C1-C2 epidural abscess post resection. There are are postsurgical changes of occipitocervical fusion extending from occiput to the C4 level, with hardware better assessed on prior CT. Erosive changes involving the occipital condyles, C1 and C2 vertebrae also better seen on prior CT. There is development of T2 hyperintensity involving the ventral medulla at the cervicomedullary junction with parenchymal volume loss. The ventral aspect of medulla abuts the odontoid process tip which may be related to scarring. Remainder of the cervical cord demonstrates no signal abnormality.Mild degenerative changes are seen with uncovertebral hypertrophy resulting in mild left neural foraminal stenosis at the C5-C6 level. Spinal canal and neural foramina are otherwise patent.There is abnormal enhancement at the medial atlantoaxial joint including surrounding the atlantodental interval, which is mildly widened similar to prior CT. Abnormal enhancement involving the C1 and C2 vertebrae as well as occipital condyle also noted. No abnormal epidural or paraspinous fluid collections. There is enhancement involving the midline posterior paraspinous soft tissues compatible with postsurgical scarring.There is high signal involving the left vertebral artery which is diminutive. Prior study demonstrated diminutive caliber but preserved flow-void.
1. There is extensive abnormal enhancement surrounding the medial atlantoaxial joint favored to represent granulation tissue related to prior infection. There is mild widening of the atlantodental interval appearing similar to prior CT. Occiput to C4 posterior fusion hardware remains in place. Osseous changes involving the occipital condyle, C1 and C2 vertebrae are better seen on CT. No abnormal fluid collections or abscess to suggest worsening infection.2. Development of T2 hyperintensity and volume loss involving the ventral medulla near the cervicomedullary junction compatible with sequela of prior parenchymal injury. 3. High signal involving the left cervical vertebral artery which is diminutive. Prior MRA demonstrated diminutive caliber but preserved flow-void. Finding may be related to worsened stenosis or occlusion and can be better assessed with follow-up CTA or MRA if clinically indicated. 