Single photon emission tomographic imaging of myocardial perfusion with 99Tcm-labelled agents is usually performed with single-detector gamma camera systems and 180° anterior data collection. With multi-detector systems, reconstruction over 180° and 360° has been reported. We used a data set of normal subjects to compare both reconstruction methods. In addition, we tested an alternative approach, reconstructing data from 240° acquisitions, excluding the right posterior views, which provide little myocardial information and which are responsible for a reduced signal-to-noise ratio. On the transverse slices, the known apical distortion with the 180° reconstruction was not noted with the 360° or 240° reconstructions. Using semi-quantitative analysis of apical, mid-ventricular and basal short-axis slices, almost complete overlap was observed between the 240° and 360° circumferential profiles of our 20 normal volunteers, except in the inferior wall where a reduction in activity was noted. However, this rinding was less pronounced with the 240° than with the 180° reconstruction. The frequent reduction in activity in the anterior wall was more prominent with the 180° than with the 240° and 360° reconstructions. A 240° acquisition represents a useful compromise between 180° and 360° imaging protocols when a single-detector device is used, allowing more homogeneous tracer distribution and a reduction in the apical distortion without material change of contrast or doubling of the acquisition time.
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