Combined throat/nasal swab sampling for SARS-CoV-2 is equivalent to nasopharyngeal sampling.

PURPOSE: PCR on a nasopharyngeal sample is the reference method for the detection of SARS-nCoV-2. However, combined throat/nasal sampling as a testing method has several advantages. We compared the combined throat/nasal sampling with nasopharyngeal sampling for detection of SARS-CoV-2 in healthcare workers suspected of COVID-19. METHODS: In 107 healthcare workers with symptoms of COVID-19, combined throat/nasal sampling and nasopharyngeal sampling was performed. Detection of SARS-CoV-2 was performed by RT-PCR targeting. RESULTS: A total of 80 healthcare workers (74.8%) tested negative with both sampling methods, and 25 healthcare workers (23.4%) tested positive with both sampling methods. There were two discrepant results with positive PCR in combined throat/nasal swabs and negative PCR in nasopharyngeal swabs (1.9%). The κ index for concordance between the 2 sampling methods was high (0.95). The median cycle threshold (Ct) value of PCR on nasopharyngeal samples was significantly lower than the Ct value of PCR on combined throat/nasal samples (19 (IQR 17-20) versus 21 (IQR 18-29) cycles, p value 0.01). CONCLUSION: Combined throat/nasal swabs yield a similar sensitivity to detect SARS-CoV-2 as nasopharyngeal swabs and are a good alternative sampling method, despite a lower Ct value for the nasopharyngeal samples.

Effect of skin tone on the accuracy of hybrid and passive stereophotogrammetry.

BACKGROUND: Three-dimensional (3D) surface images acquired from stereophotogrammetry are increasingly being used to plan or evaluate treatment by plastic surgeons. Stereophotogrammetry exists in active, passive, and hybrid forms. Active and hybrid stereophotogrammetry are believed to capture darker surfaces more accurately than passive stereophotogrammetry. The purpose of this study was to investigate whether skin tone has a clinically relevant effect on the accuracy of hybrid and passive stereophotogrammetry. MATERIALS AND METHODS: Seven subjects with different skin tones were recruited. 3D-printed face and breast were spray-painted in six different colors, ranging from white to black. The skin tones and paint colors were objectified by measuring their melanin index. 3D photos of the subjects and 3D prints were acquired with hybrid and passive stereophotogrammetry. These 3D photos were matched with specialized software, and their geometric differences were calculated. RESULTS: None of the 3D photos showed a clinically relevant mean inaccuracy. On the 3D prints, hybrid stereophotogrammetry resulted in a smaller standard deviation of the inaccuracies than passive stereophotogrammetry (0.20 ± 0.06 mm vs. 0.35 ± 0.07 mm, p < 0.001). Passive stereophotogrammetry yielded a correlation between the melanin index of the spray paint colors and the standard deviation of the inaccuracy (Pearson's R = 0.60, p = 0.04). On human subjects, no correlation or difference in standard deviation of the accuracy was found. CONCLUSION: Skin tone does not influence the accuracy of hybrid and passive 3D stereophotogrammetry in a clinically relevant way.

New software and breast boundary landmarks to calculate breast volumes from 3D surface images.

BACKGROUND: A method to accurately calculate breast volumes helps achieving a better breast surgery outcome. 3D surface imaging potentially allows these calculations in a harmless, quick, and practicable way. The calculated volume from a 3D surface image is dependent on the determined breast boundary and the method of chest wall simulation by software. Currently, there is no consensus on a robust set of breast boundary landmarks and validation studies on breast volume calculation software are scarce. The purposes of this study were to determine the robustness of newly introduced breast boundary landmarks and introduce and validate a new method to simulate a chest wall. METHODS: Sixteen subjects who underwent a unilateral simple mastectomy were included. In addition to the natural skin fold of the breast, the sternomanubrial joint, the transition of the pectoral muscle curve into the breast curvature, and the midaxillary line were used as landmarks to indicate the breast boundary. The intra- and interrater variability of these landmarks was tested. Furthermore, new chest wall simulation software was validated on the breastless chest side of the subjects. RESULTS: The intra- and interrater variability of the three breast boundary markers was small (mean 3.5-6.7 mm), and no significant difference was found between the intra- and interrater variability (p = 0.08, p = 0.06, and p = 0.10). The mean volume error of the most accurately simulated chest wall was 4.6 ± 37 ml. CONCLUSION: The newly introduced landmarks showed to be robust and our new chest wall simulation algorithm showed accurate results.Level of Evidence: Level IV, diagnostic study.

Accuracy and reproducibility of a newly developed tool for volume measurements of the arm using 3D stereophotogrammetry.

BACKGROUND: Lymph edema of the arm is a common complication after breast cancer treatment. To evaluate lymph edema volume and treatment outcome, an easy to use, objective quantification method of arm volume is necessary. Most often, water displacement is used to measure arm volume, as it is an easy and robust method that can be performed at any place with a simple equipment. However, when using water displacement, no exact localization of volume difference can be seen. To accurately measure hand and forearm volumes separately, an in-house-developed device was constructed for an accurate landmark placement. METHOD: An in-house developed measurement tool was used for placing artificial landmarks proximal to the wrist crease on ten healthy subjects. Three-dimensional (3D) images of the hand and forearm were acquired, and volume measurements of the hand and forearm were performed. Measurements were repeated to investigate the intra- and inter-rater variability caused by the landmark placement. RESULTS: Measuring volume of the hand and forearm while using artificially placed landmarks turned out to be a highly reproducible, quick, and easy procedure. Both intra- and inter-rater variability showed high reproducibility for hand (ICC = 0.96 and 0.98, respectively) and forearm (ICC = 0.99 and 0.99, respectively) volumes. CONCLUSION: Measuring volumes of the hand and forearm while using artificially placed landmarks was found to be a highly reproducible, quick, and easy procedure. The device enables to analyze the localization of lymph edema in greater details.

The effect of aging on the three-dimensional aspect of the hand: A pilot study.

BACKGROUND: With the increasing popularity of rejuvenation treatments of the skin, there has been an increase in patient inquiry for rejuvenation of the hand. Thus far, no imaging tool exists to analyze the aging process of the hand. Three-dimensional (3D) stereophotogrammetry is a reliable technique, which is used for other purposes in soft tissue analysis of the upper extremity. This pilot study aimed to investigate the possibility of visualizing the hand aging process by 3D stereophotogrammetry. METHODS: A total of 64 healthy volunteers were divided into four groups based on age and sex, and a 3D photograph of both hands was captured. Differences in the aspect of the dorsum of the hands were quantified and visualized using two methods. The first method quantified the smoothness of the old and young dorsa. The second method visualized the differences between an average young and old hand by creating a color-coded distance map. RESULTS: The first method showed that the young hands were smoother than the old hands; however, this difference was not statistically significant (p = 0.30). The distance map resulting from the second method showed a relative volume loss in the intermetacarpal spaces of the average old hand. These differences were not present when male hands were compared with female hands. CONCLUSIONS: This pilot study shows that 3D stereophotogrammetry can be used to visualize the exact areas of volume loss on the dorsum of the aging hand. On the basis of this finding, specific treatment areas can be identified, and the results of different esthetic hand surgery procedures can be objectively analyzed and compared.