Role of Magnetic Resonance Imaging in Evaluation of Trigeminal Nerve Anatomical Variations That Participate in Trigeminal Neuralgia

Abstract Background Trigeminal neuralgia (TN) is characterized by recurrent attacks of pain that cause patients distress and even can lead to psychiatric disorders. The International Classification of Headache Disorders-3 (2018) has broadly divided TN into three categories: (1) classical TN, (2) Idiopathic TN, and (3) Secondary TN. The cause of classical TN is neurovascular conflict (NVC). Because idiopathic TN patients don't have an evident cause, it's necessary to search for other factors that can cause TN. These factors include variable abnormal morphological changes of the trigeminal nerve and CPA structures. Neuroimaging plays a crucial role in the diagnosis of patients with trigeminal neuralgia. Objective To validate the diagnostic value of the associated anatomical variants (e.g., trigeminal nerve length) between the symptomatic trigeminal neuralgia and asymptomatic trigeminal nerve with no prior history of hemifacial pain or neuralgia. Patients and Methods This study was a retrospective case-control study, and the study was conducted at Ain Shams University Hospitals, Radiodiagnosis department. The study period 7 months. Included Patients with clinically diagnosed trigeminal neuralgia. Results There was a significant difference between the sides with and without TN in the measurement of the cerebellopontine angle (CPA) surface area. The CPA surface area was smaller on the symptomatic side. On the other hand, there was no significant difference in the trigeminal nerve's cisternal segment length between the symptomatic and the asymptomatic side. Conclusion In our study, by using 3D-DRIVE imaging, we demonstrate the validity of smaller CPA surface area on the symptomatic side, as a potential factor for TN diagnosis.