Moderator: Elliot K. Fishman, MD
ELLIOT K. FISHMAN, MD:
Thank you all for the informative presentations today. To conclude
our session, I would like to get each pan-elist's advice for those
who are just starting to do CT angiography. We have demonstrated
incredible CTA applications, including: peripheral vascular
disease, cardiac, kidney, aorta, pulmonary angiography, and
pediatric imaging. But these tremendous opportunities are not as
simple as they may seem to be. It is not just a matter of pushing a
So given that, while knowing that radiologists must go forward,
we can share what we know, since we are all doing this on a routine
basis. I would particularly like to hear your comments regarding
the role of contrast in CTA andthe proper delivery of contrast.
GEOFFREY D. RUBIN, MD:
My advice to anyone interested in beginning to perform CT
angiography is just to do as much as they can to understand the
operation of the CT scanner and the various responses to contrast
medium delivery in the arterial beds that will be studied. As we
move forward with CT technology to get faster and faster
acquisitions, we are learning that new challenges arise in the
different vascular beds; and they are frequently different
challenges. By staying abreast of the new results in the literature
and understanding the phenomena as they emerge, you are most likely
to be able to address them and to optimize the quality of the
images you acquire.
W. DENNIS FOLEY, MD:
I have noted over the years that there has been a relatively steep
learning curve for the average radiologist in understanding
multidetector CT. I think that is improving now. But, I certainly
encourage radiologists, if they have not paid attention to the
technology, that they must really understand it now. If you
understand the technology, then you can use it. As you mentioned,
Elliot, contrast delivery is a critical issue. I think we have to
be considered to be physiologists, as well as anatomic imagers.
I would also suggest that radiologists encourage technologists
in their department to become aware of how MDCT works, and foster
their interest in 3D imaging. That is an issue that we, as
radiologists, also have to grapple with. We have to push the PACS
vendors to incorporate 3D as part of the systems' routine
We also must be able to use the workstations; but in partnership
with our technologists who can do both routine and sophisticated 3D
display. We do not have the time to do it all, particularly in the
quantitative and segmentation aspect. So my advice is to address
the technology, address contrast delivery, and work with the
technologists. Then you have the technologists taking an active
interest in participating in what we do.
U. JOSEPH SCHOEPF, MD:
I agree with Geoff and Dennis. As radiologists, we should get the
technical bases covered--That is our job. We need to know how our
scanners and workstations work.
In addition to that, my advice would be to get in touch with the
referring physicians. Radiologists should talk with them, see what
their problems are, and see what they are dealing with everyday. If
you learn about the questions they need answered with the
diagnostic tests they are requesting from you, then you get an
insight into the significance of information that you provide. I
believe that is the surest way to secure credibility with your
clinical partners, and it will also increase your business.
BRIAN R. HERTS, MD:
I agree with everything that has been said. I would also like to
point out that there are really two customers when you are doing CT
angiography and 3D imaging. One is yourself; you are making
diagnoses easier to do, so you can make faster and simpler
diagnoses. The second customer is your referring physician. As
Joseph said, you are really communicating information more
effectively by doing CT angiography and postprocessing.
LEO P. LAWLER, MD, FRCR:
It is fascinating to go around the table because we managed to get
six physicians in the room to agree on a lot of things. It has been
interesting to hear the dynamics of our discussion and to hear the
presentations on different areas of the body. It seems to me that
similar messages were coming out. One of the big messages is that,
of course, multidetector CT is a great advance. In particular, we
have addressed the impact of multidetector CT on the timing of
contrast. I think everyone agrees that contrast timing is one of
the biggest limitations in every organ, and it is going to get
harder. So we have to get on top of that. It has to be a team
approach with the radiologists and technologists.
I definitely would suggest consulting some resources, such as
the material we are working on here. There are also some articles
in the European literature that address contrast dynamics. They are
a good place to start to understand this.
I would suggest moving from static organ imaging to pulsating
structures. We still have limits with mechanical CT, particularly
in the heart, and I would not start with CTA imaging of those
For those who may still have any doubts, these talks have
illustrated that to really harness the potential of multislice
imaging, one must do 3D and, therefore, by definition, for
segmentation, they must have optimal contrast boluses.
: The message that I would like to reinforce is that both
radiologists and technologists need to know how to use the
I have always been a strong advocate of 3D and volume imaging.
In 1986, we wrote an article that predicted that people would be
using volume imag
ing within the next couple of years. Well, we were off by about
20 years. But as you look at 16-slice CT, then you look at
64-slice, the data sets are only going to get larger. Radiologists
have to look toward the time when we will be looking at images as a
volume. Axial CT is just not going to happen. I agree with Dennis
that, right now, workflow is very bad. Many people have CT
workstations or 3D workstations in one place, and PACS in another
place. During the coming years, the big workstation vendors will be
merging their systems; so we will have workstations with CT, 3D,
and PACS in one place.
It is a very exciting time to be doing CTA. My advice to users
is to just do it. We are not perfect, and there are lots of
challenges. But there are also a lot of opportunities. We are
learning and things are changing. But the best advice I can offer
is that if you want to be doing CT angiography, and if you want it
to remain in the realm of radiology, you have to be doing it today,
and you have to be doing it well.
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