1. MRI was first developed in 1946 and has since evolved into a powerful non-invasive diagnostic tool known as magnetic resonance imaging (MRI). 2. In the early 1980s, researchers began exploring applications of MRI in cardiovascular medicine such as detecting structural abnormalities, tissue characterization, and evaluating patients with known or suspected coronary artery disease. 3. A 1991 study demonstrated MRI's ability to correctly identify substantial coronary artery stenosis, and a 1993 study showed MRI could provide visualization of major epicardial vessels in a single breath-hold.

1. Editorial Slides
VP Watch, December 31, 2001, Volume 1, Issue 39
MRI Scanner; Should Cardiologists
Have One?!

2.  The first successful nuclear magnetic resonance (NMR)
experiment was made in 1946 independently by two
scientists in the United States. Felix Bloch, working at
Stanford University, and Edward Purcell, from Harvard
University, found that when certain nuclei were placed in a
magnetic field they absorbed energy in the radiofrequency
range of the electromagnetic spectrum, and re-emitted this
energy when the nuclei transferred to their original state. For
this discovery Bloch and Purcell were awarded the Nobel
Prize for Physics in 1952.1
 Evolution of the above discovery to magnetic resonance
imaging (MRI) as the most powerful non-invasive clinical
diagnostic tool, is best owed to many scientists world wide.1

3.  In the past two decades, MRI has been slowly
introduced into the world of cardiovascular medicine.
 In early 1980s Higgins and others envisioned MRI
applications for detection of cardiac structural
abnormalities (such as congenital anomalies) as well as
acute and remote myocardial infarctions, atherosclerotic
plaques, hypertrophic cardiomyopathy, pericardial
diseases, aneurysms, and patency of bypass graft. They
also suggested that diagnostic utility of MRI includes
direct tissue characterization, and such utility may be
further extended by the use of paramagnetic contrast
media. 2

4.  In 1991, Manning et al. demonstrated the
power of noninvasive MRI coronary
angiography to identify substantial
stenosis correctly within the proximal
portion of major coronary arteries in a
group of patients undergoing conventional
contrast coronary angiography. Other
investigators also introduced MRI
application in non-invasive coronary
imaging.3,4,5

5.  In 1993, Manning et al. showed that
single breath-hold MR coronary
angiography provides visualization of
the major epicardial vessels,
suggesting MR coronary angiography
may provide a noninvasive means for
the evaluation of patients with known
or suspected coronary artery
disease.6

6.  Despite the feasibility studies shown by
Manning and others years ago, the idea of
non-invasive coronary angiography by
MRI has not been clinically adapted.
 However, several other novel clinical
applications for MRI in cardiovascular
medicine have rapidly developed in the
recent years. (see next table)
 Similar rapid progress in cardiovascular
imaging has been accomplished through
other imaging modalities, in particular CT.

7. Adapted from: Philips Medical System, Intera CV, 2001

8.  As highlighted in this week of VP Watch,
Manning et al. reported non-invasive coronary
MRA as a new clinically available tool for
screening coronary artery stenosis (particularly
left main and 3-vessel) among high risk
patients.7
 They found that the sensitivity, specificity, and
accuracy of MRA for patients with stenotic
disease of the left main coronary artery or 3-
vessel disease were 100% (95% confidence
interval, 97-100%), 85% (95% confidence
interval, 78-92%), and 87% (95% confidence
interval, 81-93%), respectively.7

9.  Overall, coronary magnetic resonance
angiography had an accuracy of 72% (95%
confidence interval, 63-81%) in diagnosing
coronary artery disease.7
 The sensitivity, specificity, and accuracy for
patients with disease of the left main coronary
artery or 3-vessel disease were 100% (95%
confidence interval, 97-100%), 85% (78-
92%), and 87% (81-93%), respectively.7

10.  The negative predictive values for
any coronary artery disease and for
left main artery or 3-vessel disease
were 81% (95% confidence interval,
73-89 %) and 100% (95%
confidence interval, 97-100%),
respectively.7

11. Conclusion:
I. Coronary MRA has shown significant accuracy for
detection of luminal stenosis in proximal portions of
epicardial arteries with profound negative predictive
value.
II. The publication of Manning et al in The New England
Journal of Medicine this week can open the road to
widespread use of MRI as a reliable clinical tool
available to cardiologists for non-invasive diagnosis of
coronary artery stenosis in selected patients.

12. Questions:
1- The long-waiting dream of a non-invasive
angiography technique for accurate diagnosis of
coronary stenosis seems to be close to cardiologists’
hands, the question is how well this tool can identify
angiographically invisible vulnerable plaques.
2- Although coronary stenosis is a surrogate marker of
vulnerable plaques and vulnerability of coronary
arteries, between MR angiography and MR plaque
characterization which one seems to be more
important for diagnosis of vulnerable patients?

13. Questions:
3- CT (MSCT and EBCT) is expected to offer similar
clinical tool for non-invasive coronary angiography
most likely at lower cost and faster technique, what
would be the advantage of coronary MRA over CT
MRA?
4- Should cardiologists buy cardiac MRI scanner, wait
for cardiac CT scanner, or send Dx request to
radiologists?!

14. Suggestion:
VP.org Editorial Suggestion:
- In addition to non-imaging screening tools, develop a
novel composite CHD risk score for coronary imaging
diagnostic tools combining luminal narrowing, wall
(plaque) vulnerability, and heamodynamic factors.
- MRI and CT industries are suggested to provide
more easily reproducible and most automated
imaging techniques (software) to allow widespread
clinical application of these emerging technologies.
Please email your thoughts to:
Discussion-Group@VP.org or DG@VP.org

15. 1. Imaging Science and Biomedical Engineering, University of Manchester; History of MRI:
http://www.isbe.man.ac.uk
2. McNamara MT, Higgins CB.; Cardiovascular applications of magnetic resonance imaging.
Magn Reson Imaging. 1984;2(3):167-83.
3. Manning WJ, Li W, Edelman RR. A preliminary report comparing magnetic resonance coronary
angiography with conventional angiography. N Engl J Med 1993;328:828-832.
4. Manning WJ, Atkinson DJ, Grossman W, Paulin S, Edelman RR.; First-pass nuclear magnetic
resonance imaging studies using gadolinium-DTPA in patients with coronary artery disease. J Am
Coll Cardiol. 1991 Oct;18(4):959-65.
5. Burstein D; MR imaging of coronary artery flow in isolated and in vivo hearts. J Magn Reson
Imaging. 1991 May-Jun;1(3):337-46.
6. Manning WJ, Li W, Boyle NG, Edelman RR. Fat-suppressed breath-hold magnetic resonance
coronary angiography. Circulation. 1993 Jan;87(1):94-104.
7. W. Yong Kim, M.D., Ph.D., Peter G. Danias, M.D., Ph.D., Matthias Stuber, Ph.D., Scott D. Flamm,
M.D., Sven Plein, M.D., Eike Nagel, M.D., Susan E. Langerak, M.Sc., Oliver M. Weber, Ph.D., Erik
M. Pedersen, M.D., Ph.D., Matthias Schmidt, M.D., René M. Botnar, Ph.D., and Warren J. Manning,
M.D. Coronary Magnetic Resonance Angiography for the Detection of Coronary Stenose; New
England Journal of Medicine 2001; 345(26):1863-1869
References

16. Vision of Yesterday, Realized Today!
Courtesy of Dr. Chun Yuan
University of Washington