Change search
ReferencesLink to record
Permanent link

Direct link
Transcranial Doppler pulsatility index: not an accurate method to assess intracranial pressure.
Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.ORCID iD: 0000-0001-6451-1940
Show others and affiliations
2010 (English)In: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 66, no 6, 1050-1057 p.Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: Transcranial Doppler sonography (TCD) assessment of intracranial blood flow velocity has been suggested to accurately determine intracranial pressure (ICP). OBJECTIVE: We attempted to validate this method in patients with communicating cerebrospinal fluid systems using predetermined pressure levels. METHODS: Ten patients underwent a lumbar infusion test, applying 4 to 5 preset ICP levels. On each level, the pulsatility index (PI) in the middle cerebral artery was determined by measuring the blood flow velocity using TCD. ICP was simultaneously measured with an intraparenchymal sensor. ICP and PI were compared using correlation analysis. For further understanding of the ICP-PI relationship, a mathematical model of the intracranial dynamics was simulated using a computer. RESULTS: The ICP-PI regression equation was based on data from 8 patients. For 2 patients, no audible Doppler signal was obtained. The equation was ICP = 23*PI + 14 (R = 0.22, P < .01, N = 35). The 95% confidence interval for a mean ICP of 20 mm Hg was -3.8 to 43.8 mm Hg. Individually, the regression coefficients varied from 42 to 90 and the offsets from -32 to +3. The mathematical simulations suggest that variations in vessel compliance, autoregulation, and arterial pressure have a serious effect on the ICP-PI relationship. CONCLUSIONS: The in vivo results show that PI is not a reliable predictor of ICP. Mathematical simulations indicate that this is caused by variations in physiological parameters.

Place, publisher, year, edition, pages
2010. Vol. 66, no 6, 1050-1057 p.
Keyword [en]
Blood flow velocity, hydrocephalus, intracranial pressure, middle cerebral artery, pulsatility indix
National Category
Medical and Health Sciences
URN: urn:nbn:se:umu:diva-34863DOI: 10.1227/01.NEU.0000369519.35932.F2ISI: 000278006200018PubMedID: 20495421OAI: diva2:326183
Available from: 2010-06-22 Created: 2010-06-22 Last updated: 2015-10-01Bibliographically approved
In thesis
1. Measurements in Idiopathic Normal Pressure Hydrocephalus: Computerized neuropsychological test battery and intracranial pulse waves
Open this publication in new window or tab >>Measurements in Idiopathic Normal Pressure Hydrocephalus: Computerized neuropsychological test battery and intracranial pulse waves
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Idiopathic Normal Pressure Hydrocephalus (INPH) is a condition affecting gait, cognition and continence. Radiological examination reveals enlarged ventricles of the brain. A shunt that drains CSF from the ventricles to the abdomen often improves the symptoms. Much research on INPH has been focused on identifying tests that predict the outcome after shunt surgery. As part of this quest, there are attempts to find measurement methods of intracranial parameters that are valid, reliable, tolerable and safe for patients.

Today's technologies for intracranial pressure (ICP) measurement are invasive, often requiring a burr-hole in the skull. Recently, a method for non-invasive ICP measurements was suggested: the Pulsatile Index (PI) calculated from transcranial Doppler data assessed from the middle cerebral artery. In this thesis the relation between PI and ICP was explored in INPH patients during controlled ICP regulation by lumbar infusion. The confidence interval for predicted ICP, based on measured PI was too large for the method to be of clinical utility.

In the quest for better predictive tests for shunt success in INPH, recent studies have shown promising results with criteria based on cardiac related ICP wave amplitudes. The brain ventricular system, and the fluid surrounding the spinal cord are in contact. In this thesis it was shown that ICP waves could be measured via lumbar subarachnoid space, with a slight underestimation.

One of the cardinal symptoms of hydrocephalus is cognitive impairment. Neuropsychological studies have demonstrated cognitive tests that are impaired and improve after shunt surgery in INPH patients. However, there is currently no standardized test battery and different studies use different tests. In response, in this thesis a fully automated computerized neuropsychological test battery was developed. The validity, reliability, responsiveness to improvement after shunt surgery and feasibility for testing INPH patients was demonstrated. It was also demonstrated that INPH patients were impaired in all subtests, compared to healthy elderly. 

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2014. 67 p.
Umeå University medical dissertations, ISSN 0346-6612 ; 1689
Hydrocephalus, Normal Pressure; Neuropsychological tests; Neuropsychology; Reliability and validity; Software; Dementia; intracranial pressure; spinal puncture; cerebrospinal fluid pressure; pulse pressure waves; Blood flow velocity; Middle cerebral artery; Pulsatility index
National Category
Medical and Health Sciences
Research subject
urn:nbn:se:umu:diva-96195 (URN)978-91-7601-155-3 (ISBN)
Public defence
2014-12-05, Sal E04 Unod R1, Umeå, 13:00 (Swedish)
Available from: 2014-11-14 Created: 2014-11-12 Last updated: 2015-10-01Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Behrens, AndersLenfeldt, NiklasAmbarki, KhalidMalm, JanEklund, AndersKoskinen, Lars-Owe
By organisation
NeurologyRadiation PhysicsNeurosurgery
In the same journal
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 196 hits
ReferencesLink to record
Permanent link

Direct link