O-RADS MRI score: analysis of misclassified cases in a prospective multicentric European cohort

Abstract

Objective: To retrospectively review the causes of categorization errors using O-RADS-MRI score and to determine the presumptive causes of these misclassifications.Methods: EURAD database was retrospectively queried to identify misclassified lesions. In this cohort, 1194 evaluable patients with 1502 pelvic masses (277 malignant/1225 benign lesions) underwent standardized MRI to characterize adnexal masses with histology or 2 years follow-up as reference standard. An expert radiologist reviewed cases with two junior radiologists and lesions termed misclassified if malignant lesion was scored≤ 3, a benign lesion was scored≥4, the site of origin was incorrect, or a non-adnexal mass was incorrectly categorized as benign or malignant.Results: There were 139/1502 (9.2%) misclassified masses in 116 women including 109 adnexal and 30 non-adnexal masses. False negative cases corresponded to 16 borderline or invasive malignant adnexal masses rated score≤3 (16/139,11.5%). False positive cases corresponded to 88 benign masses were rated score 4 (67/139,48.2%) or 5 (18/139,12.9%) or considered as suspicious non-adnexal lesions (3/139,2.2%). Misclassifications were only due to origin error in 12 adnexal masses (8 benign, 4 malignant) (8.6%,12/139) and 23 nonadnexal masses (18 benign, 5 malignant,16.5%,23/139) perceived respectively as non-adnexal and adnexal masses. Interpretive errors (n=104), failure to recognize technical insufficient exams (n=9) and perceptual errors (n=4) were found. Most interpretive were due to misinterpretation of solid tissue or incorrect assignment of mass origin. 84/139 cases were correctly reclassified by the readers with strict adherence to the score rules. Conclusion:Most errors were due to misinterpretation of solid tissue or incorrect assignment of mass origin..

Ovarian-Adnexal Reporting and Data System for Magnetic Resonance Imaging (O-RADS MRI): Genesis and Future Directions

“…After the EURAD study, readers were asked to reclassify adnexal lesions using the proposed O-RADS MRI system, 84 of 139 cases (60.4%) were re-classified correctly. 23 In this study, Thomassin Naggara et al emphasized the importance of training prior to using the O-RADS MRI system in clinical practice, similar to the training offered by the IOTA group. 24 Recently developed and implemented comprehensive educational modules (O-RADS MRI ACR website) and educational tools such as the O-RADS MRI calculator (https:// oradsmricalc.com) are important steps toward increased familiarity among radiologists and adherence to the algorithm pathway for optimized risk prediction (Table 1).…”

“…In the EURAD study, there were 139/1502 (9.2%) misclassified lesions. 23 Misclassifications were mainly due to errors in the assignment of mass origin (n = 35) or misinterpretation of solid tissue (n = 104). 23 False-negative cases included 16 borderline or invasive malignant adnexal lesions that were scored ≤3 (16/139, 11.5%).…”

“…Prior to the publication of ACR O-RADS MRI Lexicon, Thomassin Naggara et al analyzed the reason for the misclassified cases in the EURAD study. 23 This allowed the O-RADS MRI Committee to select lexicon terms and definitions intended to minimize classification errors. In the EURAD study, there were 139/1502 (9.2%) misclassified lesions.…”

“…23 Misclassifications were mainly due to errors in the assignment of mass origin (n = 35) or misinterpretation of solid tissue (n = 104). 23 False-negative cases included 16 borderline or invasive malignant adnexal lesions that were scored ≤3 (16/139, 11.5%). False-positive cases were comprised of 88 benign lesions that were assigned risk scores of 4 (67/139, 48.2%) or 5 (18/139, 12.9%) or rated as suspicious non-adnexal lesions (3/139, 2.2%).…”

“…7 Substantial effort has been made to clarify the terms “solid tissue” and “solid component” in the O-RADS MRI lexicon, which were occasionally used interchangeably and were a source of misinterpretation errors in the EURAD study (accounting for 63 among 139 misclassified adnexal lesions). 23 In the proposed lexicon, a solid component refers to any non-fluid component of a lesion. 7 There are two types of solid components: solid tissue and non-solid tissue (other solid components).…”