Planar brain surface reformations for localization of cortical brain lesions

Cortical lesions close to the central region may be difficult to localize on orthogonal MRI slices, especially when space-occupying lesions distort the brain surface relief and obscure anatomical landmarks. The purpose of this study was to evaluate, whether localization can be improved with planar brain surface (Mercator or "pancake") reformations. Three independent MRI readers localized superficial brain lesions of 30 patients on orthogonal MRI slices and on planar brain surface views reformatted from a sagittal 3D T(1)-weighted gradient echo sequence. On orthogonal MRI slices 46% of lesions were considered easy to localize, 37% difficult and 17% could not be localized. Corresponding values for planar brain surface views were 82%, 16% and 2%, respectively. Evaluation of orthogonal MRI slices took 190 min compared to 100 min for planar brain surface views. Thus, planar brain surface reformations are a helpful and time-saving means to localize superficial brain lesions.