MR acoustic radiation force imaging (MR-ARFI) can be used to localize the focal spot for non-thermal transcranial ultrasound therapies. The acoustic radiation force is proportional to the applied acoustic intensity, meaning that tissue displacements measured with MR-ARFI can potentially be used to estimate the acoustic intensity at the target. However, variable brain stiffness is an obstacle to obtaining accurate acoustic intensity estimates. Using gelatin phantoms with varying stiffnesses, we demonstrate that stiffness information from MR elastography can be used in combination with MR-ARFI to improve in situ estimates of acoustic intensity. This could enable safer and more effective treatments.