A test of performance of breast MRI interpretation in a multicentre screening study.
OBJECTIVE
The aim of this study was to assess the consistency and performance of radiologists interpreting breast magnetic resonance imaging (MRI) examinations.


METHODS
Two test sets of eight cases comprising cancers, benign disease, technical problems and parenchymal enhancement were prepared from two manufacturers' equipment (X and Y) and reported by 15 radiologists using the recording form and scoring system of the UK MRI breast screening study [(MAgnetic Resonance Imaging in Breast Screening (MARIBS)]. Variations in assessments of morphology, kinetic scores and diagnosis were measured by assessing intraobserver and interobserver variability and agreement. The sensitivity and specificity of reporting performances was determined using receiver operating characteristic (ROC) curve analysis.


RESULTS
Intraobserver variation was seen in 13 (27.7%) of 47 of the radiologists' conclusions (four technical and seven pathological differences). Substantial interobserver variation was observed in the scores recorded for morphology, pattern of enhancement, quantification of enhancement and washout pattern. The overall sensitivity of breast MRI was high [88.6%, 95% confidence interval (CI) 77.4-94.7%], combined with a specificity of 69.2% (95% CI 60.5-76.7%). The sensitivities were similar for the two test sets (P=.3), but the specificity was significantly higher for the Manufacturer X dataset (P<.001). ROC curve analysis gave an area under the curve of 0.85 (95% CI 0.79-0.92)


CONCLUSIONS
Substantial variation in all elements of the scoring system and in the overall diagnostic conclusions was observed between radiologists participating in MARIBS. High overall sensitivity was achieved with moderate specificity. Manufacturer-related differences in specificities possibly occurred because the numerical thresholds set for the scoring system were not optimised for both equipment manufacturers. Scoring systems developed on one equipment software may not be transferable to other manufacturers.
Warren
Ruth
R
Department of Radiology, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK.
Hayes
Carmel
C
Pointon
Linda
L
Hoff
Rebecca
R
Gilbert
Fiona J
FJ
Padhani
Anwar R
AR
Rubin
Caroline
C
Kaplan
Glenda
G
Raza
Kauza
K
Wilkinson
Laura
L
Hall-Craggs
Margaret
M
Kessar
Preminda
P
Rankin
Sheila
S
Dixon
Adrian K
AK
Walsh
James
J
Turnbull
Lindsay
L
Britton
Peter
P
Sinnatamby
Ruchi
R
Easton
Doug
D
Thompson
Deborah
D
Lakhani
Sunil R
SR
Leach
Martin O
MO
D001943:Breast Neoplasms / Q000175:diagnosis*; D002983:Clinical Competence; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008403:Mass Screening; D015588:Observer Variation; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity