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

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.