If whole-body CT scanning is to have value in screening apparently healthy populations, it must detect very subtle disease. This necessitates the use of both intravenous contrast and the most advanced CT scanners.
is an Associate Professor of Radiology at Johns Hopkins Medical
Institutions, Baltimore, MD.
Over the last decade, whole-body computed tomographic (CT)
screening has become increasingly common. During that time, many
have questioned the value of this examination and the effect of
profit-making incentives on the selection of CT scanners; the
scanning protocol itself, including the choice to use or forego
intravenous (IV) contrast material; and the physician-patient
For almost 30 years, CT scanning has been used successfully to
image symptomatic patients. It is essential to patient care and is
heavily relied upon by clinicians and surgeons for the detection
and staging of disease, and the monitoring of treatment.
Incidental findings on CT are common. Some are significant, such
as aneurysms and neoplasms, and some are insignificant or a normal
process of aging, such as renal cysts, calcified granulomata, and
arthritis. In our busy department, we detected the following
incidental CT findings in just 1 week: adrenal adenoma, lung
nodules, renal cell carcinoma in a potential renal donor (Figure
1); carcinoma of the rectum in a patient being evaluated for
biliary obstruction; bronchoalveolar carcinoma in a patient
undergoing coronary artery screening; and renal artery stenosis in
a hypertensive patient being scanned for abdominal pain.
The few studies on CT screening in the scientific literature
suggest that perhaps 30% of examinations detect a significant
abnormality. One study, from the Mayo Clinic, involved >1500
Investigators detected significant incidental findings in 14%,
including abdominal aortic aneurysm, lung cancer, breast cancer,
lymphoma, renal cell carcinoma, and gastric cancer. For a screening
population of apparently healthy people, that is a high incidence
of significant findings.
reported on the results of CT screening in 1700 people. Thirty-two
percent of the studies were abnormal, not including findings of
renal cysts or coronary calcification. Among the abnormalities were
19 cancers, 11 aneurysms, 55 gallstones, and 30 ovarian cysts. It
is important to note, however, that many of the scans reported in
these studies were performed without contrast en-hancement, so it
is not surprising that follow-up would be necessary to clarify some
of the abnormalities.
Clearly, we can use CT to screen for and detect disease in
asymptomatic people. The controversy lies in whether, as
radiologists, we should be offering this service.
Radiologic screening is not a new concept. We have been
performing barium enemas, chest X-rays, mammograms, and dual-energy
X-ray absorptiometry (DEXA) for years. It is not difficult to
justify using CT to screen for lung cancer in smokers or to perform
virtual colon-oscopy in patients over the age of 50 who are at high
risk for colon cancer. What is new is the use of whole-body CT to
screen for unspecified disease in people who are not at high
Whole-body CT screening gained national attention several years
ago when Oprah Winfrey had a full-body scan and reviewed the
results with a radiologist on her television show. Demand for
whole-body screening has risen sharply since, and whole-body
imaging centers have opened throughout the country.
Improvements in CT technology have been a driving force in
whole-body screening. Until the mid-1990s, CT scanners were not
capable of detecting a 5-mm renal cell carcinoma, or a 1-cm
pancreatic neoplasm. With the introduction of multidetector CT
(MDCT) technology, it became technically feasible to screen
asymptomatic people. Faster scanning meant less motion artifact
and, together with thinner collimation (0.75 mm or 0.6 mm) and
isotropic data sets, created high-resolution, high-quality
Figure 2 shows a very small hepatoma in a cirrhotic liver.
Without MDCT technology, it would not have been possible to scan
fast enough or acquire data in thin enough slices to identify such
a finding. Small lung nodules, carcinoid tumors, and renal artery
aneurysms are other examples of subtle findings that are more
easily seen on high-quality 3-dimensional (3D) images.
Another reason whole-body CT screening became popular in the
mid-1990s was increased awareness of screening tests in general.
People were already knowledgeable about the importance of screening
for high blood cholesterol, breast cancer, lung cancer, and
prostate cancer, among other conditions. They viewed CT simply as a
new screening modality, not as a new concept.
People were also more health-conscious and, in part as a
reaction to changes in health insurance, felt the need to be more
in control of their health-care decisions. They considered CT
screening a source of additional information to use in monitoring
their own health. Under these circumstances, it's not surprising
that physicians teamed up with entrepreneurs to open whole-body CT
At many screening centers, whole-body CT scans are noncontrast
studies of the chest, abdomen, and pelvis. The quality of the
equipment and the experience of the radiologist vary from one
screening center to another. The CT scanner may be electron-beam,
single-detector, or multidetector. There is no quality control; any
type of CT scanner can be used for screening studies.
The technique also varies widely from center to center, based on
the type of scanner. Slice width can range from 1 to 10 mm.
Usually, the study includes some type of 3D image reconstruction.
The examination may or may not require a doctor's referral. The
study usually also includes a consultation with a radiologist or a
clinician, such as a nurse practitioner or internal medicine
specialist, to explain the findings to the patient. In some cases,
the whole-body scan is combined with other types of screening
studies, such as a heart scan or virtual colonoscopy.
If CT screening is to be done appropriately, it is necessary to
determine the best protocol and approach to screening healthy
people. The top 2 causes of death in the United States are
cardiovascular disease and cancer; therefore, the screening
protocol should be designed with that in mind.
At Johns Hopkins Medical Institutions, we use our best scanner,
a 64-slice Siemens Sensation (Siemens Medical Solutions USA,
Malvern, PA), and we always do 3D imaging. We start with coronary
calcium scoring and then scan the chest, abdomen, and pelvis, using
IV contrast unless it is contraindicated or the patient declines
its use after weighing the risks and benefits. We always give the
patient the option of meeting with us afterward to review the
Table 1 outlines the whole-body imaging protocol we use at Johns
Hopkins. It is, essentially, the same protocol we use for CT
angiography. Note that we use 0.75-mm collimation and reconstruct
at 0.5-mm intervals. We maximize our protocol to detect
cardiovascular disease and small tumors.
We instruct patients to drink 750 mL of water as oral contrast.
This avoids interference of high-density contrast material with 3D
reconstructions. For contrast-enhanced examinations, we use
nonionic isosmolar contrast material (iodixanol, 320 mgI/mL),
intravenously injecting 120 mL at 3 to 5 mL/sec. We initiate
scanning 3 to 60 seconds after beginning the contrast injection.
Some radiologists like to scan very early to focus on the arterial
phase; others prefer to wait, so that kidney enhancement is
optimized for the detection of small renal-cell carcinoma. We scan
from the base of the skull through the pubic symphysis.
We always use iodixanol for screening studies because of its
safety profile. People who undergo whole-body CT screening are
generally healthy, and we want to minimize the risk of a serious
contrast reaction. With an osmolality of 290 mOsm/kg, iodixanol is
isotonic to human blood and, therefore, is better tolerated and
less likely to cause cardiac or renal toxicity. (Unless the patient
reports a history of kidney disease, we do not check the pa-tients'
creatinine levels prior to CT scanning, as we use iodixanol in all
Another advantage of using isosmolar contrast material is that
it appears to mix better with blood, resulting in more uniform
opacification. Figure 3A shows a CT scan for suspected pulmonary
embolism (PE). Low density in the center of the pulmonary artery
results from unopacified blood. By comparison, as shown in Figure
3B, the use of isosmolar contrast material enables detection of a
small, discrete filling defect within the pulmonary artery, as
would be expected with PE.
Three-dimensional imaging plays an important role in CT
screening. It is much easier and faster to evaluate a large volume
of information using 3D reconstructions, rather than by reviewing
2000 axial slices. Also, 3D reconstructions are useful when
discussing scan findings with a patient.
Usually, I have the patient sit with me at the monitor as I
reconstruct the 3D study. The consultation typically takes
approximately 10 minutes. As shown in Figure 4, I point out the
lungs; major abdominal organs, including the kidneys, liver, and
spleen; and the bones. I also spend a fair amount of time reviewing
angiographic images, looking at the abdominal and thoracic aorta,
mesenteric vessels, and renal arteries.
Since we begin image acquisition at the base of the skull and do
a relatively early-phase contrast injection, we can also review the
carotid arteries for atherosclerotic disease. Figure 5 shows a
patient with extensive atherosclerotic disease in the carotid
The use of IV contrast media in whole-body CT screening is
controversial. Arguments against this practice include the risk it
poses to a healthy person of having a serious contrast reaction,
the potential for nephrotoxicity, the added cost of the contrast
agent, and the necessity of having a physician on site to treat any
contrast reactions. In reality, most centers, as profit-driven
businesses, focus on the latter two reasons in arriving at the
decision to forego contrast-enhanced studies.
A key advantage of using IV contrast is that the resulting scan
is more sensitive and much more specific for the detection of small
lesions, and for characterization of any abnormalities. If a
noncontrast study reveals an abnormality that requires further
characterization, as is often the case, the radiologist will
recommend a second, contrast-enhanced study. As a result, a healthy
person must undergo 2 CT scans instead of 1.
To optimize disease detection in a healthy screening population,
we must be able to find subtle tumors. To look for vascular
disease, we need to examine the carotid arteries, the aorta, the
mesenteric arteries, the renal arteries, and other vessels. Once we
find a lesion, we need to be able to characterize it without
recommending unnecessary follow-up studies.
Figure 6 illustrates small tumors that would not be visible on a
noncontrast study. Noncontrast studies can detect large tumors but
offer little value for screening, as patients with large tumors
would undoubtedly be symptomatic.
Another controversy is whether we should be exposing healthy
people to radiation. McCauley
estimated that screening CT would induce more cancers than would be
cured by early detection, particularly in people who underwent
Brenner and Elliston
also estimated the radiation risks associated with full-body CT
screening. These investigators estimated that a single full-body CT
scan in a 45-year-old would result in an increased lifetime
mortality risk of approximately 0.8%, mostly from lung cancer. An
annual full-body CT scan over 30 years would increase the
incremental risk to 1.9%.
Realistically, any increase in risk is probably minimal.
Although some centers recommend yearly CT screening, it's unlikely
that many people would undergo annual CT scans. (We recommend that
patients repeat CT screening in 5 to 10 years, if at all.)
Nonetheless, it is important to keep radiation dose in mind and
take steps to minimize it. New scanners with dose-modulation
capabilities reduce radiation exposure. Another key step is
optimization of imaging protocols to minimize radiation dose,
taking into account body size, for example. It is also important to
establish age guidelines. In my opinion, patients should not be
screened before age 40.
In September 2002, the American College of Radiology issued a
statement indicating there was insufficient scientific evidence to
justify recommending total-body CT screening.
It is unlikely, however, that randomized, prospective studies will
ever be done to assess the value of CT screening, as it would take
millions of people and decades of follow-up to determine whether CT
screening influences the natural history of disease or
The absence of proven value is not unusual in medicine, however.
Many of the examinations and procedures we do every day have not
been subjected to rigorous scientific evaluation. The
impracticality of conducting a large, randomized, double-blinded
trial of CT screening should not necessarily dissuade us from
pursuing CT screening.
Beinfeld et al
recently estimated the cost-effectiveness of one-time whole-body CT
screening from a societal perspective. They assumed that any
benefits from screening when compared with routine care were due to
earlier detection of disease and improved survival. Estimated
costs, including the screening exam, follow-up tests, and patient
care, totaled $2,513 per patient, or $151,000 per life-year gained.
This analysis suggests that CT screening is not a very
cost-effective approach to population screening.
On an individual basis, CT screening can have positive health
effects. Some people, upon receiving a clean bill of health, are
inspired to make healthy lifestyle changes, including smoking
cessation. However, screening can also have negative effects.
Ostroff et al
suggested that individuals with a normal CT scan were less likely
to quit smoking.
I always advise patients that CT does not evaluate organ
function, and that a person can have a normal CT scan and still
have significant disease. With proper counsel, most patients
appreciate the limitations of CT and understand that it does not
replace routine medical care or justify taking unnecessary health
One area of controversy that must be addressed is the need for
physician-referral. Some self-referral imaging centers essentially
give the results to the patient and send them out the door. This is
a risky practice for both patient and radiologist. A radiologist
who performs a screening study without a physician referral
establishes a patient-physician relationship and assumes the
responsibility for follow-up.
At Johns Hopkins, we require a physician referral. We discuss
the findings with the patient, but we also send the results to a
physician who can further explain the findings, if needed, and
ensure that the patient receives necessary follow-up.
The number of self-referral body imaging (SRBI) centers is
growing. Based on a series of Internet searches, Kalish et al
reported that the number of SRBI centers totaled 161 in 2003, up
from 88 in 2001. Of the centers accepting self-referred patients,
66% were solely SRBIs, 17% were general diagnostic imaging centers,
11% were hospitals, and 6% were compre-hensive screening centers.
Of the SRBIs, 94% performed heart scans, 84% full-body scans, 78%
lung scans, 55% virtual colonoscopy, 20% abdominal-pelvic scans,
and 16% head scans.
The largest number of self-referral CT screening centers, nearly
40%, were in the western United States, with another ap-proximately
25% in the South. Centers tended to be located in areas with higher
per-capita and median household incomes and higher percentages of
people with college and advanced degrees.
Is whole-body CT screening good medicine or simply greed?
Medicare and other types of health insurance do not cover these
studies. Instead, patients pay cash, making this a potentially
lucrative for-profit venture. Body imaging centers send coupons in
the mail, conduct aggressive advertising campaigns, and set up
business in malls, all to encourage people to undergo CT screening.
It is not uncommon for SRBIs to spend a great deal of money on
decorating while using a mediocre CT scanner to perform the
screening examination and send studies off-site for interpretation
at the cheapest rates.
There are signs that the market is becoming saturated, however.
Competition between body imaging centers is increasing, and the
charge for a CT screening scan is falling, in some case to one
third to one half of the initial $800 to $1,000 price tag. There
are even mobile scanning companies that charge as little as $75 per
body part scanned.
How to succeed
To be truly successful at whole-body CT screening-defined by
finding very early-stage lesions, not simply by making money-it is
necessary to invest in the latest CT technology. Imaging protocols
must be designed to maximize the detection of important pathology.
It is important to use IV contrast and perform 3D and angiographic
imaging. Radiologists must be experienced at discriminating
meaningful and incidental findings, report them decisively and
clearly to clinicians, and have a good rapport with patients. The
approach to image interpretation must be very organized. It is
particularly important that follow-up recommendations for
incidental findings be uniform from one radiologist to another.
It is also important to be honest and careful about making
claims. One CT screening center claimed on its Web site that the
radiation dose from a CT scan is equivalent to that of sitting in
the sun for 15 minutes. Making such laughably false claims is a
serious breach of ethics. It is important to acknowledge, in terms
that patients can understand, that CT scans involve radiation
exposure. Only then can they can make an informed decision whether
or not to take that risk.
Another center claimed that anyone over the age of 30 with a
family history of heart disease, cancer, diabetes, high blood
pressure, high cholesterol, or chest pain, or a personal history of
smoking or a sedentary lifestyle could benefit from a CT screening
examination. It is inappropriate to use such claims to entice
younger people to undergo CT screening.
Another center claimed that full-body scanning could detect
heart disease when the coronary arteries are only 5% blocked. This
statement is clearly misleading. It may be possible to see a tiny
calcification at this stage, but it would be clinically
insignificant for the patient.
One of the most outlandish claims stated: "Full-body scanning
has been certified by the FDA to detect lung cancer and frequently
detects incidental tumors, cancers, and other disorders years in
advance of symptoms." This makes it sound as if the Food and Drug
Administration has approved whole-body CT screening, which is not
the case. The claim continued: "Body scans can detect: heart
disease, thyroid disease, ovarian cancer, breast cancer, prostate
cancer, etc."-essentially, any and all diseases. This type of
creative advertising by profit-driven entrepreneurs gives CT
screening a bad name.
CT screening presents both significant challenges and
significant opportunities for radiologists. Lung-cancer screening
and CT colonography are becoming increasingly common, and people
continue to want whole-body scanning, despite the controversy
associated with this study. Radiologists who include CT screening
in their practice should do it well:
- Invest in technology.
- Incorporate IV contrast.
- Require a physician referral.
- Develop a good rapport with the patients.
- Be honest about the strengths, limitations, risks, and
benefits of whole-body CT screening.
ELLIOT K. FISHMAN, MD:
Karen, at Hopkins, where are most of the people who are getting
whole-body screening CT coming from these days?
KAREN M. HORTON, MD:
We have a group comes from Executive Health who sends executives,
since they push screening and preventive medicine. The women will
come for mammograms; they'll have their Pap smears and will be
evaluated by a cardiologist. In the past, they would do a chest
X-ray. But now they offer these people whole-body screening as one
extra check. In a way, it's almost like another lab test or another
physical examination. So, in addition to going to see the
physician, doing a physical examination, which isn't that
sensitive, you can do a CT scan, and you're little bit more
sensitive in that group of patients.
Then we have some other clinicians who are very proactive for
preventive health. They mention to the patients that they might
want to get their coronary screened. If they want to get their
coronary screened, they ask if they also want to get a full-body
We don't do self-referrals, and we don't advertise the screening
or try to encourage people to come in for it. But we do offer
Do you offer screening at Stanford?
GEOFFREY D. RUBIN, MD:
We do not do whole-body CT screening at Stanford, and we very
rarely do lung cancer screening studies. We do coronary calcium
screening studies, and virtual colonoscopies, and that's it with
the CT scanner.
I guess the interesting thing is when you break the things apart.
We don't do lung cancer screening, typically, either, except as
part of the National Lung Cancer Screening. We're also doing some
minority screening of HIV patients in terms of increased lung
cancer. It's a project that Lilly's just starting. But again, those
are high-risk groups. Of course, the data is going to come along,
as you are well aware.
I have no doubt that, in the long term, coronary screening is
going to be a routine study. With regard to CT colonoscopy, the
results of Perry Pickhardt's seem to be very, very strong. It's
almost to the point that if you do the coronaries and you do the
colon, in a sense, you are really screening the whole chest and
abdomen, basically, if you were doing just those two components,
right? If virtual colonoscopy became a mainstream study and
coronary screening became a mainstream study, you might get both of
those done at age 50. If you did the colon, you essentially get the
whole abdomen for free.
I disagree, because there are two big differences. Number one, at
least at this stage, to do the colon, you don't need to give
intravenous contrast. Number two, to sufficiently study the colon,
you can use a much lower radiation dose than you would to get a
diagnostic study of the solid organs of the abdomen. So I think
it's a pretty big jump to get a diagnostic study for finding renal
cell carcinomas, or small hepatic lesions, and such from a
What do you think?
STANLEY GOLDFARB, MD:
Well, let's use the examples of screening PSAs or mammography.
Could we have anything more controversial than identifying a
population of patients that really benefits from either of these
tests? Some high-risk patients have been identified in whom these
tests are quite useful. But for PSAs, for example, one could argue
endlessly about whether we are helping patients by taking out these
localized prostate cancers that were first identified by PSA. Only
about 4% of men die of prostate cancer, but 80% of men have
prostate cancer. So I think the problem is in identifying who
benefits from a screening test.
You pointed out that under ideal circumstances, as an expert
radiologist, you could look at these and make a really informed
decision about whether or not you should pursue an abnormality you
have identified. But that expertise may not be available at every
center, in every region in the country. So, therefore, you're going
to be left with harmless abnormalities that lead to surgery or
biopsy, and every one of those procedures is going to have an
associated morbidity and mortality with it. If you have a disease
that occurs in 1% of the population, and your test has a 1%
false-positive rate, every time you identify an abnormality, 50% of
the time it will represent a false-positive result. The key is to
study patients with a high pretest probability of the disease so
that a positive result is likely a true positive.
I personally would be happy to go to Johns Hopkins and have this
screening done because I am sure you have the expertise. On the
other hand, I really should not have the test done anywhere.
It's an interesting thing. It's like many things, looking at what's
good in a selfish way. There are two different things: What's good
for society, and what's good for you, the individual. So, as a
society, there's no doubt, that whole-body screening would be an
impossible thing to do, unless we had incredible computer-aided
detection and the cost of studies went down, etc.
But for an individual patient, you can think about it this way.
The second you're born, the only sure thing is that you're going to
die; the only thing we're really arguing about is when. We have no
control in some sense; genetics plays a major role in how long you
live. Then the question is what you can do to increase your odds of
picking up things that can be addressed, such as renal cancers.
There were a number of articles written in the past couple of
years about aortic aneurysms.
The Wall Street Journal
had a very good meta-analysis quoting the then
Journal of Surgery
that 15,000 people die each year of ruptured aortic aneurysms. All
of these patients could be screened, and 95% of the aneurysms could
be salvaged, because they'd be detected early. That's a true number
I agree that screening is a difficult thing to grasp, because
all you have to do is look, as you said, at mammography.
Mammography has been around forever. Every couple of years, the
question arises again: Is mammography screening worthwhile or not?
As you mentioned, PSA screening is a mainstream of modern medicine;
but is it worthwhile or not?
With whole-body CR screening, I think the question is whether or
not the fact we have the capability means that we should use it.
It's an argumentative question, really, because you're not going to
come to an answer. As Karen said, when we screen at Hopkins, we use
isosmolar contrast to make it the safest thing possible. Do you
have patients ask you about that?
Yes. They ask, and I tell them what I would do. I think that this
is a problem of being able to understand probabilities. It is a
question you tend to ask as an individual, and then you come to the
wrong answer as an individual, because this is an intuitive, rather
than a rigorous mathematical, assessment. I am probably as guilty
as anybody of reacting intuitively to data. But the truth is that
if you have a finding on a screening with a 1% false-positive rate,
a pretest probability of 1% that you have the illness, and say, a
10% complication of the therapy, and, it is counterproductive to go
ahead and pursue this test, because you're much more likely to hurt
yourself than you are to suffer from the disease. So having said
that, you then study specific illnesses, where you start to develop
the data that say it is a correct thing to do. For example, for
aortic aneurysms, if it is a specific diameter, we know the
probability that something of that size rupturing and, therefore,
you inform the patient that he has, say, a 25% chance of dying in
the next few years. If there is a 2% mortality of the surgery, the
odds are in his favor to pursue the surgery. But when it's a 1%
chance of rupturing, and a 2% percent chance of dying in the
surgery, it's not in his best interest to go ahead and intervene at
We need to develop such detailed information about each disease
that we might uncover in a screening test before we can advise
patients to help them make an informed decision about whether the
screening procedure makes sense.
JULIA FIELDING, MD:
We were talking earlier about how the public has changed and wants
more knowledge and more control over healthcare. My problem
initially with whole-body screening was that it was economically
driven. It was never driven from science; it was driven from
profit. That's how it started.
I thought it was a bad concept because it started for profit. So
I was worried about it that way. Then, of course, the issue of
screening healthy people is a big problem, too, since there is no
outcome data about whether or you're helping or hurting them. I
think that was why it became so contentious among our group,
because we had problems both on the economic front, and then also
the chance that we were going to hurt somebody.
It's interesting, too, because, in this case, the patients are in
control because they can pay their money and get it. Up to this
point, tests were what their doctor recommended: If you needed a
mammogram, the insurance paid. I remember talking to a group of
cardiologists when they first started doing coronary screening, and
half of them were for it, and half of them were against it. They
were arguing whether or not it was going to save lives. They were
arguing whether we should do it on the population basis, but they
all had theirs done because they wanted to know about
But that's my point. It's the rational behavior. Even though it's
done. Don't confuse what the physician does as necessarily being
I understand the dilemma here, but we can argue about opinions.
We should not be arguing about the facts. The facts are that we
don't know the outcome of some of these studies. For other studies,
however, we do know the outcome of screening. Screening for colon
cancer is incredibly sensible, and I get my colonoscopy as
frequently as my doctor tells me to.
You're the only person in America who does.
On PSA, I had a long discussion with my own physician on the
rationale for the test in my own case. I acceded to his request but
I do not personally think it was all that rational.
Well, PSA has become a cottage industry.
GOLDFARB: There is going to be a refinement of the test that
will allow it to be very, very helpful, as testing is for aortic
aneurysms. I think the question isn't so much whether you should
screen people; it's what should you screen them for and which
people should you screen. Unless you can answer that question with
some reliable data, you may be doing more harm than good.
Yes. With whole-body screening, it's interesting. The people who
went in it for the money are out of business, because whole-body
screening was much more logical at NASDAQ 5000, but now it's at
1500. So they're gone. The fact that some people said that 90% of
the studies were positive, that 80% or 90% of all normal people are
abnormal, is beyond reason. No, we don't spend 2 hours with every
The way we thought about it was to think about it as a lab test.
But instead of the lab test that's specific for one thing, it's
like when you go to a doctor at age 50 and they order a full
laboratory screening--they check every one of those boxes from PSAs
So think about whole-body screening in the same ways. You get
the coronaries and the whole vascular system, so cardiovascular
disease is the number-one thing to look for. You get the aorta and
get all of these different pieces. So if you really want to find
what the value is, you'd have the value after each one of those
things. Aortic aneurysm, what's the risk of that? Kidneys, what's
the risk of having a renal-cell carcinoma? Again, although 70% of
renal cell carcinomas are picked up by serendipity, on any 1
patient, to find one is going to be an incredibly small chance.
We're not looking for pancreatic cancers; but you can find them and
we all do. We've found a number of nonfunctioning islet cell
tumors. But again, you would almost need to say that too with every
single potential risk factor, if you did everything. As Karen said
about reading the studies, we all know colleagues, particularly
residents and fellows, who cannot read a CT scan as normal.
Another big thing in terms of having experience is, when you're
50 years old, unfortunately, you don't look the same as when you
were 20. So there's a normal CT scan for a 50-year-old, or a
60-year-old, and a normal scan for a 20-year-old. You just can't be
reading the scans as if it were age blind. So I think it will be
interesting to see what happens. Some centers do a lot of
whole-body screenings. The Mayo Clinic has a large screening
program. They do a lot of executive health and have very, very
strong patients who demand them. The original demand at Hopkins was
from Executive Health.
But this is another problem I had with this. I'm a dreamer or an
idealist, I guess. I had to ask if this was all about cash on the
barrelhead. It is not covered by any insurance, so you have to have
the money to pay for it. So you're automatically stratifying the
group because people who can pay are allowed to have this
technology. The people who can't pay are not allowed to have this
technology. I had a problem with that from the get-go in a state
At some point, and it's not my decision to make, that's going to
be a societal thing. It should also be determined whether or not
the test is beneficial to any particular group. But, right from the
beginning, you're saying, "I'm withholding this from you." I wasn't
ready to do that. To be honest with you, I'm in a state hospital. I
don't have a boutique practice. I have indigent care. I've got
people, illegal aliens, with active tuberculosis. I get all that
kind of stuff coming across the border all the time. So I don't
think it would be viable for us to do that, because we have 4
people who would come for it.
Well, we certainly don't live in a socialist country; we live in a
capitalist one. So I don't reject outright the notion that some
people can afford to pay for things that other people can't.
But we haven't made that decision in medicine yet.
I understand. But I wanted to get back to some of the comments that
Elliot was making. I still have concerns about this whole process,
mostly from the treatment end. For many cancers, you know what
they're going to do--they're going to grow, they're going to get to
advanced stage, and you need to take them out. Now, you can make
arguments about prostate cancer and renal-cell carcinoma as to
whether or not they're actually going to kill the patient, but
colon cancer, like many other cancers that we detect, is fatal if
But for the biggest killer of Americans, cardiovascular disease,
we really don't know what to do with the information from a
screening study. Even if we just take it down to the coronary
calcium question, experts suggest that the identification of
coronary calcium should allow for patients to be more aggressive in
modifying their risk factors. But, to date, I'm not aware of any
data to indicate that increasing statin therapy in patients with
high coronary calcium has resulted in a reduction in adverse
outcomes in those patients. Even though we can identify potential
algorithms, I don't think any of them have proven yet to be
If we take it to the next level of giving contrast medium and
looking for carotid stenoses or even coronary stenoses through
coronary CTA screening, the questions become even greater with more
uncertain outcomes. If we detect a 50% stenosis or a 30% stenosis
in the LAD of a patient, does that patient need to go to the cath
lab to be stented? What is it that we need to do? I think that it's
a big challenge. It's easy to look, but then you have to live with
whatever decision you're going to make, and we just don't have any
basis to make those decisions right now.
Geoff, I agree, I think it's a very controversial area and that
it's an area you're just never really going to have an answer for.
I think it's like a lot of medicine. How things are practiced and
why they're practiced is very variable, from medication to getting
PSAs, things that seem to be accepted are not often accepted, not
based on the best scientific evidence. But I think it's something
we all need to be aware of, and I think time will tell how well it
works. But I think it's of interest.
An overview of 64-slice CT technology