Using Advanced Imaging Studies to Develop a Profile of High-grade Serous Ovarian Cancer

Inclusion Criteria: * ≥ 18 years of age or older * Histologically confirmed or clinically suspected FIGO stage IIIC-IV HGSOC * Signed consent to MSK Institutional tissue banking protocol IRB# 06-107 and signed or planned to sign IRB# 12-245, and planned to undergo multi-region tissue collection \[under the above IRB protocols\] and plan to undergo subsequent tissue analysis under biospecimen IRB# 15-200. * Staging standard-of-care contrast-enhanced CT of abdomen and pelvis (+/-chest) available in picture archiving and communication system (PACS) that was obtained at our institution as a part of standard-of-care work-up or submitted for from the outside * Plasma glucose ≤200 mg/dL * Negative pregnancy test, if a patient is of child-bearing potential Exclusion Criteria: * Known allergy to gadolinium-based contrast medium requiring premedication or known adverse reactions to gadolinium-based contrast medium. * Known history of impaired renal function, with documented eGFR \<30 within 30 days prior to PET/MRI. * Patients who cannot give valid informed consent because of general medical or physical condition, or physiologic status unrelated to presence of ovarian cancer * Patients who are unwilling or unable to undergo PET/MRI including patients with absolute or relative contraindications to MRI including breast tissue expanders, cardiac pacemakers and defibrillators, non MRI-compatible aneurysm clips, neurostimulators, programmable CSF shunts, vascular stents, claustrophobia, or inability to lie flat for the duration of the examination. * Patients with metallic hardware, implant, or device in the abdomen or pelvis that might distort the local magnetic field and compromise image quality. * Radiotherapy to the abdomen or pelvis within 12 months of the screening visit. * Subjects with a current diagnosis of ovarian cancer other than HGSOC * Patients with known synchronous primary endometrial cancer or past history of endometrial cancer. * Patients who have received prior chemotherapy for any abdominal or pelvic tumor. Patients may have received prior adjuvant chemotherapy for breast cancer. * With the exception of non-melanoma skin cancer and other specific malignancies as noted above, subjects with excluded known concurrent malignancy. * Unresolved bowel obstruction. * History or current evidence of any condition, therapy, or lab abnormality that might confound the results of the study or interfere with patient's participation for the full duration of the study. * Absence of any target lesions ( ≥1-2 cm) in the pelvis (right adnexa, left adnexa, infra-colic omentum, pelvic peritoneum) visible on staging standard-of-care CE-CT and accessible for tissue sampling at laparoscopy and/or primary/ interval debulking surgery.