Evaluation of Paraspinal Fat Pad as an Indicator of Posterior Ligamentous Complex Injury in Cervical Spine Trauma

Purpose To determine if the obliteration of a cervical space, the paraspinal fat pad (PFP), can be used as an indicator at computed tomography (CT) of an injury of cervical spine posterior ligamentous complex (PLC). Materials and Methods This retrospective study was approved by the institutional board review; written informed consent was obtained from healthy subjects and was waived for patients. First, PFP appearance was evaluated in an anatomic specimen and in 10 healthy subjects on spine CT scans by three radiologists (readers 1, 2, and 3) working in consensus. Then, in 85 patients with suspicion of cervical spine trauma following high-velocity trauma, readers 2 and 3 reviewed in consensus the cervical spine CT (reference for fracture and luxation) and 1.5-T magnetic resonance images (T1, T2, and short inversion time inversion-recovery sequences; reference for ligament and disk injuries and contusion or occult fracture) for traumatic injuries. CT appearance of PFP was independently analyzed by readers 1 and 2, and interobserver agreement (weighted kappa) was calculated. Relationships between PFP changes and injuries and descriptive analysis were calculated by using logistic regression and Fisher test, respectively. Results The PFP could be identified as a well-circumscribed fatty area between cervical spine and posterior muscles. Interobserver agreement was 0.76. An abnormal PFP was associated with PLC (P < .001) and arch (P = .006) injuries but not with body (P = .056), longitudinal ligaments (P = .412), or disk (P = .665) injuries. Sensitivity, specificity, positive predictive value, and negative predictive value for PLC injuries were 55% (11 of 20), 97% (38 of 39), 92% (11 of 12), and 81% (38 of 47), respectively. Conclusion PFP changes on CT scans are significantly associated with injuries of PLC in patients with spine cervical trauma. ^© RSNA, 2016 Online supplemental material is available for this article.