The comparison of the value of ct imaging and selected MRI sequences (including DWI) in the evaluation of axonal injuries

BACKGROUND Diffuse axonal injuries of the brain consist in the damage (overstretching or torsion) of white matter axons, as a result of the forces of energy waves, evoked in the moment of injury, together with its accelerating-retarding inertia effect. Patients with DAI are most frequently the casualties of high speed car accidents. Diffuse axonal injuries of the brain are one of the most common acute brain injuries, with lesions typically occurring in the periventricular white matter, corpus callosum, and on the borderline of the white and grey matter, subventricularly. The diagnosis of axonal injuries is difficult, as the majority of lesions found in DAI are of microscopic nature. MATERIAL/METHODS The material included the evaluation of 8 patients with craniocerebral injuries, normal results of brain CT (or showing slight posttraumatic lesions), and in severe neurological clinical state (continuing coma), which was all suggestive of a diffuse axonal injury. The patients were subjected to brain MRI studies within an MRI trauma protocol including FLAIR and DWI sequences, as well as sagittal T2-weighed images, which shortened the diagnostic examination time and was sufficient for the visualisation of DAI-specific lesions. RESULTS On MRI examination, seven patients were diagnosed with diffuse foci of high signal intensity, located in corpus callosum, basal ganglia, thalamus and brain stem, although the CT examination results were normal or revealing minor changes. The foci were most prominent in DWI images. DWI sequence showed a diffuse cytotoxic oedema of white matter in one case, in which the CT results were normal. CONCLUSIONS The MRI examination with DWI should become a basic diagnostic tool in DAI. Due to patients' severe condition, the diagnostic process should be shortened. This could be done with the use of some selected sequences and projections of brain MRI, including transverse DWI and FLAIR, as well as T2-weighed images in sagittal plane, which reduces the time of the examination by approx. 12-15 minutes. Correct and quick diagnosis of a diffuse axonal injury is of major therapeutic and prognostic importance.