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Numerical Simulation and in vivo Study of Optic Nerve Head Towards Non-invasive Monitoring of Intracranial Pressure
Intracranial pressure (ICP) is an important biomarker for health assessment. It is highly desirable to identify a non-invasive method for ICP monitoring in clinical practice. The anatomy of the optic nerve head (ONH) visualized using the optical coherence tomography (OCT) was recently recognized to be correlated with the ICP alternation, which might serve as a non-invasive marker for the ICP estimation. This thesis is to investigate the role of ICP on the development of optic neuropathy through numerical simulation, and further investigate a potential biomarker in the ONH for the non-invasive ICP estimation. The result from this study would facilitate the prevention and early diagnosis of ICP related ocular disease, and further, provide a method for non-invasive monitoring of ICP. A three-dimensional human eye model with a detailed characterization of the orbital components was developed to simulate the indirect traumatic optic neuropathy induced by the primary blast (shock wave). It was found there was a transient elevation of ICP and excessively high strain rate throughout the optic nerve; this was related to the axon damage and vision loss. The relative contributions between the ICP and intraocular pressure (IOP) on the peak strain and depth of the lamina cribrosa (LC) were also investigated due to their relationship to glaucoma. It was then found ICP played an equivalent role in the LC depth as that of IOP. However, IOP was still the dominant factor in deciding the peak strain in the LC. The peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer angle in the ONH was identified as the potential marker for the ICP monitoring, which was quantified through a semi-automatic method developed in this work. The robustness and reliability of the method were validated against the clinical data of patients who underwent the lumbar puncture (LP). The multivariate analysis revealed the ppRPE/BM layer angle changes were found best correlated with the translaminar pressure difference changes. Furthermore, a mathematical model was developed to interpret the ppRPE/BM layer angle variations across the radial directions. Based on the developed model, we could extract the structural ppRPE/BM layer angle through a reverse fitting. These results indicate the structural ppRPE/BM layer angle may be used as a biomarker for the disease assessment as well as the non-invasive ICP estimation.
Tong, Junfei, "Numerical Simulation and in vivo Study of Optic Nerve Head Towards Non-invasive Monitoring of Intracranial Pressure" (2019). ETD collection for University of Nebraska-Lincoln. AAI22588417.