Two basic questions usually neglected: the definition of the technical parameters and contrast injection.

In their article published online on 19 April 2005, Leschka et al. 1 shared the first experience of the new 64-slice MSCT. The adequate sample size and evaluation of performance without beta-blocker make the article of high reference value. However, we have several questions to the authors. First, the authors mentioned that the scanner was a 64-MSCT with only 32-detector rows. About the collimation, though the z-sharp technology is used, the total collimation will not be doubled.2 The actual coverage of the collimation should be 32×0.6 mm, but the authors chose to represent it as 64×0.6 mm2, which is …