This article by George RT et al from Johns Hopkins, published in the July issue of JACC, is a study using 64-slice CT, on a Toshiba scanner to assess the utility of adenosine stress MDCT as compared to microsphere myocardial blood flow (MBF) measurements.
The study was performed in dogs and the conditions during practical human scanning were simulated. Perfusion defects were very well seen and appreciated and a semi-quantitative analysis was also performed by comparing this defect to normal perfused myocardium. To get good pictures, beta blockers were used, which can dampen the effect of adenosine, though practically it didn't seem to make a difference in this article.
In practice, this may actually work with dual-source CT, since if the effect of heart rate is eliminated, adenosine can be used with impunity to give us a combined stress perfusion scan with an angiogram study with one injection of contrast and one run.
An interesting Japanese article is available which talks of a similar study - this is free full-text.
George RT and Lardo AC, Johns Hopkins University have been kind enough to lend this image. "These are two MDCT perfusion images from the same animal. The animal had an mid LAD stenosis and imaging was performed according to the protocol described in the JACC paper during adenosine infusion. The image on the left is a multi-planar reconstructed image in the cardiac short axis showing a clear perfusion defect in the anteroseptal, anterior, and anterolateral walls. The image on the right is a color coded map that assigns a color scale to the attenuation density measured in hounsfield units."