We report a patient who was treated with intravenous thrombolysis, and subsequently developed a Locked-In Syndrome (LIS). After 2 days, magnetic resonance imaging showed a large bilateral pontomedullary infarction. However, in contrast to the patient's clinical situation, the follow-up T2-weighted MR images up to day 26 did not display the infarction. This phenomenon is known as the so-called fogging effect.