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

Figures

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  Figure 1. Image of the parathyroid speckle and autofluorescence imager (ParaSPAI).

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  Figure 2. Representative white light, near-infrared autofluorescence (NIRAF), indocyanine green (ICG) fluorescence, and speckle contrast images of a devascularized (A–D) and a well-perfused (E–H) parathyroid gland, acquired with the imaging device. The parathyroid glands are indicated with white ellipses in white light and ICG fluorescence images, and with dotted contours generated by automated segmentation in NIRAF and speckle contrast images.

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  Figure 3. Indocyanine green (ICG) scores assigned to 37 parathyroid glands imaged intraoperatively, assigned by 3 different scorers. Red boxes indicate instances of disagreement between the scorers. These all involve discrepancies in assigning ICG score 1.

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  Figure 4. An example indocyanine green (ICG) fluorescence image showing a parathyroid gland that received differing ICG scores. One scorer assigned a score of 2, and the other two assigned a score of 1.

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  Figure 5. Boxplots showing distribution of speckle contrast for parathyroid glands assigned indocyanine green (ICG) scores 0, 1 and 2 by three different scorers. Each box represents the interquartile range for data in that group, the red horizontal line indicates the median for the group, whiskers extend to the most extreme data point not considered an outlier, and outliers are represented by red crosses. Significant differences (p < 0.05) between groups are indicated with black asterisks (*).

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  Figure 6. Boxplots showing distribution of mean-normalized fluorescence intensity for parathyroid glands assigned indocyanine green (ICG) scores 0, 1 and 2 by three different scorers. Each box represents the interquartile range for data in that group, the red horizontal line indicates the median for the group, whiskers extend to the most extreme data point not considered an outlier, and outliers are represented by red crosses.

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  Figure 7. Scatterplot of speckle contrast of 37 parathyroid glands against their respective mean-normalized indocyanine green (ICG) fluorescence intensity. The line of best fit relating the two quantities is indicated by the dashed line. A linear correlation coefficient of − 0.81 was obtained, suggesting strong similarity between the two techniques.