Wound areas by computerized planimetry of digital images: accuracy and reliability.
BACKGROUND
Tracking wound size is an essential part of treatment. Because a wound's initial size may affect apparent healing rates, its surface area (S) and its surface area-to-perimeter (S/P) ratio are useful to document healing. Assessments of these parameters can be made by computerized planimetry of digital images using suitable software.


OBJECTIVE
Because different caregivers often evaluate wounds and because measurement time is important, the objective of this study was to determine accuracy, repeatability, and measurement time of S and S/P from measurements of images recorded by digital photography.


METHODS
Six wound images of various complexities with known areas were measured in triplicate by 20 senior nursing students during 2 sessions 1 week apart. Images included an ellipse, 2 traced venous ulcers, and photographs of a pressure, diabetic plantar, and venous ulcer. Area error was determined as the percentage difference between known and planimetry measured areas. Reliability was assessed from test-retest coefficient of variations (CV%) from which the smallest meaningful percentage change (SMPC) was determined.


RESULTS
Area errors (mean +/- SD) ranged from -2.95% +/- 7.01% to +2.32% +/- 6.04%. For well-defined image margins, area and S/P SMPC values were all less than 3.2%. For borders that were not as well defined, SMPCs were larger, ranging between 6.2% and 10.8%. Wound measurement time decreased from 93.4 +/- 35.1 seconds at session 1 to 67.7 +/- 24.4 at session 2 (P < .001).


CONCLUSIONS
: Results based on the specific software used and on the outcomes of the study group indicate that simple computer-based planimetry of digital images can provide rapid, accurate, and reliable estimates of wound area and S/P ratios.
Mayrovitz
Harvey N
HN
College of Medical Sciences, Department of Nursing, Nova Southeastern University, Ft Lauderdale, Florida, USA.
Soontupe
Lisa B
LB
D000465:Algorithms; D006801:Humans; D007871:Leg Ulcer / Q000175:diagnosis*; D009730:Nursing Assessment; D010781:Photography / Q000295:instrumentation* / Q000379:methods; D003668:Pressure Ulcer / Q000175:diagnosis*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012984:Software; D013223:Statistics as Topic; D014945:Wound Healing