The clinical application of non-invasive intracranial blood volume pulse wave monitoring

Abstract

An ultrasonic method was used to non-invasively measure intracranial blood volume (IBV) pulse waveforms. This technology has previously shown a strong association between invasively recorded ICP pulse waves and non-invasively recorded IBV pulse waves. The objective of the present study was to investigate the diagnostic value of non-invasively measured IBV pulse waves in the cases of different pathologies. A total of 75 patients were examined and these included cases of acute, chronic and stabilized hydrocephalus, spinal cord injury and terminal blood flow. These were compared to a control group of 53 healthy volunteers. The object of comparison was normalized and averaged IBV pulse waves. Pathological IBV pulse waveforms were compared with IBV pulse waveforms of the normal group using sub-wave values, the area under waveform curve and the Euclidean distance calculation. The non-invasively measured IBV pulse waveform is not significantly dependent on acoustic path, gender or age. A detectable change in IBV pulse waveform shape was observed in situations when disturbance in intracranial hydrodynamics was present, e.g. during hypoventilation tests, in cases of terminal blood flow and hydrocephaly, depicting the level of hydrocephalus activity and the patient's compensatory capabilities as well as the effect of treatment.

Cerebrovascular Reactivity Measured by Near-Infrared Spectroscopy

“…Success has previously been reported in quantifying relative CBV noninvasively with an ultrasound time-of-flight measurement. 20 This measurement was then used to measure vascular reactivity as a phase shift between the relative blood volume and the ABP changes at the respiratory frequency as opposed to analyzing at the frequency of slow waves as is done with the PRx and the HVx. 6 The theoretical advantage of using respiratory frequency waveform analysis is the regular periodicity when compared with the sporadic nature of slow waves.…”

Non-Invasive Intracranial Pulse Wave Monitoring

“…The study found that results can be obtained which are similar to MRI technology by using the non-invasive ultrasonic method for intracranial blood volume pulse wave (IBVPW) measurement (Ragauskas and Daubaris, 1995;Ragauskas et al, -2004Deltuva, 1999;Matukevicius, 2000;Rocka, 2003;Ragaisis, 2003;Kvascevicius, 2003;Kalasauskas, 2003;Chambers et al, 2005;Fountas et al, 2005). The method has been tested using simultaneous invasive ICP and non-invasive IBV wave monitoring of TBI patients.…”

“…A-9676. The analysis involved 87 hours of simultaneous monitoring of invasive and non-invasive data (Ragaisis, 2003;Chambers et al, 2005). The diagnostic value of IBV pulse waves has been investigated in previous studies (Ragauskas et al, -2004Rocka, 2003;Kvascevicius, 2003;Kalasauskas, 2003;Fountas et al, 2005).…”

“…A total of 75 patients were examined using ultrasonic non-invasive method and they included cases of acute, chronic and stabilized hydrocephalus, spinal cord injury and terminal blood flow (Rocka, 2003;Kvascevicius, 2003;Chambers et al, 2005). They were compared to a control group of 53 healthy volunteers.…”

To what extent is the bipolar rheoencephalographic signal contaminated by scalp blood flow? A clinical study to quantify its extra and non-extracranial components

“…Other authors focused on the devices and mathematical approach of tomography impedance of the head [18, 19]. Besides measuring electrical impedance, other devices have been proposed to assess the intracranial blood volume based on the time-of-flight of short ultrasonic pulses from one side of the skull to the other [20]. …”