Pre- operative MRI measurement of the Meckel's cave volume in percutaneous balloon compression of the trigeminal nerve

Objective To explore the feasibility of measuring the volume of Meckel's cave by MRI before operation and its value in guiding percutaneous balloon compression (PBC) of trigeminal nerve (TN). Methods The pre-operative MRI and operative data of 31 patients, who underwent PBC of TN, were analyzed retrospectively. Axial scanning was performed using T2 weighted three-dimensional high-resolution MRI, and then coronal and sagittal images were reconstructed. Volumes of Meckel's cave were measured by two radi-ologists, and their consistence was assessed using intr-aclass correlation coefficient. Pearson and Spearman analyses were used to assess the correlations of the volumes of Meckel's cave among coronal, sagittal, and axial MRI images, and between that measured by MRI and the filling volume of operative balloon, respectively. Bland-Altman plot was used to assess their agreements.Results There was high consistency in volumes of Meck-el's cave between the two radiologists with intraclass correlation coefficient from 0.921 to 0.962. High corre-lations and good agreements in volumes of Meckel's cave were obtained from the three orientations, with Pearson coefficients and differences of 0.96 and 0.01 ml (coronal vs sagittal), 0.95 and 0.01 ml (coronal vs axial), and 0.95 and 0.00 ml (sagittal vs axial), respectively. The moderate correlation and good agreements were also obtained between MRI and operative balloon volume (& rho; = 0.448, p < 0.05; difference, 0.02 ml).Conclusion It is feasible to measure the volume of Meck-el's cave by MRI before operation, and it is of guiding significance for the individual selection of balloon filling volume in PBC of TN. Advances in knowledge This is the first study to inves-tigate the relationships between the three-dimensional high resolution MRI images and the clinical volume of Meckel's cave. The high-resolution MRI method can help guide PBC of TN.