Is it a normal phenomenon for pediatric patients to have brain leptomeningeal contrast enhancement on 3-tesla magnetic resonance imaging?

Abstract

Determining whether sevoflurane sedation in children leads to “pseudo” prominent leptomeningeal contrast enhancement (pLMCE) on 3 Tesla magnetic resonance imaging will help reduce overdiagnosis by radiologists and clarify the pathophysiological changes of pLMCE.

Key Words: Pediatrics patients, Sevoflurane, Brain, Prominent leptomeningeal contrast enhancement, Magnetic resonance imaging

Core Tip: Prominent leptomeningeal contrast enhancement (pLMCE) often indicates the presence of intracranial infection, tumours, or other abnormal pathological changes. Researchers have frequently observed “pseudo” pLMCE in the brains of young pediatric patients anaesthetized with propofol during 3-tesla contra-spin echo T1-weighted imaging. This condition should not be misinterpreted as meningeal pathology. Currently, sevoflurane is a commonly used anaesthetic drug in pediatric patients. Therefore, it is important to identify the presence or absence of pLMCE during anaesthesia with sevoflurane to prevent misdiagnosis by radiologists and elucidate the physiological mechanisms associated with the anaesthesia process that led to pLMCE.

TO THE EDITOR

We read with interest the paper by Hilal et al[1] entitled “Does sevoflurane sedation in pediatric patients lead to ‘pseudo’ leptomeningeal enhancement in the brain on 3 Tesla magnetic resonance imaging?”

We agree with the authors that due to vascular fragility and immaturity in sevoflurane-sedated pediatric patients, leptomeningeal contrast enhancement (LMCE) is common on postcontrast spin-echo T1-weighted MR images and is not a pathological change in the meninges.

Since the introduction of contrast material, numerous studies have demonstrated a correlation between LMCE and pathological conditions of the brain[2]. McKinney et al[3] discovered that prominent leptomeningeal contrast enhancement (pLMCE) can occur in pediatric patients who are under anaesthesia with propofol. However, in clinical practice, the administration of sevoflurane has become a common anaesthetic practice for pediatric patients undergoing magnetic resonance imaging (MRI) due to advantages such as rapid induction and recovery[4]. Nevertheless, whether sevoflurane can also induce pLMCE remains a scientific question that needs resolution. Therefore, through a retrospective analysis of 63 pediatric patients, we discovered that sevoflurane administration can indeed lead to pLMCE, and we clearly emphasized that this is a physiological rather than a pathological change.

The absence of clear evidence to support relevant examinations may cause unnecessary financial burdens for patients who may have meningeal enhancement. As radiologists, we should fully recognize the signs of pLMCE when evaluating patient images and carefully inquire about and document information such as symptoms, previous diseases, and drug use to more accurately assess specific signs of pLMCE, thereby assisting clinicians in determining whether further examination is necessary. Accordingly, it is crucial to obtain an in-depth understanding of the complex and diverse clinical history behind each pediatric patient presenting pLMCE signs and to combine expertise and skills to make informed decisions to avoid overdiagnosis. In doing so, we can provide more accurate, effective, and acceptable medical services to each individual.

We also found statistically significant associations between LMCE grades and patient age and weight. The younger the child is, the less mature their blood-brain barrier[5], vasculature[6], and dynamic perfusion[7]. The blood-brain barrier is an important protective layer that limits the entry of substances into the brain from the external environment to maintain normal neuronal function. However, in childhood, this barrier is relatively weak and susceptible to external factors such as anaesthesia. Additionally, the vasculature of children is not fully developed, which means that blood circulation that supplies oxygen and nutrients to the brain may be less efficient than that in adults, leading to instability under anaesthesia. Furthermore, there are differences in dynamic perfusion or the ability to adjust blood flow based on changes in the demand for oxygen and nutrients within specific regions or functional areas of the brain as a whole. This regulatory mechanism is not fully formed and fluctuates more dramatically in pediatric patients than in adults, which may be the underlying mechanism that leads to pLMCE.

In conclusion, this retrospective analysis revealed the true cause of pLMCE signs induced by sevoflurane. These imaging results should not be misinterpreted as meningeal pathology to prevent overdiagnosis by radiologists. The prevalence of pLMCE may be greater in young children because they have weak and immature blood vessels. To obtain a more comprehensive understanding of how pLMCE signs manifest across devices with different magnetic strengths, we can expand the current research and include additional experimental conditions. The scans were performed using MRI devices with different magnetic field intensities and models to determine whether there was a correlation between the results and pLMCE signs. Additionally, in the current study, complete avoidance of sedatives for MRI examinations could not be achieved due to the involvement of children. In future studies, a control group that did not receive anaesthesia but still underwent MRI could be considered. This approach will help with comparisons of potential differences between the two groups and eliminate any possible effects of sedatives. Further exploration of pLMCE signs in various magnetic fields and devices, introduction of nonsedated MRI examination as a control group along with other improved methods, and large-scale multicentre prospective studies to address these limitations can lead to more accurate, reliable, and universally applicable conclusions.

ACKNOWLEDGEMENTS

The authors thank the participants selfless and valuable assistance in this study. The authors thank the anonymous reviewers for their comments and suggestions.