Abstract: An apparatus for identifying and quantifying image distortions within a patient magnetic resonance image set comprises a structure of magnetic resonance compatible materials with a high level of rigidity, where the structure is configured to cover the whole image volume of the brain region of the patient and sized to fit within a brain magnetic resonance coil when worn by a patient. A plurality of magnetic resonance fiducial markers is placed on the structure, thereby permitting the measurement of three-dimensional distances between the markers when the patient undergoes a magnetic resonance imaging procedure. Also presented is a process for identifying and quantifying image distortions within a patient magnetic resonance image set using the apparatus where the geometrical distortion is quantified and compared with a set threshold or a standard image.