Dual-energy X-ray absorptiometry for detecting neurogenic pulmonary edema in a mouse model of subarachnoid hemorrhage

Abstract

Murine subarachnoid hemorrhage (SAH) induced using the filament perforation method is a useful in vivo experimental model to investigate the pathophysiological mechanisms in the brain underlying SAH. However, identifying mice with comorbid acute neurogenic pulmonary edema (NPE), a life-threatening systemic consequence often induced by SAH, in this model is difficult without histopathological investigations. Herein, we present an imaging procedure involving dual-energy X-ray absorptiometry (DXA) to identify NPE in a murine model of SAH. We quantified the lung lean mass (LM) and compared the relationship between micro-computed tomography (CT) evidence of Hounsfield unit (HU) values and histopathological findings of PE. Of the 85 mice with successful induction of SAH by filament perforation, 16 (19%) had NPE, as verified by postmortem histology. The DXA-LM values correlate well with CT-HU levels (r = 0.63, p < 0.0001). Regarding the relationship between LM and HU in mice with post-SAH NPE, the LM was positively associated with HU values (r² = 0.43; p = 0.0056). A receiver operating characteristics curve of LM revealed a sensitivity of 87% and specificity of 57% for detecting PE, with a similar area under the curve as the HU (0.79 ± 0.06 vs. 0.84 ± 0.07; p = 0.21). These data suggest that confirming acute NPE using DXA-LM is a valuable method for selecting a clinically relevant murine NPE model that could be used in future experimental SAH studies.