Diagnostic Approach for Trigeminal Neuralgia

Imaging Studies

The American College of Radiology recommends MRI as the preferred modality for investigating the trigeminal nerve 1
High-resolution MRI with contrast of the trigeminal ganglion is recommended, including 3-D heavily T2-weighted MRI sequences, MR angiography (MRA), pre- and postcontrast imaging, and thin-cut high-resolution techniques through the course of the trigeminal nerve 2, 3, 4
MRI can identify structural causes in patients with TN, including neurovascular compression, which is the most common cause in classical TN 5
The trigeminal nerve size is often smaller on the symptomatic side, as detected by MRI 3

Diffusion tensor imaging (DTI) can detect microstructural tissue changes in symptomatic nerves compared to asymptomatic nerves, with a strength of evidence supporting its use in characterizing peripheral trigeminal neuropathy 2, 3
MR neurography is an emerging technique useful for characterizing peripheral trigeminal neuropathy, with a moderate level of evidence supporting its use 2, 3
Advanced MRI techniques have detected structural alterations in gray and white matter in patients with trigeminal neuralgia, providing high-quality evidence for their use in diagnosis 3

Classical TN is associated with neurovascular compression of the trigeminal nerve in or around the root entry zone, with strong evidence from the British Journal of Anaesthesia supporting this classification 5
Type 2 TN is characterized by more prolonged pain between the sharp shooting attacks, possibly of more central origin, with moderate evidence supporting this classification 5
Secondary TN is symptomatic of other conditions such as tumors or multiple sclerosis, with strong evidence from the British Journal of Anaesthesia supporting this classification 5

Other trigeminal autonomic cephalgias, such as SUNCT and SUNA, can be distinguished from TN using diagnostic criteria, with strong evidence from the British Journal of Anaesthesia supporting this distinction 5
Giant cell arteritis, post-stroke facial pain, and persistent idiopathic facial pain can be distinguished from TN using diagnostic criteria, with moderate to strong evidence supporting these distinctions 5