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The Scout Device’s Reliability: Methodological Issues

Sabour, Siamak MD, PhD, DSc, MSc

Advances in Skin & Wound Care: August 2017 - Volume 30 - Issue 8 - p 344
doi: 10.1097/01.ASW.0000521116.18779.7c
Departments: Letters

Professor, Safety Promotion and Injury Prevention Research Center, Department of Clinical Epidemiology, School of Health, Shahid Beheshti University of Medical Sciences Tehran, Iran

I was interested to read, “A Reliability Study Using a Long-Wave Infrared Thermography Device to Identify Relative Tissue Temperature Variations of the Body Surface and Underlying Tissue,” by Langemo et al, published in the March issue.1 The Scout (WoundVision LLC, Indianapolis, Indiana) is an FDA-approved visual and thermal imaging device and software analysis tool that provides clinicians with a reliable and reproducible way to incorporate long-wave infrared thermography and relative temperature differential into clinical wound assessment by consistently identifying control areas against which to measure wound temperature. The authors aimed to evaluate 2 aspects of the Scout’s reliability: (1) within- and between-reader agreement of initial patient encounter control area images and (2) between-reader agreement of follow-up encounter control area images. The 3 readers (wound care professionals experienced in control area selection) placed a control area on each of the 26 wounds at 3 different times (n = 78 independent placements) to establish within-reader agreement. To establish between-reader agreement, the readers again placed a control area on each of the 26 wounds (n = 26 independent placements).

Based on the results reported by the authors, the control area measurements were very consistent both within (percent coefficient of variation [%CV] approximately 1%) and between readers (%CV approximately 2%). The average maximum temperature within-reader %CV was 1.14%, and the between-reader %CV was 1.97%. The average minimum temperature had a within-reader %CV of 1.1%, and the between-reader %CV was 2.01%.1 However, these results are not the most appropriate measures to assess reliability. First, to the best of my knowledge, in reliability analysis, an individual approach instead of a group approach should be considered.2–5 Therefore, for quantitative variables, intraclass correlation coefficient (ICC) agreement single measure, not the group measure (%CV, or average), should be reported.2–5 Moreover, %CV as one of the estimates to assess reliability cannot cover an individual approach.

As the authors pointed out in their conclusion, clinicians can repeatedly and reliably perform a relative temperature differential analysis using the Scout device to determine an appropriate control area for wound temperature assessment. Such a conclusion should be supported by an individual-based methodology. Otherwise, mismanagement of the patient cannot be avoided.

—Siamak Sabour, MD, PhD, DSc, MSc

Professor, Safety Promotion and Injury Prevention Research

Center, Department of Clinical Epidemiology, School of Health,

Shahid Beheshti University of Medical Sciences

Tehran, Iran

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References

1. Langemo DK, Spahn JG. A reliability study using a long-wave infrared thermography device to identify relative tissue temperature variations of the body surface and underlying tissue. Adv Skin Wound Care 2017;30:109–19.
2. Sabour S. Reliability of immunocytochemistry and fluorescence in situ hybridization on fine-needle aspiration cytology samples of breast cancers: methodological issues. Diagn Cytopathol 2016;44:1128–9.
3. Sabour S. Reliability assurance of EML4-ALK rearrangement detection in non-small cell lung cancer: a methodological and statistical issue. J Thorac Oncol 2016;11(7):e92–3.
4. Sabour S, Farzaneh F, Peymani P. Evaluation of the sensitivity and reliability of primary rainbow trout hepatocyte vitellogenin expression as a screening assay for estrogen mimics: methodological issues. Aquat Toxicol 2015;164:175–6.
5. Sabour S. Methodologic concerns in reliability of noncalcified coronary artery plaque burden quantification. AJR Am J Roentgenol 2014;203(3):W343.
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In response

The authors appreciate the thoughtful input from Dr Sabour in relation to the article published in the March issue. The Scout (WoundVision LLC) is an FDA-cleared visual and thermal imaging device and software analysis tool to provide clinicians with a reliable and reproducible way to incorporate long-wave infrared thermography and relative temperature differential into clinical wound assessment by consistently identifying control areas against which to measure wound temperature. He expressed that, in his opinion, an ICC would have been the preferred statistical method to assess within- and between-reader agreement. The authors acknowledge that ICC is indeed one approach. The authors used the statistical approach of %CV as they did in the 3 previously published articles in the journal on the testing of the Scout, because this was the statistical approach recommended by the US FDA, who reviewed and approved this device.

Again, thank you for your thoughtful input.

—Diane Langemo, PhD, RN, FAAN

President, Langemo & Associates, and Professor Emeritus,

University of North Dakota

Grand Forks, North Dakota

—James Spahn, MD, FACS

Founder, Chairman of the Board, and Chief Executive Officer,

WoundVision LLC; and Founder, Chairman of the Board, EHOB Inc

Indianapolis, Indiana

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