scientific visualization Scientific visualization ( also spelled scientific visualisation) is an interdisciplinary branch of science concerned with the visualization of scientific phenomena. Michael Friendly (2008)"Milestones in the history of thematic cartography, st ...

, a maximum intensity projection (MIP) is a method for 3D data that

projects A project is a type of assignment, typically involving research or design, that is carefully planned to achieve a specific objective. An alternative view sees a project managerially as a sequence of events: a "set of interrelated tasks to be ...

in the visualization plane the

voxel In computing, a voxel is a representation of a value on a three-dimensional regular grid, akin to the two-dimensional pixel. Voxels are frequently used in the Data visualization, visualization and analysis of medical imaging, medical and scient ...

s with maximum intensity that fall in the way of parallel rays traced from the viewpoint to the plane of projection. This implies that two MIP renderings from opposite viewpoints are symmetrical images if they are rendered using

orthographic projection Orthographic projection (also orthogonal projection and analemma) is a means of representing Three-dimensional space, three-dimensional objects in Plane (mathematics), two dimensions. Orthographic projection is a form of parallel projection in ...

. MIP is used for the detection of lung nodules in

lung cancer Lung cancer, also known as lung carcinoma, is a malignant tumor that begins in the lung. Lung cancer is caused by genetic damage to the DNA of cells in the airways, often caused by cigarette smoking or inhaling damaging chemicals. Damaged ...

screening programs which use

computed tomography A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

scans. MIP enhances the 3D nature of these nodules, making them stand out from pulmonary bronchi and vasculature. MIP imaging is also used routinely by physicians in interpreting

Positron Emission Tomography Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, r ...

(PET) or

Magnetic Resonance Angiography Magnetic resonance angiography (MRA) is a group of techniques based on magnetic resonance imaging (MRI) to image blood vessels. Magnetic resonance angiography is used to generate images of arteries (and less commonly veins) in order to evaluate ...

studies.

Additional techniques

This technique is computationally fast, but the 2D results do not provide a good sense of depth of the original data. To improve the sense of 3D, animations are usually rendered of several MIP frames in which the viewpoint is slightly changed from one to the other, thus creating the illusion of

rotation Rotation or rotational/rotary motion is the circular movement of an object around a central line, known as an ''axis of rotation''. A plane figure can rotate in either a clockwise or counterclockwise sense around a perpendicular axis intersect ...

. This helps the viewer's

perception Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous syste ...

to find the relative 3D positions of the object components. However, since the projection is orthographic the viewer cannot distinguish between left or right, front or back and even if the object is rotating clockwise or anti-clockwise. Use of depth weighting during production of rotating cines of MIP images can avoid the problem of difficulty of distinguishing right from left, and clockwise vs anti-clockwise rotation. An alternate version of MIP is Local maximum intensity projection. In this technique we don't take the global maximum value, but the first maximum value that is above a certain threshold. Because - in general - we can terminate the ray earlier this technique is faster and also can give better results in some settings as it approximates occlusion. Choice of Local MIP vs Full MIP depends on the display goals and how the MIP is to be used.

History

MIP Display was invented for use in Nuclear Medicine by Jerold Wallis, MD, in 1988 at Washington University in St. Louis, and subsequently published in IEEE Transactions on Medical Imaging. In the setting of Nuclear Medicine, it was originally called MAP (Maximum Activity Projection).

References

{{DEFAULTSORT:Maximum Intensity Projection Object visualization

Additional techniques

History

See also

References