MRI offers no additional information beyond CT for cervical spine trauma

By Will Boggs MD

NEW YORK (Reuters Health) - Computed tomography (CT) effectively detects clinically significant cervical spine injuries in adults, but MRI provides no additional meaningful information, according to a prospective observational study.

Missed cervical spine injuries can have devastating consequences, so when such injuries cannot be ruled out clinically, radiological examination is necessary. What constitutes the optimal imaging, though, remains controversial.

Dr. Kenji Inaba and colleagues from the University of Southern California Medical Center in Los Angeles investigated the accuracy of CT and MRI for cervical spine clearance in 830 patients who were awake, alert, and able to be examined and who presented with midline cervical tenderness or focal neurologic deficits.

Just under one in five of these patients (164/830, 19.8%) received a diagnosis of cervical spine injury, but only 23 (2.8%) had clinically significant injuries (as defined by the requirement for surgical intervention or halo placement).

CT correctly identified all clinically significant injuries. Three patients had additional findings observed on MRI, but none of these findings altered the treatment prescribed on the basis of CT findings.

None of the 681 patients with a normal CT received a discharge diagnosis of clinically significant cervical spine injury.

Among 100 patients who underwent MRI, 46 had findings that had not been noted on the CT scan, according to the July 30th JAMA Surgery online report. Most of these additional findings were ligamentous injuries (n=42), although two patients had new spinous process fractures that did not require treatment.

CT had a 100% positive predictive value for detecting cervical spine injury and a 100% sensitivity and specificity for detecting clinically significant injuries.

"Elimination of MRI from the routine workup of the cervical spine in patients with blunt trauma and a normal CT scan who are awake, alert, and able to be examined is safe and cost-effective," the researchers conclude.

"Because nothing in medicine is ever absolute, we are not stopping with this study," Dr. Inaba told Reuters Health. "At this time, we are well into a prospective, observational multi-center study as part of the Western Trauma Association multi-center trials group designed to validate these findings."

Dr. Martin A. Schreiber from Oregon Health & Science University, Portland, Oregon, who wrote an invited commentary on this report, agreed. "I do not believe that MRI has any utility in the initial evaluation of patients with potential cervical spine injuries in the absence of neurologic findings," he told Reuters Health. "In patients with cervical pain or tenderness in whom the spine cannot be initially cleared, we leave the collar on and reassess later."

"MRI is an important part of the evaluation of . . . potential cervical spine injuries in those patients who have unexplained neurologic findings, such as weakness, sensory loss, or paresthesias," he said. "The MRI has the ability to find spinal cord hematomas, herniated disks, and cord signal abnormalities that are not seen on CT."

In his commentary, Dr. Schreiber pointed out that this study "is more focused on equivocal CT findings than on how to evaluate patients with persistent tenderness or a focal neurologic defect (and) the authors do not address the evaluation and care of patients with motor deficits and potential cervical spine injuries because there were none in the study."

Dr. Schreiber concludes, "Although it would be ideal to dispense with MRI as a diagnostic test in patients with potential cervical spine injuries, this study leaves many unanswered questions. I look forward to more prospective data on this topic from this group of investigators."

SOURCE: http://bit.ly/V2xsap

JAMA Surg 2014.

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