1. What is the RMI (RCOG) Calculator?

The RMI (Risk of Malignancy Index) is a scoring system developed by the Royal College of Obstetricians and Gynaecologists (RCOG) to help assess the risk of ovarian cancer in women with adnexal masses.

2. How Does the Calculator Work?

The calculator uses the RMI equation:

Where:

• \( U \) — Ultrasound score (0-3)
• \( M \) — Menopausal status (1 for premenopausal, 3 for postmenopausal)
• \( CA125 \) — CA125 level in IU/mL

Explanation: The RMI combines ultrasound findings, menopausal status, and CA125 level to estimate the risk of ovarian malignancy.

3. Importance of RMI Calculation

Details: RMI helps guide clinical management of adnexal masses, with higher scores indicating greater likelihood of malignancy and need for specialist referral.

4. Using the Calculator

Tips: Enter ultrasound score (0-3), select menopausal status, and enter CA125 level in IU/mL. All values must be valid.

5. Frequently Asked Questions (FAQ)

Q1: What are the ultrasound score criteria?
A: U=1 for each of: multilocular cyst, solid areas, metastases, ascites, bilateral lesions (max score 3).

Q2: What RMI values suggest malignancy?
A: RMI ≥200 suggests high risk of malignancy and warrants specialist referral.

Q3: How accurate is the RMI?
A: Sensitivity ~78% and specificity ~87% for detecting ovarian cancer at cutoff of 200.

Q4: Are there limitations to RMI?
A: Less accurate in premenopausal women and certain histologic subtypes. Should be combined with clinical judgment.

Q5: What are alternatives to RMI?
A: Other models include ROMA, LR2, and IOTA models which may offer improved accuracy.