Bilirubin-Biliverdin Concentration Measurement using Photoacoustic Spectroscopic Analysis for Determining Hemorrhage Age.

The onset of intracerebral hemorrhage and its progression toward acute brain injury have been correlated with the concentration of unconjugated bilirubin (BR). In addition, BR has been considered a novel predictor of outcome from intracranial hemorrhage. Since the existing invasive approach for determining localized BR and biliverdin (BV) concentration within the hemorrhagic brain lesion is not feasible, the predictive capability of BR in terms of determining the onset of hemorrhage and understanding the consequences of its progression (age) is unknown. In this study, we have demonstrated a photoacoustic approach to the noninvasive measurement of bilirubin-biliverdin ratio which can be utilized longitudinally to approximate the onset of the hemorrhage. The photoacoustic imaging-based measurements of BV and BR in tissues and fluids can potentially be used to determine hemorrhage "age", quantitatively evaluate the hemorrhage resorption or detect a rebleeding, and assess responses to therapy and prognosis. This article is protected by copyright. All rights reserved.