Tan ET, Wilmes LJ, Joe BN, Onishi N, Arasu VA, Hylton NM, Marinelli L, Newitt DC. Denoising and Multiple Tissue Compartment Visualization of Multi-b-Valued Breast Diffusion MRI.
J Magn Reson Imaging 2020;
53:271-282. [PMID:
32614125 DOI:
10.1002/jmri.27268]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND
Multi-b-valued/multi-shell diffusion provides potentially valuable metrics in breast MRI but suffers from low signal-to-noise ratio and has potentially long scan times.
PURPOSE
To investigate the effects of model-based denoising with no loss of spatial resolution on multi-shell breast diffusion MRI; to determine the effects of downsampling on multi-shell diffusion; and to quantify these effects in multi-b-valued (three directions per b-value) acquisitions.
STUDY TYPE
Prospective ("fully-sampled" multi-shell) and retrospective longitudinal (multi-b).
SUBJECTS
One normal subject (multi-shell) and 10 breast cancer subjects imaging at four timepoints (multi-b).
FIELD STRENGTH/SEQUENCE
3T multi-shell acquisition and 1.5T multi-b acquisition.
ASSESSMENT
The "fully-sampled" multi-shell acquisition was retrospectively downsampled to determine the bias and error from downsampling. Mean, axial/parallel, radial diffusivity, and fractional anisotropy (FA) were analyzed. Denoising was applied retrospectively to the multi-b-valued breast cancer subject dataset and assessed subjectively for image noise level and tumor conspicuity.
STATISTICAL TESTS
Parametric paired t-test (P < 0.05 considered statistically significant) on mean and coefficient of variation of each metric-the apparent diffusion coefficient (ADC) from all b-values, fast ADC, slow ADC, and perfusion fraction. Paired and two-sample t-tests for each metric comparing normal and tumor tissue.
RESULTS
In the multi-shell data, denoising effectively suppressed FA (-45% to -78%), with small biases in mean diffusivity (-5% in normal, +23% in tumor, and -4% in vascular compartments). In the multi-b data, denoising resulted in small biases to the ADC metrics in tumor and normal contralateral tissue (by -3% to +11%), but greatly reduced the coefficient of variation for every metric (by -1% to -24%). Denoising improved differentiation of tumor and normal tissue regions in most metrics and timepoints; subjectively, image noise level and tumor conspicuity were improved in the fast ADC maps.
DATA CONCLUSION
Model-based denoising effectively suppressed erroneously high FA and improved the accuracy of diffusivity metrics.
EVIDENCE LEVEL
3 TECHNICAL EFFICACY STAGE: 1.
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