Clinical significance of "positive" cervical spine MRI findings following a negative CT

PURPOSE

To review and analyze the clinical significance of positive acute traumatic findings seen on MRI of the cervical spine (MRCS) following a negative CT of the cervical spine (CTCS) for trauma.

METHODS

We performed a sub-cohort analysis of 54 patients with negative CTCS and a positive MRCS after spine trauma from the previous multicenter study of the Research Consortium of New England Centers for Trauma (ReCONECT). Both CTCS and MRCS were independently reviewed by two emergency radiologists and two spine surgeons. The surgeons also commented on the clinical significance of the traumatic findings seen on MRCS and grouped them into unstable, potentially unstable, and stable injuries.

RESULTS

Among 35 unevaluable patients, MRCS showed one unstable (hyperextension) and two potentially unstable (hyperflexion) injuries. Subtle findings were seen on CTCS in 2 of 3 patients upon careful retrospective review that would have suggested these injuries. Of 19 patients presenting with cervicalgia, 2/5 (40%) patients with neurological deficit demonstrated clinically significant findings on MRCS with predisposing factors seen on CT. None of the 14 patients with isolated cervicalgia and no neurological deficit had clinically significant findings on their MRCS.

CONCLUSION

While CTCS is adequate for clearing the cervical spine in patients with isolated cervicalgia, MRCS can play a critical role in patients with neurological deficits and normal CTCS. Clinically significant traumatic findings were seen in 8.5% of unevaluable patients on MRCS, though these injuries in fact could be identified on the CT in 2 of 3 patients upon careful retrospective review.

Accuracy of craniocervical measurements on CT for identifying partial or complete craniocervical ligament injuries in pediatric patients

PURPOSE

To assess the accuracy of craniocervical measurements for identifying craniocervical injuries and the frequency of subjective findings of craniocervical injuries on CT in pediatric patients.

METHODS

Case-controlled retrospective review of patients ≤ 16 years old with craniocervical junction injuries. Receiver operator curves were created for common craniocervical measurements on CT comparing patients with complete and partial craniocervical injuries to uninjured cohort. Frequency of subjective CT findings of craniocervical injury was assessed in the injured cohort.

RESULTS

For complete disruption injuries (CD) (n = 27), C1-C2 distance (AUC = 0.90, 95%CI = 0.83-0.97), atlanto-occipital distance (AUC = 0.95-0.98, 95%CI = 0.90-1.00), and basion-dens distance (AUC = 0.90, 95%CI = 0.82-0.98) had excellent accuracy diagnosing injury. Powers ratio (AUC = 0.85, 95%CI = 0.76-0.94) had good, basion-posterior axial line (AUC = 0.74, 95%CI = 0.61-0.86) fair, and atlanto-dental distance (AUC = 0.69, 95%CI = 0.57-0.82) poor accuracy. For partial disruption injuries (PD) (n = 21), basion-dens distance (AUC = 0.75, 95%CI = 0.62-0.88) had fair accuracy diagnosing injury. Powers ratio (AUC = 0.63, 95%CI = 0.47-0.79), C1-C2 distance (AUC = 0.60, 95%CI = 0.45-0.75), atlanto-dental distance (AUC = 0.55, 95%CI = 0.39 = 0.71), atlanto-occipital distance (AUC = 0.63-0.65, 95%CI = 0.47-0.81), and basion-posterior axial line (AUC = 0.60, 95%CI = 0.44-0.76) all had poor accuracy. Eighty-one percent (n = 22) of CD and 38% (n = 8) of PD patients had non-concentric atlanto-occipital joints. One hundred percent of CD patients had ≥ 1 soft tissue finding and eighty-one percent (n = 22) had ≥ 2 findings. Seventy-three percent (n = 16) of PD patients had ≥ 1 soft tissue finding. Eighty-six percent (n = 18) of PD patients had non-concentric atlanto-occipital joints and/or soft tissue findings.

CONCLUSION

Craniocervical measurements have poor accuracy for identifying craniocervical injuries in pediatric patients with incomplete craniocervical ligament disruption. Subjective findings of craniocervical injury are frequently present on CT in pediatric patients and can help increase sensitivity for identifying injury.

Imaging of pediatric cervical spine trauma

While pediatric cervical spine injuries (CSI) are rare, they are associated with high morbidity and mortality and sometimes require expeditious surgical management. In this article, we aim to improve the diagnostic accuracy of pediatric CSI by reviewing normal pediatric cervical anatomy, typical pediatric CSI patterns, and common mimics of pediatric CSI. A literature review was conducted on pediatric CSI, its epidemiology, and the various imaging manifestations and mimics. The most common pediatric CSI occur in the upper cervical spine owing to the higher fulcrum and larger head at a young age, namely prior to age 9 years, while lower CSI occur more frequently in patients older than 9 years. While various craniocervical measurements may be utilized to identify craniocervical disruption, soft tissue injuries may be the only manifestation, thus making pediatric CSI difficult to diagnose on initial imaging. In the acute setting, CT cervical spine is an appropriate initial imaging modality for pediatric CSI evaluation. MRI serves as an additional tool to exclude or identify injuries when initial findings are equivocal. It is essential to recognize the unique anatomy and biomechanics of the pediatric spine and thus discern common pediatric CSI patterns and their mimics.

Imaging of cranio-cervical junction traumas

The craniocervical junction (CCJ) or upper cervical spine (UCS) has anatomic features and a biomechanics completely different from the other spinal segment of the spine. Several ligaments and muscles control its motion and function and ensure the maximum mobility and the visual and auditory spatial exploration. UCS traumas represent approximately one-third of all cervical spine injuries. Most of UCS traumas results from blows to the head and sudden deceleration of the body. Thanks to the improvement of the Advanced Trauma Life Support protocols dissociative injuries of CCJ have become less lethal onsite. In other less severe but unstable injuries, patients are neurologically intact at presentation, but they may deteriorate during the stay in hospital, with important clinical and medico-legal consequences. Knowing the peculiarities of UCS is fundamental for the early detection of imaging findings that influences the patient management and outcome. The classification of UCS traumas is mechanistic. More than in any other spinal segment, fractures of CCJ bones can occur without generating instability; on the contrary highly unstable injuries may not be associated with bone fractures. An early and correct diagnosis of occipito-cervical instability may prevent secondary neurological injury. The goal of imaging is to identify which patients can benefit of surgical stabilization and prevent secondary neurologic damage. Actual helical multidetector-CT (MDCT) offers high sensitivity and specificity for bone lesions and displacements in cervical spine traumas, but magnetic resonance imaging (MRI) is increasingly being used to evaluate soft tissues and ligaments, and mainly to identify possible spinal cord injury.

Blunt cervical spine injury in adult polytrauma: incidence, injury patterns and predictors of significant ligament injury on CT

AIM

To describe the pattern of cervical spine fractures in adult major trauma and identify computed tomography (CT) parameters that can predict significant ligament injury when fractures are absent; to define the normal range for parameters used; and identify common variations due to position of cervical immobilisation in a trauma patient.

MATERIALS AND METHODS

In this retrospective study all polytrauma patients imaged using multidetector CT over a period of 5 years were identified. Patients with cervical spine fracture and suspected ligament injury in the absence of fracture were collated based on the polytrauma CT report. Predictors of ligament injury were defined based on published historical data on plain radiographs and posterior paraspinal fat pad assessment at CT. These parameters were recorded for each study with comparison to subsequent magnetic resonance imaging (MRI) as the reference standard.

RESULTS

Significant ligament injury on MRI was detected at the craniocervical junction, when CT showed a basion dens interval of >10 mm, widened incongruous C0/C1 facet joint space of >3 mm, and widened C1/2 facet joint space of >6 mm. In the subaxial cervical spine, facet subluxation >50% and obscured posterior paraspinal fat pad were the only reliable predictors of ligament injury, as confirmed on subsequent MRI.

CONCLUSION

When fractures are absent, signs of significant ligament injury on CT at the craniocervical junction were increased basion dens interval and widened facet joints. In the subaxial cervical spine, >50% subluxation of a facet joint and obscured posterior paraspinal fat pad are indicators of significant ligament injury.