MR scanner systems should be adequately characterized in diffusion-MRI of the breast.
Breast imaging represents a relatively recent and promising field of application of quantitative diffusion-MRI techniques. In view of the importance of guaranteeing and assessing its reliability in clinical as well as research settings, the aim of this study was to specifically characterize how the main MR scanner system-related factors affect quantitative measurements in diffusion-MRI of the breast. In particular, phantom acquisitions were performed on three 1.5 T MR scanner systems by different manufacturers, all equipped with a dedicated multi-channel breast coil as well as acquisition sequences for diffusion-MRI of the breast. We assessed the accuracy, inter-scan and inter-scanner reproducibility of the mean apparent diffusion coefficient measured along the main orthogonal directions (<ADC>) as well as of diffusion-tensor imaging (DTI)-derived mean diffusivity (MD) measurements. Additionally, we estimated spatial non-uniformity of <ADC> (NU<ADC>) and MD (NUMD) maps. We showed that the signal-to-noise ratio as well as overall calibration of high strength diffusion gradients system in typical acquisition sequences for diffusion-MRI of the breast varied across MR scanner systems, introducing systematic bias in the measurements of diffusion indices. While <ADC> and MD values were not appreciably different from each other, they substantially varied across MR scanner systems. The mean of the accuracies of measured <ADC> and MD was in the range [-2.3%,11.9%], and the mean of the coefficients of variation for <ADC> and MD measurements across MR scanner systems was 6.8%. The coefficient of variation for repeated measurements of both <ADC> and MD was < 1%, while NU<ADC> and NUMD values were <4%. Our results highlight that MR scanner system-related factors can substantially affect quantitative diffusion-MRI of the breast. Therefore, a specific quality control program for assessing and monitoring the performance of MR scanner systems for diffusion-MRI of the breast is highly recommended at every site, especially in multicenter and longitudinal studies.
Medical Physics Unit, Pisa University Hospital "Azienda Ospedaliero-Universitaria Pisana", Pisa, Italy.
Marco
M
Giannelli
Department of Oncology and Advanced Techniques, Medical Physics Unit, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
Roberto
R
Sghedoni
Division of Radiology, Breast Unit, Massa Hospital, Azienda USL Massa e Carrara, Massa, Italy.
Chiara
C
Iacconi
Department of Oncology and Advanced Techniques, Medical Physics Unit, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
Mauro
M
Iori
Medical Physics Unit, Pisa University Hospital "Azienda Ospedaliero-Universitaria Pisana", Pisa, Italy.
Antonio Claudio
AC
Traino
Department of Biomedicine and Prevention, Medical Physics Section, University of Rome "Tor Vergata", Rome, Italy.
Maria
M
Guerrisi
Department of Clinical and Experimental Biomedical Sciences, University of Florence, Florence, Italy.
Mario
M
Mascalchi
Department of Biomedicine and Prevention, Medical Physics Section, University of Rome "Tor Vergata", Rome, Italy ; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States of America ; Harvard Medical School, Boston, Massachusetts, United States of America.
Nicola
N
Toschi
Department of Clinical and Experimental Biomedical Sciences, University of Florence, Florence, Italy ; Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy.
Stefano
S
Diciotti
D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio