MRI Findings in Trigeminal Neuralgia Without Apparent Vascular Abnormality

Background: Trigmenial neuralgia [TN] is a challanging health problem. It usually ascribed to vascular abnromalities. However, a significant proportion do not show apparent abnormality in the vascular system. Thus, its diagosis is a challenge. It is suggested that magnetic resonance imaging [MRI] could play a role in diagnosis of such cases. The aim of the work: This study was designed to evaluate the MRI finding in different causes of trigeminal neuralgia without apparent vascular abnormality. Patients and Methods: This is a prospective study, including 40 cases presented clinically with TN. All were submitted to full clinical evalations [history taking, clinical examination and laboratory inestigations]. Then, MRI was performed for all pateints and different measures [] were recorded and the dianosis was determined. Results: The majority of lesions were unilateral [47.5% on the left and 40.0% on the right]. Tumors were the commonest [30.0%] followed by the vascular and idiopathic categories [each 22.5%]. The type of TN were vascular compression [22.5%], secondary types [55.0%] and the idiopathic [22.5%]. The mean pontine angle was signficanly lower in the affected than the non affected side [29.3 ± 6.7° vs 37.01±7.6°]. The diagnosist perofmrance of tigeminal pontine angle, length of cisternal segment and cross section area of CPA showed that the AUC are 0.8 and above. The best was regsitered for trigemenal pontine angle [0.83] followed by length of isternal segment [0.81]. The sensitivity was 88.9%, 88.9% and 77.8% for tigeminal pontine angle, length of cisternal segment and cross section area of CPA, respectivley. Conclusion: MRI is an excellent imaging modality for diagnosing the etiology TN. FIESTA MRI act as adjuvant to increase diagnostic accuracy and determine specific etiology of TN through measurement of trigeminal pontine angle, length of cisternal segment of nerve and cross sectional area of CPA, espeically in idiopathic cases.