The first magnetic resonance imaging (MRI) of K.C.’s brain was performed in 1990. Further scanning was performed in 1996 and 2002 and both demonstrated similar findings to those of the first scan. MRI results display diffuse atrophy indicating thinning of brain tissue in all cortical lobes as well as enlargement of the ventricles. The degree of atrophy is greater in the left hemisphere compared to the right hemisphere. In the left hemisphere, a posterior lesion (i.e., softening of brain tissue) in the occipital and temporal lobes and an anterior lesion in the frontal and parietal lobes were apparent on the MR images.

The posterior lesion appears to be caused by increased pressure within the brain as a result of the head trauma during the motorcycle accident. The damage due to the posterior lesion is related to difficulty with visual imagery and perception of colour and face matching, and therefore contributes to his autobiographical episodic memory loss. The tissues spared in occipital and temporal lobes relate to K.C.’s preserved aspects of perception and recognition, including line orientation, form discrimination, reading, and recognition of objects and familiar faces.  
   
It is speculated that the anterior lesion is a secondary consequence of a subdural hematoma that was removed immediately after the motorcycle accident. The damage to the frontal and parietal lobes may be related to K.C.’s autobiographical memory loss. The tissues spared in these regions relate to K.C.'s preserved executive functions, including working memory and abstract reasoning.

Upon visual analysis of the MR images (see figure below), damage was apparent in the inner temporal lobe, while the outer temporal lobe remains unaffected. The damage to K.C.’s inner temporal lobes and the hippocampal formation, is associated with his inability to learn new things and form new memories. It is uncertain whether or not this damage, and K.C.'s associated personality change, is related to his autobiographical memory loss. The unaffected outer temporal lobe is related to K.C.’s preserved semantic memory and implicit memory.

MR image indicating damage in K.C.'s medial temporal lobe.