[11C]-(R)-Rolipram to Measure cAMP Signaling Before and After Ketamine

Single-group diagnostic study in adults with MDD undergoing two PET scans with IV [11C]-(R)-rolipram before and after ketamine infusion; scans last up to two hours and include concurrent brain MRI.

Primary endpoint is change in PDE4 binding (volume of distribution, VT) pre- versus post-ketamine; secondary endpoints include correlation of PET measures with clinical ratings (MADRS, HAM-D).