Development of new optical imaging systems of oxygen metabolism and simultaneous measurement in hemodynamic changes using awake mice

Abstract

Background: PET allows the measurement of CBF, CBV and CMRO2 in human and plays an important role in the diagnosis of pathologic conditions and clinical research. On the other hand, in animal studies, there is no optical imaging system for evaluating changes in CBF and CBV, and oxygen metabolism, from the same brain area under awake condition.

New method: In the present study, we developed a simultaneous measurement system of LSI and IOSI, which was verified by LDF. Moreover, to evaluate oxygen metabolism, FAI was performed from the same brain area as LSI and IOSI measurements.

Results: The change in CBF according to LSI was correlated with that by LDF. Similarly, the change in CBV obtained by IOSI was also correlated with RBC concentration change measured by LDF. The change in oxygen metabolism by FAI was associated with that in CBF obtained by LSI, although the change in CBF was greater than that in oxygen metabolism.

Comparison with existing method(s): We revealed that the relationship between oxygen metabolism and CBF as measured by our system was in good agreement with the relationship between CMRO2 and CBF in human PET studies.

Conclusions: Our measurement system of CBF, CBV and oxygen metabolism is not only useful for studying neurovascular coupling, but also easily corroborates human PET studies.

Keywords: Cerebral blood flow; Cerebral blood volume; Flavoprotein autofluorescence imaging; Intrinsic optical signal imaging; Laser speckle imaging; Oxygen metabolism.