New cerebral lesions on T2*-weighted gradient-echo imaging after cardiac valve surgery.

Background: It is well known that silent ischemic brain lesions on diffusion-weighted imaging (DWI) commonly occur after various interventional procedures or surgeries. However, to our knowledge, postoperative new lesions on T2*-weighted gradient-echo imaging (GRE) have never been explored.
Methods: This prospective observational study enrolled 19 consecutive patients undergoing cardiac valve surgery. Preoperative and postoperative (within 7 days) GRE and DWI were performed. New GRE lesions were defined as signal loss lesions on postoperative GRE which were not observed on preoperative GRE. Long-term follow-up GRE was performed in a limited number of cases.
Results: Twelve patients developed 26 small (<10 mm) new GRE lesions. Of these patients, 1 had a generalized seizure accompanied by confusion and facial weakness with DWI lesions, and 1 showed confusion of short duration without DWI lesions. Long-term follow-up GRE was performed 3 years after surgery in 4 patients. Of the 12 new GRE lesions in these 4 patients, 11 lesions were still observable on long-term follow-up GRE.
Conclusions: New cerebral lesions on GRE after cardiac valve surgery are common and are presumed to be rapidly developed microbleeds and mostly asymptomatic. Further studies are needed to investigate the precise nature and clinical implications of new GRE lesions.
(Copyright (c) 2010 S. Karger AG, Basel.)