The added prognostic value of magnetic resonance imaging in traumatic brain injury: The importance of traumatic axonal injury when performing ordinal logistic regression

Evolution of Severe Closed Head Injury: Assessing Ventricular Volume and Behavioral Measures at 30 and 90 Days Post-Injury

Background: Assessing functional outcomes in Severe Closed Head Injury (SCHI) is complex due to brain parenchymal changes. This study examines the Ventricles to Intracranial Volume Ratio (VBR) as a metric for these changes and its correlation with behavioral scales. Methods: Thirty-one SCHI patients were included. VBR was derived from CT scans at 3, 30, and 90 days post-injury and compared with Levels of Cognitive Functioning (LCF), Disability Rating Scale (DRS), and Early Rehabilitation Barthel Index (ERBI) assessments at 30 and 90 days. Results: Ten patients were excluded post-decompressive craniectomy or ventriculoperitoneal shunt. Findings indicated a VBR decrease at 3 days, suggesting acute phase compression, followed by an increase from 30 to 90 days, indicative of post-acute brain atrophy. VBR correlated positively with the Marshall score in the initial 72 h, positioning it as an early indicator of subsequent brain atrophy. Nevertheless, in contrast to the Marshall score, VBR had stronger associations with DRS and ERBI at 90 days. Conclusions: VBR, alongside behavioral assessments, presents a robust framework for evaluating SCHI progression. It supports early functional outcome correlations informing therapeutic approaches. VBR's reliability underscores its utility in neurorehabilitation for ongoing SCHI assessment and aiding clinical decisions.

Association between Traumatic Subarachnoid Hemorrhage and Acute Respiratory Failure in Moderate-to-Severe Traumatic Brain Injury Patients

Acute respiratory failure (ARF) with a high incidence among moderate-to-severe traumatic brain injury (M-STBI) patients plays a pivotal role in worsening neurological outcomes. Traumatic subarachnoid hemorrhage (tSAH) is highly prevalent in M-STBI, which is associated with significant adverse outcomes. In this retrospective cohort study, we aimed to explore the association between the severity of the tSAH and ARF in the M-STBI population. A total of 771 subjects were reviewed. Clinical and neuroimaging data of M-STBI patients were retrospectively collected, and ARF was ascertained retrospectively based on their electronic medical record. The degree of tSAH was classified according to Fisher’s criteria, and the grade of tSAH was dichotomized to a low Fisher grade (Fisher grade 1–2) and a high Fisher grade (Fisher grade 3–4). After exclusion procedures, the data of 695 M-STBI patients were analyzed. A total of 284 (30.8%) had a high Fisher grade on admission. The overall rate of ARF within 48 h upon admission was 34.4% (239/695); it was 29.5% (142/481) and 46.3% (99/214) for the low and high Fisher groups, respectively. In a full cohort, a high Fisher grade was associated with ARF after adjusting for age, gender, GCS, smoking history, comorbidities, multiple injuries, characteristics of TBI, and pulmonary factors (OR 1.78; 95% CI, 1.11–2.85, p = 0.016). This result remained robust in the comparisons after PSM (71/132, 42.8% vs. 53/132, 31.9%; OR, 1.59; 95% CI, 1.02–2.49, p = 0.042). A high Fisher SAH grade exposure on admission is associated with ARF in M-STBI patients.

Predictors of return to work after moderate-to-severe traumatic brain injury: a systematic review of current literature and recommendations for future research

PURPOSE

To identify factors associated with employment between six months and five years after traumatic brain injury (TBI).

METHODS

Using a predefined search algorithm, four electronic databases were searched for literature published between 2014 and the first half of April 2021 containing predictors of employment outcome. Data were selected in accordance with the PRISMA flow and the whole process was conducted by two reviewers who had to attain a consensus. The study results were discussed with an expert panel, in order to provide guidance for future research on this topic.

RESULTS

This review found clear evidence for employment status at time of injury, occupation at time of injury, Glasgow Coma Scale, length of stay, disability level and primary payer to be predictors of return to work after TBI.

CONCLUSIONS

More literature investigating in depth the functioning and environmental factors is required for further improvement of predictions, rehabilitation and policy.Implications for rehabilitationThis study identifies predictors of return to work in TBI patients, which can be used to identify patients with high risk early in the recovery process.Current literature shows difficulties with general functioning are a barrier for return to work, but gives no indication about effective therapeutic interventions.More knowledge about modifiable factors is desirable to improve rehabilitation and, thereby, employment outcomes after TBI.

Prognostic Value of Hemorrhagic Brainstem Injury on Early Computed Tomography: A TRACK-TBI Study

BACKGROUND

Traumatic brainstem injury has yet to be incorporated into widely used imaging classification systems for traumatic brain injury (TBI), and questions remain regarding prognostic implications for this TBI subgroup. To address this, retrospective data on patients from the multicenter prospective Transforming Research and Clinical Knowledge in TBI study were studied.

METHODS

Patients with brainstem and cerebrum injury (BSI+) were matched by age, sex, and admission Glasgow Coma Scale (GCS) score to patients with cerebrum injuries only. All patients had an interpretable head computed tomography (CT) scan from the first 48 hours after injury and a 6-month Glasgow Outcome Scale Extended (GOSE) score. CT scans were reviewed for brainstem lesions and, when present, characterized by location, size, and type (traumatic axonal injury, contusion, or Duret hemorrhage). Clinical, demographic, and outcome data were then compared between the two groups.

RESULTS

Mann-Whitney U-tests showed no significant difference in 6-month GOSE scores in patients with BSI+ (mean 2.7) compared with patients with similar but only cerebrum injuries (mean 3.9), although there is a trend (p = 0.10). However, subclassification by brainstem lesion type, traumatic axonal injury (mean 4.0) versus Duret hemorrhage or contusion (mean 1.4), did identify a proportion of BSI+ with significantly less favorable outcome (p = 0.002). The incorporation of brainstem lesion type (traumatic axonal injury vs. contusion/Duret), along with GCS into a multivariate logistic regression model of favorable outcome (GOSE score 4-8) did show a significant contribution to the prognostication of this brainstem injury subgroup (odds ratio 0.08, 95% confidence interval 0.00-0.67, p = 0.01).

CONCLUSIONS

These findings suggest two groups of patients with brainstem injuries may exist with divergent recovery potential after TBI. These data support the notion that newer CT imaging classification systems may augment traditional clinical measures, such as GCS in identifying those patients with TBI and brainstem injuries that stand a higher chance of favorable outcome.

[Clinical and MRI predictors of coma duration, intensive care and outcome of traumatic brain injury]

OBJECTIVE

This research is aimed to study the clinical and MRI predictors of coma duration, the intensity of critical care, and outcome of traumatic brain injury (TBI).

MATERIAL AND METHODS

The data from 309 patients with TBI of varying severity were included in the analysis, of whom 257 (86.7%) were treated in the intensive care unit (ICU), including 196 (63.4%) patients admitted in a comatose state lasting longer than 1 day. All patients underwent brain MRI within 21 days after the injury. MRI findings were classified according to MRI grading scale of brain damage level and localization proposed previously.

RESULTS

The proposed MRI grading significantly correlated with the Glasgow coma (GCS, r=-0.67; p<0.0001) and Glasgow outcome (0.69; p<0.001) scores in the entire group. In a subgroup of comatose patients (GCS<9) it correlated with coma duration (r=0.52; p<0.0001). Spearman correlation analysis showed a significant relationship between the MRI classification and a number of parameters: ICU length of stay (r=0.62; p<0.0001), the duration of artificial ventilation (r=0.47; p<0.0001), the rate of artificial ventilation, sedatives, analgesics, mannitol, hypertonic saline and vasopressors usage (p<0.01). These data confirm the relationship between higher grades of MRI classification (deep brain damage) and the need for the escalation of intensive care main components.

CONCLUSION

Our results support the hypothesis that the levels and localization of brain damage, estimated by the proposed MRI grading scale, might be predictors of coma duration, intensity and duration of intensive care, and TBI outcomes. A prognosis based on clinical and neuroimaging data comparison can be valuable for planning and efficient use of the hospital beds and ICU resources, for optimizing the patient flow and timing of patient transfer to neurorehabilitation facilities.

Two Coarse Spatial Patterns of Altered Brain Microstructure Predict Post-traumatic Amnesia in the Subacute Stage of Severe Traumatic Brain Injury

Introduction: Diffuse traumatic axonal injury (TAI) is one of the key mechanisms leading to impaired consciousness after severe traumatic brain injury (TBI). In addition, preferential regional expression of TAI in the brain may also influence clinical outcome. Aim: We addressed the question whether the regional expression of microstructural changes as revealed by whole-brain diffusion tensor imaging (DTI) in the subacute stage after severe TBI may predict the duration of post-traumatic amnesia (PTA). Method: Fourteen patients underwent whole-brain DTI in the subacute stage after severe TBI. Mean fractional anisotropy (FA) and mean diffusivity (MD) were calculated for five bilateral brain regions: fronto-temporal, parieto-occipital, and midsagittal hemispheric white matter, as well as brainstem and basal ganglia. Region-specific calculation of mean FA and MD only considered voxels that showed no tissue damage, using an exclusive mask with all voxels that belonged to local brain lesions or microbleeds. Mean FA or MD of the five brain regions were entered in separate partial least squares (PLS) regression analyses to identify patterns of regional microstructural changes that account for inter-individual variations in PTA. Results: For FA, PLS analysis revealed two spatial patterns that significantly correlated with individual PTA. The lower the mean FA values in all five brain regions, the longer that PTA lasted. A pattern characterized by lower FA values in the deeper brain regions relative to the FA values in the hemispheric regions also correlated with longer PTA. Similar trends were found for MD, but opposite in sign. The spatial FA changes as revealed by PLS components predicted the duration of PTA. Individual PTA duration, as predicted by a leave-one-out cross-validation analysis, correlated with true PTA values (Spearman r = 0.68, p permutation = 0.008). Conclusion: Two coarse spatial patterns of microstructural damage, indexed as reduction in FA, were relevant to recovery of consciousness after TBI. One pattern expressed was consistent with diffuse microstructural damage across the entire brain. A second pattern was indicative of a preferential damage of deep midline brain structures.

Limited Colocalization of Microbleeds and Microstructural Changes after Severe Traumatic Brain Injury

Severe traumatic brain injury (TBI) produces shearing forces on long-range axons and brain vessels, causing axonal and vascular injury. To examine whether microbleeds and axonal injury colocalize after TBI, we performed whole-brain susceptibility-weighted imaging (SWI) and diffusion tensor imaging (DTI) in 14 patients during the subacute phase after severe TBI. SWI was used to determine the number and volumes of microbleeds in five brain regions: the frontotemporal lobe; parieto-occipital lobe; midsagittal region (cingular cortex, parasagittal white matter, and corpus callosum); deep nuclei (basal ganglia and thalamus); and brainstem. Averaged fractional anisotropy (FA) and mean diffusivity (MD) were measured to assess microstructural changes in the normal appearing white matter attributed to axonal injury in the same five regions. Regional expressions of microbleeds and microstructure were used in a partial least-squares model to predict the impairment of consciousness in the subacute stage after TBI as measured with the Coma Recovery Scale-Revised (CRS-R). Only in the midsagittal region, the expression of microbleeds was correlated with regional changes in microstructure as revealed by DTI. Microbleeds and microstructural DTI-based metrics of deep, but not superficial, brain regions were able to predict individual CRS-R. Our results suggest that microbleeds are not strictly related to axonal pathology in other than the midsagittal region. While each measure alone was predictive, the combination of both metrics scaled best with individual CRS-R. Structural alterations in deep brain structures are relevant in terms of determining the severity of impaired consciousness in the acute stage after TBI.

Association of cause of injury and traumatic axonal injury: a clinical MRI study of moderate and severe traumatic brain injury

OBJECTIVE

The authors investigated the association between the cause of injury and the occurrence and grade of traumatic axonal injury (TAI) on clinical MRI in patients with moderate or severe traumatic brain injury (TBI).

METHODS

Data for a total of 396 consecutive patients, aged 7-70 years, with moderate or severe TBI admitted to a level 1 trauma center were prospectively registered. Data were included for analysis from the 219 patients who had MRI performed within 35 days (median 8, IQR 4-17 days) and for whom cause of injury was known. Cause of injury was registered as road traffic accident (RTA) or fall (both with respective subcategories), alpine skiing or snowboarding accident, or violence. The MRI protocol consisted of T2*-weighted gradient echo, FLAIR, and diffusion-weighted imaging scans. TAI lesions were evaluated in a blinded manner and categorized into 3 grades, hemispheric/cerebellar white matter (grade 1), corpus callosum (grade 2), and brainstem (grade 3). The absence of TAI was analyzed as grade 0. Contusions and mass lesions on CT were also registered.

RESULTS

Cause of injury did not differ between included and nonincluded patients. TAI was found in 83% of patients in the included group after RTAs and 62% after falls (p < 0.001). Observed TAI grades differed between the subcategories of both RTAs (p = 0.004) and falls (p = 0.006). Pedestrians in RTAs, car drivers/passengers in RTAs, and alpine skiers had the highest prevalence of TAI (89%-100%) and the highest TAI grades (70%-82% TAI grades 2-3). TAI was found in 76% of patients after falls from > own height (45% TAI grade 2-3), 63% after falls down the stairs (26% TAI grade 2-3), and 31% after falls from ≤ own height (12% TAI grade 2-3). Moreover, 53% of patients with TAI after RTAs and 68% with TAI after falls had cortical contusions or mass lesions on CT.

CONCLUSIONS

This prospective study of moderate and severe TBI is to the authors' knowledge the first clinical MRI study to demonstrate both the high prevalence and grade of TAI after most of the different types of RTAs, alpine skiing accidents, and falls from a height. Importantly, TAI was also common following more low-energy trauma such as falls down the stairs or from own height. Physicians managing TBI patients in the acute phase should be aware of the possibility of TAI no matter the cause of injury and also when the CT scan shows cortical contusions or mass lesions.