1H-MR spectroscopic monitoring of posttraumatic metabolism following controlled cortical impact injury: pilot study

Elevated cerebrospinal fluid concentrations of N-acetylaspartate correlate with poor outcome in a pilot study of severe brain trauma

Primary objective: Examine the correlation between acute cerebrospinal fluid (CSF) levels of N-acetylaspartate (NAA) and injury severity upon admission in addition to long-term functional outcomes of severe traumatic brain injury (TBI). Design and rationale: This exploratory study assessed CSF NAA levels in the first four days after severe TBI, and correlated these findings with Glasgow Coma Scale (GCS) score and long-term outcomes at 3, 6, 12, and 24 months post-injury. Methods: CSF was collected after passive drainage via an indwelling ventriculostomy placed as standard of care in a total of 28 people with severe TBI. NAA levels were assayed using triple quadrupole mass spectrometry. Functional outcomes were assessed using the Glasgow Outcomes Scale (GOS) and Disability Rating Scale (DRS). Results: In this pilot study, better functional outcomes, assessed using the GOS and DRS, were found in individuals with lower acute CSF NAA levels after TBI. Key findings were that average NAA level was associated with GCS (p = .02), and GOS at 3 (p = .01), 6 (p = .04), 12 (p = .007), and 24 months (p = .002). Implications: The results of this study add to a growing body of neuroimaging evidence that raw NAA values are reduced and variable after TBI, potentially impacting patient outcomes, warranting additional exploration into this finding. This line of inquiry could lead to improved diagnosis and prognosis in patients with TBI.

1H-MR spectroscopy in traumatic brain injury

Traumatic brain injury (TBI) is a common cause of neurological damage and disability. Conventional imaging (CT scan or MRI) is highly sensitive in detecting lesions and provides important clinical information regarding the need for acute intervention. However, abnormalities detected by CT scan or conventional MRI have limited importance in the classification of the degree of clinical severity and in predicting patients' outcome. This can be explained by the widespread microscopic tissue damage occurring after trauma, which is not observable with the conventional structural imaging methods. Advances in neuroimaging over the past two decades have greatly helped in the clinical care and management of patients with TBI. The advent of newer and more sensitive imaging techniques is now being used to better characterize the nature and evolution of injury and the underlying mechanisms that lead to progressive neurodegeneration, recovery or subsequent plasticity. This review will describe the role of proton magnetic resonance spectroscopic (MRS), an advanced MRI technique as related to its use in TBI. Proton MRS is a noninvasive approach that acquires metabolite information reflecting neuronal integrity and function from multiple brain regions and allows to assess clinical severity and to predict disease outcome.

Neuroimaging of animal models of brain disease

The main aim of this review is to describe some of the many animal models that have proved to be valuable from a neuroimaging perspective. This paper complements other articles in this volume, with a focus on animal models of the pathology of human brain disorders for investigations with modern non-invasive neuroimaging techniques. The use of animal model systems forms a fundamental part of neuroscience research efforts to improve the prevention, diagnosis, understanding and treatment of neurological conditions. Without such models it would be impossible to investigate such topics as the underlying mechanisms of neuronal cell damage and death, or to screen compounds for possible anticonvulsant properties. The adequacy of any one particular model depends on the suitability of information gained during experimental conditions. It is important, therefore, to understand the various types of animal model available and choose an appropriate model for the research question.