Current approaches for measuring wrinkle reduction tend to rely on static photographs and subjective visual assessment. However, a three-dimensional imaging technique has the capability of measuring whether and how much cosmetic interventions, such neurotoxin injections, fillers and facelifts, work, according to a new study.
Researchers from the Perelman School of Medicine at the University of Pennsylvania, describe the procedure, called three-dimensional speckle tracking photogrammetry, in the May issue of Plastic and Reconstructive Surgery. Photogrammetry is the photographic measurement of distance between objects.
The procedure measures dynamic facial wrinkles and their subsequent reduction following injection, presenting results as a color-coded heat map. By comparing patients’ before- and after-treatment heat maps, physicians can objectively evaluate wrinkle reduction, optimal dosage for maximum aesthetic benefit and other variables.
“The DIC [digital image correlation] 3-D dynamic imaging technology, unlike the standard 3-D imaging systems, is able to capture not only a 3-D facial image, but it is able to capture that image in motion with extremely precise measurements. This capability, in combination with the software system, permits the measurement of dynamic facial strain (or movement), which is the major cause of most facial wrinkles,” says senior author Ivona Percec, M.D., Ph.D., director of basic science research and associate director of cosmetic surgery in the division of plastic surgery at Penn.
The DIC Study
Researchers evaluated 14 patients, who received 20 units of onabotulinumtoxinA in the glabella, using a dual camera system and 3-D optical analysis. They applied white foundation and black speckle makeup to each patient before and two weeks after injection and tracked movement of the speckles by digital camera.
“After neurotoxin injection, average vertical stretch of the glabella during brow furrowing decreased from 2.51 percent to 1.15 percent…, and average vertical stretch in the forehead decreased from 6.73 percent to 1.67 percent…,” according to the abstract.
Horizontal compression in the glabella decreased from 9.11 percent to 2.60 percent and from 4.83 percent to 0.83 percent in the forehead.
“… this technology is an excellent option for clinical researchers who are interested in studying facial strain and how interventions, such as fillers, neurotoxins, facelifts and other surgical interventions, can affect and improve facial strain. The technology may also be useful for evaluating more subtle interventions such as chemical peels and laser resurfacing,” Dr. Percec tells Cosmetic Surgery Times. “A researcher wanting to incorporate this technology would require a dedicated camera room, much like the other standard 3-D imaging systems, as well as someone trained on the software and analysis. Affordability is relative to each practice of course, but the system is in a similar price point to a high end cosmetic laser.”
Any physician wanting to learn more about treatment outcomes, facial anatomy and aging could use the technology in novel ways to advance their understanding, according to Dr. Percec.
“However, this technology remains a research tool that requires a dedicated research effort,” she says. “Though future studies will need to explore the use of digital image correlation in larger groups, our results are the first to show the modality can be applied to study a range of challenges in plastic surgery."