Biomedical Engineering Reference
In-Depth Information
1
Introduction
Joseph V. Hajnal, Derek L.G. Hill, and David. J. Hawkes
CONTENTS
1.1 Preface.............................................................................................................. 1
1.2 Historical Background................................................................................... 4
1.3 Overview of the Topic.................................................................................... 6
References ................................................................................................. 7
1.1
Preface
Image registration is the process of aligning images so that corresponding fea-
tures can easily be related. The term is also used to mean aligning images with
a computer model or aligning features in an image with locations in physical
space. The images might be acquired with different sensors (e.g., sensitive to
different parts of the electromagnetic spectrum) or the same sensor at different
times. Image registration has applications in many fields; the one that is
addressed in this topic is medical imaging. This encompasses a wide range of
image usage, but the main emphasis is on radiological imaging.
The past 25 years have seen remarkable developments in medical imaging
technology. Universities and industry have made huge investments in
inventing and developing the technology needed to acquire images from
multiple imaging modalities. Medical images are increasingly widely used in
healthcare and biomedical research; a very wide range of imaging modalities
is now available. X-ray computed tomography (CT) images are sensitive to
tissue density and atomic composition, and the x-ray attenuation coefficient
and magnetic resonance imaging (MR) images are related to proton density,
relaxation times, flow, and other parameters. The introduction of contrast
agents provides information on the patency and function of tubular struc-
tures such as blood vessels, the bile duct, and the bowel, as well as the state
