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Post-bariatric body shape

Artec EVA 3D scanner can detect post-op body shape changes

The Artec EVA is a state-of-the-art technology for 3D surface scanning that uses the structured light triangulation technique to receive 3D data from surfaces

Utilising the Artec EVA three-dimensional (3D) mobile imaging scanner can provide an objective and reproducible source for the detection of body shape changes after bariatric surgery, according to researchers from RWTH Aachen University Hospital, Aachen, Germany, who recommended its use when evaluating central obesity, especially for research issues and body imaging before and after bariatric surgery.

Body scans produce images that are used for evaluating patient outcome or planning complex surgical procedures in plastic reconstructive surgery, such as body contour surgery or breast asymmetry. In the paper, ‘3D Optical Imaging as a New Tool for the Objective Evaluation of Body Shape Changes After Bariatric Surgery’, published in Obesity Surgery, the authors note that post-bariatric surgery body shape changes are usually measured by 2D methods, such as hip and waist circumference, however,  this can result in significant measurement errors and poor reproducibility. Therefore, they decided to assess the validity of using a 3D mobile scanner, the Artec EVA (Artec Group), to see if it could be an objective and reproducible source for the detection of post-op body shape changes.

The authors write that the Artec EVA is a state-of-the-art technology for 3D surface scanning that uses the structured light triangulation technique to receive 3D data from surfaces. Two cameras take pictures of a certain point P. Predefined light patterns of parallel stripes are used to identify P in both pictures, and a three-dimensional picture is constructed.

Artec EVA three-dimensional (3D) mobile imaging scanner

To perform a 3D scan, Artec EVA is circled around the object at a working distance of 40–100cm until every spot of interest is captured. The data files are then processed using Artec Studio software version 11.0 and a 3D scan is created as a Joint Photographic Experts Group File Interchange Format (.jpg) together with texture mapping information inside a Material Template Library file (.mtl). Artec Studio software works with every modern and fast PC, and no further hardware is necessary.

In total, 25 bariatric patients were scanned one week before and six months after surgery with patients standing straight with their feet close together and arms crossed behind their back to expose both claviculae (Figure 1a). Men were scanned with their upper body undressed and women were scanned in their bras. The data were analysed, and the volume of the torso, the abdominal circumference and distances between specific anatomical landmarks were calculated. The results of the processed three-dimensional measurements were compared with clinical data concerning weight loss and waist circumference.

Outcomes

The mean preoperative body weight was 157kg and the BMI53.3. Fifty-two percent of all procedures were sleeve gastrectomies (n=13) and remaining were Roux-en-Y gastric bypasses (RYGB) (n=12). The 6-month follow-up is also depicted in Table 1 and shows the measured weight loss.

“The incidences of overweight and obesity increase globally, and bariatric surgery is still the most effective treatment option for obesity. Therefore, three-dimensional imaging should become a common tool to measure central obesity in bariatric patients.”

The heat maps of two matched scans illustrate the areas of body shape changes after bariatric surgery (Figure 1d). At six months, the mean volume loss of the torso was 10.346 l (p< 0.0001), circumference loss (cumb 24.76 ± 8.479, p < 0.0001; cmax 25.27 ± 13.12, p<0.0001) and loss of distance (dumb 38.11 ± 26.36, p < 0.0001 and des 47.33 ± 24.25, p<0.0001) were also significant at the six months. The median measurement error between two independent operators was 0.031% (0.003–0.07%).

Three-dimensional reconstructions of the torso. a Three-dimensional scan before alignment with and without texture. b Three-dimensional reconstruction of the torso. The arms, legs, and head were removed for three-dimensional measurement. The clavicula is marked in red. Bright lines in blue torsos depict dumb and des. Purple lines in green torsos depict cmax and cumb. c Pre- and postoperative torso. d Heat map of matched pre- and postoperative scans depicting areas of body shape changes. The colored scale illustrates the extent of body shape change in centimeters. Gray color depicts areas of body shape change > 30 cm

The authors reported a strong, positive monotonic correlation between body weight loss and volume loss after bariatric surgery (p=0.0005), as well as a moderate, positive correlation between %TWL and %TVL (p=0.0175). The circumferential measurement cumb also correlated strongly with weight loss (p=0.0011). However, the change in the clinical measurement of waist circumference did not correlate significantly with weight loss after bariatric surgery, and the researchers could not show a statistically significant correlation between the change in cumb and waist circumference measured with a tape. Furthermore, the changes in the distance between umbilicus and claviculae did not correlate with weight loss.

“The incidences of overweight and obesity increase globally, and bariatric surgery is still the most effective treatment option for obesity,” the authors noted. “Therefore, three-dimensional imaging should become a common tool to measure central obesity in bariatric patients.”

To access this paper, please click here

For more information about the Artec EVA scanner, pleasse click here

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