because of its relevance, several initiatives for the noninvasive evaluation of icp have been developed in the world over the last 50 years, with varying degrees of diagnostic accuracy when compared to invasive methods: doppler transcranial ultrasonography (dtc)14, skull vibrations15, brain tissue resonance16, transcranial time-of-flight17, venous ophthalmodynamometry 18, assessment of the optic nerve sheath diameter (onsd)19, displacement of the tympanic membrane20-21, otoacoustic emissions22, magnetic resonance imaging (mri) to estimate intracranial compliance23, guided eyeball compression by ultrasound24 and recording of visual evoked potentials25. these different initiatives attempt to overcome the challenges of providing the icp pulse waveform , the absolute value in mmhg, the continuous monitoring capability and the icp trend over time.
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16. MICHAELI, D.; RAPPAPORT, ZH Tissue resonance analysis; a novel method for noninvasive monitoring of intracranial pressure. Technical note. Journal of neurosurgery, v. 96, n. 6, p. 1132-1137, 1 Jun. 2002.
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18. QUERFURTH, HW et al. Ophthalmodynamometry for ICP prediction and pilot test on Mt. Everest. BMC neurology, v. 10, p. 106, 1 Nov. 2010.
19. GEERAERTS, T. et al. Ultrasonography of the optic nerve sheath may be useful for detecting raised intracranial pressure after severe brain injury. Intensive care medicine, v. 33, n. 10, p. 1704-1711, 1 out. 2007.
20. REID, A. et al. Mean intracranial pressure monitoring by a non-invasive audiological technique: a pilot study. Journal of Neurology, Neurosurgery, and Psychiatry, v. 52, n. 5, p. 610-612, May 1, 1989.
21. SHIMBLES, S. et al. Clinical comparison of tympanic membrane displacement with invasive intracranial pressure measurements. Physiological measurement, v. 26, n. 6, p. 1085-1092, Dec. 7, 2005.
22. FRANK, AM et al. Non-invasive measurement of intracranial pressure changes by otoacoustic emissions (OAEs) -a report of preliminary data. Zentralblatt fur Neurochirurgie, v. 61, n. 4, p. 177-180, 1998.
23. ALPERIN, NJ et al. MR-Intracranial pressure (ICP): a method to measure intracranial elastance and pressure noninvasively by means of MR imaging: baboon and human study. Radiology, v. 217, n. 3, p. 877-885, 1 dez. 2000.
24. BARTUSIS L, et al. Ophthalmic artery as a non-invasive intracranial pressure measurement electronic system. Elektron ir Elektrotechnika. 2012; 122 (6): 45-8.
25. ZHAO, YL; ZHOU, JY; ZHU, GH Clinical experience with the noninvasive ICP monitoring system. Neurochirurgical record. Supplement, v. 95, p. 351-355, 2003.