Hypertension Assessment in Patients with Traumatic Brain Injury. Neurocrit Care. 2023 Nov 6. Epub ahead of print. PMID: 37932509.