Diffuse axonal injury outcome
Diffuse axonal injury, and more generally traumatic brain injury, often results in physical, cognitive, and behavioral impairments that can be temporary or permanent 1) 2) 3) 4) 5) 6) 7) 8) 9) 10).
Cicuendez et al. attempted to determine whether any Magnetic resonance imaging findings of traumatic axonal injury (TAI) could be related to prognosis in 264 patients with severe traumatic brain injury. They performed an ordinal logistic regression, adjusted for the prognostic factors according to the International Mission for Prognosis and Analysis of Clinical Trial in TBI studies, adding each MR feature related to prognosis one at a time. A new prognostic model was described by adding these MR features to the classic prognostic factors. The model was externally validated in a prospective series. Harrel's c-statistic and ordinal c-index (ORC) was calculated to measure its predictive accuracy.
They found 178 patients with TAI lesions. Lesions in the basal ganglia/thalamus, corpus callosum (CC) and brain stem were associated with poor outcome (P < 0.01). The highest OR was for TAI lesions in the splenium (OR: 2.6) and brain stem dorsal lesions (OR: 3.1). They only found significant differences in outcome between hemorrhagic and non-hemorrhagic TAI lesions in the subgroup of patients with white matter and basal ganglia/thalamus lesions (P = 0.01). They obtained a superior discriminatory capacity by adding these MR findings to the previous prognostic model (Harrel's c-statistic 0.72 and ORC 0.7) in a prospective series of 93 patients.
The prognostic model including MR findings maintained a superior discriminatory capacity than that obtained for the model with the classic prognostic factors alone 11).
The outcome of patients after DAI has been linked to the number of lesions identified through imaging. A longitudinal study that analyzed the evolution of traumatic axonal injury using magnetic resonance imaging (MRI) of 58 patients with moderate or severe TBI showed that the greater the number of lesions observed early after trauma, the greater the impairment of functionality after 12 months 12).
A study of 26 DAI patients indicated that the volume and number of lesions identified by MRI performed within 48 h of hospital admission strongly correlated with the level of disability observed at the time of hospital discharge 13).
DAI with hypoxia, as measured by peripheral oxygen saturation, and hypotension with New Injury Severity Score (NISS) value - had a statistically significant association with patient mortality; on the other hand, severity of DAI and length of hospital stay were the only significant predictors for dependence. Therefore, severity of DAI emerged as a risk factor for both mortality and dependence 14).
Clinical evidence of DAI on MRI may only be useful for predicting short-term in-hospital functional outcome. Given no association of DAI and long-term TBI outcomes, providers should be cautious in attributing DAI to future neurologic function, quality of life, and/or survival 15).
Brain atrophy progresses over time, but patients showed better executive function (EF) and verbal episodic memory (EVM) in some of the tests, which could be due to neuroplasticity 16).