When performing a PA region analysis on a Oxy-Hemo Mode datasets, what is the difference between sO2 Avr and sO2 Avr Total? What is the difference between HbT Avr and HbT?
sO2 Avr measurements represent the average oxygen saturation levels within your tissue, excluding %sO2 values of zero. In contrast, sO2 Avr Total measurements represent the average oxygen saturation levels within the tissue, including areas where %sO2 values of zero exists. Therefore, sO2 Avr may provide a better indication of blood oxygenation, whereas sO2 Avr Total may provide a better indication of tissue oxygenation.
If for example, the target tissue displays large areas with no oxygenation signal, this is important information on what is going on overall (average total).
The sO2 average gives information about the areas that actually are oxygenated.
The combination of the two is a good thing to have - especially since it takes just one click to switch between them, with no extra experiments.
HbT Avr is similar to sO2 Avr in that it provides the average HbT signal in the tissue of interest (however, no zero HbT values exist). In contrast, HbT is the sum of the HbT values for each pixel within the PA region, which is why it is such a large number.