In patients with a normal cervical spine CT but persistent tenderness or neurology, how often is a subsequent MRI abnormal? And what happens afterwards? Here's an answer from Gelong...
(Spoiler alert... the real question should be, "does MRI find occult injury that results in genuine improvements in patient-oriented outcomes? Or does it cause harm from overdiagnosis?")
These authors from a single centre, looked retrospectively at a cohort of trauma patients that had both a negative cervical spine CT and a subsequent MRI. (Adult patients had to be alert and <72 hours between the studies.)
228 patients were included.
Of the 181 patients that had the MRI for persistent tenderness, 35 (20% or one-in-five) had an abnormal MRI. Of those, 14 were treated with a rigid collar and no patients underwent surgery.
Of the 47 patients that had the MRI for neurological findings, 11 (23%) had an abnormal MRI. Four patients were managed with collars. Two patients required surgery and the manuscript described their presentation & hospital course. Their neurologic issues were not subtle.
The authors appropriately conclude that the MRI is of “questionable” utility in those without neurology.
But could the MRI be even worse? Could it identify injuries that would heal just fine had we never found them only to subject patients to weeks of unnecessary immobilisation, discomfort, and potential harm? Unfortunately, this was not really addressed in this study.
With technology advances, MRI will only get more sensitive at finding “abnormalities." In addition, MRI will become more readily available. We need to have some serious discussions; just because we can, should we?
Foster G, Russel B, Hibble B, et al. Magnetic resonance imaging cervical spine in trauma: A retrospective single-centre audit of patient outcomes. Emerg Med Aus. 2021 Sep 3.doi: 10.1111/1742-6723.13842. [link to article]