Utility of Adding Magnetic Resonance Imaging to Computed Tomography Alone in the Evaluation of Cervical Spine Injury A Propensity-Matched Analysis Andrew J. Schoenfeld, MD, MSc,  Daniel G. Tobert, MD,  Hai V. Le, MD,  Dana A. Leonard, BA, y Allan L. Yau, BS, z Prashant Rajan, BS, § Charles H. Cho, MD, MBA, { James D. Kang, MD,  Christopher M. Bono, MD,  and Mitchel B. Harris, MD, FACS  Study Design. Adult patients who received computed tomogra- phy (CT) alone or CT-magnetic resonance imaging (MRI) for the evaluation of cervical spine injury. Objective. To evaluate the utility of CT-MRI in the diagnosis of cervical spine injury using propensity-matched techniques. Summary of Background Data. The optimal evaluation (CT alone vs. CT and MRI) for patients with suspected cervical spine injury in the setting of blunt trauma remains controversial. Methods. The primary outcome was the identification of a cervical spine injury, with decision for surgery and change in management considered secondarily. A propensity score was developed based on the likelihood of receiving evaluation with CT-MRI, and this score was used to balance the cohorts and develop two groups of patients around whom there was a degree of clinical equipoise in terms of the imaging protocol. Logistic regression was used to evaluate for significant differences in injury detection in patients evaluated with CT alone as com- pared to those receiving CT-MRI. Results. Between 2007 and 2014, 8060 patients were evaluat- ed using CT and 693 with CT-MRI. Following propensity-score matching, each cohort contained 668 patients. There were no significant differences between the two groups in baseline characteristics. The odds of identifying a cervical spine injury were significantly higher in the CT-MRI group, even after adjusting for prior injury recognition on CT (odds ratios 2.6; 95% confidence interval 1.7–4.0; P < 0.001). However, only 53/ 668 patients (8%) in the CT-MRI group had injuries identified on MRI not previously recognized by CT. Only a minority of these patients (n ¼ 5/668, 1%) necessitated surgical intervention. Conclusion. In this propensity-matched cohort, the addition of MRI to CT alone identified missed injuries at a rate of 8%. Only a minority of these were serious enough to warrant surgery. This speaks against the standard addition of MRI to CT-alone protocols in cervical spine evaluation after trauma. Key words: cervical clearance, computed tomography, evaluation of cervical trauma, magnetic resonance imaging. Level of Evidence: 3 Spine 2018;43:179–184 A t present, the optimal protocol for the evaluation of cervical spine injury, particularly in obtunded blunt trauma patients, remains controversial. 1–7 In an alert, cooperative patient with a normal neurologic exami- nation, negative computed tomography (CT) imaging is accepted as sufficient to certify that the cervical spine is free of significant injury. 1–3 When a patient has impaired mental status, concomitant closed head trauma or other distracting injuries, there is persistent concern that CT evaluation may miss clinically significant injuries. 1–3,7 Al- though it is well recognized that magnetic resonance imag- ing (MRI) is more sensitive than CT in detecting cervical injuries, particularly those involving the ligaments and soft- tissues, the incorporation of such imaging modalities as a standard part of an evaluation protocol adds expense as well as logistical challenges. 1–3,7 Recent studies have reported that the addition of MRI in the evaluation of patients with suspected cervical spine From the  Department of Orthopaedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA; y Department of Orthopae- dic Surgery, Brigham and Women’s Hospital, Boston, MA; z Tufts University School of Medicine, Boston, MA; § Orthopaedic and Arthritis Center for Outcomes Research, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA; and { Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA. Acknowledgment date: February 28, 2017. First revision date: May 2, 2017. Second revision date: May 16, 2017. Acceptance date: May 23, 2017. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. Relevant financial activities outside the submitted work: board membership, grants, royalties. Address correspondence and reprint requests to Andrew J. Schoenfeld, MD, MSc, Department of Orthopaedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115; E-mail: ajschoen@neomed.edu DOI: 10.1097/BRS.0000000000002285 Spine www.spinejournal.com 179 SPINE Volume 43, Number 3, pp 179–184 ß 2018 Wolters Kluwer Health, Inc. All rights reserved. DIAGNOSTICS Copyright © 2018 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.