American Board of Internal Medicine (ABIM) Certification Practice Exam

What diagnostic imaging finding is associated with Creutzfeldt-Jakob disease?

1. Hyperdense masses in the cerebellum

2. Hyperintensities in the cerebral cortex

3. Calcium deposits in the thalamus

4. Ventricular dilation

The correct answer is: Hyperintensities in the cerebral cortex

Creutzfeldt-Jakob disease (CJD) is a type of prion disease that affects the brain and leads to rapidly progressive neurodegeneration. One of the characteristic findings on MRI, particularly in the early stages of the disease, is the presence of hyperintensities in the cerebral cortex. These hyperintensities appear as bright areas on T2-weighted and fluid-attenuated inversion recovery (FLAIR) MRI sequences, indicating areas of increased signal reflective of lesions. This finding is primarily noted in the context of the cortical and sometimes subcortical regions of the brain, and they may be seen in conjunction with other changes such as basal ganglia abnormalities. In cases of CJD, additional imaging features may include diffusion-weighted imaging (DWI) changes that further emphasize the acute nature of the disease. The correlation of these imaging findings with clinical symptoms—such as rapidly progressive dementia, myoclonus, and other neurological deficits—helps in making the diagnosis of this rare yet severe condition. The identification of these specific hyperintensities is crucial for differential diagnosis, particularly when considering other forms of rapidly progressive dementia or other degenerative diseases.