Dynamic Magnetic Resonance Imaging Evaluation of Craniovertebral Junction Abnormalities

Abstract

Dynamic MRI was able to detect cases of cord compression that were not seen in neutral position and was diagnostic in all cases of mobile AAI where mobility at this joint affects the treatment options. Dynamic MRI is extremely useful for evaluating craniovertebral junction abnormalities and, in particular, cord compression.

Revisiting Anterior Atlantoaxial Subluxation with Overlooked Information on MR Images

“…Sometimes, this may not be apparent in the neutral position and is only evident during flexion. 8 This explains why only 1 patient among the 5 patients with focal myelopathy in the nAAA subluxation group demonstrated spinal canal narrowing. Therefore, suspicion of atlantoaxial joint instability should always be kept in mind once focal high cervical myelopathy is depicted as the only significant finding.…”

“…The atlas slips backward when the cervical spine is in the neutral or extension positions. A few studies have reported MR imaging findings of AAA subluxation, 8,9 but none has focused on the diagnostic implications of abnormalities in the associated structures or suggested a method to improve the false-negative diagnostic rate in nAAA subluxation patients. To our knowledge, this study is the first attempt to do so.…”

“…Dynamic MR imaging provides additional information over the routine neutral-positioning scan. 8,9 However, it is time-consuming and impractical for daily imaging practice. Additionally, the lengthy scanning time may increase the risk of procedure-related cord compression; also, the falsenegative rate of dynamic MR imaging was reported to be as high as 17%.…”

Dynamic MRI in the Evaluation of Atlantoaxial Stability in Pediatric Down Syndrome Patients

“…Patients with Down syndrome face an increased incidence of radiographic instability, approaching 30% in some studies [1-5, 6, 7]. The actual number of symptomatic patients varies, however, but may be as few as 1.5% depending on how symptomatology is defined [7, 8, 9-13].…”

“…Including these views increases the detection or exclusion of true instability [2, 6, 14-16]. In this study, we selected what we felt to be definable indicators of neuraxis injury using parameters on dynamic MRI.…”