Purpose: This study evaluated intraobserver and interobserver variability in the measurement of apparent diffusion coefficient (ADC) values in breast carcinomas. Materials and methods: Twenty-eight patients with solid breast lesions >10 mm underwent conventional contrast-enhanced magnetic resonance imaging (MRI) and diffusion-weighted MRI (DW-MRI). Two observers (expert and trainee) segmented the lesion from the surrounding breast tissue on DW images with high b-value (1,000 s/mm 2). This analysis was repeated by the expert reader after 6 months. Volumes were analysed to obtain mean, median and standard deviation (SD) of the ADC values. Interobserver and intraobserver variation was analysed using the Bland-Altman graph. Results: All lesions were breast carcinomas, with a mean ADC value of 1.07 × 10 -3 mm 2/s. The mean of the differences was 0.012 × 10 -3 mm 2/s, corresponding to an intraobserver variability of 1.1% (limits of agreement: -5%/+8%). The mean interobserver difference was 0.022 × 10 -3 mm 2/s, corresponding to an interobserver variability of 2% (limits of agreement: -9%/+14%). Conclusions: We found a low intraobserver and interobserver variability in calculating ADC in breast carcinomas, which supports its potential use in routine clinical practice.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging