Forrest Lensing
As the use of MR imaging in the emergency department increases, it has become increasingly important to recognize the pitfalls associated with MR imaging in the acute setting. We arrived at our research topic after seeing several elderly patients imaged acutely with MRI of the cervical spine. These patients had little or no bone marrow edema on STIR imaging despite the presence of an acute odontoid fracture on the subsequently obtained CT. We are taught to rely on the STIR sequence for the presence of bone marrow edema, and its utility in detecting osteoporotic fractures has been previously shown. The utility of the STIR sequence in detecting bone marrow edema in the setting of acute odontoid fractures, however, appears dubious in certain populations.
Elderly patients may present with acute odontoid injuries related to relatively minor trauma, likely due to decreased bone mineralization. These patients may not recall the incident of trauma and may present with symptoms of neck pain, radiculopathy, or other, less specific symptoms. In practice, when I evaluate a cervical spine MRI in an elderly patient, I carefully evaluate the odontoid process on T1- and T2-weighted images, and examine the soft tissues at the cranio-cervical junction for ancillary signs of an acute odontoid injury. If I detect suspicious findings and a CT has not been performed, I recommend CT of the cervical spine in order to better delineate the osseous structures.
As emergent MR imaging becomes more ubiquitous and elderly population growth continues, I believe it is critical for the practicing radiologist to be aware of the potential lack of sensitivity of the STIR sequence in this relatively common injury.