Three-dimensional Surface Imaging for Clinical Decision Making in Pectus Excavatum

To evaluate pectus excavatum, 3-dimensional surface imaging is a promising radiation-free alternative to computed tomography and plain radiographs. Given that 3-dimensional images concern the external surface, the conventional Haller index, and correction index are not applicable as these are based on internal diameters. Therefore, external equivalents have been introduced for 3-dimensional images. However, cut-off values to help determine surgical candidacy using external indices are lacking. A prospective cohort study was conducted. Consecutive patients referred for suspected pectus excavatum received a computed tomography (≥18 years) or plain radiographs (<18 years). The external Haller index and external correction index were calculated from additionally acquired 3-dimensional images. Cut-off values for the 3-dimensional image derived indices were obtained by receiver-operating characteristic curve analyses, using a conventional Haller index ≥3.25, and computed tomography derived correction index ≥28.0% as indicative for surgery. Sixty-one and 63 patients were included in the computed tomography and radiograph group, respectively. To determine potential surgical candidacy, receiver-operating characteristic analyses found an optimum cut-off of ≥1.83 for the external Haller index in both the computed tomography and radiograph group with a positive predictive value between 0.90 and 0.97 and a negative predictive value between 0.72 and 0.81. The optimal cut-off for the external correction index was ≥15.2% with a positive predictive value of 0.86 and negative predictive value of 0.93. The 3-dimensional image derived external Haller index and external correction index are accurate radiation-free alternatives to facilitate surgical decision-making among patients suspected of pectus excavatum with values of ≥1.83 and ≥15.2% indicative for surgery

Three-Dimensional Imaging of the Chest Wall: A Comparison Between Three Different Imaging Systems

Background: Three-dimensional (3D) imaging is being used progressively to create models of patients with anterior chest wall deformities. Resulting models are used for clinical decision-making, surgical planning, and analysis. However, given the broad range of 3D imaging systems available and the fact that planning and analysis techniques are often only validated for a single system, it is important to analyze potential intrasystem and intersystem differences. The objective of this study was to investigate the accuracy and reproducibility of three commercially available 3D imaging systems that are used to obtain images of the anterior chest wall. Methods: Among 15 healthy volunteers, 3D images of the anterior chest wall were acquired twice per imaging device. Reproducibility was determined by comparison of consecutive images acquired per device while the true accuracy was calculated by comparison of 3D image derived and calipered anthropometric measurements. A maximum difference of 1.00 mm. was considered clinically acceptable. Results: All devices demonstrated statistically comparable (P = 0.21) reproducibility with a mean absolute difference of 0.59 mm. (SD: 1.05), 0.54 mm. (SD: 2.08), and 0.48 mm. (SD: 0.60) for the 3dMD, EinScan Pro 2X Plus, and Artec Leo, respectively. The true accuracy was, respectively, 0.89 mm. (SD: 0.66), 1.27 mm. (SD: 0.94), and 0.81 mm. (SD: 0.71) for the 3dMD, EinScan, and Artec device and did not statistically differ (P = 0.085). Conclusions: Three-dimensional imaging of the anterior chest wall utilizing the 3dMD and Artec Leo is feasible with comparable reproducibility and accuracy, whereas the EinScan Pro 2X Plus is reproducible but not clinically accurate

Photographic documentation and severity quantification of pectus excavatum through three-dimensional optical surface imaging

Conventional photography is commonly used to visually document pectus excavatum and objectively assess chest wall changes over time without repeated exposure to ionising radiation, as in our centre since 2008. However, as conventional photography is labour-intensive and lacks three-dimensional (3D) information that is essential in 3D deformities like pectus excavatum, we developed a novel imaging and processing protocol based on 3D optical surface imaging. The objective of this study was to report our developed protocol to visually document pectus excavatum through 3D imaging. We also investigated the absolute agreement of the 3D image- and conventional photography-derived pectus excavatum depth to investigate whether both techniques could be used interchangeably to measure pectus excavatum depth and assess its evolution. The protocol consisted of three consecutive steps: patient positioning and instructions, data acquisition, and data processing. Three-dimensional imaging through the developed protocol was feasible for all 19 participants. The 3D image- and photography-derived pectus excavatum depth demonstrated good to excellent agreement (intraclass correlation coefficient: 0.97; 95%-confidence interval: 0.88 to 0.99; p < 0.001). In conclusion, 3D imaging through the developed protocol is a feasible and attractive alternative to document the surface geometry of pectus excavatum and can be used interchangeably with conventional photography to determine pectus severity. Clinical registration number: NCT04185870

Optical imaging versus CT and plain radiography to quantify pectus severity: A systematic review and meta-analysis

Background: Computed tomography (CT) and two-view chest radiographies are the most commonly used imaging techniques to quantify the severity of pectus excavatum (PE) and pectus carinatum (PC). Both modalities expose patients to ionizing radiation that should ideally be avoided, especially in pediatric patients. In an effort to diminish this exposure, three-dimensional (3D) optical surface imaging has recently been proposed as an alternative method. To assess its clinical value as a tool to determine pectus severity we conducted a systematic review in which we assessed all studies that compared 3D scan-based pectus severity measurements with those derived from CT-scans and radiographies. Methods: Six scientific databases and three registries were searched through April 30th, 2019. Data regarding the correlation between severity measures was extracted and submitted to meta-analysis using the random-effects model and I2-test for heterogeneity. Results: Five observational studies were included, enrolling 75 participants in total. Pooled analysis of participants with PE demonstrated a high positive correlation coefficient of 0.89 [95% confidence interval (CI): 0.81 to 0.93; P<0.001] between the CT-derived Haller index (HI) and its 3D scan equivalent based on external measures. No heterogeneity was detected (I2=0.00%; P=0.834). Conclusions: 3D optical surface scanning is an attractive and promising imaging technique to determine the severity of PE without exposure to ionizing radiation. However, further research is needed to determine novel cut-off values for 3D scans to facilitate clinical decision making and help determine surgical candidacy. No evidence was found that supports nor discards the use of 3D scans to determine PC severity

Wastewater surveillance monitoring of SARS-CoV-2 variants of concern and dynamics of transmission and community burden of COVID-19

ABSTRACTWastewater-based surveillance is a valuable approach for monitoring COVID-19 at community level. Monitoring SARS-CoV-2 variants of concern (VOC) in wastewater has become increasingly relevant when clinical testing capacity and case-based surveillance are limited. In this study, we ascertained the turnover of six VOC in Alberta wastewater from May 2020 to May 2022. Wastewater samples from nine wastewater treatment plants across Alberta were analysed using VOC-specific RT-qPCR assays. The performance of the RT-qPCR assays in identifying VOC in wastewater was evaluated against next generation sequencing. The relative abundance of each VOC in wastewater was compared to positivity rate in COVID-19 testing. VOC-specific RT-qPCR assays performed comparatively well against next generation sequencing; concordance rates ranged from 89% to 98% for detection of Alpha, Beta, Gamma, Omicron BA.1 and Omicron BA.2, with a slightly lower rate of 85% for Delta (p < 0.01). Elevated relative abundance of Alpha, Delta, Omicron BA.1 and BA.2 were each associated with increased COVID-19 positivity rate. Alpha, Delta and Omicron BA.2 reached 90% relative abundance in wastewater within 80, 111 and 62 days after their initial detection, respectively. Omicron BA.1 increased more rapidly, reaching a 90% relative abundance in wastewater after 35 days. Our results from VOC surveillance in wastewater correspond with clinical observations that Omicron is the VOC with highest disease burden over the shortest period in Alberta to date. The findings suggest that changes in relative abundance of a VOC in wastewater can be used as a supplementary indicator to track and perhaps predict COVID-19 burden in a population