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Electron
Beam CT (EBCT) vs. Multi-Detector Row CT (MDCT)
1. What are your thoughts about the use of the "new" electron
beam CT equipment in terms of coronary, carotid, renal and peripheral
CT angio when compared to the evolving multihead detector CT technology.
GE is trying to sell EBA as a "better", "faster",
"easier" alternative…especially for non-radiologists
(e.g. cardiologists, vascular surgeons). Is EBA really a reasonable
alternative?
| Answer:
The electron beam is a good scanner for doing coronary artery
calcification because of its speed. However, because of its limited
resolution, I would not use it for CT angiography. |
2.
I have seen advertisements for electron beam tomography. How does
EBCT scanning compare with CT scanning for various diagnostic scans?
| Answer:
For cardiac scoring they are both the same, but for anything else,
go with MDCT. |
3.
Could you tell me if it is really true that EBCT is the only FDA approved
scanning technique at this point for Cardiac Scoring? I've also heard
that multi-slice scanners have a greater percentage of error in scoring
due to the fact that although the scan is gated, the scans are matched
up in post processing vs. real time gating. Could you share your thoughts?
| Answer:
To my knowledge, the FDA has not approved one scanner over the
others. Both multidetector and EBCT have similar results for coronary
calcification scoring. |
References
Kopp AF, Ohnesorge B, Becker C et al. Reproducibility and accuracy
of coronary calcium measurements with multi-detector row versus Electron
Beam CT. Radiology 2002; 225 (1): 113-119.
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Summary:
EBCT and MDCT scanners were used to image a phantom which mimicked
a beating heart, with a number of protocols and a variety of pulse
rates. Acquisition times, reproducibility and accuracy of coronary
artery calcium measurements were compared. The MDCT acquisition
times were significantly shorter: "Our study showed that nonoverlapping
sequential scanning is the most important contributor to the interexamination
variability of Agatston and volumetric calcium scores, because of
partial volume errors in plaque registration. We demonstrated that
coupling retrospective gating with nearly isotropic volumetric imaging
data by using spiral multi-detector row CT provided the best input
data for quantification of CAC volume." By obtaining EKG-gated
volume datasets with overlapping reconstructions (2.5 mm collimation,
1.0 mm increment), the mean interexamination variability was reduced
from 35% to 4%.
Schoenhagen
P, Halliburton SS, Stillman AE et al. Noninvasive imaging of coronary
arteries: Current and future role of multi-detector row CT. Radiology
2004; 232(1): 7-17.
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Summary:
The introduction of this article provides a nice overview of EBCT
and MDCT, comparing technique, strengths and weaknesses. EBCT has
better temporal resolution; however, the advantages of MDCT include
higher signal-to-noise ratio, higher spatial resolution and faster
scan time.
Hunold
P, Vogt FA, Schmermund A et al. Radiation exposure during cardiac CT:
Effective doses at multi-detector row CT and electron-beam CT. Radiology
2003; 226: 145-152.
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Summary: This study compared the effective dose from electron-beam
CT, multi-detector row CT and catheter coronary angiography. A phantom
was scanned with protocols for calcium scoring and coronary angiography.
The MDCT unit was a 4 slice scanner, and the protocols were: calcium
scoring 4 x 2.5 mm acquisition; CT angiography 4 x 1 mm acquisition.
EBCT resulted in lower doses for both coronary artery calcium (CAC)
scoring (1.0 to 1.3 mSv) and EBCT angiography (1.5 to 2 mSv) compared
to MDCT (1.5 to 6.2 mSv for CAC; 6.7 to 13 mSv for MDCT angiography).
In addition, the dose from 4 slice MDCT was higher than that from
catheter coronary angiography (2.1 to 2.5 mSv).
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