Whole body CT screening

1. WHOLE BODY SCREENING –
RISKS AND BENEFITS
Wan Najwa Zaini Wan Mohamed, Radiologist, JPD HQE 2

2. US AIRPORT’S WHOLE BODY IMAGING

3. US AIRPORT’S WHOLE BODY IMAGING
Problems:
•Privacy Concerns
•Health Concerns
•Scanner Effectiveness
•Security Delays
•Staff Requirements, Workload

4. US AIRPORT’S WHOLE BODY IMAGING
•Nov 2010 Campaign - Stop whole
body imaging in U.S. airports! Join
National Opt-Out Day
•2013 – 250 backscatter scan
machines removed from US airports

5. WHOLE BODY SCREENING
1. INTRODUCTION
2. PRINCIPLES IN SCREENING
3. RADIATION ISSUES IN CT
4. COST ISSUES
5. THE DEBATE: THE PROS AND CONS
6. CURRENT POLICIES
7. THE FUTURE OF WHOLE BODY IMAGING

6. Whole Body Screening
INTRODUCTION

7. INTRODUCTION
 Sectional imaging such as Computed Tomography
(CT) or Magnetic Resonance Imaging (MRI) have
revolutionized the capabilities for imaging, image
guided therapeutic intervention and improved
targeted radiation therapy.
 The CT scan is much more widely available than
the MRI
 Has benefitted many patients – clinching the
diagnosis, guiding surgery, providing a road map,
staging a disease more accurately and allowing
radiation therapy to proceed more precisely.

8. INTRODUCTION
 Many varieties available – single, spiral, multislice,
dual source technology, electron beam CT.
 Faster and rapid scan time in millisecond or sub
second duration.
 Allows elegant multiplanar and 3D reconstructions
e.g. Virtual colonoscopy.
 Not surprising that CT scan has now been explored
and employed in whole body screening
programmes – to detect diseases before they
become more advanced

9. INTRODUCTION
 First public appearance in a Wall Street Journal
article published in early 2000 – reported on the
efforts of several radiologists who were seeking to
make CT part of preventive medicine programs.
 Many CT screening centres have sprouted up
based on the promise of wellness screening.
 As whole body CT is being marketed directly to
consumers, the consumers (patients) are now
beginning to demand the test.

10. INTRODUCTION
 Yet, several questions have not been
answered adequately for WBCT screening:
1. Large scale randomized clinical trials (RCT) for
evaluation of whole body screening in apparently
healthy individual has not been published to date.
2. Should intravenous contrast media be used for all
whole body screening CT scans?
3. Guidelines that exist for follow up or further
evaluation for overall WBCT screening when
abnormalities are detected, e.g. callback rate.

11. INTRODUCTION
4. Cost effectiveness of whole body screening CT
5. Indices for whole body CT such as negative
predictive rate, sensitivity, specificity, false
negative, false positive and others are unknown.

12. Whole Body Screening
PRINCIPLES IN SCREENING

13. PRINCIPLES IN SCREENING
 What is a screening test?
 a test, procedure or investigation that is used to
look for disease before it manifests with signs
and symptoms.
 can be applied to the whole population or to a
subset of the population
 is considered effective if it reduces deaths from
the disease being screened for

14. PRINCIPLES IN SCREENING
 Main considerations:
1. Does the disease merit screening? A disease that
is so slowly progressing that treating it early may not make
a difference to the lifespan.
2. Is there a reliable screening test for the
disease in question? The false positive and false
negative rates, positive and negative predictive values and
accuracy are important parameters.
3. Is there available and effective intervention/
treatment for the disease in question, if
detected early? No point in screening if there is no
cure or effective treatment.

15. PRINCIPLES IN SCREENING
 Therefore, screening should not be taken
lightly and requires careful cost-benefit
analysis.
 For individuals opting for any screening
test/procedure/investigation, they should be
counseled as to the pros and cons, benefits
and risks (if any) entailed in the process.

16. Whole Body Screening
RADIATION ISSUES IN CT

17. RADIATION ISSUES IN CT
 Estimated effective doses from diagnostic CT
procedures: 1 to 10 milliSieverts (mSv)
 A CT examination with an effective dose of
10 mSv may be associated with an increased
risk of fatal cancer of approximately 1 chance
in 2000.
 CT scan must only be performed when the
benefits outweigh the risks

18. RADIATION ISSUES IN CT
 The amount of radiation dose received by the
patient is variable by a factor of 10, depending
on the patient’s size, make and type of CT
scanner, scanning parameters and body part.
 CT studies account for the largest population
radiation dose from medical diagnostic studies.
 Based on UNSCEAR 2000 Report on Sources
And Effects of Ionising Radiation: CT studies
are increasing rapidly over the years from 14%
in the period 1955-1990 to 33% in the period
1991-1996

19. Whole Body Screening
COST ISSUES

20. COST ISSUES
 When an abnormality is detected, the follow-up
tests and treatment can be costly.
 Insurance companies are more likely to cover
the cost of further testing if the screening study
is positive, but there is no assurance that they
will cover the entire cost.
 Self-referred whole-body CT itself is not
covered.
 Undoubtedly will increase overall healthcare
expenditures.

21. COST ISSUES

22. Whole Body Screening
THE DEBATE: THE PROS AND THE CONS

24. THE DEBATE: THE PROS AND THE CONS
 Researchers, physicians and healthcare
administrators across the globe are engaging in
healthy scientific discourse about the
controversies and issues surrounding whole-
body CT screening.
 Experts participated in a recent panel
discussion on CT screening at the 2002
scientific assembly and annual meeting of the
Radiological Society of North America (RSNA
2002), and research studies on the topic
continue to be published in scientific and
medical journals.

25. THE PROS
 Dr. Michael Brant-Zawadzki, a radiologist with
wide experience in targeted CT screening as
well as whole-body CT, has found that in
screening self-referred patients older than 40
years, about one in a hundred will be found to
have a cancer.
 Cancers of the lung and kidney are among the
most common to be detected, but pancreatic
cancer, potentially dangerous lesions of the
abdominal aorta called aneurysms, and
lymphoma,, also have been found by screening
CT (RadioGraphics 2002;22:1532-39).

26. THE PROS
 Dr. Brant-Zawadzki cites a study carried out
at the Mayo Clinic reporting that, when CT
screening for lung cancer was extended to
the pelvic region, 14% of those examined
were found to have clinically significant
abnormalities.

27. THE CONS
 Dr. E. Stephen Amis Jr., estimates that as
many as 80 percent of abnormalities
detected by whole-body CT may not be life-
threatening.
 In a study presented at RSNA 2002, more
than one-third of nearly 1,200 patients were
referred for follow-up studies (Casola et al.).
These patients may suffer considerable
anxiety, and some of the follow-up tests
themselves involve an element of risk.

28. THE CONS
 Surgery, for instance, carries risks of an adverse
reaction to anesthesia, bleeding, infection, and
scarring.
 Additional radiologic exams increase total
radiation exposure, and there is a chance of an
allergic reaction if contrast material is injected.
 The other major concern about whole-body CT
is that a reading of "normal" may be incorrect
and, as a result, patients will be falsely
reassured (false negative).

29. THE CONS
 The fact that no intravenous contrast material
is used in whole-body CT has been held out
as an advantage, but non-contrast scans of
the abdomen and pelvis provide only limited
information. Small lesions in the liver,
kidneys, or pancreas may readily be missed.
 There is good reason not to screen persons
younger than 40 years, as the yield of
significant disease will be extremely low.

30. Whole Body Screening
CURRENT POLICIES

31. CURRENT POLICIES
 In all medical procedures, there must be
indications and justification for its use.
 Consideration of the available resources
versus clinically useful information that alters
management inclusive of financial and safety
issues cannot be compromised.
 This is even more imperative with medical
procedures requiring ionizing radiation.

32. CURRENT POLICIES
 Justification, Optimisation and Dose
Limitation remains the main tenets for
radiology practitioners.
 In clinical scenarios where benefit exceeds
risks and further management of the patient
is dependent on information gleaned from
the CT scan, then the examination is deemed
justified.
 CT scans should be performed keeping in
mind the principle of ALARA.

33. CURRENT POLICIES
 Where CT may be considered appropriate for
screening:
 Cardiac – Calcium scoring, CT Angiogram
 Colon– Virtual Colonography
 Lung – still controversial
Targeted CT screening procedures

34. CURRENT POLICIES
 Targeted CT screening procedure
 CT Cardiac – Calcium scoring
 most useful for patients with a medium risk level for
coronary artery disease
 total calcium score greater than 400 HU (by Agatston
method)
 Cardiac CT Angiogram
 to detect significant coronary artery stenosis
 only asymptomatic and low to moderate
cardiovascular risk patients with positive stress ECG

35. CURRENT POLICIES
 CT Colonography (Virtual Colonoscopy)
 radiation dose ranges from 1.8mSv to 15 mSv.
 average 8 mSv (barium enema 7 mSv).
 to detect polyps and early colonic cancers
 Can be considered if part of a programme for
colorectal cancer screening
 For average-risk individuals 50 years and older

36. CURRENT POLICIES
 CT Lung
 to detect early lung cancers
 Still controvertial even if applied in high risk
individuals (e.g. smokers)
 ongoing trials in screening lung CT in the at risk
population for example the National Lung
Screening Trial in the USA

37. CURRENT POLICIES
 Whole Body Screening in the Healthy/
Asymptomatic Individual
 To date, the College of Radiology (CoR) does
not see any clear benefit from whole body
screening CT scans in healthy individuals.
 The CoR does not recommend whole body
screening CT scan including routine CT lung in
healthy asymptomatic individuals in the absence
of risk factors as the risks outweigh the potential
benefits.

38. CURRENT POLICIES
 The appropriateness of CT screening
examinations may change with new
evidence, improvements or changes in CT
technology, disease pattern, type, treatment
and various other factors.
 The American College of Radiology (ACR)
believes that there is insufficient evidence
showing that whole-body CT screening
prolongs life or is cost-efficient.

39. CURRENT POLICIES
 The ACR takes the position that whole-body CT
cannot be recommended for those who lack
symptoms and who have no family history of
disease.
 Many findings that will not affect patients' health will
nevertheless cause anxiety, lead to unnecessary
follow-up examinations and treatments, and waste
money.
 The U.S. Food and Drug Administration (FDA)
concurs that whole-body CT has not been
convincingly shown to detect disease early enough
to spare patients from serious illness or premature
death.

40. CURRENT POLICIES
 Even if such benefit is demonstrated, states the
FDA, it might not be great enough to offset
potential harm from screening.
 The FDA has said that a CT finding of
abnormality despite the absence of significant
disease is far likelier than the discovery of
actual life-threatening disease.
 Even if a serious condition is found, the patient
will benefit only if there is effective treatment
and if the disease is found early enough to
respond to this treatment.

41. CURRENT POLICIES

42. Whole Body Screening
THE FUTURE OF WHOLE BODY SCREENING

43. THE FUTURE OF WHOLE BODY SCREENING
 New CT scanners currently under development
will reduce the amount of radiation. If screening
is limited to persons older than 50 years,
exposing children or women of childbearing age
will not be an issue.
 Future scanning may routinely include the use
of oral and intravenous contrast material.
Results could be reported to a central database
so as to better determine the effectiveness of
whole-body CT.

44. THE FUTURE OF WHOLE BODY IMAGING
 MRI
 Superior to CT in many ways
 But, more expensive, not readily available in
all centres, time consuming, difficult to
perform
 Imaging of the lung was suboptimal
 However, with the recent breakthrough in MR
technology, whole body, high-quality MRI
screening is now feasible.

45. THE FUTURE OF WHOLE BODY IMAGING
 the MR systems manufactured nowadays
allow much faster imaging of the entire body,
while maintaining high image quality that
even machines made 1 year ago did not
possess.
 Basically, new designs of transmit-receiver
coils, easier movement of the imaging table,
and new data-acquisition techniques have
allowed rapid imaging of the entire body as
well as acceptable image quality of the lungs.

46. THE FUTURE OF WHOLE BODY IMAGING
 High-quality, whole body MRI imaging that
would take 2 hours even 1 year ago now can
be done in 10-15 minutes, making the
technique very suitable for rapid, highly
accurate whole body imaging in an easily
tolerable time frame.
 It remains to be seen if the public will
demand screening with whole body MRI
because of its superiority of disease
detection and higher safety than that offered
by CT.

47. THE FUTURE OF WHOLE BODY IMAGING

48. THANK YOU FOR YOUR ATTENTION