 There are two punctate foci of restricted diffusion in the right superior frontal gyrus and left inferior frontal gyrus. There is diffuse global volume loss that is more focally pronounced in the bilateral hippocampi, greater on the right. There are scattered predominantly subcortical white matter T2 signal abnormalities, with lesser degree of periventricular white matter involvement, along with symmetric involvement of the bilateral external capsules and subinsular white matter. There is no associated susceptibility abnormality. There is unchanged volume loss in the anterior temporal lobes bilaterally with ex vacuo dilatation of the temporal horns. There is a partial empty sella. There is no midline shift or herniation. The skull and extracranial soft tissues are unremarkable.
1.Two punctate subcortical foci of restricted diffusion in the left inferior frontal gyrus and the right superior frontal gyrus superimposed upon a background of extensive predominantly peripheral subcortical white matter T2 signal abnormalities likely represent acute upon chronic microembolic disease. Therefore, cardiac and cerebrovascular imaging may be useful. A variant of CADASIL and metastatic lesions given the history of colon cancer are perhaps less likely. Nevertheless, further evaluation with contrast enhanced MRI can also be considered for the evaluation of metastatic disease, if clinically indicated.2.Global volume loss that is most pronounced in the hippocampi supports the clinical suspicion of Alzheimer's disease.