Noninvasive in vivo monitoring of methemoglobin formation and reduction with broadband diffuse optical spectroscopy

Abstract

We present noninvasive, quantitative in vivo measurements of methemoglobin formation and reduction in a rabbit model using broadband diffuse optical spectroscopy (DOS). Broadband DOS combines multifrequency frequency-domain photon migration (FDPM) with time-independent near infrared (NIR) spectroscopy to quantitatively measure bulk tissue absorption and scattering spectra between 600 nm and 1,000 nm. Tissue concentrations (denoted by brackets) of methemoglobin ([MetHb]), deoxyhemoglobin ([Hb-R]), and oxyhemoglobin ([HbO2]) were determined from absorption spectra acquired in "real time" during nitrite infusions in nine pathogen-free New Zealand White rabbits. As little as 30 nM [MetHb] changes were detected for levels of [MetHb] that ranged from 0.80 to 5.72 microM, representing 2.2 to 14.9% of the total hemoglobin content (%MetHb). These values agreed well with on-site ex vivo cooximetry data (r2= 0.902, P < 0.0001, n = 4). The reduction of MetHb to functional hemoglobins was also carried out with intravenous injections of methylene blue (MB). As little as 10 nM changes in [MB] were detectable at levels of up to 150 nM in tissue. Our results demonstrate, for the first time, the ability of broadband DOS to noninvasively quantify real-time changes in [MetHb] and four additional chromophore concentrations ([Hb-R], [HbO2], [H2O], and [MB]) despite significant overlapping spectral features. These techniques are expected to be useful in evaluating dynamics of drug delivery and therapeutic efficacy in blood chemistry, human, and preclinical animal models.

Applications of Polidocanol in Varicose Vein Treatment Assisted by Exposure to Nd:YAG Laser Radiation

“…We assume that in the spectral range (1,000-1,100) nm the absorption is due rather to the main components of the tissue (melanin, water and hemoglobin/ oxihemoglobin); methemoglobin, especially, has the absorption three times greater than oxihemoglobin in this spectral range (Lee et al, 2006), (Fig.13).…”

“…13. The absorption spectra of hemoglobin (Hb-R), Oxihemoglobin (Hb-O 2 ) and Methemoglobin (MetHb) (Lee et al, 2006) In an attempt to change the chromophore to obtain significant rates of MetHb, while seeking to increase photon absorption, J. Moreno Moraga & all (n.d.) started the combined application of microfoam sclerosants, proven to be efficient for vein sclerosis, with the action of pulsed 1.06 µm Nd:YAG laser beams.…”

Cyst fluid hemoglobin species in endometriosis and its malignant transformation: The role of metallobiology

“…Finally, the method reported in the present study is not a serum-based test; thus, it may not exhibit the characteristics of the reliable, fast, low-cost, efficient bedside tests and non-invasive techniques that are clinically required for the assessment of the metHb/(oxyHb+metHb) ratio in cyst fluid. A number of studies have used broadband diffuse optical spectroscopy and frequency-domain near-infrared spectroscopy (NIRS) to assess tissue concentrations of metHb, oxyHb and deoxyHb (32,33). Lee et al (33) reported noninvasive, quantitative in vivo measurements of metHb formation using broadband diffuse optical spectroscopy (33).…”

“…A number of studies have used broadband diffuse optical spectroscopy and frequency-domain near-infrared spectroscopy (NIRS) to assess tissue concentrations of metHb, oxyHb and deoxyHb (32,33). Lee et al (33) reported noninvasive, quantitative in vivo measurements of metHb formation using broadband diffuse optical spectroscopy (33). NIRS may provide new avenues for future determination of the metHb/(oxyHb+metHb) ratio through transvaginal application of this modality.…”

The Vitamin B12 Analog Cobinamide Is an Effective Antidote for Oral Cyanide Poisoning

“…The probe was placed on the shaved surface of the right inner thigh of the animal for muscle measurements. The broadband DOS system combines multi-frequency domain photon migration with timeindependent near-infrared spectroscopy to accurately measure bulk tissue absorption and scattering spectra [26][27][28][29][30][31][32]. Tissue concentrations of oxy-and deoxyhemoglobin, water, and CytcOx redox state changes (changes from baseline of the differential between oxidized and reduced CytcOx concentrations) were calculated by a linear least squares fit of the wavelength-dependent extinction coefficient spectra of each chromophore as previously reported.…”