2008 Radiology Exam - Spec Proced/NM Case 1

Signalment: 7.5 year old female canine – Springer Spaniel.

History: Decreased conscious proprioception left, neck pain.
Ventrodorsal and lateral images of a cervical spine myelogram were available. Selected images are shown here.

See images below. Click to enlarge.

Findings: Large lobulated filling defect centered at the C1-2 intervertebral disc space. On the lateral view the dorsal subarachnoid space is attenuated. On the ventrodorsal, the filling defect is on the left with a “golf tee” sign. The spinal cord is deviated to the right and narrows.
Oblique views were available of the area if candidates asked, and the location on the left side, golf tee sign and deviation of the spinal cord are more prominent.

Radiographic Diagnosis: C1-2 left sided intradural-extramedullary mass with spinal cord compression.

Differential diagnoses: Neoplasia, with cyst or granuloma less likely. Most likely neoplastic types to consider include meningioma and nerve sheath tumor.

Recommendations: Surgery, although diagnostics to further describe the lesion, such as MRI or CT post-myelography would be considered.

Candidate Performance:
Candidates were expected to identify the abnormal site, be able to classify the lesion as intradural-extramedullary and give a reasonable ranked differential list. Candidates were only given the additional views if they specifically asked and identified the area to be imaged, as would occur on the clinic floor. For example, oblique views were not given if the candidate asked for oblique views of C6-7. Most candidates that identified the lesion were successful in describing the findings and had appropriate differential lists. A few candidates struggled with localization between extradural, intradural-extramedullary and intramedullary. Candidates that were unsuccessful on the case could not identify the lesion. Some candidates did not conclude on any abnormalities, while others described normal areas as abnormal and misdiagnosed lesions.