Design of a breast phantom for quantitative MRI

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Purpose To assess the ability of a recent, anatomically-designed breast phantom incorporating T1 and diffusion elements to serve as a quality control device for quantitative comparison of apparent diffusion coefficient (ADC) measurements calculated from diffusion-weighted MRI (DWI) within and across MRI systems. Materials and Methods A bilateral breast phantom incorporating multiple T1 and diffusion tissue mimics and a geometric distortion array was imaged with DWI on 1.5 T and 3.0 T scanners from two different manufacturers, using three different breast coils (three configurations total). Multiple measurements were acquired to assess the bias and variability of different diffusion weighted single-shot echo-planar imaging (SS-EPI) sequences on the scanner-coil systems. Results The repeatability of ADC measurements was mixed: the standard deviation relative to baseline across scanner-coil-sequences ranged from low variability (0.47, 95% Confidence Interval (CI): 0.22–1.00) to high variability (1.69, 95% CI: 0.17–17.26), depending on material, with the lowest and highest variability from the same scanner-coil-sequence. Assessment of image distortion showed that Right/Left measurements of the geometric distortion array were 1 to 16 % larger on the left coil side compared to the right coil side independent of scanner-coil systems, diffusion weighting, and phase-encoding direction. Conclusions This breast phantom can be used to measure scanner-coil-sequence bias and variability for DWI. When establishing a multi-system study, this breast phantom may be used to minimize protocol differences (e.g. due to available sequences or shimming technique), to correct for bias that cannot be minimized, and to weigh results from each system depending on respective variability.

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Variability and bias assessment in breast ADC measurement across multiple systems

Keenan

Peskin

Wilmes

et al. 2016

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“…The outer container is dependent on both the anatomy of interest and the RF hardware in use (eg, a 15.0 cm diameter sphere is not a good match for a breast coil). Previous work demonstrated that using phantoms with correct geometry for the anatomy of interest, which is also appropriately sized for the RF hardware, is important for assessing quantitative imaging performance . The reference solutions within the phantom are dictated by the quantitative parameters of interest.…”

Section: Deployed Nist Reference Objectsmentioning

confidence: 99%

“…Finally, the UCSF/NIST breast phantom, which has T 1 and ADC values representative of fibroglandular and fat tissue, was used by the I‐SPY 2 clinical trial . The phantom is designed to test both sides of breast coils, which requires a unique geometry.…”

Section: Deployed Nist Reference Objectsmentioning

confidence: 99%

“…NIST created three reference objects that have been commercialized and are being actively used by the MRI community: the ISMRM/NIST system phantom, 7,21 the QIBA/NIH/ NIST isotropic diffusion phantom, 3,22,23 and the University of California San Francisco (UCSF)/NIST breast phantom. 4,5 The NIST reference objects have been used to identify measurement errors and then improve the stability of acquisitions in technique/pulse sequence development and protocol development for multisite studies. These reference objects were necessary to aid standardization, but they are insufficient given the wide range of qMRI applications-that is, there is still a need for additional reference objects.…”

Section: Deployed Nist Reference Objectsmentioning

confidence: 99%

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Recommendations towards standards for quantitative MRI (qMRI) and outstanding needs

Keenan

Biller

Delfino

et al. 2019

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Assessment of tumor morphology on diffusion‐weighted (DWI) breast MRI: Diagnostic value of reduced field of view DWI

Barentsz

Taviani

Chang

et al. 2015

PURPOSE To compare the diagnostic value of conventional, bilateral diffusion-weighted imaging (DWI) and high-resolution targeted DWI of known breast lesions. MATERIALS AND METHODS Twenty-one consecutive patients with known breast cancer or suspicious breast lesions were scanned with the conventional bilateral DWI technique, a high-resolution, reduced field of view (rFOV) DWI technique and dynamic contrast enhanced MRI (3.0 T). We compared bilateral DWI and rFOV DWI quantitatively by measuring the lesions’ ADC values. For qualitative comparison, three dedicated breast radiologists scored image quality and performed lesion interpretation. RESULTS In a phantom, ADC values were in good agreement with the reference values. Twenty-one patients (30 lesions: 14 invasive carcinomas, 10 benign lesions (of which 5 cysts), 3 high risk and 3 in situ carcinomas) were included. Cysts and high-risk lesions were excluded from the quantitative analysis. Quantitatively, both bilateral and rFOV DWI measured lower ADC values in invasive tumors than other lesions. In vivo, rFOV DWI gave lower ADC values than bilateral DWI (1.11× 10−3 mm2/s vs. 1.24 × 10−3 mm2/s, P=0.002). ROIs were comparable in size between the two techniques (2.90 vs. 2.13 cm2, P=0.721). Qualitatively, all three radiologists scored sharpness of rFOV DWI images as significantly higher than bilateral DWI (P ≤ 0.002). ROC curve analysis showed a higher AUC in BI-RADS classification for rFOV DWI compared to bilateral DWI (0.71 to 0.93 vs. 0.61 to 0.76, respectively). CONCLUSION Tumor morphology can be assessed in more detail with high-resolution DWI (rFOV) than with standard bilateral DWI by providing significantly sharper images.