Brian Gale and David Stark, MD
The term image coregistration (a.k.a. fusion imaging) refers to
a process by which images from one "functional" modality (usually
nuclear medicine) are overlaid upon images from an "anatomic"
modality (generally computed tomography or magnetic resonance). The
result is often a visually stunning combination of a detailed
anatomic image accented by the overlaid, colorful "hot spot."
The advent of image coregistration has been greeted positively
by virtually all who have performed or written about it. Most of
the published papers on the subject discuss how well the particular
method discussed achieves the desired anatomic alignment. Authors
generally assume that by apparently increasing lesion conspicuity,
image coregistration will improve diagnostic accuracy across the
board. These impressions are cute, but lack scientific rigor.
"Show me the money!" said Cuba Gooding, Jr. in
Ronald Reagan, during the SALT III negotiations in Reykjavik,
Iceland delivered perhaps his most memorable quote when he declared
"Trust, but verify."
Radiologists need to verify whether this technique actually
increases the accuracy or efficiency of image interpretation,
compared with interpretation of the unfused "functional" and
"anatomic" images. Until a thorough scientific study is performed,
we won't know if this simple image processing technique truly
improves the practice of diagnostic radiology, or if we are simply
looking at a new, sexy version of the same old data.