<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v2.0 20040830//EN" "journalpublishing.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="2.0" xml:lang="en" article-type="reviewer-report"><front><journal-meta><journal-id journal-id-type="nlm-ta">JMIRx Med</journal-id><journal-id journal-id-type="publisher-id">xmed</journal-id><journal-id journal-id-type="index">34</journal-id><journal-title>JMIRx Med</journal-title><abbrev-journal-title>JMIRx Med</abbrev-journal-title><issn pub-type="epub">2563-6316</issn></journal-meta><article-meta><article-id pub-id-type="publisher-id">54012</article-id><article-id pub-id-type="doi">10.2196/54012</article-id><title-group><article-title>Peer Review of &#x201C;Predicting Waist Circumference From a Single Computed Tomography Image Using a Mobile App (Measure It): Development and Evaluation Study&#x201D;</article-title></title-group><contrib-group><contrib contrib-type="author"><name name-style="western"><surname>Arefin</surname><given-names>Mohammed Shahriar</given-names></name><degrees>MS</degrees><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff id="aff1"><institution>Department of Bioengineering, Temple University</institution>, <addr-line>Philadelphia</addr-line><addr-line>PA</addr-line>, <country>United States</country></aff><contrib-group><contrib contrib-type="editor"><name name-style="western"><surname>Meinert</surname><given-names>Edward</given-names></name></contrib></contrib-group><pub-date pub-type="collection"><year>2023</year></pub-date><pub-date pub-type="epub"><day>12</day><month>12</month><year>2023</year></pub-date><volume>4</volume><elocation-id>e54012</elocation-id><history><date date-type="received"><day>26</day><month>10</month><year>2023</year></date><date date-type="accepted"><day>26</day><month>10</month><year>2023</year></date></history><copyright-statement>&#x00A9; Mohammed Shahriar Arefin. Originally published in JMIRx Med (<ext-link ext-link-type="uri" xlink:href="https://med.jmirx.org">https://med.jmirx.org</ext-link>), 12.12.2023. </copyright-statement><copyright-year>2023</copyright-year><license license-type="open-access" xlink:href="https://creativecommons.org/licenses/by/4.0/"><p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (<ext-link ext-link-type="uri" xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link>), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIRx Med, is properly cited. The complete bibliographic information, a link to the original publication on <ext-link ext-link-type="uri" xlink:href="https://med.jmirx.org/">https://med.jmirx.org/</ext-link>, as well as this copyright and license information must be included.</p></license><self-uri xlink:type="simple" xlink:href="https://xmed.jmir.org/2023/1/e54012"/><related-article related-article-type="companion" ext-link-type="doi" xlink:href="11/10/2023:38852" xlink:title="Preprint (JMIR Preprints)" xlink:type="simple">https://preprints.jmir.org/preprint/38852</related-article><related-article related-article-type="companion" ext-link-type="doi" xlink:href="10.2196/53817" xlink:title="Authors' Response to Peer-Review Reports" xlink:type="simple">https://med.jmirx.org/2023/1/e53817</related-article><related-article related-article-type="companion" ext-link-type="doi" xlink:href="10.2196/38852" xlink:title="Published Article" xlink:type="simple">https://med.jmirx.org/2023/1/e38852</related-article><kwd-group><kwd>waist circumference</kwd><kwd>computed tomography</kwd><kwd>abdominal CT</kwd><kwd>mobile health</kwd><kwd>health apps</kwd><kwd>CT</kwd><kwd>CT scan</kwd><kwd>CT image</kwd><kwd>mobile app</kwd><kwd>app</kwd><kwd>application</kwd><kwd>waist</kwd><kwd>body</kwd><kwd>body mass</kwd><kwd>BMI</kwd><kwd>morbidity</kwd><kwd>mortality</kwd><kwd>clinical</kwd><kwd>tool</kwd><kwd>prototype</kwd><kwd>design</kwd><kwd>obesity</kwd><kwd>abdominal</kwd><kwd>usability</kwd><kwd>validity</kwd><kwd>medical</kwd></kwd-group></article-meta></front><body><sec id="s1"><title/><p><italic>This is a peer-review report submitted for the paper &#x201C;Predicting Waist Circumference From a Single Computed Tomography Image Using a Mobile App (Measure It): Development and Evaluation Study.&#x201D;</italic></p></sec><sec id="s2"><title>Round 1 Review</title><sec id="s1-1"><title>General Comments</title><p>The authors created a mobile app that predicts waist circumference (WC) from computed tomography (CT) images [<xref ref-type="bibr" rid="ref1">1</xref>]. After creating the app, the authors conducted a preliminary study involving 20 patients. The results showed that the developed app can predict WC from CT images with high accuracy. Though the paper showed some promising results, the authors still need to clarify a few important points. I hope the authors would be happy to clarify those points.</p></sec><sec id="s1-2"><title>Specific Comments</title><sec id="s1-2-1"><title>Major Comments</title><list list-type="simple"><list-item><p><named-content content-type="indent">&#x2003;</named-content>1. What was the primary reason for selecting equation 1 as a reference method for WC calculation? Isn&#x2019;t it possible to calculate the exact circumference from the CT images using image-processing algorithms? Wouldn&#x2019;t it be more representative compared to the manual WC detection procedure?</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>2. Keeping the mobile app aside, how much different is this study compared to Ciudin et al [<xref ref-type="bibr" rid="ref2">2</xref>]?</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>3. On page 3, please expand the discussion on &#x201C;App Requirements.&#x201D; It is not evident what was meant by &#x201C;app requirements&#x201D; in this section.</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>4. How many images were taken from each CT slice? As the measurements for the waist parameters (a and b) were taken using a manual process, what kind of procedure was followed to ensure that the person-to-person variability remains low?</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>5. In Figures 3 and 4, there is a small dot around the top of the figures. Is this a data point? Additionally, proper x- and y-axis labels are missing. Please add appropriate units on the x- and y-axis.</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>6. In the Discussion section, it was claimed that &#x201C;this is the first of a kind mobile app helping physicians to estimate WC.&#x201D; Do the authors think the physicians would be able to use apps such as [<xref ref-type="bibr" rid="ref3">3</xref>] to assess WC?</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>7. In the Discussion section, it was stated that &#x201C;Moreover, the simplicity of the app may reduce the time required for physicians to assess WC.&#x201D; How fast is the app compared to the manual approach?</p></list-item></list></sec><sec id="s1-2-2"><title>Minor Comments</title><list list-type="simple"><list-item><p><named-content content-type="indent">&#x2003;</named-content>8. The authors stated that &#x201C;WC cannot be physically assessed in patients with intellectual or motor disabilities&#x201D; but did not provide any other details as to why it can&#x2019;t be assessed. The authors should discuss this in detail in the Introduction.</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>9. The sentence &#x201C;However, for a radiologist, this method requires training and can be more or less time consuming&#x201D; seems confusing. If possible, please restructure this sentence.</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>10. In equation 1, what is denoted by &#x201C;p&#x201D;?</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>11. Although the authors discussed in the Methods section how the measurements were taken just above the iliac crest and the CT images were taken from the last slice to ensure that those are not taken from different places, do the authors think that there could be some positional errors being introduced based on your approach?</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>12. On page 3, it was stated that there were further modifications to the app design. What kind of modifications were carried out? Did the authors discard the prior mobile app&#x2013;based WC measurements (mWCs) after modifying the app?</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>13. Please try to make sure that periods and commas are being used appropriately. On page 4, one of the sentences was &#x201C;The mean BMI was 26&#x00B1;4; 27,8&#x00B1;2,7 for women and 24.2&#x00B1;4,4 for men.&#x201D; For women, a comma was used as a decimal point. On the other hand, for men, a period was used as a decimal point.</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>14. In Table 1, what is the unit for &#x201C;Confidence Interval&#x201D;?</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>15. What kind of procedure was used to perform the diagnostic test to detect abdominal obesity? Please discuss this in the Methods section.</p></list-item></list></sec></sec></sec><sec id="s3"><title>Round 2 Review</title><p>Thanks to the authors for providing a detailed revised version and comments.</p><p>If the authors can clear up a few more confusions, then it would be great.</p><sec id="s2-1"><title>Minor Comments</title><list list-type="simple"><list-item><p><named-content content-type="indent">&#x2003;</named-content>1. The authors stated that the app has an accuracy of 83% when using the mWC to detect abdominal obesity. Is it sufficient compared to the conventional approaches? Just a simple comparison/comment would suffice.</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>2. Related to comment 11 of the round 1 review, how much impact can positional errors have in abdominal obesity classification? This can be explained or discussed in the Discussion.</p></list-item><list-item><p><named-content content-type="indent">&#x2003;</named-content>3. The Figure 3 regression shows that one of the app measurements was (WC_App=120) when the true value should have been around ~65 (standing app difference=55). But in Figure 4, that point seems to be missing (mean of standing + app ~92, so the difference ~55 should be around ~92 in the Bland-Altman plot). Can you please clarify this? If my calculations are wrong, I am extremely sorry about that.</p></list-item></list><p>Overall, the authors discussed all of the comments raised by the reviewer.</p></sec></sec></body><back><fn-group><fn fn-type="conflict"><p>None declared.</p></fn></fn-group><glossary><title>Abbreviations</title><def-list><def-item><term id="abb1">CT</term><def><p>computed tomography</p></def></def-item><def-item><term id="abb2">mWC</term><def><p>mobile app&#x2013;based waist circumference measurement</p></def></def-item><def-item><term id="abb3">WC</term><def><p>waist circumference</p></def></def-item></def-list></glossary><ref-list><title>References</title><ref id="ref1"><label>1</label><nlm-citation citation-type="journal"><person-group person-group-type="author"><name name-style="western"><surname>Masmoudi</surname><given-names>A</given-names></name><name name-style="western"><surname>Zouari</surname><given-names>A</given-names></name><name name-style="western"><surname>Bouzid</surname><given-names>A</given-names></name><etal/></person-group><article-title>Predicting waist circumference from a single computed tomography image using a mobile app (Measure It): development and evaluation study</article-title><source>JMIRx Med</source><year>2023</year><volume>4</volume><fpage>e38852</fpage><pub-id pub-id-type="doi">10.2196/38852</pub-id></nlm-citation></ref><ref id="ref2"><label>2</label><nlm-citation citation-type="journal"><person-group person-group-type="author"><name name-style="western"><surname>Ciudin</surname><given-names>A</given-names></name><name name-style="western"><surname>Salvador</surname><given-names>R</given-names></name><name name-style="western"><surname>Budoy</surname><given-names>A</given-names></name><etal/></person-group><article-title>Measurement of waist circumference for retrospective studies - prospective validation of use of CT images to assess abdominal circumference</article-title><source>Endocrinol Nutr</source><year>2014</year><month>03</month><volume>61</volume><issue>3</issue><fpage>147</fpage><lpage>152</lpage><pub-id pub-id-type="doi">10.1016/j.endonu.2013.10.004</pub-id><pub-id pub-id-type="medline">24342428</pub-id></nlm-citation></ref><ref id="ref3"><label>3</label><nlm-citation citation-type="web"><source>3DLOOK</source><access-date>2023-11-16</access-date><comment><ext-link ext-link-type="uri" xlink:href="https://3dlook.ai/">https://3dlook.ai/</ext-link></comment></nlm-citation></ref></ref-list></back></article>