Is MRI a Suitable Option in Diagnosing Acoustic Neuroma? A Comparative Analysis with Histopathology

Abstract

Background: Acoustic neuroma also known as vestibular schwannoma is the most common benign tumor of the cerebellopontine angle and makes up eight to ten percent of the primary intracranial tumors. Magnetic Resonance Imaging or MRI is diagnostic imaging method of choice for acoustic neuromas. It allows adequate visualization and characterization of the tumor helping the neurosurgeons in determining the boundaries and location of the tumor. Objective: To evaluate the accuracy of MRI in the diagnosis of acoustic neuroma, at a tertiary care hospital in Karachi Pakistan. Study Design: Prospective case series. Settings: Abbasi Shaheed Hospital and Civil Hospital, Karachi Pakistan. Duration: 03 years starting from January 2019 to December 2021. Methods: Included patients had a suspicion of acoustic neuroma as referred to the Department of Radiology. Exclusion criterion was patients who have had a metastatic, residual or recurring acoustic neuroma, or those patients whose data was incomplete. Various demographic variables, history, clinical examination and radiographic data was recorded in a proforma. The same MRI machine was used for all the patients. The cases included in the study underwent a surgical removal of the tumor with histopathologic examination. Results: The final study population in our case series is n= 45 patients. The mean age of the patients was 51.9 +/- 10.5 years. N= 20 patients were male and rest were female. We accurately diagnosed all the cases on MRI and they were confirmed on histopathology as well. The total number of cases in our study population were n= 35 (77.77%), the rest of the patients either had meningioma, arachnoid cyst, abscess or epidermoid tumors. The specificity of the MRI diagnosis was 91.7% and the sensitivity was found to be 97.7%. The positive predictive value and negative predictive values were 97.6% and 91.8% while the overall accuracy was found to be 96.5%. Conclusion: MRI is a safe, convenient, and accurate instrument for the diagnosis and evaluation of acoustic neuromas and is useful for the mitigation of unnecessary interventions in this population.