Maximum Intensity Projection

Rendering using Maximum Intensity Projection
Is a 3D rendering technique that is achieved by evaluating each voxel value along a line from the observer’s eyes through the object and then sampling only the highest value as the display value. It is achieved by displaying only the highest attenuation values from the data encountered along a ray projected through the dataset to the observer’s eyes.
In clinical practice, it is extremely useful for evaluating high ‘contrast’ radio-opaque substances. For instance, it can be utilized to evaluate the form and extent of the endodontic filling material in root canal treatment or it can also be utilized to evaluate the presence or absence of a foreign body material in osseous and/or soft tissue structures. It is best used when the objects to be investigated are the ‘brightest‘ objects in the image.
However, MIP ability to represent anatomical spatial interrelations is rather limited because of lack of the visual cues for depth perception. It has a tendency to misrepresent positions because the projection technique doesn’t take spatial location into calculation, only the maximal or (most attenuated) value is displayed. For the same reason, structures of sub-maximal attenuation along the projection line are obscured which may lead to sub-optimal interpretation results. In such a case, other 3D projection techniques in conjunction with MPR projections can be employed to enhance the interpretation process.