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.

Radiological protocol in spinal trauma: literature review and Spinal Cord Society position statement

PURPOSE

The Spinal Cord Society constituted a panel tasked with reviewing the literature on the radiological evaluation of spinal trauma with or without spinal cord injury and recommend a protocol. This position statement provides recommendations for the use of each modality, i.e., radiographs (X-rays), computed tomography (CT), magnetic resonance imaging (MRI), as well as vascular imaging, and makes suggestions on identifying or clearing spinal injury in trauma patients.

METHODS

PubMed was searched for the corresponding keywords from January 1, 1980, to August 1, 2017. A MEDLINE search was subsequently undertaken after applying MeSH filters. Appropriate cross-references were retrieved. Out of the 545 articles retrieved, 105 relevant papers that address the present topic were studied and the extracted content was circulated for further discussions. A draft position statement was compiled and circulated among the panel members via e-mail. The draft was modified by incorporating relevant suggestions to reach a consensus.

RESULTS AND CONCLUSION

For imaging cervical and thoracolumbar spine trauma patients, CT without contrast is generally considered to be the initial line of imaging and radiographs are required if CT is unavailable or unaffordable. CT screening in polytrauma cases is best done with a multidetector CT by utilizing the reformatted images obtained when scanning the chest, abdomen, and pelvis (CT-CAP). MRI is indicated in cases with neurological involvement and advanced cervical degenerative changes and to determine the extent of soft tissue injury, i.e., disco-ligamentous injuries as well as epidural space compromise. MRI is also usually performed when X-rays and CT are unable to correlate with patient symptomatology. These slides can be retrieved under Electronic Supplementary Material.

Clinical identifiers for detecting underlying closed cervical fractures

BACKGROUND

Although uncommon, closed cervical fractures (CCFs) may present in orthopedic clinical settings despite previous workup. The objective of this study was to describe the characteristics associated with missed CCF.

METHODS

The study was a retrospective database exploration of a cohort of subjects within a department of surgery with cervical pain. The sample consisted of 162 patients seen for a surgical consult for a number of cervical conditions. The examination time frame represented a clinical examination and imaging confirmation of diagnosis after an original initial visit by another provider. Descriptive and diagnostic accuracy values including sensitivity/specificity and positive/negative likelihood ratios (LR+/LR-) were calculated for each targeted variable. Clustered analyses were calculated using the patient history and situational characteristics.

RESULTS

Eleven patients in the sample were diagnosed with CCF (6.7%). Six variables were significantly associated with a missed CCF. Using these six variables, it was found that failure to exhibit a condition of 2 of the 6 variables (1 or fewer) was the strongest in ruling out the condition (LR- = 0.0; post-test probability with a negative finding = 0%), whereas a finding of 4 of 6 was the most diagnostic for ruling in the condition (LR+ = 32; post-test probability with a positive finding = 70%).

CONCLUSIONS

The findings in this sample suggest that select patient history or situational factors are still useful even after initial examination and clinicians must stay vigilant because CCFs may be missed during emergent care screens.

Evaluation of a dedicated MDCT protocol using iterative image reconstruction after cervical spine trauma

AIM

To evaluate radiation exposure for 64-row computed tomography (CT) of the cervical spine comparing two optimized protocols using filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR), respectively.

MATERIALS AND METHODS

Sixty-seven studies using FBP (scanner 1) were retrospectively compared with 80 studies using ASIR (scanner 2). The key scanning parameters were identical (120 kV dose modulation, 64 × 0.625 mm collimation, pitch 0.531:1). In protocol 2, the noise index (NI) was increased from 5 to 25, and ASIR and the high-definition (HD) mode were used. The scan length, CT dose index (CTDI), and dose-length product (DLP) were recorded. The image quality was analysed subjectively by using a three-point scale (0; 1; 2), and objectively by using a region of interest (ROI) analysis. Mann-Whitney U and Wilcoxon's test were used.

RESULTS

In the FBP group, the mean CTDI was 21.43 mGy, mean scan length 186.3 mm, and mean DLP 441.15 mGy cm. In the ASIR group, the mean CTDI was 9.57 mGy, mean scan length 195.21 mm, and mean DLP 204.23 mGy cm. The differences were significant for CTDI and DLP (p < 0.001) and scan length (p = 0.01). There was no significant difference in the subjective image quality (p > 0.05). The estimated mean effective dose decreased from 2.38 mSv (FBP) to 1.10 mSv (ASIR).

CONCLUSION

The radiation dose of 64-row MDCT can be reduced to a level comparable to plain radiography without loss of subjective image quality by implementation of ASIR in a dedicated cervical spine trauma protocol. These results might contribute to an improved relative risk-to-benefit ratio and support the justification of CT as a first-line imaging tool to evaluate cervical spine trauma.