Structural Findings in the Brain MRI of Patients with Acute Carbon Monoxide Poisoning

Abstract

<em>Background:</em> Carbon monoxide (CO) poisoning may lead to hypoxic/anoxic injury and eventually ischemic encephalopathy. Magnetic resonance imaging (MRI) has a well-recognized role in assessment of the severity of brain damage caused by CO poisoning. In this study, we aimed to present and analyze the structural abnormalities in the brain MRI and especially in diffusion weighted MRI (DWI) images in a series of patients with acute CO poisoning. <br/><em>Methods:</em> This cross-sectional observational study was performed on patients with moderate to severe CO poisoning admitted to Mashhad Medical Toxicology Center of Imam Reza Hospital, Mashhad, Iran, during autumn and winter 2013. After stabilization, patients underwent brain MRI. T1 weighted, T2 weighted and FLAIR images in sagittal, axial and coronal sections, and DWI in axial sections were performed for each patient. <br/><em>Results:</em> Eighteen patients (77.8% men) were enrolled in this study with median age of 29.5 years. Eleven patients (61.1%) had abnormal MRI signals and in 7 cases no abnormality or nonspecific abnormalities were detected. The most common involved region in brain MRI was white matter (38.9%) followed by globus pallidus (33.3%). Patients with signal abnormality in brain MRI had significantly longer duration of exposure to CO compared to those without signal changes (10.6 ± 6.2 h vs. 3.4 ± 2.8 h, P = 0.011). Nine patients had restricted diffusion in DWI. Patients with restricted diffusion in DWI had also longer duration of exposure to CO compared to patients with normal DWI (12.1 ± 5.5 h vs. 3.5 ± 2.9 h, P = 0.001). <br/><em>Conclusion:</em> The white matter and globus pallidus were the most common affected regions in brain following acute CO poisoning. Signal abnormalities and restricted diffusion in MRI were correlated with duration of exposure to CO but not with the carboxyhemoglobin levels.