Introduction: In spinal imaging, an accurate assessment of central canal stenosis via axial imaging is critical. Most imaging programs generate oblique axial images due to a fixed reference line that does not account for curves in the spine. Using PACS viewers with specialized scout line functions we will compare the cervical central canal diameter in both static and user-adjustable scout line modes.
Methods: We evaluated a consecutive series of 35 patients who received cervical CT scans. Inclusion criteria consisted of patients 18 years or older, with minimal or moderate degenerative changes that underwent cervical CT for head trauma. Patients were excluded if they had pathology causing cervical central canal stenosis, or previous neck surgery. We analyzed the diameter of the central canal using the default non-adjustable reference line on the PACS viewer. We then chose the scout angle on the midline sagittal that most bisected the endplates in a parallel fashion accounting for lordosis and kyphosis. The levels analyzed included C2 to T1 as C1-C2 does not have a disc. The two measurements were then compared directly.
Results: The average difference between the measurements of the central canal using the standard CT scout line versus the adjustable scout line ranged from -0.99 mm at the C2-C3 level and 1.85 mm at the C6-T1 level. Pearson r and ICC showed moderate to low correlation between the standard measurements and adjusted scout line measurements. Inter-observer agreement of the measurements across all levels suggested that the readers agreed on the adjustable scout line measurements more so than when using the standard CT scout line to make the measurements.
Conclusions: This study demonstrates the importance of being able to adjust the scout line in advanced cervical spine imaging in order to obtain true axial images.
Patient Care: By understanding the limitations of conventional cervical CT scans and obtaining an understanding of new and improved methods to view the spine, we believe we will improve the management of patients with neck pain.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Identify the common curves of the cervical spine, 2) Be able to critically evaluate the cervical bony anatomy on CT scan, 3) Be competent at evaluating a cervical spine using adjustable scout line images