PHOENIX, ARIZ. — Magnetic resonance imaging provides more detail about traumatic brain and spinal cord injuries but computerized tomography is much faster, according to a colonel in the U.S. Army Medical Corps who served in Afghanistan.
In head traumas, MRI is superior for all pathologies except skull fracture and acute subarachnoid hemorrhage, Geoffrey S.F. Ling, M.D., said at a meeting sponsored by the Society of Critical Care Medicine. It can give far more information about edema, diffuse axonal injury, contusions, hematomas, and posterior fossa lesions, but these can all be diagnosed more quickly with CT scans, he said; rarely does information gathered with an MRI change clinical management of the patient.
Consequently, Dr. Ling, director of the division of critical care medicine at the Uniformed Services University of the Health Sciences in Bethesda, Md., said he reserves use of MRI to establish a diagnosis in a patient who is not improving after several days in an intensive care unit and to establish a prognosis.
Dr. Ling recommended CT scans for all patients at high risk for intracranial pathology. These would include patients with focal neural signs, penetrating wounds, depressed skull fractures that are palpable, and impaired motor skills in the absence of alcohol or drugs.
CT scans should also be considered in moderate-risk cases: patients with a history of changed mental status, amnesia, progressive headache, serious facial injury, vomiting, evidence of a skull fracture, multiple traumas, possible child abuse, and age younger than 2 years.
“If the patient was knocked out for more than 5 minutes, I would go ahead and do a CT scan,” he said. Plain x-rays should be used only in cervical spine injuries such as whiplash, for which they can diagnose tiny fractures, according to Dr. Ling. “The only time I will use plain films is for the neck,” he said.