Assessment of maxillary sinus volume for the sinus lift operation by three-dimensional magnetic resonance imaging

Objectives: To calculate sinus and bone graft volumes and vertical bone hei ghts from sequential magnetic resonance imaging (MRI) examinations in patie nts undergoing a sinus lift operation. Methods: MRI scans were obtained pre-operatively and at 10 days and 10 week s post-operatively, using a 0.95 tesla MRI scanner and a three-dimensional (3D) magnetisation prepared, rapid acquisition gradient-echo (MP-RAGE) sequ ence. Results: Estimates of the bone graft volumes required for a desired vertica l bone height were made from the pre-operative MRI scan. Measurements of th e graft volumes and bone heights actually achieved were made from the post- operative scans. The MRI appearance of the graft changed between the 10 day and 10 week scans. Conclusions: We have proposed a technique which has the potential to give t he surgeon an estimate of the optimum volume of graft for the sinus lift op eration from the pre-operative MRI scan alone and demonstrated its applicat ion in a Single patient. Changes in the sequential MRI appearance of the gr aft are consistent with replacement of fluid by a matrix of trabecular bone .