Biomedical Engineering Reference
In-Depth Information
workstations for rigid-body intermodality registration and serial MR regis-
tration. One factor holding up routine use of this technology has been that
many medical images, although intrinsically digital in origin for some time,
continue to be stored and reviewed in analog form, usually as “radiographic
films.” Fast and convenient access to digital image data is now rapidly becom-
ing feasible with the increase in use of digital image archiving and communi-
cation. This provides the necessary infrastructure for combining images from
different modalities or images taken at widely separated time intervals.
Another factor is that image registration is often only one component in an
image processing and analysis package directed to a specific clinical problem.
Progress needs to be made in other areas, most notably image segmentation,
before a wide range of image analysis protocols can enter routine clinical use.
16.2
Future Application of Image Registration
Below are a few personal observations and predictions on where this exciting
technology will lead in the next few years, and where to expect significant
progress.
16.2.1
Perfusion Studies
Rigid and nonrigid registration are essential enabling technologies for per-
fusion imaging because patients cannot be relied on to stay sufficiently still
during dynamic studies lasting many minutes. (This is especially relevant
in MRI.) Perfusion imaging is likely to have many clinical applications.
Cardiac MR imaging is progressing fast, and interest in tumor metabolism
and angiogenesis is driving advances in MR imaging for oncology.
16.2.2
Registration in Multimedia Electronic Patient Records
Multimedia electronic patient record systems will soon be widely used in hospi-
tals. These incorporate radiological images as well as much other nontext-based
information about patients. Integrating this information and relating it to atlas
data could be achieved transparently with the potential for improved diagnosis
and decision support. Indeed, once such systems are established, it will seem
strange not to align all the images acquired from a patient.
16.2.3
The Role of Deformation Fields Generated
by Nonrigid Registration
Medical image registration, and nonrigid registration in particular, have great
potential beyond simply lining up images. Some of these applications have
already been discussed in this topic, but it is worth highlighting them again here.
