| A cerebral aneurysm is a weakened portion of an artery in the brain. When a cerebral aneurysm ruptures, a specific type of bleeding known as a Subarachnoid Hemorrhage (SAH) occurs.; Currently, clinicians must rely upon a three-tiered pathway (clinical history, CT scan evidence, and lumbar puncture results), to diagnose SAH and differentiate it from a traumatic tap. To help the physicians distinguish between a traumatic spinal tap and a possible SAH, a fast and an effective point of care diagnostic instrument is required. This thesis describes the software and hardware components of such a diagnostic instrument.; Bilirubin, which results from the chemical decomposition of whole blood, can be detected by differentiating its optical signature from that of fresh blood. Since elevated levels of bilirubin occur starting 10--12 hours after a cerebral aneurysm rupture, the presence of bilrubin in a spinal fluid sample along with an intense and persistent headache can be a clear indicator of a probable SAH. In this thesis, a diagnostic system is implemented that is based on visible spectroscopy that quickly and objectively differentiates low-blood volume SAH from a traumatic spinal tap. The system integrates innovative hardware and powerful software interface. This technology provides clinicians, with the resources necessary for assessing patients with suspected aneurismal SAH beyond the current 12-hour limitation imposed by CT scans. Furthermore, this method improves patient care and results in rapid and appropriate treatment of the patient. To perform this diagnosis, bilirubin is quantified in human CSF over a range of concentrations.; The software component explored in this thesis includes algorithms in various domains, from statistical to a control theory based mathematical model. These algorithms account for the noise and distortion from metabolites in CSF and blood, leading to the quantification of bilirubin and methemoglobin spectroscopically. In addition, the configurations for a hardware platform are introduced, including a PC-spectrometer, which are portable and user-friendly and composed of specific components designed to have the required sensitivity and specificity. Finally, the prototype uses purpose built algorithms contained within the platform, such that physicians can use it in the hospital as a point of care diagnostic instrument. (Abstract shortened by UMI.)... |
