In Reply We thank Vitali and colleagues for their correspondence. We studied serial diffusion-weighted brain magnetic resonance imaging in sporadic Creutzfeldt-Jakob disease using a visual rating method.1 The rarity and very rapid clinical declines seen in this disease make serial imaging studies of a large patient sample at a single institution challenging. There is an unmet need for imaging biomarkers of progression that might be practical for use in a study that necessitates different scanners across a large region, thereby closer to the patient’s home. Our main finding was an increase in diffusion-weighted signal intensity in 59 of 62 brain regions, with the most marked changes being seen in the caudate and putamen.1 We went on to study histopathological correlates of signal change in a single brain region, the left frontal cortex.