Delta thermal radiomics: An application in dairy cow teats

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Infrared thermograms can indirectly detect blood flow and changes in blood flow on the skin.

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Radiomics is a machine learning medical image analysis technique that reveals semantic and nonsemantic features.

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Radiomics of dairy cow teat thermograms is a novel quantitative means of assessing changes in skin temperature before and after milking.

We describe a novel approach for analyzing thermal images by way of radiomics (i.e., thermal radiomics) and how it can be used to monitor short-term temperature changes of dairy cow hind teats; that is, delta thermal radiomics. The heat generated from metabolic activities and blood-flow patterns can be visualized using thermal radiography of the skin surface. The hind teats from 25 dairy cows were imaged with a digital thermal camera and the images were converted to medical images (DICOM format) by mapping the multi-channel colorized thermal image to a monochromatic image whose intensities represent temperature. The 50 teats (left and right hind) were then manually segmented by 2 investigators. Radiomics analysis, which is a common method of extracting semantic and nonsemantic image biomarkers from medical images for machine learning, was performed. To evaluate whether this approach can detect pre- and postmilking differences, 18 cows were imaged before and after milking, the teats were manually segmented, and radiomic calculations were performed. Student's t-test was used to provide an estimate of the likelihood of whether postmilking thermal image biomarkers are the same as premilking thermal image biomarkers, and Cohen's d was used to evaluate the size of the effect (d > 1.2). To evaluate uncertainties from manual segmentation, the Dice similarity score (DS) between the 2 investigators' segments was computed. The average DS (95% confidence limit) was 0.952 (0.913–0.982) when comparing the 2 investigators' segmentations. There was no significant difference in DS when comparing the left and right segmented teats, suggesting that teats can be segmented consistently. No differences (d < 0.36) were observed when comparing image biomarkers from one investigator's segments with the other's, suggesting that image biomarkers computed from one investigator's segmentation of teats are not likely to differ from those computed from the other investigator. When comparing image biomarkers before and after milking, 109 image biomarkers were analyzed, and 17 image biomarkers were simultaneously significant and exhibited effect size. Thus, delta thermal radiomics offers a noninvasive and quantitative method of monitoring skin temperature changes in humans and animals after an intervention. The advantage of this approach is that it can reveal both perceptible and imperceptible surface temperature features that may be useful for detecting and managing dairy teat health.

Development and evaluation of a standardized technique to assess teat skin temperature of dairy cows using infrared thermography

Much research has been done to develop methods to assess dimensional teat traits in dairy cows. In contrast, diagnostic techniques to reliably assess the circulatory system of teats are limited. Infrared thermography facilitates measurements of skin temperature and could be used to detect physiological and pathological changes to the teat tissue associated with machine milking, as temperature reflects the underlying blood circulation and tissue metabolism. Our objective was to develop and evaluate a scanning technique to quantify teat skin temperature in dairy cows using infrared thermography. Using a portable thermography camera, 2 operators obtained duplicate scans of both hind teats from 20 Holstein cows, resulting in 80 thermographic images (20 cows × 2 operators × 2 images). Average teat skin temperatures at the proximal, middle, and distal teat aspects were determined. We used Pearson correlation coefficients (r), intraclass correlation coefficients (ICC), and concordance correlation coefficients (CCC) to assess interoperator reproducibility (i.e., agreement between measurements performed by different operators) and intraoperator repeatability (i.e., agreement between measurements performed by the same operator). Pearson correlation coefficients revealed a very strong correlation for measurements at the proximal, middle, and distal aspects of the teat, respectively, between operators (r ≥0.95) and duplicate scans (r ≥0.94) within operators. Intraclass correlation coefficients and CCC indicated excellent interoperator reproducibility (ICC ≥0.95, CCC ≥0.95) and excellent intraoperator repeatability (ICC ≥0.94, CCC ≥0.94), respectively, for measurements at all 3 aspects. Least squares means (95% confidence interval) for average teat skin temperatures at the proximal, middle, and distal teat aspects, respectively, were 33.2 (32.6-33.8), 32.4 (31.5-33.2), and 30.9 (29.8-32.0) °C for operator 1, and 33.2 (32.6-33.8), 32.4 (31.6-33.3), and 31.0 (29.9-32.0) °C for operator 2. Average temperatures between duplicate scans within operators at the proximal, middle, and distal aspects, respectively, were 33.3 (32.7-33.9), 32.5 (31.7-33.3), and 31.0 (29.9-32.1) °C for the first scan and 33.2 (32.6-33.8), 32.3 (31.5-33.1), and 30.8 (29.7-31.9) °C for the second scan. We conclude that infrared thermography facilitates precise measurements of skin temperatures of cows' hind teats.

Imaging osteomyelitis with streptavidin and indium-111-labeled biotin

Animal studies of infection imaging by a two-step protocol have shown that important improvements in target to nontarget ratios are possible. In this protocol, unlabeled streptavidin is administered and allowed sufficient time to accumulate in the lesion, probably by nonspecific processes, and to clear elsewhere. Thereafter, 111Inbiotin is administered. A fraction of the labeled biotin may be retained in the lesion because of biotin's high affinity for streptavidin while most of the activity is cleared through the kidneys.

METHODS

Radioscintigraphy with unlabeled streptavidin followed with 111Inlabeled biotin was performed in 15 patients with chronic osteomyelitis. As controls, each patients received either 111In-labeled biotin without the preadministration of streptavidin or 111In-labeled nonspecific IgG.

RESULTS

Regions of focal uptake were identified in all patients receiving streptavidin followed by radiolabeled biotin as early as 10 min postadministration of radioactivity, and retention of label was evident through 24 hr. Coincident regions of abnormal accumulation were apparent with 111In-IgG, but only in delayed images. Moreover, with 111In-biotin alone, without the preadministration of streptavidin, focal accumulations were detected in areas similar to that identified with the two-step protocol. Although, these observations were only in the earliest images.

CONCLUSION

The results of this preliminary clinical investigation suggest that a two-step protocol with unlabeled streptavidin and radiolabeled biotin may be an alternative for the detection of infection.