An artificial object of known size and composition that is imaged to test, adjust or monitor an MRI systems homogeneity, imaging performance and orientation aspects. A phantom is usually a fluid-filled container or bottle often filled with a plastic structure of various sizes and shapes.

See also Daily Quality Assurance.

An undesirable background interference or disturbance that affects image quality.
The Noise is commonly characterized by the standard deviation of signal intensity in the image of a uniform object (phantom) in the absence of artifacts. The measured noise may depend on the particular phantom used due to variable effects on the Q of the receiver coil.
Noisy images appear when the SNR-Rate is too low - this is induced by the operator. Image artifacts and RF noise can often be caused by the presence and/or operation of a medical device in the MR environment. There are various noise sources in any electronic system, including Johnson noise, shot noise, thermal noise. Materials produce their own characteristic static magnetic field that can perturb the relationship between position and frequency essential to accurate image reconstruction.
RF noise, which often appears as static on the image, can be caused by a medical device located anywhere in the MR procedure room. RF noise is a result of excessive electromagnetic emissions from the medical device that interfere with the proper operation of the MR scanner. Since the MR procedure room is shielded from extraneous RF fields entering the room (Faraday cage), operation of electromagnetically noisy equipment outside the room does not typically affect the MR scanner.

See Signal to Noise Ratio and Radio Frequency Noise Artifact.

The smallest distance between two points in the object that can be distinguished as separate details in the image, generally indicated as a length or a number of black and white line pairs per mm (lp/mm).
The specific criterion for resolution to be used, depends on the type of test used (e.g., bar pattern or contrast-detail phantom). As the ability to separate or detect objects depends on their contrast and the noise, and the different MR parameters of objects will affect image contrast differently for different imaging techniques, care must be taken in comparing the results of resolution phantom tests of different machines and no single simple measure of resolution can be specified.
The resolution may be an isotropic one. The resolution may be larger than the size corresponding to the discrete image element (pixel), although it cannot be smaller.

The interaction of the patient with the RF coil, which causes shifts of the resonance frequency and damping of the coil's resonance and hence reduction of the quality factor because of magnetic induction and dielectric losses in the patient.
The design and construction of a MRI coil is determined by the load on the coil. The load is either a phantom or the actual sample being imaged.

See also Radio Frequency Coil.

Manganese chloride (MnCl2) is used as an oral contrast agent (LumenHance®) for MRI of the abdomen and/or pelvis. MnCl2 has also been used in magnetic resonance imaging of animals to maximize the contrast of different tissues e.g. in mice and crayfish with different injection methods. Caused by the hepatic uptake, manganese chloride has potential as a hepatobiliary contrast agent.
Manganese chloride is produced by the reaction of hydrochloric acid with manganese oxide or manganese carbonate. In an aqueous solution, manganese chloride can serve as phantom fluid, used for e.g. the daily quality assurance.

See also Classifications, Characteristics, etc.