CHICAGO — Magnetic resonance imaging can pick up acute cervical spine trauma that is not visible on computed tomography scans, and should be considered in certain trauma patients, according to a study presented at the annual meeting of the Radiological Society of North America.
“Certainly, there is an added cost to ordering an MRI, compared to CT, but when you consider it in the context of such potential catastrophic consequences as quadriplegia, it may not be so expensive,” remarked Joseph Jen-Sho Chen, a 4th-year medical student at the University of Pittsburgh, who presented the research.
Although CT screening is widely accepted as being the standard of care for acute cervical spine injuries, it is not perfect, Mr. Chen told this newspaper.
“CT is very good for finding bone fractures, but it is known to be very poor for finding soft tissue, ligamentous, and spinal cord injuries, which are much better diagnosed by MRI,” he said.
He estimated that the cost of an MRI is about double that of a CT scan.
In his retrospective review, he assessed the benefit of MRI within 72 hours of a negative CT scan of the cervical spine in 91 level I and II trauma patients.
Almost half (45%) of the cases involved motor vehicle accidents, 29% involved falls, 10% involved other vehicles, 8% involved assault, 4% involved sports, and the rest involved pedestrian/vehicle or occupational accidents.
One-third of the patients presented with focal neurologic deficits, one-third had neck pain, 21% had mental status changes, and 18% were obtunded.
Of the 91 patients, 43 had positive CT findings, 5 had equivocal findings, and 43 had a negative CT, he said.
Of those patients with a negative CT, 34 had a negative MRI, but 9 (21%) had positive MRI findings.
Additional findings uncovered by MRI included cord compressions (five patients), cord contusion/edema (four), ligamentous injuries (three), epidural hemorrhage (two), and prevertebral edema (one).
Three of these patients had minor changes to their management based on the additional MRI findings (extended cervical collars) and six had major changes that involved surgery, he said.
Mr. Chen said five of the six patients with additional findings on MRI would likely have received an MRI in most settings, because they had focal neurologic deficits, which is considered an indication for MRI.
However, one patient might not have been referred for MRI in many hospitals because his only complaint was neck pain, Mr. Chen said.
“Definitely patients with focal neurologic deficits should go on to MRI after a negative CT but also I think [it's necessary for] patients whose physical symptoms don't match with the CT scan … like this patient with severe neck pain and no CT findings,” he said.
CT of a trauma patient shows no evidence of osseous injury.
MRI, 36 hours later, shows injuries and cord contusion. Photos courtesy Joseph Jen-Sho Chen