[Diagnostic accuracy and interobserver variability in the BI-RADS ultrasound system].
OBJECTIVE
To determine the predictive values and the interobserver variability of the descriptors and diagnostic categories of the BI-RADS- Ultrasound system and its usefulness for predicting malignancy in solid breast nodules.


METHODS
We evaluated 601 consecutive solid nodules in 554 patients studied with ultrasound. All ultrasound examinations were performed by one of the three radiologists that participated in the study and the static images were reviewed by all three radiologists independently; radiologists were blind to the clinical history and to the findings at mammography and at histological study.


RESULTS
The descriptors that best predicted benignity were circumscribed margins and oval shape (NPV, > 96%), parallel orientation (NPV, 84%-91%), and abrupt interface (NPV, 81%-90%). The descriptors that best predicted malignancy were spiculated margins (PPV, 77%-85%), echogenic halo (PPV, 61%-71%), and nonparallel orientation (PPV, 53%-54%). Interobserver concordance was good for lesion shape (kappa=0.61), circumscribed margins (kappa=0.65), and calcifications (kappa=0.63). The descriptors that presented the highest prognostic values for malignancy were spiculated margins (OR=14.68-10.45) and nonparallel orientation (OR=3.95-6.17). Final assessment category 3 yielded an excellent NPV for all three radiologists (99%-100%). The interobserver concordance was good for category 5 (kappa=0.77) and for category 3 (kappa=0.68); it was moderate for category 4 (kappa=0.59).


CONCLUSIONS
The BI-RADS- Ultrasound system helps differentiate benign breast lesions from malignant ones and has a good or moderate interobserver concordance. Final assessment category 3 yielded an excellent negative predictive value, making it possible to avoid biopsies in lesions in this category.
Santana Montesdeoca
J M
JM
Servicio de Radiología y Diagnóstico por la Imagen, Hospital Universitario Insular de Gran Canaria, Las Palmas de Gran Canaria, España. jmsantanamontesdeoca@gmail.com
Gómez Arnáiz
A
A
Fuentes Pavón
R
R
Alemán Flores
P
P
Limiñana Cañal
J M
JM
Jorrín Moreno
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001941:Breast Diseases / Q000000981:diagnostic imaging*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011873:Radiology Information Systems; D015203:Reproducibility of Results; D014463:Ultrasonography; D055815:Young Adult