Figure 2.

Brain MRI of a 53-year-old man with relapsing-remitting multiple sclerosis

Contrast axial brain MRI scan images obtained from the patient (described in panel 3) during and after relapse with documented cognitive impairment. MRI was obtained on a 3·0T GE Signa Excite HD 12 Twin-Speed scanner (GE, Milwaukee, WI, USA). At both timepoints, T1-weighted images were acquired with a single-dose intravenous bolus of 0·1 mmol/kg gadolinium-pentetic acid 5 min after injection. The lesions that appear by use of this method represent a breakdown of the blood–brain barrier, allowing myelin-reactive T cells to enter the CNS and cause a cascade of inflammatory changes that lead to oedema, demyelination, and axonal loss. During the relapse timepoint, several gadolinium-enhancing MRI brain lesions of 0·8 cm³ or greater volume were present (arrows). In total, 13 lesions were identified but not all are visible in these sections. The gadolinium-enhancing lesions were no longer observable at the recovery timepoint, indicating a recovery of the blood–brain barrier, although some tissue damage (not shown) might persist.