SHAPE Society

1. Non-Invasive Imaging of the
Vulnerable Plaque and the
Vulnerable Patient
Non-invasive coronary angiography by CT and EBT
David G. King;
Director, Clinical Sciences
GE Imatron

2. Acknowledgements:
John Rumberger:
“The tip of the iceberg” ….
20%20%

3. 66%66%
33%33%
20%20%
Lipid RichLipid Rich
FibroticFibrotic
Fibrotic &Fibrotic &
CalcifiedCalcified
The “Tip of theThe “Tip of the
AtheroscleroticAtherosclerotic
IcebergIceberg””
Coronary Artery Plaque:Coronary Artery Plaque:
approximate amounts of lipid rich, fibrotic and calcified plaqueapproximate amounts of lipid rich, fibrotic and calcified plaque
PlaquePlaque
DetectableDetectable
by Intravascularby Intravascular
Ultrasound,Ultrasound,
PathologyPathology
PlaquePlaque
DetectableDetectable
by EBTby EBT

4. Acknowledgements:
John Rumberger:
“The tip of the iceberg” …..
“The Vulnerable Patient” ….. Jim Fixx,
1932-1984
Sir Winston Churchill
1874-1965

5. Non-calcified plaque components by EBT
Clinical significance unclear!

6. Points for discussion
Why non-invasive CTA?
Who/what needs to be imaged?
What needs to be measured?
How can the patient outcome be
changed as a result?
EBT 50 ms movie

7. Points for discussion
Critical scanning parameters?
Scan speed
Triggering
Slice width
Image noise
Best use of dose delivered?
With or w/o contrast injection? EBT 50 ms movie

8. Points for discussion
Optimum display of results:
Volume rendered?
Multiplanar reconstructions?
Maximum intensity projection?
Density distribution analysis?
EBT 50 ms movie

9. MSCT: LightSpeed – longer exposure,
improved contrast resolution
Soft Plaque with Central Ulcer
Courtesy of Dr. Dowe, Atlantic Medical Imaging

10. Courtesy Dr. Sablayrolles Centre Cardiologique du Nord – Saint Denis
MSCT: SnapShot LightSpeed Ultra
Stenosis in LAD 2nd
Segment

11. Non-contrast EBT or EBA?
CAC study 50 ms EBA movie

12. Non-calcified ROI analysis
NormalNormal
CorAthCorAth
Courtesy L.` Teichholz, MD
Density distribution in CAC studies

13. Density distribution
• The mean voxel intensity (HU) within the ROI in
the proximal LAD is lower in patients with disease
as compared to normals (p<0.005).
• The standard deviation of voxel intensities (HU)
within the ROI in the proximal LAD is higher in
patients with disease as compared to normals
(p<0.00001).
• The percent of voxels with HU < 0 within the ROI
in the proximal LAD is higher in patients with
disease as compared to normals (p<0.00001).
Courtesy L. Teichholz, MD

14. Contrast-enhanced EBA
High speed & thin slices,
yield improved spatial
resolution
Venous branches, motion –
diagnostic value?

15. The need for speed
300 msec 250 msec 200 msec 150 msec 100 msec 50 msec

16. Phantom “stenoses”
Requires coronary angiography?
250 msec 100 msec 50 msec
???
???

17. Conclusions
• Benefits of high resolution
coronary vessel imaging:
– Learn more about the
atherosclerotic disease
process, hard & soft plaque
– Steer high risk subjects
towards the appropriate
intervention
– Reassure those with low
probability of obstruction
– Keep the “normals” out of
the cathlab