Noninvasive photoacoustic microscopy of methemoglobin in vivo
Various causes can lead to methemoglobinemia, and it has the potential to be confused with other diseases. In vivo measurements of methemoglobin have significant applications in the clinics. We quantified the average and the distributed percentage of methemoglobin both in vitro and in vivo using photoacoustic microscopy (PAM). Based on the absorption spectra of methemoglobin, oxyhemoglobin, and deoxyhemoglobin, three wavelengths were chosen to differentiate methemoglobin from the others. We imaged the methemoglobin percentage in microtubes that mimicked blood vessels as a phantom experiment. The methemoglobin concentrations calculated from the photoacoustic signals were in accordance with the preset concentrations. We also demonstrated the ability of PAM to quantitatively image methemoglobin distribution in vivo in a mouse ear.
Additional Information© 2015 Society of Photo-Optical Instrumentation Engineers. The authors gratefully acknowledge the suggestions made by the reviewers of this manuscript, and by Prof. James Ballard at Washington University in St. Louis. This research was supported in part by National Institutes of Health grants DP1 EB016986, R01 CA186567, U01 NS090579, R01 EB016963, R01 EB010049, R01 CA157277, S10 RR028864, S10 RR026922, and R01 CA159959 as well as National Science Foundation grant 1255930. L.W. has a financial interest in Microphotoacoustics, Inc. and Endra, Inc., which, however, did not support this work.
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