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Wound Area Measurement with Digital Planimetry: Improved Accuracy and Precision with Calibration Based on 2 Rulers.

Foltynski P, Ladyzynski P, Ciechanowska A, Migalska-Musial K, Judzewicz G, Sabalinska S - PLoS ONE (2015)

Bottom Line: It was also showed that wound area range and camera type do not influence the precision of area measurement with digital planimetry based on two ruler calibration, however the measurements based on smartphone camera were significantly less accurate than these based on D-SLR or compact cameras.Area measurement on flat surface was more precise with the digital planimetry with 2 rulers than performed with the Visitrak device, the Silhouette Mobile device or the AreaMe software-based method.The calibration in digital planimetry with using 2 rulers remarkably increases precision and accuracy of measurement and therefore should be recommended instead of calibration based on single ruler.

View Article: PubMed Central - PubMed

Affiliation: Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland.

ABSTRACT

Introduction: In the treatment of chronic wounds the wound surface area change over time is useful parameter in assessment of the applied therapy plan. The more precise the method of wound area measurement the earlier may be identified and changed inappropriate treatment plan. Digital planimetry may be used in wound area measurement and therapy assessment when it is properly used, but the common problem is the camera lens orientation during the taking of a picture. The camera lens axis should be perpendicular to the wound plane, and if it is not, the measured area differ from the true area.

Results: Current study shows that the use of 2 rulers placed in parallel below and above the wound for the calibration increases on average 3.8 times the precision of area measurement in comparison to the measurement with one ruler used for calibration. The proposed procedure of calibration increases also 4 times accuracy of area measurement. It was also showed that wound area range and camera type do not influence the precision of area measurement with digital planimetry based on two ruler calibration, however the measurements based on smartphone camera were significantly less accurate than these based on D-SLR or compact cameras. Area measurement on flat surface was more precise with the digital planimetry with 2 rulers than performed with the Visitrak device, the Silhouette Mobile device or the AreaMe software-based method.

Conclusion: The calibration in digital planimetry with using 2 rulers remarkably increases precision and accuracy of measurement and therefore should be recommended instead of calibration based on single ruler.

No MeSH data available.


Box-plot of relative errors of area measurement expressed in percentage for the digital planimetry method based on 2 rulers for 3 camera types: D-SLR, Compact, and Smartphone.An asterix denotes statistically significant difference between the medians.
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pone.0134622.g004: Box-plot of relative errors of area measurement expressed in percentage for the digital planimetry method based on 2 rulers for 3 camera types: D-SLR, Compact, and Smartphone.An asterix denotes statistically significant difference between the medians.

Mentions: The influence of the camera type on the accuracy of digital planimetry with 2 rulers was tested by comparing medians of REs. The result of the Kruskal-Wallis test was significant with p = 0.005. Fig 4 shows box-plot of REs with p-values of detailed analysis in which each camera was compared with each other. The insignificant difference was between the D-SLR and the compact cameras (p = 0.164), and significant differences were between the smartphone camera and each of the two other cameras with p = 0.002 and p = 0.031 for the D-SLR and the compact camera, respectively.


Wound Area Measurement with Digital Planimetry: Improved Accuracy and Precision with Calibration Based on 2 Rulers.

Foltynski P, Ladyzynski P, Ciechanowska A, Migalska-Musial K, Judzewicz G, Sabalinska S - PLoS ONE (2015)

Box-plot of relative errors of area measurement expressed in percentage for the digital planimetry method based on 2 rulers for 3 camera types: D-SLR, Compact, and Smartphone.An asterix denotes statistically significant difference between the medians.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4529141&req=5

pone.0134622.g004: Box-plot of relative errors of area measurement expressed in percentage for the digital planimetry method based on 2 rulers for 3 camera types: D-SLR, Compact, and Smartphone.An asterix denotes statistically significant difference between the medians.
Mentions: The influence of the camera type on the accuracy of digital planimetry with 2 rulers was tested by comparing medians of REs. The result of the Kruskal-Wallis test was significant with p = 0.005. Fig 4 shows box-plot of REs with p-values of detailed analysis in which each camera was compared with each other. The insignificant difference was between the D-SLR and the compact cameras (p = 0.164), and significant differences were between the smartphone camera and each of the two other cameras with p = 0.002 and p = 0.031 for the D-SLR and the compact camera, respectively.

Bottom Line: It was also showed that wound area range and camera type do not influence the precision of area measurement with digital planimetry based on two ruler calibration, however the measurements based on smartphone camera were significantly less accurate than these based on D-SLR or compact cameras.Area measurement on flat surface was more precise with the digital planimetry with 2 rulers than performed with the Visitrak device, the Silhouette Mobile device or the AreaMe software-based method.The calibration in digital planimetry with using 2 rulers remarkably increases precision and accuracy of measurement and therefore should be recommended instead of calibration based on single ruler.

View Article: PubMed Central - PubMed

Affiliation: Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland.

ABSTRACT

Introduction: In the treatment of chronic wounds the wound surface area change over time is useful parameter in assessment of the applied therapy plan. The more precise the method of wound area measurement the earlier may be identified and changed inappropriate treatment plan. Digital planimetry may be used in wound area measurement and therapy assessment when it is properly used, but the common problem is the camera lens orientation during the taking of a picture. The camera lens axis should be perpendicular to the wound plane, and if it is not, the measured area differ from the true area.

Results: Current study shows that the use of 2 rulers placed in parallel below and above the wound for the calibration increases on average 3.8 times the precision of area measurement in comparison to the measurement with one ruler used for calibration. The proposed procedure of calibration increases also 4 times accuracy of area measurement. It was also showed that wound area range and camera type do not influence the precision of area measurement with digital planimetry based on two ruler calibration, however the measurements based on smartphone camera were significantly less accurate than these based on D-SLR or compact cameras. Area measurement on flat surface was more precise with the digital planimetry with 2 rulers than performed with the Visitrak device, the Silhouette Mobile device or the AreaMe software-based method.

Conclusion: The calibration in digital planimetry with using 2 rulers remarkably increases precision and accuracy of measurement and therefore should be recommended instead of calibration based on single ruler.

No MeSH data available.