Such results are different from Figures 3(c) and 3(d), which indicate that physiological interference has relatively low influence on deoxyhemoglobin
concentration change measurement.
It was hypothesized that the main component in hyperacute thrombi might be oxyhemoglobin, instead of deoxyhemoglobin
or hemosiderin, which made the clot invisible to the identification of negative susceptibility vessel sign (SVS). On the contrary, it was found that the negative SVS remained invisible on follow-up SWI in all patients without recanalization, indicating that this sign may not be simply related to the component of oxyhemoglobin, and other undetermined factors may also be involved.
in blood is paramagnetic which will distort the external magnetic field of nearby hydrogen nuclei spins and further affect the MR image.
Buursma, "Spectrophotometry of hemoglobin: absorption spectra of bovine oxyhemoglobin, deoxyhemoglobin
, carboxyhemoglobin, and methemoglobin," Comparative Biochemistry and Physiology, vol.
In addition, it was difficult to understand which hemoglobin form (oxyhemoglobin, deoxyhemoglobin
, and methemoglobin) is within the erythrocyte and how the hematoporphyrin conformation and the hemoglobin oxygen-binding capacity change.
Based on its intrinsic characters, QSMs have found its power in differentiating diamagnetic calcification from paramagnetic materials [7, 39], quantifying the deoxyhemoglobin
concentration [9, 12], depicting the deep brain structure , quantifying contrast agent concentration , characterizing white matter fiber tracks, and so forth [1-4, 42].
fMRI detects changes in the concentration of deoxyhemoglobin
, dependent on a complex interplay among CBF, blood volume and cerebral oxygen consumption (13,19).
The light emitted similarly absorbed by oxy- and deoxyhemoglobin
, and so, through backlighting, the red blood cells are captured since they are the ones that absorb the light.
(12) Since methylene blue has a peak light absorption that closely corresponds to the light absorption of deoxyhemoglobin
, it is believed that the artifactual desaturation is due to the difference in light absorption between deoxyhemoglobin
Previous research using NIRS in lower limb exercise assessment has demonstrated a similar mono-exponential response in the deoxyhemoglobin
(HHb) NIRS signal to that of pulmonary V[O.sub.2] (23).
They come in two types: oxyhemoglobin (OH) carry oxygen and deoxyhemoglobin
(DH) are those that have delivered their oxygen.
It does so based on the coupling of blood flow and neuron activity and the difference in water 1H spin relaxation between environments of deoxyhemoglobin