Longitudinal White Matter Changes following Carbon Monoxide Poisoning: A 9-Month Follow-Up Voxelwise Diffusional Kurtosis Imaging Study

Heterogeneous Diffusion Metrics Patterns in Delayed Encephalopathy After Acute Carbon Monoxide Poisoning: A Case Report

Delayed encephalopathy (DE) following acute carbon monoxide (CO) poisoning is characterized by a wide range of neurological symptoms, including akinetic mutism, cognitive impairment, and gait disturbances. Herein, we reported the case of a 61-year-old patient with DE after acute CO poisoning, who displayed heterogeneous patterns of cortical and subcortical structural integrity on diffusion tensor imaging (DTI). Four distinct patterns of diffusion tensor metrics (fractional anisotropy [FA] and mean diffusivity [MD]) were observed in the patient compared to age-matched controls (a decrease in FA and an increase in MD, a decrease in FA only, an increase in MD only, and an increase in FA and MD). This study revealed heterogeneous patterns of cortical and subcortical damage associated with DE after CO poisoning, contributing to a deeper understanding of the diverse clinical symptoms observed in this patient.

Delayed neuropsychiatric sequelae with improvement of decreased cerebral bold flow by single-photon emission computed tomography during hyperbaric oxygen therapy: A case report with a 10-year follow-up

Background

Delayed neuropsychiatric sequelae (DNS) occurs in 10%-30% of acute carbon monoxide poisoning cases. Patients with this condition present higher brain dysfunction. Hyperbaric oxygen (HBO) therapy was reportedly an effective treatment for DNS in the acute phase. Favorable predictive factors affecting the prognosis of patients with DNS after HBO therapy include younger age and longer interictal periods. However, the relationship between these factors and neuroimaging findings remains unclear.

Case Presentation

The patient was a 59-year-old man with DNS, who developed major depressive disorder and attempted suicide with charcoal briquettes. He was diagnosed with carbon monoxide poisoning and underwent acute HBO therapy. After a 1-month lucid period, the patient developed intermittent carbon monoxide poisoning with cognitive dysfunction, following which HBO therapy was re-initiated. Following treatment, the patient returned to work for 10 years. Frontal lobe hypoperfusion, measured by single-photon emission computed tomography and cognitive impairment, improved with HBO therapy. However, magnetic resonance imaging revealed brain volume atrophy over time.

Conclusion

This study reported a case of DNS that completely resolved within a 10-year follow-up period. Cerebral blood flow reduction, mainly in the frontal lobe, improved along with cognitive recovery during HBO therapy. Despite gradually progressive brain atrophy over the past decade, no noted deficits in cerebral blood flow were observed in the frontal lobes. These findings suggest that improvement in cerebral blood flow during HBO therapy and its retention may be factors associated with a favorable prognosis in patients with DNS.

A patient with toxic encephalopathy associated with acute carbon monoxide poisoning–A clinical case

Carbon monoxide (CO) is a colorless, odorless, and lacking in irritative properties gas. It has a higher affinity towards hemoglobin than oxygen and thus the complex carboxyhemoglobin develops. Acute CO poisoning leads to poly-organic insufficiency and the organs that suffer the most are the ones with higher oxygen needs- the brain, the heart and the kidneys. We present a clinical case of 49-year-old woman with a sudden appearance of complaints of dizziness, stiffness throughout the entire body, inability to move. Subsequently she was found by her relatives with disorientated and “foaming around her mouth”. Earlier she had been using a gasoline generator because of a power outage. Her laboratory results came out with higher carboxyhemoglobin (40%), nitrogen waste products and mixed type acidosis. From the conducted brain MRI there were changes, correlating to toxic encephalopathy after acute CO poisoning.

Glutamate Chemical Exchange Saturation Transfer (GluCEST) Magnetic Resonance Imaging of Rat Brain With Acute Carbon Monoxide Poisoning

OBJECTIVES

To evaluate the diagnostic and prognostic values of glutamate chemical exchange saturation transfer (GluCEST) magnetic resonance imaging as a quantitative method for pathogenetic research and clinical application of carbon monoxide (CO) poisoning-induced encephalopathy combined with the proton magnetic resonance spectroscopy (¹H-MRS) and the related histopathological and behavioral changes.

METHODS

A total of 63 Sprague-Dawley rats were randomly divided into four groups. Group A (n = 12) was used for animal modeling verification; Group B (n = 15) was used for magnetic resonance molecular imaging, Group C (n = 15) was used for animal behavior experiments, and Group D (n = 21) was used for histopathological examination. All the above quantitative results were analyzed by statistics.

RESULTS

The peak value of carboxyhemoglobin saturation in the blood after modeling was 7.3-fold higher than before and lasted at least 2.5 h. The GluCEST values of the parietal lobe, hippocampus, and thalamus were significantly higher than the base values in CO poisoning rats (p < 0.05) and the ¹H-MRS showed significant differences in the parietal lobe and hippocampus. In the Morris water maze tests, the average latency and distance were significantly prolonged in poisoned rats (p < 0.05), and the cumulative time was shorter and negatively correlated with GluCEST.

CONCLUSION

The GluCEST imaging non-invasively reflects the changes of glutamate in the brain in vivo with higher sensitivity and spatial resolution than ¹H-MRS. Our study implies that GluCEST imaging may be used as a new imaging method for providing a pathogenetic and prognostic assessment of CO-associated encephalopathy.

Gray matter nuclei damage in acute carbon monoxide intoxication assessed in vivo using diffusion tensor MR imaging

OBJECTIVE

To observe the structural changes of gray matter nuclei in patients with acute carbon monoxide intoxication by diffusion tensor imaging (DTI), quantify the degree of deep gray matter damage in the brain by adopting imaging technology and research the characteristics of the damage and its pertinence with memory and cognitive impairment.

METHODS

Twenty-five patients with acute carbon monoxide intoxication and 25 healthy volunteers matched in sex and age were examined by routine head MRI and diffusion tensor imaging (DTI). Bilateral hippocampus, dater nucleus, thalamus, amygdala, globus pallidus and putamen were taken as regions of interest. The mean diffusion coefficient (MD), anisotropic fraction (FA) and appearance of deep gray matter nucleus in patients with acute carbon monoxide intoxication were analyzed. It found that the change of diffusion coefficient (ADC) and its clinical correlation with cognitive impairment were generated by carbon monoxide intoxication.

RESULTS

Compared with the healthy control group, the FA values of bilateral globus pallidus, hippocampus, dater nucleus and putamen decreased, while the FA values of amygdala and thalamus had no statistical significance; the MD values and ADC values of hippocampus, globus pallidus and putamen increased, while the MD and ADC values of dater nucleus, thalamus and amygdala had no statistical significance, either.

CONCLUSION

DTI is capable of sensitively reflecting the damage of gray matter nuclei caused by acute carbon monoxide intoxication and quantifying the degree of hypoxic brain damage in a certain extent, and may be related to cognitive impairment.