Emerging CT technologies are improving cardiac imaging capabilities. Multi-detector spiral CT has increased slices from 4 to 64, improving spatial resolution but still limited by cardiac motion. Future technologies aim to image the whole heart in one beat through faster rotation and more slices to reduce motion artifacts. However, simply adding slices does not solve resolution and radiation issues. Significant advances in temporal resolution, better software, and single heart beat imaging are needed to optimize cardiac CT imaging.

1. Emerging CT
technologies are racing
to meet the future of
noninvasive cardiology
S. Achenbach
Disclosure: Research Support,
Siemens Medical Solutions

2. CARDIAC IMAGING:
- Complex Anatomy
- Small Dimensions
- Rapid Movement

3. Z
Continuous x-ray data
acquisition and table feed
Simultaneous recording of
ECG signal
Multi-Detector Spiral/Helical CT

4. Z
Continuous x-ray data
acquisition and table feed
Simultaneous recording of
ECG signal
ECG-gated image
reonstruction
Multi-Detector Spiral/Helical CT

5. Z
Continuous x-ray data
acquisition and table feed
Simultaneous recording of
ECG signal
ECG-gated image
reonstruction
Partial scan reconstruction
Multi-Detector Spiral/Helical CT

6. 16-slice MSCT:
370-500 ms rotation
16 x 0.5-0.75 mm collimation
~ 18 s breathhold, 80 - 100 ml of contrast
64-slice MSCT:
330-420 ms rotation
64 x 0.5-0.6 mm collimation
~ 6-12 s breathhold, 50-70 ml of contrast

7. 16-slice MSCT:
370-500 ms rotation
16 x 0.5-0.75 mm collimation
~ 18 s breathhold, 80 - 100 ml of contrast
64-slice MSCT:
330-420 ms rotation
64 x 0.5-0.6 mm collimation
~ 6-12 s breathhold, 50-70 ml of contrast
Spatial resolution:
0.4 mm x 0.4 mm x 0.4 mm
Temporal resolution: ~165 ms

8. EBT (3mm) 4 slice (1.25mm) 16 slice (0.75mm) 64 slice (0.6mm)
1994 2000 2002
2004

9. EBT (3mm) 4 slice (1.25mm) 16 slice (0.75mm) 64 slice (0.6mm)
1994 2000 2002
2004

10. 96-99% negative
predictive value for
detection of
coronary stenoses
Mollet et al, JACC 2005
Morgan-Hughes et al, Heart 2005
Kuettner et al, JACC 2005
Achenbach et al, Eur Heart J 2005
Hoffmann et al, JAMA 2005
Raff et al, JACC 2005
Leschke et al, Eur Heart J 2005
Leber et al, JACC 2005
Mollet et al, Circulation 2005

11. 96-100% sensitivity
for bypass graft
occlusion
Nieman et al, Radiology 2003
Schlosser et al, JACC 2004,
Martuscelli et al, Circulation 2004
Chiurlia et al, AJC 2005

13. Limited spatial and
temporal resolution
as compared to
- cardiac cath
- size and speed of
coronary arteries
-

15. LIMITATIONS:
Motion artifacts -- heart rate -- temporal res.
Spatial resolution -- radiation
Several heart beats -- arrhythmias

16. FUTURE PATHS:
> 64 slices: shorter breathhold /
less contrast
>> 64 slices: one heart beat (120 mm)?
< 0.5 mm slices: spatial resolution – radiation!
Faster rotation: better temporal resolution

17. FUTURE PATHS:
Better temporal resolution
=> Prospective triggering
=> Less radiation
=> Thinner slices?

18. We will see:
Up to 256-slice scanners
Faster temporal resolution
Better software
Heart 2005

19. We will see:
Up to 256-slice scanners
Faster temporal resolution
Better software

20. We will see:
Up to 256-slice scanners
Faster temporal resolution
Better software Heart Phantom with Stent at 95bpm
Sensation 64, 165ms 83ms

21. SUMMARY
Temporal resolution and spatial resolution
as well as radiation/noise are issues in
cardiac CT
Simply adding more slices will not solve
the major problems
=> One heart beat (256 sl.)
=> Temporal resolution
=> COST?

22. 2005
10 years
1995

23. 2005
10 years 10 years
2015
?
1995

24. Education, carefully performed studies,
and good guidelines will be at least as
important as new technology..

25. www.SCCT.org
Society of Cardiovascular CT