A limitation of abdominal MRI can be the assessment of malignancies by difficulties to distinguish bowel from other organs or malignant masses. The use of oral contrast agents can reduce this problem. Properties of an ideal oral contrast agent are little or no absorption by the stomach or intestines, complete excretion, no motion or susceptibility artifacts, and uniform marking of the GI tract.
Gastrointestinal MRI contrast agents are divided in materials with bright appearance or dark appearance. The choice of a negative or a positive oral contrast agent depends on the specific problem or the pulse sequence.

See also Positive Oral Contrast Agents, Negative Oral Contrast Agents, Gastrointestinal Diamagnetic Contrast Agents, Gastrointestinal Paramagnetic Contrast Agents and Gastrointestinal Superparamagnetic Contrast Agents.

See also the related poll result: 'The development of contrast agents in MRI is'

(OMP) Various mixtures of gastrointestinal diamagnetic contrast agents for use as negative oral contrast agents to darken the bowel.

If available, some graphic aids can be helpful to show image orientations.
1) A graphic icon of the labeled primary axes (A, L, H) with relative lengths given by direction sines and orientation as if viewed from the normal to the image plane can help orient the viewer, both to identify image plane orientation and to indicate possible in plane rotation.
2) Ingraphic prescription of obliques from other images, a sample original image with an overlaid line or set of lines indicating the intersection of the original and oblique image planes can help orient the viewer.
The location in the R/L and P/A directions can be specified relative to the axis of the magnet.
The F/H location can be specified relative to a convenient patient structure.
The orientation of single oblique slices can be specified by rotating a slice in one of the basic orientations toward one of the other two basic orthogonal planes about an axis defined by the intersection of the 2 planes.
Double oblique slices can be specified as the result of tipping a single oblique plane toward the remaining basic orientation plane, about an axis defined by the intersection of the oblique plane and the remaining basic plane. In double oblique angulations, the first rotation is chosen about the vertical image axis and the second about the (new) horizontal axis.
Angles are chosen to have magnitudes less than 90° (for single oblique slices less than 45°); the sign of the angle is taken to be positive when the rotation brings positive axes closer together.

A plane, section or a slice perpendicular to one another.

A gradient system, which changes the readout gradient sinusoidally by connecting a capacitor to the self inductance generated by the gradient coil. Oscillating gradient systems were initially used in the development of EPI.
This electrical oscillating circuit can be driven with minimal power to generate the gradient amplitudes and switching frequencies required for echo planar imaging (EPI).
Disadvantages are that it is not possible to use any arbitrary trapezoidal gradient wave form as can be used in standard MRI. Also, the gradients are inflexible and cannot be used to create other ultrafast sequences and beside, nonlinear sampling of the MR signal is required.