O-RADS MRI Reporting: Checklist and Worked Examples

O-RADS MRI standardizes MRI risk stratification of ovarian and adnexal lesions that remain indeterminate after ultrasound. This page is for the O-RADS MRI pathway; it does not use the same algorithm as O-RADS US. A score describes imaging risk in the appropriate clinical setting. It is not a histologic diagnosis or a management decision by itself.

Editable report framework

Examination: [Pelvic MRI, without / with intravenous contrast; sequences performed and whether dynamic contrast-enhanced imaging was obtained].
Indication/clinical context: [Ultrasound finding; symptoms; age, LMP/menopausal status when known; relevant cancer risk and oncologic/gynecologic surgical history].
Comparison: [Study and date / none available].

Technique: [Multiplanar T2, T1/fat-suppressed imaging, DWI and ADC; contrast administration and DCE temporal resolution]. [State motion, omitted sequences, or coverage limitations.]

Findings:
Uterus: [Presence, size, myometrium, and relationship to the lesion].
Right adnexa: [Ovary visibility and three dimensions; lesion origin, largest diameter/three dimensions, cyst contents, locularity, wall/septa, and enhancing solid tissue/signal].
Left adnexa: [Ovary visibility and three dimensions; lesion origin, largest diameter/three dimensions, and the same descriptors].
Free fluid/peritoneum: [Fluid, peritoneal/omental nodules or thickening].
Other: [Relevant findings].

Target lesion: [Side, origin, three dimensions, morphology, and enhancement].
O-RADS MRI: [Score 0–5 and category; supporting feature and DCE / non-DCE pathway]. [PPV percentage is optional in the report; include according to local practice].

Impression:
1. [Lesion origin and decisive imaging features].
2. [O-RADS MRI score, if applicable, and approximate category-level risk meaning].
3. [Clinically appropriate next evaluation or communication, according to local protocol].

Confirm scope and protocol before scoring

• O-RADS MRI was developed for adnexal lesions in an average-risk patient without acute symptoms. Confirm its scope in acute pelvic pain, suspected infection, known cancer, high inherited risk, or pregnancy; do not let the score replace those contexts.
• Confirm that the MRI finding is the same target seen on ultrasound. The uterus, both adnexa, entire lesion, and peritoneum should be adequately imaged.
• Document T2, T1/fat-suppressed T1, DWI/ADC, postcontrast assessment, and DCE temporal resolution. DCE allows time-intensity curve comparison. If DCE cannot be performed, use the ACR chart's 30–40-second postcontrast comparison pathway only when the acquisition meets those conditions; for risk stratification of enhancing solid tissue, this early non-DCE comparison cannot separate the O-RADS MRI 3 and 4 groups distinguished by DCE curves. This limitation does not preclude categories based on other descriptors for cysts without solid tissue.
• State whether the lesion arises from the ovary, tube, paraovarian region, or another organ. O-RADS MRI does not apply to masses of nonadnexal origin.
• If the lesion is incompletely covered, required sequences are missing, or artifact prevents assessment, do not force a category. State the reason and use O-RADS MRI 0.

Score 1 is for normal ovaries and physiologic findings. The ACR chart lists approximate positive predictive values of <0.5% for score 2, 5% for score 3, 50% for score 4, and 90% for score 5. These are category-level values from the source cohort, not an individual's probability or an automatic treatment recommendation. ACR reporting guidance allows the numeric score and risk-category term together, or either alone with an explanatory glossary/legend; including the PPV percentage is optional.

Relating findings to the score

Describe fluid and solid components first. A unilocular cyst with simple or endometriotic fluid, a characteristic fat-containing lesion, and homogeneously T2-dark/DWI-dark solid tissue generally follow the score 2 pathway. Some unilocular proteinaceous or hemorrhagic cysts with an enhancing wall, and smooth multilocular cysts without enhancing solid tissue, may be score 3.

When enhancing solid tissue is present, assess its T2 and high-b-value DWI signal, then compare enhancement kinetics with the myometrium. A low-risk DCE curve supports score 3, an intermediate-risk curve score 4, and a high-risk curve score 5. Peritoneal or omental nodularity is also within score 5. Current ACR chart and governing concepts control the exceptions; this summary does not replace the decision system.

Fictional worked examples

These are fictional teaching reports and do not describe patient outcomes.

Smooth unilocular endometriotic cyst

Examination: Pelvic MRI with multiplanar sequences before and after intravenous gadolinium; DCE imaging obtained.
Indication: Left ovarian cyst remains indeterminate after ultrasound in a 34-year-old premenopausal patient.
Comparison: Pelvic ultrasound dated 2026-10-10.

Findings: A 4.2 cm unilocular cystic lesion is present in the left ovary. The contents are T1 hyperintense with T2 shading; the thin wall enhances smoothly. No enhancing solid tissue or papillary projection is seen. The right ovary is unremarkable. The uterus and imaged peritoneum are unremarkable, without ascites or peritoneal nodularity.

Impression: 4.2 cm unilocular left ovarian cyst with endometriotic-type contents and no enhancing solid tissue. O-RADS MRI 2 (almost certainly benign).

Solid tissue with high-risk enhancement

Examination: Pelvic MRI with multiplanar T2, T1/fat-suppressed T1, DWI/ADC, and intravenous contrast; DCE temporal resolution of 15 seconds.
Indication: Further characterization of a right adnexal mass seen on ultrasound in a 58-year-old postmenopausal patient.
Comparison: Ultrasound dated 2026-10-15; no prior MRI.

Findings: A 5.1 cm solid-cystic lesion is present in the right ovary with irregular margins. Its solid tissue is not T2-dark/DWI-dark and shows an early steep time-intensity curve with high-risk enhancement relative to the myometrium. The left ovary is without a mass. Moderate pelvic ascites and nodular peritoneal/omental thickening are present.

Impression: Right adnexal solid-cystic mass with high-risk enhancement and peritoneal/omental nodularity; O-RADS MRI 5 (high risk). Prompt gynecologic oncology assessment should be considered in the clinical context.

The second example's score is not a diagnosis or stage. Management and communication should follow actual findings, clinical condition, and local urgent-result policy. If incomplete coverage, motion, or omitted sequences prevent assessment of solid tissue, report O-RADS MRI 0, explain the limitation, and recommend completion based on the clinical question rather than assigning a score from 2 to 5.

Final checklist and common pitfalls

• Indication, comparison, pathway, and technical adequacy are stated.
• Origin, side, three dimensions, fluid type, locularity, wall/septa, and enhancing solid tissue are described.
• DCE or non-DCE method and timing are documented; the peritoneum and omentum are reviewed.
• Both ovaries are addressed with visibility and three dimensions; each lesion is described, with the most concerning listed first when there are multiple lesions.
• Findings justify the score; category PPV is not presented as individual risk.
• O-RADS US is not copied as an MRI score, and O-RADS MRI is not applied to a nonadnexal mass.
• Recommendations are guided by context and local pathways rather than generated automatically by the score.

For the separate ultrasound pathway, see O-RADS US v2022 for adnexal lesions. For a broader pelvic MRI structure, see the normal female pelvic MRI example.

References

• American College of Radiology. O-RADS MRI Risk Stratification and Management System, May 2020, chart updated May 2024. ACR risk-score chart (PDF) (opens in a new tab)
• American College of Radiology. O-RADS MRI: How to Report: Essential Components and Lexicon Descriptors, 2023. ACR reporting components and sample reports (PDF) (opens in a new tab)
• Sadowski EA, Thomassin-Naggara I, Rockall A, et al. O-RADS MRI Risk Stratification System: Guide for Assessing Adnexal Lesions from the ACR O-RADS Committee. Radiology. 2022;303(1):35–47. doi:10.1148/radiol.204371. Article (opens in a new tab)
• Thomassin-Naggara I, Poncelet E, Jalaguier-Coudray A, et al. Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) Score for Risk Stratification of Sonographically Indeterminate Adnexal Masses. JAMA Netw Open. 2020;3(1):e1919896. doi:10.1001/jamanetworkopen.2019.19896. Original multicenter validation (opens in a new tab)

Clinical note: This educational framework does not replace independent image review, official O-RADS sources, or clinical judgment. The worked cases are fictional.