Comparing laser speckle contrast imaging and indocyanine green angiography for assessment of parathyroid perfusion

Abstract Accurate intraoperative assessment of parathyroid blood flow is crucial to preserve function postoperatively. Indocyanine green (ICG) angiography has been successfully employed, however its conventional application has limitations. A label-free method overcomes these limitations, and laser speckle contrast imaging (LSCI) is one such method that can accurately detect and quantify differences in parathyroid perfusion. In this study, twenty-one patients undergoing thyroidectomy or parathyroidectomy were recruited to compare LSCI and ICG fluorescence intraoperatively. An experimental imaging device was used to image a total of 37 parathyroid glands. Scores of 0, 1 or 2 were assigned for ICG fluorescence by three observers based on perceived intensity: 0 for little to no fluorescence, 1 for moderate or patchy fluorescence, and 2 for strong fluorescence. Speckle contrast values were grouped according to these scores. Analyses of variance were performed to detect significant differences between groups. Lastly, ICG fluorescence intensity was calculated for each parathyroid gland and compared with speckle contrast in a linear regression. Results showed significant differences in speckle contrast between groups such that parathyroids with ICG score 0 had higher speckle contrast than those assigned ICG score 1, which in turn had higher speckle contrast than those assigned ICG score 2. This was further supported by a correlation coefficient of -0.81 between mean-normalized ICG fluorescence intensity and speckle contrast. This suggests that ICG angiography and LSCI detect similar differences in blood flow to parathyroid glands. Laser speckle contrast imaging shows promise as a label-free alternative that overcomes current limitations of ICG angiography for parathyroid assessment

Data from: Non-invasive monitoring of temporal and spatial blood flow during bone graft healing using diffuse correlation spectroscopy

No description availabl

BloodFlow

BloodFlo

Instrument and probe placement.

<p>(a) Diffuse correlation spectroscopy system consists of a long coherence source, a contact probe, four photon-counting APDs (avalanche photodiodes) and an autocorrelator. (b) Measurement positions P1—P6 were chosen so that they were 1.5 mm apart along the femur starting from the proximal end. The source (red dot) and detectors (blue dots) in the probe were aligned along the femur.</p

Longitudinal blood flow changes at proximal, central and distal part of the femur.

<p>Longitudinal relative blood flow (<i>rBF</i>) changes of the graft leg at (a) proximal (P2), (b) central (P4) and (c) distal (P6) locations are shown for the autograft (black circle) and allograft (red star) groups. Longitudinal changes in Δ<i>rBF</i> (graft-specific blood flow) at (d) proximal, (e) central and (f) distal locations are shown for the autograft (black circle) and allograft (red star) groups. Each data point is the group average and the associated error bar is the standard error of the mean. The pentagram denotes that the <i>rBF</i> or Δ<i>rBF</i> of two groups in the same week is significantly different (<i>p</i> < 0.05).</p

Longitudinal group-averaged relative blood flow (<i>rBF</i>)_changes at different source-detector separations (SDs).

<p><i>rBF</i> changes during 9 weeks of measurement at P4 (graft leg) and P7 (contralateral control leg) for (a) SD = 2.9 mm, (b) 3.6 mm, (c) 4.3 mm and (d) 5.0 mm of autograft group (n = 7) and allograft group (n = 10). Each data point is the mean <i>rBF</i> of all the mice in the same graft group and the associated error bar is the standard error of the mean. The diamond sign denotes that <i>rBF</i> were significantly different between the graft leg and the contralateral control femurs in the autograft group at the corresponding week (<i>p</i> < 0.05). The plus sign denotes that <i>rBF</i> were significantly different between the grafted femur and the contralateral control femur in the allograft group at the corresponding week (<i>p</i> < 0.05).</p