ObjectiveTo investigate the feasibility of electroencephalography (EEG) power spectrum analysis monitoring noninvasive intracranial pressure (ICP). MethodsBetween September 2008 and May 2009, the EEG signals were recorded in 62 patients (70 cases/times) with central nervous system (CNS). By using self-designed software, EEG power spectrum analysis was conducted and pressure index (PI) was calculated automatically. ICP was measured by lumbar puncture (LP). ResultsThe mean ICP was (239.74±116.25) mm H2O (70-500 mm H2O, 1 mm H2O=0.009 8 kPa), and 52.9% of patients had increased ICP. The mean PI was 0.29±0.20 (0.02-0.85). The Spearman rank test showed that there was a significant negative correlation between PI and ICP (rs=-0.849, P<0.01). The data from the patients with diffuse lesions of CNS and focal lesions were analyzed separately; the results showed there were significant negative correlations between PI and ICP in both groups (rs=-0.815, -0.912; P<0.01). ConclusionThe PI obtained from EEG analysis is correlated with ICP. Analysis of specific parameters from EEG power spectrum might reflect the ICP. Further research should be carried out.
At present, the monitoring methods fwor intracranial pressure adopted in clinical practice are almost all invasive. The invasive monitoring methods for intracranial pressure were accurate, but they were harmful to the patient's body. Therefore, non-invasive methods for intracranial pressure monitoring must be developed. Since 1980, many non-invasive methods have been sprung out in succession, but they can not be used clinically. In this paper, research contents and progress of present non-invasive intracranial pressure monitoring are summarized. Advantages and disadvantages of various ways are analyzed. And finally, perspectives of development for intracranial pressure monitoring are presented.
We used near-infrared spectroscopy technology to monitor and assess the treatment effect of dehydrating agent in injured rat brain in real time style. We employed the brain edema model in rats resulting from Feeney's freefall damage, then treated with different doses of mannitol, and collected reduced scattering coefficient (μ's) and intracranial pressure (ICP) values after the injury and during the treatment. The results showed that brain edema happened 1 h after the injury in rats' brain tissue, peaked around 72 h after injury, and then began to decrease gradually. The reduced scattering coefficient and ICP values of the treatment group injected with mannitol all decreased after administration. Compared with the effect of low-dose mannitol treatment, that of high-dose mannitol treatment was much better. The duration of the plateau was longer and most experiments results declined significantly. From this we conclude that the reduced scattering coefficient and ICP are consistent with the trend changes, and the reduced scattering coefficient could be used as an indicator for monitoring cerebral edema.
Correlation between nonlinear subharmonic scattering of ultrasound contrast agent microbubbles and ambient pressure is expected to be used for local brain tissue pressure monitoring. Although high-frequency ultrasound has achieved high-resolution imaging of intracranial microvessels, the research on high-frequency subharmonic scattering characteristics of microbubbles is insufficient at present, which restricts the research progress of estimating local brain tissue pressure based on high-frequency subharmonic scattering of microbubbles. Therefore, under the excitation of 10 MHz high-frequency ultrasound, the effects of different acoustic pressures and ambient pressures on the high-frequency subharmonic scattering characteristics of three different ultrasound contrast agents including SonoVue, Sonazoid and Huashengxian were investigated in this in vitro study. Results showed that the subharmonic scattering amplitudes of the three microbubbles increased with the increase of ambient pressure at the peak negative acoustic pressures of 696, 766 and 817 kPa, and there was a favorable linear correlation between subharmonic amplitude and ambient pressure. Under the above three acoustic pressures, the highest correlation coefficient of SonoVue was 0.948 (P = 0.03), the highest sensitivity of pressure measurement was 0.248 dB/mm Hg and the minimum root mean square error (RMSE) was 2.64 mm Hg. Sonazoid's highest correlation coefficient was 0.982 (P < 0.01), the highest sensitivity of pressure measurement was 0.052 dB/mm Hg and the minimum RMSE was 1.51 mm Hg. The highest correlation coefficient of Huashengxian was 0.969 (P = 0.02), the highest sensitivity of pressure measurement was 0.098 dB/mm Hg and the minimum RMSE was 2.00 mm Hg. The above in vitro experimental results indicate that by selecting ultrasound contrast agent microbubbles and optimizing acoustic pressure, the correlation between high-frequency subharmonic scattering of microbubbles and ambient pressure can be improved, the sensitivity of pressure measurement can be upgraded, and the measurement error can be reduced to meet the clinical demand for local brain tissue pressure measurement, which provided an important experimental basis for subsequent research in vivo.
Idiopathic intracranial hypertension (IIH) is a neurological disorder characterized by an unexplained increase in intracranial pressure that primarily affects obese women of childbearing age, but individuals of any age, gender, or weight may also be affected. Its signature symptoms include disc edema, headache, visual disturbance, and throbbing tinnitus. Due to potentially serious complications, such as vision loss, accurate diagnosis and appropriate treatment management are critical to improving patients' quality of life. Ophthalmologists play a key role in the treatment process, as about half of patients first visit the eye department. Diagnosis of IIH depends not only on clinical presentation, but also on the exclusion of other diseases that may cause similar symptoms, and imaging and other tests to ensure an accurate diagnosis. In order to improve diagnostic accuracy and treatment efficiency, multidisciplinary collaborative diagnosis and treatment mode is advocated, especially in the face of patients with complex trauma or systemic diseases, which can effectively shorten the treatment time and ensure patient safety. Future research directions include establishing China's IIH epidemiological database, exploring clinical diagnosis and treatment methods and basic scientific research, aiming at forming diagnosis and treatment standards suitable for China's national conditions, improving medical level and improving patient prognosis. At the same time, a deeper understanding of the different forms of IIH will better serve the affected populations.