The comparative study of magnetic resonance angiography diagnosis and pathology of blunt vertebral artery injury.

STUDY DESIGN: Observational and comparative study of the vertebral artery injury detected by 2-dimensional (2-D) time-of-flight magnetic resonance angiography (MRA) for admitting patients. Construct a strike-induced flexion injury model of cervical spine with blunt vertebral artery injury in dogs.

OBJECTIVES: To evaluate the value of MRA for diagnosing vertebral artery injury in cervical spinal trauma patients, and conduct a comparative study of MRA image and pathology of blunt vertebral artery injury in an animal experiment.

SUMMARY OF BACKGROUND DATA: The 2-D time-of-flight MRA is the most important method for diagnosing vertebral artery injury. However, there is still controversy over MRA's accuracy in detecting vertebral artery injury of varying degrees. In addition, to our knowledge, no animal studies regarding this subject have been found in the literature so far.

METHODS: In a clinical study, 319 patients with close cervical spinal trauma underwent 2-D time-of-flight MRA prospective examination. The 2-D time-of-flight MRA detected vertebral artery injury in 52 of the 319 subjects. Of the 52 patients, 51 had unilateral vertebral artery injuries, including 22 injuries on the left vertebral artery and 29 on the right vertebral artery. One case involved bilateral vertebral artery injury. In an animal experiment, the strike-induced flexion injury model of cervical spine was constructed based on an animal experiment with 26 adult dogs. A radiograph was taken immediately after injury, and 2-D time-of-flight MRA was taken in 24-36 hours. The vertebral artery sample was then harvested for pathologic examination.

RESULTS: In the animal experiment, cervical facet dislocation occurred in 14 of the 26 dogs. Of the 26 dogs, 7 had unilateral vertebral artery injury as detected by MRA. There were 2 dogs that had incomplete blood flow imaging on one side of the vertebral artery, which MRA diagnosed as suspect positive. There were no vertebral artery injuries in the other 17 dogs. The vertebral artery sample of all 26 dogs underwent the pathologic study. Of the 7 dogs with positive MRA, 4 had disruption of the intima and media, and 3 had disruption of the intima. Of the 2 dogs with suspicious positive MRA diagnosis, 1 had no intima injury, while the other had intima disruption and late mural thrombus. There was no intima injury in the 17 dogs with negative MRA findings.

CONCLUSIONS: The 2-D time-of-flight MRA is an effective diagnostic method for blunt vertebral artery injury. It may have difficulties differentiating spasm, small disruption of the intima from others under certain conditions.