High-Resolution 3D Magnetic Resonance Imaging of the Sixth Cranial Nerve: Anatomic and Pathologic Considerations by Segment

Background: Weakness of the sixth cranial nerve is the most common cause of an ocular motor cranial nerve palsy. It is often difficult to identify a corresponding abnormality on neuroimaging to correlate with the clinical examination. Evidence Acquisition: High-resolution 3D skull base magnetic resonance imaging (MRI) allows for visualization of the sixth nerve along much of its course and may increase sensitivity for abnormalities in regions that previously were challenging to evaluate. In this review, the authors share their experience with high-resolution imaging of the sixth nerve. Results: For each segment, anatomic features visible on high-resolution imaging are described along with relevant pathologic entities. Conclusions: We present a segmental approach to high-resolution 3D MRI for evaluation of the sixth nerve from the nuclear to the orbital segment.