RU208296U1 - Phantom for monitoring quantitative magnetic resonance imaging parameters - Google Patents

Abstract

This utility model relates to the field of medical technology, namely, to the means of quality control of images obtained during magnetic resonance imaging (MRI) using quantitative imaging methods. From the prior art, a phantom is known to control the parameters of diffusion-weighted images of magnetic resonance imaging (utility model RU 187202 U1), the disadvantages of which in terms of quality control of images obtained during quantitative magnetic resonance imaging include the absence of a section uniformly filled with MP- contrast fluid with a diameter corresponding to the diameter of the cylindrical body of the phantom. The absence of this section in the phantom body makes it impossible to perform tests for the constancy of MRI parameters, which include testing the signal-to-noise ratio, brightness distribution inhomogeneity, and image artifacts. The technical problem solved by the claimed utility model is to ensure an increase in the accuracy of determining quantitative characteristics when performing MRI using quantitative imaging methods (including diffusion-weighted modes; methods for constructing quantitative maps T1, T2; methods for constructing maps of the fat fraction) under conditions performing tests for the constancy of parameters and, as a result, a high level of diagnostic significance of such studies, as well as the possibility of conducting multicenter studies and monitoring the dynamics of the course of the disease. The technical result is to create a phantom to control the parameters of quantitative imaging methods in magnetic resonance imaging, including diffusion-weighted modes; methods for constructing quantitative maps T1, T2; methods for constructing maps of the fat fraction, as well as performing tests to check the constancy of parameters, such as signal-to-noise ratio, inhomogeneity in the distribution of brightness, image artifacts, and spatial non-linearity.

Description

This useful model relates to the field of medical technology, namely, to the means of quality control of images obtained during magnetic resonance imaging (MRI) using quantitative imaging methods.

A phantom is known from the prior art for evaluating the parameters of magnetic resonance images when testing MRI according to the accreditation program of the American Society of Radiologists (ACR) (Kaljuste D., Nigul M. Evaluation of the ACR MRI phantom for quality assurance tests of 1.5 T MRI scanners in Estonian hospitals // Proceedings of the Estonian Academy of Sciences. - 2014. - No 63 (3). - P. 328-334). The phantom is equipped with inserts for evaluating parameters of MRI image quality as part of periodic tests, including parameters such as signal-to-noise ratio, non-uniformity of brightness distribution, spatial resolution, etc. However, it does not include inserts that can be used to control parameters of quantitative MRI imaging methods ... Due to the absence of such inserts, this phantom cannot be used to control the parameters of quantitative MRI imaging methods.

The closest analogue is a phantom for controlling the parameters of diffusion-weighted images of magnetic resonance imaging (utility model RU 187202 U1), the disadvantages of which in terms of quality control of images obtained during quantitative magnetic resonance imaging include the absence of a section uniformly filled with MP- contrast fluid with a diameter corresponding to the diameter of the cylindrical body of the phantom. The absence of this section in the phantom body makes it impossible to perform tests for the constancy of MRI parameters, which include tests of the signal-to-noise ratio parameter, inhomogeneity of the brightness distribution, and image artifacts.

The technical problem solved by the claimed utility model is to ensure an increase in the accuracy of determining quantitative characteristics when performing MRI using quantitative imaging methods (including diffusion-weighted modes; methods for constructing quantitative maps T1, T2; methods for constructing maps of fat fraction) in conditions performing tests for the constancy of parameters and, as a consequence, a high level of diagnostic significance of such studies, as well as the possibility of conducting multicenter studies and observing the dynamics of the course of the disease.

The technical result consists in creating a phantom for controlling the parameters of quantitative visualization methods in magnetic resonance imaging, including diffusion-weighted modes; methods for constructing quantitative maps T1, T2; methods for constructing maps of the fat fraction, as well as performing tests to check the constancy of parameters such as signal-to-noise ratio, non-uniformity of brightness distribution, image artifacts, spatial nonlinearity, performed in accordance with the recommendations (GOST R 59092-2020, ACR Magnetic Resonance Imaging. Quality Control Manual. 2015 - 126 p., IEC 62464-1-2018).

The inventive phantom device consists of a cylindrical body with a cover for fixing the inserts with solutions.

Inside the phantom body there are:

- inserts with solutions for MRI control using quantitative imaging methods. Insert fill solutions are determined by the quantitative imaging methods tested;

- a homogeneous section with a diameter corresponding to the diameter of the phantom body and a thickness of at least 5 cm, for performing tests for constancy of parameters.

On the outer side of the phantom body there are two positioning marks perpendicular to the axis of the phantom body. Also, on the back of the phantom cover, a hole was made with a screw plug for additional filling with background solution and for removing the air bubble. The internal volume of the phantom can be filled with water or an MP contrast liquid (for example, an aqueous solution of CuSO4).

Thus, the solution to the technical problem posed is achieved by the fact that, in addition to essential features characteristic of analogues (the presence of a cylindrical body with a lid and the presence of inserts with solutions for MRI control using quantitative imaging methods), the declared phantom contains the following distinctive structural elements:

- the presence of a homogeneous section with a diameter corresponding to the diameter of the phantom body and a thickness of at least 5 cm to perform tests for the constancy of parameters;

- the presence of two positioning marks, perpendicular to the axis of the phantom body;

- the presence of a screw plug for additional filling with background solution and for removing the air bubble.

FIG. 1 shows a diagram of the device of the proposed phantom. The phantom consists of a cylindrical body (1) with samples of solutions (2), the samples do not occupy the entire volume of the phantom, as a result of which, it can be logically divided into two sections: a section for controlling quantitative MRI imaging methods (3) and a homogeneous section for conducting tests for the constancy of parameters (4).

FIG. 2 shows an example of an MP image of a phantom (measured diffusion coefficient map) obtained using the T1-weighted MRI mode. FIG. 2 shows the inserts for controlling the parameters of diffusion-weighted MRI images.

When using a phantom in a preferred embodiment of the claimed utility model, it is pre-kept in the scanning room to stabilize the temperature, and if there is an air bubble of more than 1 cm ³ inside the phantom body, it is necessary to unscrew the screw plug and fill in the corresponding MR contrast liquid. The positioning of the phantom inside the magnetic resonance imager is carried out using two positioning marks. The phantom can be used in SE spin echo MRI scans to perform constancy tests, as well as in MRI modes using quantitative imaging techniques such as diffusion-weighted modes; methods for constructing quantitative maps T1, T2; methods for constructing fat fraction maps. Using the phantom, the parameters are estimated by highlighting the region of interest (ROI) on the corresponding images, followed by entering into the protocol the mean values of the signal inside the ROI and comparing it with the acceptable range of the signal level inside the ROI, established during acceptance tests or according to the manufacturer's technical documentation. Phantom also provides the ability to calculate correction factors if necessary.

Table 1 summarizes the possible characteristics of insert filling solutions used for MRI control using quantitative imaging techniques.

Claims (1)

A phantom for monitoring the parameters of quantitative magnetic resonance imaging, consisting of a cylindrical body with a lid, filled with water or MP-contrast liquid, and containing inserts with solutions for monitoring MRI using quantitative imaging methods, characterized in that it contains a uniform section having a diameter, corresponding to the diameter of the phantom body, and a thickness of at least 5 cm, for performing tests to check the constancy of parameters, and also includes two positioning marks perpendicular to the axis of the phantom body, and a screw plug for additional filling with background solution and for removing the air bubble.

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