MR Scanner Systems Should Be Adequately Characterized in Diffusion-MRI of the Breast

Abstract

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.

ADC Histograms from Routine DWI for Longitudinal Studies in Cerebral Small Vessel Disease: A Field Study in CADASIL

“…In contrast, when the analysis was restricted to data obtained after the two last scanner upgrades which provided the most concordant diffusion data with the reference method, variations related to the scanner effect were found 10 times less than those related to patient characteristics. These data suggest that MR scanner upgrades can alter diffusion quantification during a long term follow-up study of cSVD but also that a reduction of related-variations can be obtained using appropriate technology and quality control as was proposed by a recent study on diffusion MRI of the breast[31]. The use of phantoms across upgrades for reducing scanner related variations may be particularly useful for correcting these variations.…”

Assessment and quantification of sources of variability in breast apparent diffusion coefficient (ADC) measurements at diffusion weighted imaging

“…The phantom utilized in this study is simple, inexpensive, offers a highly reproducible material to monitor temporal stability of MRI systems, and is well suited for performing serial ADC quality assurance measurements as may be required on systems on which ADC measures are employed in treatment response studies [15,19]. Phantom ADC measurements were within 1% of the ADC reported for water at 0 • C (1.099 × 10 − 3 mm 2 /s) [15] and results indicate that scanner stability has a minimal effect on the repeatability of ADC measurements, with a CoV of 6%, which is in line with other reports in the literature [15].…”

“…Malyarenko et al [15] used a similar phantom to investigate the repeatability of ADC measurements across multiple scanners and found standard deviations at the isocentre to be less than 2% of that reported for water at 0 • C, with a day-to-day repeatability within 4.5%. Giannelli et al [19] reported that short term stability for an individual scanner was of the order of 1%, and inter-scanner measures (using MRI scanners from 3 different manufactures) resulted in around 7% of the measured mean diffusion value. Off-centre measurements demonstrated significant differences greater than 10%, and were vendor and system-specific [15] and therefore most likely to be attributable to gradient non-linearity.…”

Diffusion-weighted magnetic resonance imaging in cancer: Reported apparent diffusion coefficients,in-vitroandin-vivoreproducibility

“…Overall the authors concluded that there were significant intra-vendor and inter-vendor variations in the computed ADC values. Giannelli et al [139] (2014) used an in-house isotropic water (per 1000 g distilled water: 1.25 g NiSO4.6H2O + 5 g NaCl) phantom made of two cylindrical bottles to resemble female breast. DW-MRI of the phantom was performed using three scanners from three vendors (Philips, Siemens, GE) at 1.5T field strength.…”