18-fluorofuranylnorprogesterone (FFNP) PET/MRI as a Potential Biomarker of Response to Progesterone Therapy

Inclusion Criteria: * Female age 18 or older * Histologically confirmed CAH or Grade 1 EC * No prior surgical or hormonal treatment for CAH or Grade 1 EC * Planned treatment with levonorgestrel-releasing intrauterine device (LR-IUD) for CAH or grade 1 EC Exclusion Criteria: * Inability to complete PET/MR scans due to severe claustrophobia * Institutionalized subject (prisoner or nursing home subject) * Implanted metallic devices, parts, vascular clips, or other foreign bodies. * Known hypersensitivity to gadolinium or FFNP or to any component of gadolinium or FFNP refractory to standard medications (antihistamines, steroids) * Impaired kidney function (serum creatinine level \> 1.8 mg/dl or a glomerular filtration rate \< 60 as approximated using serum creatinine levels) unless anuric and on dialysis. * Any woman who is pregnant or has reason to believe she is pregnant (the possibility of pregnancy has to be excluded by negative urine (β-HCG) results, obtained within 24 hours before FFNP administration, or on the basis of patient history) * Prior hormone treatment for breast cancer