A male patient, 60 years getting repeated sexual obsessions of tasting female excreta, forces, in particular, focusing on unattainable partner indulging in compulsive masturbation going on since 4 decades though married, not interested in sex with wife, emotionally blunt. Prescribed with Sertraline, dutasteride, clonazepam but no appreciable improvement. What could be the other diagnosis and measures?

Do you think MRI is required?