BREAST IMAGING REPORTING AND DATA SYSTEM STANDARDIZED MAMMOGRAPHY LEXICON - OBSERVER VARIABILITY IN LESION DESCRIPTION

OBJECTIVE. The American College of Radiology has recommended the Breas t Imaging Reporting and Data System (BI-RADS) as a standardized scheme for describing mammographic lesions, The objective of this study was to measure inter- and intraobserver variabilities of radiologists' des criptions of mammographic lesions with the BI-RADS standardized lexico n. MATERIALS AND METHODS. Sixty mammographic studies with abnormal fin dings were independently evaluated by five radiologists. Readers descr ibed each lesion by selecting a single term from the BI-RADS lexicon f or each of eight morphologic categories: calcification distribution, n umber, and description; mass margin, shape, and density; associated fi ndings; and special cases, Additionally, each reader assessed the sign ificance of each lesion on a five-point scale, One observer read each case twice. Inter- and intraobserver variabilities for each descriptio n acid interpretation category of the BI-RADS lexicon were determined with Cohen's kappa statistic, Radiologists' specific use of calcificat ion descriptors was evaluated in detail. RESULTS. Substantial agreemen t was observed between readers for choosing terms to describe masses a nd calcifications (kappa value range, 0.50 +/- 0.02-0.77 +/- 0.03). In traobserver agreement for these categories was similar (kappa value ra nge, 0.57 +/- 0.07-0.84 +/- 0.09). Considerable inter- and intraobserv er variabilities were noted for the ''associated findings'' and ''spec ial cases'' categories (kappa value range, -0.02 +/- 0.14-0.38 +/- 0.1 2), a result that in part reflected the small number of cases to which these categories were assigned, Moderate interobserver variability an d little intraobserver variability in the interpretation of lesion sig nificance were noted when an assessment classification similar to that of BI-RADS was used. Use of terms to describe calcifications did not always conform to BI-RADS-defined levels of suspicion. CONCLUSION. BI- RADS is moderately successful in providing a standardized language for physicians to describe lesion morphology, Efforts to reevaluate speci fic terms and the diagnostic significance assigned to calcification de scriptors may prove useful in maintaining the promise of improved qual ity with the BI-RADS standardized mammography lexicon.