What are the recommended imaging modalities for ovarian cancer?

Recommended Imaging Modalities for Ovarian Cancer

For ovarian cancer staging and follow-up, contrast-enhanced CT of the abdomen and pelvis is the primary recommended imaging modality, with MRI and PET/CT serving as valuable adjuncts in specific clinical scenarios. 1

Initial Evaluation of Adnexal Masses

• Transvaginal ultrasound is the first-line imaging modality for evaluating suspected adnexal masses, providing detailed assessment of ovarian morphology and structure 1, 2
• Color Doppler ultrasound assessment can be added to transvaginal ultrasound to improve characterization of adnexal masses by evaluating vascularity patterns 2, 3
• For indeterminate adnexal masses on ultrasound (approximately 20% of cases), pelvic MRI is the recommended second-line test due to its superior tissue characterization 1, 3

Staging of Confirmed Ovarian Cancer

Primary Staging Modality

• Contrast-enhanced CT of the chest, abdomen, and pelvis is the modality of choice for initial staging of ovarian cancer 1, 3
• CT provides comprehensive assessment of disease extent, including peritoneal implants, omental involvement, lymphadenopathy, and distant metastases 1
• CT findings help determine tumor resectability and guide decisions regarding primary debulking surgery versus neoadjuvant chemotherapy 1

Adjunctive Imaging Modalities

• MRI is recommended for:

  • Patients with borderline tumors or early-stage ovarian cancers with fertility preservation (to minimize radiation exposure) 1
  • Cases where CT findings are inconclusive 1
  • Patients with contraindications to iodinated contrast (severe renal insufficiency) 1, 3

• FDG-PET/CT is valuable for:

  • Improving accuracy of staging when combined with CT 1
  • Detecting small peritoneal implants or lymph node metastases that may be difficult to identify on CT alone 1
  • Note: PET/CT is not recommended for primary ovarian cancer detection due to high false-positive rates 1

Evaluation of Recurrent Disease

• CT of the chest, abdomen, and pelvis with intravenous contrast is the primary modality for detecting recurrent disease 1
• FDG-PET/CT has superior accuracy compared to CT alone for detecting recurrent disease, particularly in cases with rising CA-125 levels but negative or equivocal CT findings 1
• MRI may be used when CT findings are inconclusive or when patients have contraindications to CT contrast agents 1

Important Considerations and Pitfalls

• Ultrasound alone is insufficient for comprehensive staging of ovarian cancer despite its value in initial evaluation 1
• CT without intravenous contrast offers limited evaluation of disease extent and should be avoided when possible 1
• False-negative results can occur with PET/CT in borderline tumors, mucinous tumors, early carcinomas, and other low-grade types 1
• False-positive PET/CT results can occur with fibromas, dermoid cysts, hydrosalpinges, and endometriosis 1
• Incomplete imaging evaluation may lead to understaging, which occurs in up to 40% of patients at laparotomy 1

Imaging Protocol Recommendations

• CT abdomen and pelvis should be performed with:

  • Intravenous contrast administration
  • Thin-slice acquisition (≤5 mm)
  • Multiplanar reconstructions 1

• MRI pelvis should include:

  • T1-weighted sequences with and without fat suppression
  • T2-weighted sequences
  • Dynamic contrast-enhanced sequences when not contraindicated 1

• PET/CT should be performed:

  • After adequate fasting (4-6 hours)
  • With standard FDG dose based on patient weight
  • With diagnostic quality CT component with intravenous contrast when possible 1