Magnetic Resonance Imaging in Acute Spinal Injury By Adam E. Flanders, Lisa M. Tartaglino, David P. Friedman, and Lucille F. Aquilone A N ESTIMATED 10,000 people in the United States sustain a spinal cord injury (SCI) each year with a prevalence of approxi- mately 200,000 people in any given year.Q The total lifetime cost for medical treatment and rehabilitation per individual can exceed one million dollars depending on the type of injury. In addition, the obvious social, psychological, and emotional burdens to the patient, family, and society are enormous. Injury to the cervical spinal cord can result in quadriplegia (paralysis involving both the arms and the legs), whereas injury to the spinal cord below the cervical region can result in paraple- gia (paralysis of the lower extremities only). More than half of all SCIs induce quadriplegia, and a similar percentage of all SCIs are com- plete (no motor or sensory function below the neurological level). Although more than 95% of paraplegic individuals can return to an indepen- dent lifestyle, this is achievable only to a vari- able degree with quadriplegic injuries. Because SCIs are endemic to teenagers and young adults, the impact on society in terms of loss of produc- tive years is substantial. The proportion of injuries to the spinal axis varies by location. The cervical spine is prone to injury because of its supportive function of the head and the extended flexibility of the neck. Injuries to the cervical axis account for more than half of all spinal injuries and are usually the result of motor vehicle accidents, diving injuries, or contact sports.3 The thoracic cage offers additional stability to the thoracic spine, and injuries to this area are relatively uncom- mon. Tremendous force is required to distract the thoracic segments. Intrinsic abnormalities to one or more thoracic vertebral bodies can predispose to an injury at this location. Fracture dislocations at the thoracolumbar junction (lap- belt injury) and lumbar spine are frequently associated with high speed motor vehicle acci- dents or falls from heights. The radiological evaluation of spinal injury has undergone a remarkable evolution with the development of magnetic resonance imaging (MRI). Although plain radiographs, myelogra- phy, and computed tomography (CT) were once the mainstay of spine imaging, MRI has recently become a necessity in the evaluation of SCI. The depiction by MRI of the soft tissue injuries associated with SC1 is unrivaled by any other imaging modality and has supplanted myelogra- phy in most instances. 4-11 Moreover, MRI is the only method available that allows for direct evaluation of the spinal cord parenchyma.h*x~“J2-i~ This information has radically changed our abilities to assessthe patient in the emergent period and has altered our understanding of the pathophysiology and prognosis of SCI.7,16-” TECHNIQUE The ability to safely perform MR in the emergent period on the spinal injury patient is complicated by additional technical factors in- cluding minimizing the movement of the pa- tient, monitoring the patient’s vital signs, and maintaining the patient’s ventilator-y support. It is therefore appropriate to addressthese techni- cal factors individually. Equipment Adequate images of the spinal axis can proba- bly be attained with any commercial magnet currently in use. There are distinct advantages to using the ultra-low to low static field strength units over high field strength in the emergent ABBREVIATIONS ALL, anterior longitudinal ligament; CSF, cerebrospi- nal fluid; CT, computed tomography; 3-DFT, three- dimensional Fourier transformation; FSE, fast spin echo; MRA, magnetic resonance angiography; MRI, magnetic resonance imaging; PLL, posterior longitu- dinal ligament; PPM, posttraumatic progressive my- elopathy; RARE. rapid acquisition with relaxation enhancement; SCI, spinal cord injury From the Department of Diagnostic Radiology. Thomas Jefferson University Hospital, Philadelphia, PA. Address reprint requests to Adam E. Flanders? MD, Depart- ment of Diagnostic Radiology, Thomas Jefferson Universil) Hospital, Suite 1072 Main Building, 10th and Sansom Sts. Philadebhia, PA 19107. Copyright 0 1992 by W.B. Saunders Cornpan) 0037-198X19212704-0006$5.OOiO Seminars in Roentgenology, Vol XXVII, No 4 (October), 1992: pp 271-298 271