This is one more article from Japan, by Yamamuro M, in the February issue of Radiology, on an 8-slice CT using segment reconstruction techniques, comparing cardiac CT to SPECT and CMR (the gold standard) in assessing ejection fraction and volumes.
The found excellent correlation with CMR with results better than with SPECT. The authors did not find the overestimation of systolic volumes and consequent underestimation of the ejection fraction, that has been the general problem in practice and with other authors. They ascribe this to the use of segmental reconstruction techniques, but as shown in the earlier post on the article in European Radiology, that does not seem to make much of a difference.
The use of segmental reconstruction techniques would help only with high heart rates. With low heart rates, in any case only single or at the most two segment reconstruction can be performed and most of the earlier studies have controlled heart rate using beta-blockers. This argument by the authors does not seem to make sense.
For the time being, it would be better to assume that there is some underestimation of the ejection fraction on cardiac CT as compared to CMR.