Inclusion Criteria:

- Women eligible for gastric bypass surgery

- Pre-menopausal women

- All women will have signed an informed consent form prior to participating in study
procedures

Exclusion Criteria:

- Women with a history of breast cancer

- Women currently taking exogenous hormone replacement therapy

- Women currently taking a SERM

- Women currently taking an aromatase inhibitor

- Pregnant or lactating women

- Women who have been pregnant or lactating in the past 2 years

- Women who have metallic or other surgical implants

- All subjects will have a determination of their estimated glomerular filtration rate
(eGFR) within 24 hours of undergoing any study where gadolinium based contrast agents
will be administered

- Subjects should not have a known history of recent onset acute renal dysfunction

- Subjects with a history of stable chronic renal dysfunction may participate in
studies using GBCA based on their eGFR, as outlined below

- Subjects should not have severe liver dysfunction, particularly when associated with
kidney disease

- Subjects should receive GBCAs in the perioperative period (i.e. within 4 weeks) after
renal or liver transplantation