Demystifying dyssynchrony for diagnosis and prognosis: Tips for measuring heterogeneous phase distribution

Excerpt

Scintigraphic patterns can be visually assessed with reasonable accuracy. For example, radionuclide distribution on a scintigraphic image can easily be visually defined as heterogeneous. However, the quantitation of heterogeneity on nuclear medicine images has remained an important and complex issue. Region-of-interest analysis that provides mean, maximum, minimum, and standard deviation (SD) is the most popular means of evaluating regional data, but these variables do not reflect all image features, and minor abnormalities in distribution cannot be precisely quantified using these conventional variables. Consider a situation where minor changes in heterogeneous distribution can be visually identified on myocardial perfusion images of patients with cardiomyopathy. For example, the average of individual segments in a 17-segment model of polar maps cannot so clearly identify an obvious visible abnormality. …