Preoperative Visualization of Cortical Veins by 3D Reconstruction of Magnetic Resonance Images (MRI): Correlation with Intraoperative Findings

The topography of the superficial cortical veins shows a high interindividual variation. Brain pathologies may cause additional displacement. We aimed to preoperatively visualize the exact anatomic localization of the veins with regards to the lesion and the planned neurosurgical resections. We included 23 patients with MRI-documented brain lesions in the study. Structural MRI (1.5 T) was acquired with a slice thickness of 1.2mm and an in-plane resolution of 1.0mm. In addition, contrast-enhanced venous MRA was recorded using 64 slices with 2mm thickness. Interactive image registration of both datasets was performed on a Picker voxelQ workstation. Manual segmentation of the brain was done prior to 3D reconstruction of the combined dataset using volume rendering techniques. Digital intraoperative photographs were acquired and all surgically relevant veins were identified by the neurosurgeon. Semitransparent superimposition of photographs and 3D reconstructions was used to evaluate the quality of the preoperative reconstructions. The spatial accuracy of the image registration procedure was 0.8mm. Preoperative 3D image processing correctly visualized 78.2% of the surgically relevant veins. Intraoperatively documented veins were missed in 11.7% by the 3D images. False positive findings in 3D images occurred in 4.5% and in 2.2% arterial vessels were mistaken as veins. The preoperative visualization of cortical veins via MRI and MRA is an accurate and reliable method, which helps to plan and modify cortical resections.