The length of the exam depends on the type of study being performed. 1  MRI of the Brain … 20-45 minute scan time. 2  MRI of the Orbits … 20-35 minute scan time. 3  MRI of the TMJ … 45-60 minute scan time.  MRI of the Soft Tissue Neck … 25-35 minute scan 1  time. MRI of the Cervical Spine … 20-35 minute scan time.