O-RADS scoring system for adnexal lesions: Diagnostic performance on TVUS performed by an expert sonographer and MRI.

RATIONALE AND OBJECTIVE: To determine the diagnostic performance of transvaginal ultrasound (TVUS) performed by an US specialist and MRI based on the O-RADS scoring system. MATERIALS AND METHODS: Between March 5th 2013 and December 31st 2021, 227 patients, referred to our center, underwent TVUS and pelvic MRI for characterization of an adnexal lesion proven by surgery or two years of negative follow-up. All lesions were classified according to O-RADS US and O-RADS MRI risk scoring systems. Imaging data were then correlated with histopathological diagnosis or negative follow-up for 2 years. RESULTS: The prevalence of malignancy was 11.1%. Sensitivity of O-RADS US / O-RADS MRI were respectively of 83.3%/83.3% and specificity was 73.2%/92.9% (p < 0.001). O-RADS MRI was more accurate than O-RADS US even when performed by an US specialist (p < 0.001). When MRI was used after US, 51 lesions were reclassified correctly by MRI and only 4 lesions incorrectly reclassified. Most of the lesions (49/51) rated O-RADS US 4 or 5 and reclassified correctly by MRI were benign, mainly including cystadenomas or cystadenofibromas. Only 4 lesions were misclassified by MRI but correctly classified by ultrasound. CONCLUSION: Our study suggests that MR imaging has equally high sensitivity but higher specificity than TVUS for the characterization of adnexal lesions based on O-RADS scoring system. MRI should be the recommended second-line technique when a mass is discovered during TVUS and is rated O-RADS 4 and 5 over than TVUS by an US specialist.

[Imagerie dans les cancers de l'ovaire]. / Imaging of ovarian cancers.

IMAGING OF OVARIAN CANCERS Imaging of ovarian lesions is based on the triptych: pelvic ultrasound with Doppler, magnetic resonance imaging (MRI) and computed tomography (CT). Endovaginal pelvic ultrasound is the first-line examination; tools are available to help with its interpretation (IOTA group rules, O-RADS US classification). When an ovarian mass is detected on ultrasound and if its characterization is «undetermined¼ or complex, MRI with perfusion sequences is used to clarify the criteria. Finally, a thoraco- abdominopelvic CT scan is necessary for extension assessment in the case of ovarian cancer, in particular to look for peritoneal carcinosis and to anticipate surgical difficulties.

IMAGERIE DANS LES CANCERS DE L'OVAIRE L'imagerie des lésions ovariennes repose sur le triptyque : échographie pelvienne avec Doppler, imagerie par résonance magnétique (IRM) et tomodensitométrie (TDM). L'échographie pelvienne par voie endovaginale est l'examen de première intention ; des outils aident à son interprétation (règles du groupe IOTA, classification O-RADS US). Lorsqu'une masse ovarienne est détectée à l'échographie et si sa caractérisation est « indéterminée ¼ ou complexe, la réalisation d'une IRM avec séquences de perfusion permet d'en préciser les critères. Enfin, la TDM thoraco-abdomino-pelvienne est nécessaire au bilan d'extension en cas de cancer de l'ovaire, notamment à la recherche de carcinose péritonéale et pour anticiper des difficultés chirurgicales.