Trauma of the spine and spinal cord.

Although CT continues to be of great importance in the evaluation of the spine after acute trauma, MRI is gaining acceptance and is considered indispensable in some situations. At our institution, in all patients who have suffered head trauma and have an immobilized cervical spine, a CT of the cervical spine is obtained at the same time as the head CT. In these patients, 3 mm thick spiral sections (pitch=1) from C1 to C7 are obtained and obviate the need for cervical spine radiographs. A reduced charge is billed for this examination, which has been found to be cost effective in these patients. If doubt remains, the region-of-interest is re-studied using 1 mm thick sections. If the CT examination is normal and there are no neurological symptoms, the diagnostic evaluation of the patient is terminated. If the CT is normal but neurological symptoms are present, MRI is obtained. If the examination is abnormal in absence of neurological symptoms, MRI is not performed. That is, MRI is reserved for patients with neurological symptoms or those in whom the suspicion of an underlying lesion may change the surgical approach. Our MR protocol for the acutely injured spine includes sagittal T1and FSE T2-weighted images and axial T1and GRE T2-weighted images. No contrast is necessary in these patients. The sagittal FSE T2-weighted images provide high resolution at the expense of less susceptibility effects, thereby underestimating the presence and degree of hematomas. For this reason, the axial T2-weighted images need to be obtained using a low flip angle technique which increases the visualization of susceptibility effects, making acute hemorrhages more visually obvious. For purposes of this review, I will discuss the utility of MR to image the spine, spinal cord (and nerves), and vascular structures in the setting of acute trauma, mostly involving the cervical region.