An anthropomorphic phantom for quantitative evaluation of breast MRI

Abstract

Purpose: In this study, the authors aim to develop a physical, tissue-mimicking phantom for quantitative evaluation of breast MRI protocols. The objective of this phantom is to address the need for improved standardization in breast MRI and provide a platform for evaluating the influence of image protocol parameters on lesion detection and discrimination. Quantitative comparisons between patient and phantom image properties are presented. Methods: The phantom is constructed using a mixture of lard and egg whites, resulting in a random structure with separate adipose-and glandular-mimicking components. T 1 and T 2 relaxation times of the lard and egg components of the phantom were estimated at 1.5 T from inversion recovery and spin-echo scans, respectively, using maximum-likelihood methods. The image structure was examined quantitatively by calculating and comparing spatial covariance matrices of phantom and patient images. A static, enhancing lesion was introduced by creating a hollow mold with stereolithography and filling it with a gadolinium-doped water solution. Results: Measured phantom relaxation values fall within 2 standard errors of human values from the literature and are reasonably stable over 9 months of testing. Comparison of the covariance matrices of phantom and patient data demonstrates that the phantom and patient data have similar image structure. Their covariance matrices are the same to within error bars in the anterior-posterior direction and to within about two error bars in the right-left direction. The signal from the phantom's adipose-mimicking material can be suppressed using active fat-suppression protocols. A static, enhancing lesion can also be included with the ability to change morphology and contrast agent concentration. Conclusions: The authors have constructed a phantom and demonstrated its ability to mimic human breast images in terms of key physical properties that are relevant to breast MRI. This phantom provides a platform for the optimization and standardization of breast MRI imaging protocols for lesion detection and characterization.

Design of a breast phantom for quantitative MRI

“…Unlike previous breast phantoms (6, 7), this phantom incorporates diffusion mimics. One challenge in developing the diffusion phantom unit was selecting appropriate materials that at bore temperature exhibit the range of ADC values reported in the literature for normal and diseased breast tissue in vivo (9, 11).…”

“…One such improvement is the capability to assess contrast-enhanced measurements. Typical T 1 measurements in the breast are contrast-enhanced with gadolinium; hence, it is worth considering the inclusion of a dynamic contrast component similar to that used by Freed et al (7) in the next iteration of the phantom. In addition, an alternative adipose tissue mimic will be explored.…”

“…In an effort to develop a new breast phantom, we evaluated phantoms presented in the literature. We found that these phantoms were either incompatible with some breast coil types (6), or unable to assess diffusion MRI (7). …”

Development of a patient-specific two-compartment anthropomorphic breast phantom

“…Previous studies have developed uncompressed breast phantoms with a stochastic glandular tissue distribution approximating patient data (Freed et al , 2011b; Cai et al , 2011). The physical phantom generated in our study is the first non-cadaveric and non-tissue-based phantom, to our knowledge, to accurately model the uncompressed breast and the glandular tissue distribution for a specific patient.…”

Candidate for Tissue Mimicking Material Made of an Epoxy Matrix Loaded With Alginate Microspheres

“…There are materials which contain substances such as honey syrup or egg whites [17,18]. These materials are also proposed as phantom materials because their properties at some frequencies agree with tissue properties.…”