Investig Magn Reson Imaging.  2023 Mar;27(1):10-20. 10.13104/imri.2022.1009.

A Novel Magnetic Resonance Quality Assurance Phantom (KMRP-4): Multi-Site Comparison With the American College of Radiology Phantom

• Kumar S
• Kim JM
• Cha JG
• Hwang JY
• Jung SE
• Lee C
• Oh CH

• KMID: 2543026
• DOI: http://doi.org/10.13104/imri.2022.1009

Abstract

Purpose
To propose a novel standard magnetic resonance imaging (MRI) phantom, hereafter called the Korea Magnetic Resonance Phantom-4th edition (KMRP-4). Its related quality control (QC) assessment protocols and its comparison with the American College of Radiology (ACR) phantom and its QC assessment protocols.
Materials and Methods
Internally, the KMRP-4 phantom is composed of cubic and triangular vessels, brain tissue structures, and a uniform region designed to facilitate a variety of QC protocols. Using magnetic resonance (MR) images of these structures, we quantitatively evaluated a total of 10 parameters, seven from those of existing ACR protocols (i.e., geometric accuracy, high-contrast spatial resolution, slice thickness accuracy, slice position accuracy, image intensity uniformity, percent signal ghosting, and low-contrast object detectability) and three additional parameters for evaluating vessel conspicuity, brain tissue contrast, and signal-to-noise ratio (SNR) introduced in the KMRP-4 protocols. Twentytwo MRI systems of 0.32–3.0 T static magnetic field strength were tested using both ACR and KMRP-4 phantoms. Mann–Whitney U-tests were performed on the seven evaluation items of the ACR method to compare KMRP-4 and ACR methods.
Results
The results of Mann–Whitney U-test demonstrated that p-values were more than 0.05 for all seven items that could be assessed with both ACR and KMRP-4, indicating similar results between the two methods. Additionally, assessments of vessel conspicuity, brain tissue contrast, and SNR using the KMRP-4 method demonstrated utility of the KMRP-4 phantom.
Conclusion
A novel standard phantom and related QC methods were developed to perform objective, observer-independent, and semi-automatic QC tests. Quantitative comparisons of MR images with KMPR-4 and ACR phantoms were performed. Results demonstrated the utility of the newly proposed KMRP-4 phantom and its related QC methods.

Keyword

Quality assurance phantom; Magnetic resonance imaging (MRI); ACR phantom; KMRP-4 phantom