Transcranial Doppler Pulsatility Index: What it is and What it Isn’t
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Transcranial Doppler (TCD) pulsatility index (PI) has traditionally been interpreted as a descriptor of distal cerebrovascular resistance (CVR). We sought to evaluate the relationship between PI and CVR in situations, where CVR increases (mild hypocapnia) and decreases (plateau waves of intracranial pressure—ICP).
Recordings from patients with head-injury undergoing monitoring of arterial blood pressure (ABP), ICP, cerebral perfusion pressure (CPP), and TCD assessed cerebral blood flow velocities (FV) were analyzed. The Gosling pulsatility index (PI) was compared between baseline and ICP plateau waves (n = 20 patients) or short term (30–60 min) hypocapnia (n = 31). In addition, a modeling study was conducted with the “spectral” PI (calculated using fundamental harmonic of FV) resulting in a theoretical formula expressing the dependence of PI on balance of cerebrovascular impedances.
PI increased significantly (p < 0.001) while CVR decreased (p < 0.001) during plateau waves. During hypocapnia PI and CVR increased (p < 0.001). The modeling formula explained more than 65% of the variability of Gosling PI and 90% of the variability of the “spectral” PI (R = 0.81 and R = 0.95, respectively).
TCD pulsatility index can be easily and quickly assessed but is usually misinterpreted as a descriptor of CVR. The mathematical model presents a complex relationship between PI and multiple haemodynamic variables.
- Kontos HA. Validity of cerebral arterial blood flow calculations from velocity measurements. Stroke. 1989;20(1):1–3. CrossRef
- Gosling RG, King DH. Arterial assessment by Doppler-shift ultrasound. Proc R Soc Med. 1974;67(6 Pt 1):447–9.
- Bellner J, Romner B, Reinstrup P, Kristiansson KA, Ryding E, Brandt L. Transcranial Doppler sonography pulsatility index (PI) reflects intracranial pressure (ICP). Surg Neurol. 2004;62(1):45–51. CrossRef
- Behrens A, Lenfeldt N, Ambarki K, Malm J, Eklund A, Koskinen LO. Transcranial Doppler pulsatility index: not an accurate method to assess intracranial pressure. Neurosurgery. 2010;66(6):1050–7. CrossRef
- Figaji AA, Zwane E, Fieggen AG, Siesjo P, Peter JC. Transcranial Doppler pulsatility index is not a reliable indicator of intracranial pressure in children with severe traumatic brain injury. Surg Neurol. 2009;72(4):389–94. CrossRef
- Melo JR, Di Rocco F, Blanot S, et al. Transcranial Doppler can predict intracranial hypertension in children with severe traumatic brain injuries. Childs Nerv Syst. 2011;27(6):979–84. CrossRef
- Soehle M, Chatfield DA, Czosnyka M, Kirkpatrick PJ. Predictive value of initial clinical status, intracranial pressure and transcranial Doppler pulsatility after subarachnoid haemorrhage. Acta Neurochir (Wien). 2007;149(6):575–83. CrossRef
- Giller CA, Hodges K, Batjer HH. Transcranial Doppler pulsatility in vasodilation and stenosis. J Neurosurg. 1990;72(6):901–6. CrossRef
- Lim MH, Cho YI, Jeong SK. Homocysteine and pulsatility index of cerebral arteries. Stroke. 2009;40(10):3216–20. CrossRef
- Czosnyka M, Richards HK, Whitehouse HE, Pickard JD. Relationship between transcranial Doppler-determined pulsatility index and cerebrovascular resistance: an experimental study. J Neurosurg. 1996;84(1):79–84. CrossRef
- Rosner MJ, Becker DP. Origin and evolution of plateau waves. Experimental observations and a theoretical model. J Neurosurg. 1984;60(2):312–24. CrossRef
- Steiner LA, Balestreri M, Johnston AJ, et al. Sustained moderate reductions in arterial CO2 after brain trauma time-course of cerebral blood flow velocity and intracranial pressure. Intensive Care Med. 2004;30(12):2180–7. CrossRef
- Hsu HY, Chern CM, Kuo JS, Kuo TB, Chen YT, Hu HH. Correlations among critical closing pressure, pulsatility index and cerebrovascular resistance. Ultrasound Med Biol. 2004;30(10):1329–35. CrossRef
- Kim DJ, Kasprowicz M, Carrera E, et al. The monitoring of relative changes in compartmental compliances of brain. Physiol Meas. 2009;30(7):647–59. CrossRef
- Czosnyka M, Smielewski P, Piechnik S, et al. Hemodynamic characterization of intracranial pressure plateau waves in head-injury patients. J Neurosurg. 1999;91(1):11–9. CrossRef
- Helmy A, Vizcaychipi M, Gupta AK. Traumatic brain injury: intensive care management. Br J Anaesth. 2007;99(1):32–42. CrossRef
- Lundberg N. Continuous recording and control of ventricular fluid pressure in neurosurgical practice. Acta Psychiatr Scand Suppl. 1960;36(149):1–193.
- Brain Trauma F, American Association of Neurological Surgeon, Congress of Neurological Surgeons, et al. Guidelines for the management of severe traumatic brain injury. XIV. Hyperventilation. J Neurotrauma 2007; 24 Suppl 1:S87–S90.
- Raichle ME, Posner JB, Plum F. Cerebral blood flow during and after hyperventilation. Arch Neurol. 1970;23(5):394–403. CrossRef
- Czosnyka M, Richards HK, Reinhard M, et al. Cerebrovascular time constant: dependence on cerebral perfusion pressure and end-tidal carbon dioxide concentration. Neurol Res. 2012;34(1):17–24. CrossRef
- Czosnyka M, Piechnik S, Richards HK, Kirkpatrick P, Smielewski P, Pickard JD. Contribution of mathematical modelling to the interpretation of bedside tests of cerebrovascular autoregulation. J Neurol Neurosurg Psychiatry. 1997;63(6):721–31. CrossRef
- Carrera E, Steiner LA, Castellani G, et al. Changes in cerebral compartmental compliances during mild hypocapnia in patients with traumatic brain injury. J Neurotrauma. 2011;28(6):889–96. CrossRef
- Alperin N, Sivaramakrishnan A, Lichtor T. Magnetic resonance imaging-based measurements of cerebrospinal fluid and blood flow as indicators of intracranial compliance in patients with Chiari malformation. J Neurosurg. 2005;103(1):46–52. CrossRef
- Baledent O, Fin L, Khuoy L, et al. Brain hydrodynamics study by phase-contrast magnetic resonance imaging and transcranial color doppler. J Magn Reson Imaging. 2006;24(5):995–1004. CrossRef
- Michel E, Zernikow B. Goslig’s Doppler pulsatility index revisited. Ultrasound Med Biol. 1998;24(4):597–9. CrossRef
- Transcranial Doppler Pulsatility Index: What it is and What it Isn’t
Volume 17, Issue 1 , pp 58-66
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- Cerebral hemodynamics
- Plateau waves
- Transcranial doppler
- Traumatic brain injury
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- Author Affiliations
- 1. Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital, University of Cambridge, Hills Road, Box 167, Cambridge, CB2 0QQ, UK
- 2. Department of Anesthesiology, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
- 3. Institute of Biomedical Engineering and Instrumentation, Wroclaw University of Technology, Wroclaw, Poland
- 4. Department of Neurosurgery, University Hospital of Basel, Basel, Switzerland
- 5. Department of Anaesthesia, Lausanne University Hospital, Lausanne, Switzerland
- 6. Department of Neurology, University of Freiburg, Freiburg, Germany
- 7. Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland