Computed Tomography Scan Reconstruction Research Articles

Residual encoder-decoder based architecture for medical image denoising

AbstractHigh-resolution computed tomography (CT) scans require high doses of X-rays, posing potential health risks to patients, including genetic damage and cancer. Conversely, low doses of X-rays result in noise and artifacts in the reconstructed CT scans. Consequently, the problem of denoising low-dose CT (LDCT) images has become a critical yet challenging issue in the field of CT imaging. However, existing deep learning-based LDCT image denoising methods frequently result in the loss of high-frequency features, such as edges and textures, due to the use of mean squared error loss. To address this issue, we propose a method based on high-frequency feature learning to enhance the denoising performance of existing models. Our method is designed to simultaneously learn the primary task of LDCT image denoising and the auxiliary task of LDCT edge detection, thereby improving the denoising performance without increasing the number of model parameters and the inference time. Our method significantly improves the denoising performance of the RED-CNN model, achieving competitive results compared to state-of-the-art denoising models on the AAPM and Qin-LUNG-CT datasets.

Image fast reconstruction for sparse view computed tomography with reduced sampling integration time

Industrial computed tomography (CT) can detect the internal structure of objects nondestructively. Its scanning and image reconstruction are time-consuming, which limits its application in the fast detection field. In this work, we reduce the sampling integration time in sparse view CT to achieve ultra-fast scanning in only 5 s. However, this ultra-fast scanning method produces more noise and streak artifacts in the reconstructed CT images. The existing reconstruction methods cannot effectively reconstruct high quality CT images under this ultra-fast scanning. To solve this issue, a faster and higher quality CT image reconstruction method is proposed in this paper. We construct a novel objective function using multi-directional TV and adaptive non-local means (ANLM), and design a solution algorithm to solve the objective function. The multi-directional TV-norm takes into account the differences in horizontal, vertical, and 45° directional gradients to obtain more image detail information, while the ANLM-norm focuses on noise suppression. Simulation and practical experiments show that the proposed method can reconstruct higher quality CT images under faster CT scanning strategy, and the peak signal to noise ratio (PSNR) is 1.3 dB higher than the optimal baseline algorithm. On the other hand, our method converges faster and achieves a shorter CT image reconstruction time, which is 47 s shorter than the current popular iterative reconstruction methods. This reconstruction method provides a reliable scheme for faster CT scanning and image reconstruction.

Comparison of chest radiographs against minimum intensity projection reconstruction computed tomography scans for detection of airway stenosis in children with lymphobronchial tuberculosis.

Ideally, suspected airway compression in symptomatic children with lymphobronchial tuberculosis (TB) would be diagnosed using modern computed tomography (CT) assisted by coronal minimum intensity projection (MinIP) reconstructions. However, in TB-endemic regions with limited resources, practitioners rely on conventional radiography for diagnosing TB and its complications. Furthermore, airway compression detected on conventional radiographs would upgrade a patient into the severe category according to the new World Health Organization guidelines, precluding the patient from shorter treatment protocols. The accuracy of conventional radiographs in the context of detecting airway compression in children with TB has not been specifically evaluated against an imaging gold standard. We aimed to compare frontal chest radiographs against thick-slab angled coronal CT MinIP in identifying airway stenosis at ten specific sites and to determine observer agreement between the modalities regarding the degree of stenosis. This retrospective cross-sectional study compared chest radiographs with standardized angled coronal CT MinIP in children with symptomatic lymphobronchial TB at ten predetermined airway locations. Chest radiographs were evaluated by one pediatric radiologist and CT MinIP reconstructions were independently interpreted by three readers. Sensitivity and specificity were calculated using CT MinIP as the gold standard. Stenosis was graded as 1 for mild (1-50%), 2 for moderate (51-75%), 3a for severe (76-99%), and 3b for total occlusion (100%). Agreement between the two modalities regarding severity of stenosis was calculated using the kappa coefficient for each affected site. A total of 37 patients were included in the study. The median age of patients was 14.3 months (interquartile range 8.0-23.2). Three hundred and seventy individual bronchi (10 from each of the 37 patients) were evaluated for stenosis. Chest radiographs showed that 31 out of 37 (84%) patients had stenosis in at least one of ten evaluated sites, most commonly the left main bronchus and bronchus intermedius, and this was confirmed via CT MinIP. The gold standard (CT MinIP) demonstrated stenosis in at least one of ten sites in all 37 patients (100%). Left main bronchus stenosis was detected by chest radiography with a 92.9% sensitivity and 100% specificity. Sensitivity and specificity for bronchus intermedius stenosis were 80% and 75%, respectively. There was substantial agreement for grade of stenosis between chest radiographs and CT (kappa=0.67) for the left main bronchus and moderate agreement (kappa=0.58) for the bronchus intermedius. Severe stenosis was found in 78 bronchi on CT compared to 32 bronchi (Grade 3a: 9, Grade 3b: 23) on chest radiographs. The diagnosis of pulmonary TB in children continues to rely heavily on imaging, and we have shown that in young children, chest radiographs had a high sensitivity and specificity for detecting airway stenosis at certain anatomical sites, when adequately visualized, resulting from tuberculous lymph node compression at left main bronchus and bronchus intermedius. For most sites, the interobserver agreement was poor. Stenosis of the left main bronchus and bronchus intermedius should be the focus of chest radiograph interpretation and can assist both diagnosis and classification of patients for treatment.

Glenoid component placement in reverse shoulder arthroplasty assisted with augmented reality through a head-mounted display leads to low deviation between planned and postoperative parameters.

Navigated augmented reality (AR) through a head-mounted display (HMD) may lead to accurate glenoid component placement in reverse shoulder arthroplasty (RSA). The purpose of this study is to evaluate the deviation between planned, intra- and postoperative inclination, retroversion, entry point, depth, and rotation of the glenoid component placement assisted by a navigated AR through HMD during RSA. Both shoulders of 6 fresh frozen human cadavers, free from fractures or other bony pathologies, were used. Preoperative computed tomography (CT) scans were used for the 3-dimensional (3D) planning. The glenoid component placement was assisted using a navigated AR system through an HMD in all specimens. Intraoperative inclination, retroversion, depth, and rotation were measured by the system. A postoperative CT scan was performed. The pre- and postoperative 3D CT scan reconstructions were superimposed to calculate the deviation between planned and postoperative inclination, retroversion, entry point, depth, and rotation of the glenoid component placement. Additionally, a comparison between intra- and postoperative values was calculated. Outliers were defined as >10° inclination, >10° retroversion, >3 mm entry point. The registration algorithm of the scapulae prior to the procedure was correctly completed for all cases. The deviations between planned and postoperative values were 1.0°±0.7° for inclination, 1.8°±1.3° for retroversion, 1.1±0.4 mm for entry point, 0.7±0.6 mm for depth, and 1.7°±1.6° for rotation. The deviation between intra- and postoperative values were 0.9°±0.8° for inclination, 1.2°±1.1° for retroversion, 0.6±0.5 mm for depth, and 0.3°±0.2° for rotation. There were no outliers between planned and postoperative parameters. In this study, the use of a navigated AR system through an HMD for RSA led to low deviation between planned and postoperative values and between intra- and postoperative parameters.

Computed Tomography Scan Evidence for Left Atrial Appendage Short-Term Remodeling Following Percutaneous Occlusion: Impact of Device Oversizing.

Background The interrelationships between left atrial appendage (LAA) dimensions and device following implantation are unknown. We aimed to analyze the impact of Watchman device implantation on LAA dimensions following its percutaneous closure and potential predictors of remodeling. Methods and Results All consecutive LAA closure procedures performed at 2 centers between November 2017 and December 2020 were included in the WATCH-DUAL (Watchman 2.5 Versus Watchman FLX in a Dual-Center Left Atrial Appendage Closure Cohort) registry. This study included patients who had pre- and postintervention computed tomography scan analysis. The LAA and device dimensions were measured in a centralized core lab by 3-dimensional computed tomography scan reconstruction methods, focusing on the device landing zone. This analysis included 104 patients (age, 76.0 [range, 72.0-83.0] years; 72% men; 53% Watchman FLX; 47% Watchman 2.5). The baseline characteristics were comparable between Watchman 2.5 and Watchman FLX groups, except for the higher use of oversizing in the latter group. The median delay for computed tomography control was 49 (range, 43-64) days. The landing zone area (median, 446 [range, 363-523] versus 290 [222-366] mm2; P<0.001) and minimal diameter (median, 23.0 [range, 20.7-24.8] versus 16.7 [14.7-19.4] mm; P<0.001) significantly increased after implantation. The absolute (median, 157 [range, 98-220] versus 85 [18-148] mm2, P<0.001) and relative (median, 50% [range, 32%-79%] versus 26% [4%-50%]; P<0.001) increases in landing zone area were more pronounced in patients with oversized device. Baseline LAA dimensions were smaller, landing zone eccentricity larger, and oversized device more frequent in patients with significant overexpansion compared with the others. Conclusions LAA dimensions increased at the site of the Watchman prosthesis after implantation, suggesting a local positive remodeling after the procedure. This phenomenon was more pronounced in the case of oversized devices.

Effect of the Innominate Bone Horizontal Rotation on Acetabular Version: A Retrospective Radiological Study on a Middle Eastern Population

Background: The impact of acetabular horizontal rotation on the development of femoroacetabular impingement and subsequently osteoarthritis is well-studied in the literature. However, there is not a clear relationship between the rotation of the hemipelvis and the version of the acetabulum. Purpose: The purpose of this study was to evaluate the influence of the rotation of the hemipelvis on the version of the acetabulum. Methods: Through a retrospective study, three-dimensional reconstructions of high-resolution CT (computed tomography) scans of 154 patients receiving pelvic scans for non-orthopedic causes were selected from our institution’s database. The horizontal rotation of the different parts of the hemipelvis was evaluated using the following parameters: superior iliac spine angle (SIS), inferior iliac spine angle (IIS), roof edge angle (REA), equatorial edge angle (EEA) and ischiopubic angle (IPA). Results: The results showed a significant positive correlation between the different angles of the innominate bone and the version of the acetabulum such as when the proximal innominate bone rotates, the cranial part of the acetabulum rotates in the opposite direction. Increased anteversion angles in females compared to males were also observed. Conclusion: The observations suggest that, in an asymptomatic population, the acetabulum should not be considered a separate entity independent from the rest of the innominate bone and that the version of the acetabulum correlates with the rotation of the hemipelvis.

Three Zone Scanning Protocol For Lung Ultrasound: An Anatomical Basis.

Lung ultrasound is rapidly gaining popularity based on point of care ease of use, diagnostic fidelity and lack of ionizing radiation. This was particularly notable at the beginning of the COVID-19 pandemic, where concerns of contamination of the x-ray department led to a reluctance to order frequent chest x-rays. Early COVID-19 lung involvement is of a bronchopneumonia, and patches of consolidation adjacent to the chest wall were easily detectable by ultrasound. A large number of proposed scanning protocols were advocated and are often complex and largely based on traditional stethoscope examination or access points on the chest wall rather than the underlying lung anatomy. A surgical understanding of lung anatomy and related surface anatomy has led us to develop a simplified three zone scanning protocol in 2013. The anterior zone corresponds to the upper lobe, and the posterior zone is divided between upper lobe and lower lobe. The relationship between lung lobes and the surface of the chest wall provides the anatomical basis for a simple three scanning zone lung ultrasound protocol.

A simple method for calculating acetabular posterior wall fracture fragment percentages on three-dimensional computed tomography scan reconstruction images

A simple method for calculating acetabular posterior wall fracture fragment percentages on three-dimensional computed tomography scan reconstruction images

Patient-specific instrumentation reduces deviations between planned and postosteotomy humeral retrotorsion and height in shoulder arthroplasty.

Patient-specific instrumentation (PSI) may potentially improve humeral osteotomy in shoulder arthroplasty. The purpose of this study was to compare the deviation between planned and postosteotomy humeral inclination, retrotorsion, and height in shoulder arthroplasty, using PSI vs. standard cutting guides (SCG). Twenty fresh-frozen cadaveric specimens were allocated to undergo humeral osteotomy using either PSI or SCG, such that the 2 groups have similar age, gender, and side. Preosteotomy computed tomography (CT) scan was performed and used for the 3-dimensional (3D) planning. The osteotomy procedure was performed using a PSI designed for each specimen or an SCG depending on the group. A postosteotomy CT scan was performed. The preosteotomy and postosteotomy 3D CT scan reconstructions were superimposed to calculate the deviation between planned and postosteotomy inclination, retrotorsion, and height. Outliers were defined as cases with 1 or more of the following deviations: >5° inclination, >10° retrotorsion, and >3 mm height. The deviation and outliers in inclination, retrotorsion, and height were compared between the 2 groups. The deviations between planned and postosteotomy parameters were similar among the PSI and SCG groups for inclination (P=.260), whereas they were significantly greater in the SCG group for retrotorsion (P<.001) and height (P=.003). There were 8 outliers in the SCG group, compared with only 1 outlier in the PSI group (P=.005). Most outliers in the SCG group were due to deviation >10° in retrotorsion. After 3D planning, PSI had less deviation between planned and postosteotomy humeral retrotorsion and height, relative to SCG.

Three-Dimensional Reconstruction of Monochamus alternatus Galleries Using CT Scans.

Simple SummaryAs one of the most important boring pests in China, the longhorn beetle Monochamus alternatus directly damages or kills pine trees as a vector of pine wood nematode disease. The study of the distribution of M. alternatus and its gallery construction behavior is key to exploring the survival and reproductive mechanisms and population variation, as well as the associated disaster prevention and control planning. In this study, CT technology was used to scan wood segments of Pinus densiflora harmed by M. alternatus, and three-dimensional reconstruction technology was used to obtain gallery models. The results showed that the gallery types of M. alternatus were single and most of them were C-shaped, and a few were S-shaped or Y-shaped. There was no significant difference in the structural parameters of the three galleries. Each gallery has only one larva, which does not collude with each other. CT scanning and three-dimensional reconstruction technology can realize the non-destructive identification and detection of the gallery of M. alternatus, which provides a new idea and method for understanding its hidden feeding behavior and control strategy.As a vector of pine wood nematode disease, Monochamus alternatus is wood-boring, cryptic, and extremely difficult to control—features that have made them a disastrous problem. In this study, we present a method of scanning the galleries of Monochamus alternatus using CT (computed tomography) technology to obtain their systematic structure via 3D (three-dimensional) reconstruction, so as to clarify the gallery types and their structural parameters. TLC (thin-layer chromatography) scanning on wood segments damaged by M. alternatus was performed using a 128-row spiral CT GE Revolution EVO to obtain 64-layer CT scanned images. From the scanned images, we were able to clearly identify the beetle larvae and their galleries. The galleries were clearly delineated from the peripheral xylem, except for parts that were blocked by a frass–feces mixture, which were slightly blurred. Three-dimensional reconstruction of the galleries showed that most of the gallery types were C-shaped, and a few were S-shaped or Y-shaped. There was only one larva per gallery, and the galleries were separate. The vicinity of the entrance hole and the anterior part of the pupal chamber were blocked with a frass–feces mixture. There were no significant differences among the galleries’ parameters, such as the width of the entrance holes, tunneling depth, vertical length, blockage length and volume, total length of the galleries, and boring volume. With MIMICS (Materialise’s interactive medical image control system) image processing software, the images of each layer were made into a composite image, providing an effective way to visualize the 3D distribution of galleries. Using the methodology outlined in this study, both a single gallery structure and the spatial distribution of multiple galleries of M. alternatus can be shown, and the specific parameters of galleries can also be accurately calculated, which provides new ideas and methods for carrying out ecological and scientific research and precise prevention and control techniques of M. alternatus.

Three-Dimensional Computed Tomography Reconstructions Do Not Improve the Interobserver Reliability of the AO/Orthopaedic Trauma Association and Young and Burgess Pelvic Fracture Classifications.

To evaluate the value of three-dimensional (3D) computed tomography (CT) scans on the interobserver and intraobserver reliability of AO/Orthopaedic Trauma Association (OTA) and Young and Burgess (YB) classifications for pelvic ring injuries. Seven reviewers (four fellowship-trained orthopaedic trauma surgeons and three fellows) independently classified 36 pelvic ring injuries using radiographs and axial two-dimensional (2D) CT scan images and then repeated this process 2months later with the addition of 3D CT images. Interobserver and intraobserver reliability was assessed. The interobserver reliability of the AO/OTA classification using 2D vs. 3D CT scans was considered fair (k 0.23, CI 0.17-0.29) vs. slight (k 0.16, CI 0.09-0.22), with no observed difference [mean difference (MD) -0.07, CI 0.16-0.01]. The interobserver reliability of the YB classification using 2D vs. 3D CT scans was considered fair for both (k 0.37, CI 0.32-0.42, vs. 0.37, CI 0.30-0.45), with no observed difference (MD -0.0005, CI -0.08 to 0.08).The intraobserver reliability of the AO/OTA vs. YB classifications was considered fair (k 0.35, CI 0.26-0.44) vs. moderate (k 0.49, CI 0.40-0.57), with the YB classification having higher kappa value (MD 0.13, CI 0.01-0.26, p = 0.03). The addition of 3D CT scan reconstructions to radiographs and 2D CT did not improve the interobserver reliability of AO/OTA and YB classifications for pelvic ring injuries.

Anterior fontanelle closure and diagnosis of non-syndromic craniosynostosis: a comparative study using computed tomography

ObjectiveSuspicion of early anterior fontanel (AF) closure is a common reason for referral to a pediatric neurosurgeon because of the suspected increased risk of developing craniosynostosis (CS) in spite of the absence of evidence in the literature. The aim of this study was to analyze the association between AF closure and the diagnosis of non-syndromic CS in Brazilian children. MethodsAn observational and case-cohort study was conducted to compare the incidence of closed AF between healthy children (group 1) and children diagnosed with non-syndromic CS (group 2) at a pediatric neurosurgery referral center. The accuracies of completely closed AF and diagnosis of CS were assessed. ResultsHigh-resolution three-dimensional reconstruction computed tomography scans were obtained for 140 children aged < 13 months, of whom 62.9% were boys and 37.1% were girls (p < 0.001). The most common types of non-syndromic CS were trigonocephaly (34, 48%) and scaphocephaly (25, 35.7%). Closed fontanel (27, 38.6%) was observed in both groups, and a sensitivity of 36.1%, specificity of 72%, the positive predictive value of 59%, and negative predictive value of 51% were observed in the patients diagnosed with CS when AF closure occurred before the age of 6 months. ConclusionThe results of this comparative study of AF closure and CS diagnosis suggest that early AF closure does not imply a diagnosis of CS. Pediatricians should be aware of the risk of misdiagnosis of CS in cases with a widely open AF in spite of the presence of CS.

Comparison of Dorsal-to-Ventral Ratios of the Cervical Paraspinal Musculature in French Bulldogs With and Without Cervical Intervertebral Disk Disease and Two Other Breeds Based on CT Scan Measurements

Objective: To objectively assess the cervical paraspinal musculature of French bulldogs (FBs) using computed tomography (CT) scan-based measurements, outline differences in other breeds published in the literature, and investigate the potential influence of its cervical paraspinal musculature on predisposed sites for intervertebral disk disease.Animals: Thirty FBs that underwent CT scans of the cervical spine from the skull to C7/T1 were enrolled. Fifteen dogs were patients suffering from intervertebral disk herniation (IVDH group), and 15 dogs underwent CT scans due to brachycephalic obstructive airway syndrome (BOAS group).Methods: At the level of each cervical intervertebral disk from C2/C3 to C7/T1, measurements were performed and statistically analyzed. On the sagittal CT scan reconstruction, the height ratio of the dorsal to ventral paraspinal musculature and the angle of the disk axis to vertebral body length were assessed. On the transverse plane, the area ratio of the dorsal and ventral paraspinal musculature and the ratio of force moments were determined at each intervertebral disk level. Finally, ratios were compared to the values of Labrador retrievers and dachshunds published by Hartmann et al. (1).Results: Comparing the two FB groups, one significant difference was detected in the mean height ratio of the dorsal to ventral paraspinal musculature at the level of C5/C6 (P = 0.0092) and C6/C7 (P = 0.0076), with IVDH FBs having the more prominent dorsal paraspinal musculature. At the level of C3/C4, a significantly less prominent dorsal paraspinal musculature in FBs than in dachshunds (P = 0.0058) and a significantly steeper disk to vertebral body angulation were observed (P = 0.0005).Conclusion: Although some incidental differences were found, most parameters did not significantly differ between the BOAS and IVDH FBs. Significant conformational differences in the cervical paraspinal musculature and disk to vertebral body length angulation were found between FBs and two other breeds (chondrodystrophic and non-chondrodystrophic). This study's findings suggest that the paraspinal musculature is an additional biomechanical influencing factor on the preferential sites of IVDH in the cervical spine and that other major factors exist in IVDH development, especially in FBs.

Conditional Generative Adversarial Networks for low-dose CT image denoising aiming at preservation of critical image content.

X-ray Computed Tomography (CT) is an imaging modality where patients are exposed to potentially harmful ionizing radiation. To limit patient risk, reduced-dose protocols are desirable, which inherently lead to an increased noise level in the reconstructed CT scans. Consequently, noise reduction algorithms are indispensable in the reconstruction processing chain. In this paper, we propose to leverage a conditional Generative Adversarial Networks (cGAN) model, to translate CT images from low-to-routine dose. However, when aiming to produce realistic images, such generative models may alter critical image content. Therefore, we propose to employ a frequency-based separation of the input prior to applying the cGAN model, in order to limit the cGAN to high-frequency bands, while leaving low-frequency bands untouched. The results of the proposed method are compared to a state-of-the-art model within the cGAN model as well as in a single-network setting. The proposed method generates visually superior results compared to the single-network model and the cGAN model in terms of quality of texture and preservation of fine structural details. It also appeared that the PSNR, SSIM and TV metrics are less important than a careful visual evaluation of the results. The obtained results demonstrate the relevance of defining and separating the input image into desired and undesired content, rather than blindly denoising entire images. This study shows promising results for further investigation of generative models towards finding a reliable deep learning-based noise reduction algorithm for low-dose CT acquisition.

Does vaporized hydrogen peroxide sterilization affect the geometrical properties of anatomic models and guides 3D printed from computed tomography images?

BackgroundMaterial extrusion is used to 3D print anatomic models and guides. Sterilization is required if a 3D printed part touches the patient during an intervention. Vaporized Hydrogen Peroxide (VHP) is one method of sterilization. There are four factors to consider when sterilizing an anatomic model or guide: sterility, biocompatibility, mechanical properties, and geometric fidelity. This project focuses on geometric fidelity for material extrusion of one polymer acrylonitrile butadiene styrene (ABS) using VHP.MethodsDe-identified computed tomography (CT) image data from 16 patients was segmented using Mimics Innovation Suite (Materialise NV, Leuven, Belgium). Eight patients had maxillary and mandibular defects depicted with the anatomic models, and eight had mandibular defects for the anatomic guides. Anatomic models and guides designed from the surfaces of CT scan reconstruction and segementation were 3D printed in medical-grade acrylonitrile butadiene styrene (ABS) material extrusion. The 16 parts underwent low-temperature sterilization with VHP. The dimensional error was estimated after sterilization by comparing scanned images of the 3D printed parts.ResultsThe average of the estimated mean differences between the printed pieces before and after sterilization were − 0,011 ± 0,252 mm (95%CI − 0,011; − 0,010) for the models and 0,003 ± 0,057 mm (95%CI 0,002; 0,003) for the guides. Regarding the dimensional error of the sterilized parts compared to the original design, the estimated mean differences were − 0,082 ± 0,626 mm (95%CI − 0,083; − 0,081) for the models and 0,126 ± 0,205 mm (95%CI 0,126, 0,127) for the guides.ConclusionThis project tested and verified dimensional stability, one of the four prerequisites for introducing vaporized hydrogen peroxide into 3D printing of anatomic models and guides; the 3D printed parts maintained dimensional stability after sterilization.

Covered Endovascular Reconstruction of the Popliteal Artery Bifurcation in a Patient with a Popliteal Aneurysm

Popliteal artery aneurysms (PAAs) can present as extensive disease entities that predispose to distal ischaemic complications. Endovascular repair has become a common intervention but is typically limited to a single tube exclusion of the PAA that necessitates a distal landing zone. Presented is a technique of covered endovascular reconstruction of the popliteal artery bifurcation (CERPAB) using Viabahn Endoprosthesis (Gore & Associates, Flagstaff, AZ, USA) covered stent grafts delivered via a percutaneous femoral approach in a patient with extensive PAA with anterior tibial artery (ATA) and tibioperoneal trunk (TPT) involvement. A 79 year old patient presented with a PAA (20 mm diameter) with irregular luminal narrowing extending into the proximal ATA (5 mm diameter) and TPT (6 mm diameter), which was regarded as aneurysmal (normal diameter 3 mm). The patient was asymptomatic but showed growth under surveillance. Under general anaesthesia and through a percutaneous antegrade left femoral approach a 9 × 150 mm standard profile Viabahn stent graft was placed in the popliteal artery as a main body through a 10 F sheath using a 0.035 inch wire. The ATA and TPT were cannulated separately with subsequent placement, simultaneous deployment and kissing balloon dilatation of 6 × 50 mm and 7 × 50 mm low profile stent grafts in the respective arteries using a 0.018 inch platform through a single sheath, overlapping the popliteal stent graft by 3 cm. Procedural angiography (Fig. 1) showed successful exclusion of the PAA with adequate run off distally. Post-operatively, dual antiplatelet therapy with clopidogrel and aspirin was started and the patient was discharged home the next day. Follow up computed tomography at three months showed adequate patency (Fig. 2) with no complications during this period.Figure 2(A) Computed tomography angiography at the three month follow up showing a patent covered reconstruction of the popliteal artery bifurcation by Viabahn stent grafts with 3 cm of overlap. (B) Volume rendered computed tomography scan reconstruction of the covered endovascular reconstruction at the three month follow up.View Large Image Figure ViewerDownload Hi-res image Download (PPT) CERPAB seems to be a possible modality for treatment of patients with PAAs and involvement of the ATA and TPT by reconstructing the popliteal bifurcation and successfully excluding the aneurysmal tract from the peripheral circulation. This procedure is reminiscent of covered endovascular repair of the aortic or femoral bifurcation and allowed exclusion of the PAA without a distal landing zone. To the best of the authors’ knowledge, this is the first time such a procedure has been reported.

Morphological Characteristics of Acromion and Acromioclavicular Joint in Patients with Shoulder Impingement Syndrome and Related Recommendations: A Three-Dimensional Analysis Based on Multiplanar Reconstruction of Computed Tomography Scans.

ObjectiveTo find out which structure is crucial for the formation of shoulder impingement syndrome with the purpose of directing surgical procedures of subacromial decompression and discussing whether it is necessary to manage acromioclavicular joint during operation and how to do it properly.MethodsThis was a retrospective study. Clinical data and preoperative computed tomography (CT) images were collected from patients who were diagnosed with rotator cuff tears between January 2017 and August 2019 (sample size: 46) and those who were diagnosed without rotator cuff tears between March 2018 and August 2019 (sample size: 44) in our institution, respectively. Three‐dimensional models of shoulders were established by multiplanar reconstruction of CT scans and measurements were performed on these models. The parameters such as the acromial length and width, the axial tilt, and the distance from acromial margin to glenoid plane were measured in an adjusted axial plane, and the critical shoulder angle and the spatial volume under acromioclavicular joint were measured in an adjusted coronal plane. The demographic characteristics, the acromial morphology and the spatial volume under acromioclavicular joint were compared to find significant differences between the two groups. The association between the axial tilt and the distance from acromial margin to glenoid plane was evaluated by an ordinary least squares linear regression.ResultsThe patients with rotator cuff tears consisted of 16 males and 30 females, among which 30 right shoulders and 16 left shoulders were included. The patients without rotator cuff tears consisted of 28 males and 16 females, among which 15 right shoulders and 29 left shoulders were involved. Significant differences between the groups were found in the acromial width (3.332 cm vs 3.111 cm), the axial tilt (33.765° vs 23.829°), the critical shoulder angle (32.630° vs 30.363°), the distance from anterior 3 cm of lateral acromial margin (range, 2.476 cm–3.302 cm vs 1.993 cm–3.089 cm), and anterior 0.9 cm of medial acromial margin (range, 0.967 cm–2.369 cm vs 0.668 cm–1.993 cm) to glenoid plane, and the spatial volume under acromioclavicular joint (1.089 cm vs 1.446 cm) in the two groups. No significant differences were found in the age (60.0 years vs 58.3 years) or the acromial length (4.187 cm vs 4.184 cm). Significant association was revealed by linear regression analysis between the axial tilt and the distance from anterior two‐thirds of lateral acromial margin to glenoid plane, and similar association was also found in the anterior half of medial margin.ConclusionAnterior two‐thirds of lateral acromial margin, anterior half of medial acromial margin, and inferior aspect of acromioclavicular joint are crucial structures and need to be fully decompressed when treating patients with rotator cuff tears.

A Neonate with an Abnormally Shaped Head

A female newborn has an abnormally shaped head (Figs 1 and 2). Figure 1. Profile of infant. Figure 2. View of top of infant’s head. ### Prenatal and Birth Histories ### Presentation (Day 1) The infant’s respiratory distress resolved 2 hours after birth and she transitioned off CPAP. Dysmorphic features were noted on physical examination at 2 days of age and hence, further evaluation was undertaken. ### Vital Signs ### Physical Examination (Day 2)

Validation of a simple technique of volumetric analysis of complex incisional hernias without 3D CT scan reconstruction.

Volumetric analysis is being increasingly utilized in the preoperative evaluation of complex incisional hernias. Three-dimensional (3D) reconstruction of abdominal computed tomography (CT) scan has been used to obtain surface area (SA) and volume (Vol.) measurements, while others have used simple mathematical formulas to obtain SA and Vol. estimates without 3D reconstruction. Our objective was to assess the correlation of SA and Vol. measurements and estimates of complex incisional hernias. We conducted a retrospective agreement study of adults who underwent abdominal wall reconstruction from 2007 to 2018. Demographics, hernia characteristics, and operative data were collected from the medical record. SA and Vol. measurements were obtained after 3D CT reconstruction. Linear CT variables were obtained independently by two surgeons and SA and Vol. estimates were calculated. Because both surgeons reported similar results, only lead author values are reported in the abstract. We used Pearson's correlation coefficient (r) to assess inter-rater agreement and the agreement between SA and Vol. measurements and estimates. A total of 108 patients were eligible for analysis. The mean age was 57 ± 11years and 53 (49%) were female. 42 (39%) hernias were recurrent, 10 (9%) patients had a stoma, and 9 (8%) had a history of open abdomen. The mean defect width was 11 ± 4cm and mean defect surface area (DSA) was 150 ± 95cm2. Inter-rater agreement of SA and Vol. estimates was high (r ≥ 0.80). There was high correlation between SA and Vol. measurements and estimates for DSA, hernia sac volume (HSV), abdominal cavity volume (ACV), and HSV/ACV ratio (r = 0.81, 0.89, 0.94 and 0.91, respectively). SA and Vol. estimates demonstrated high level of agreement with SA and Vol. measurements using 3D reconstruction. SA and Vol. estimates can be obtained using simple mathematical formulas using easily obtained linear variables negating the need for the time and effort consuming 3D reconstruction.

A proposal for needle projections in transcutaneous injection laryngoplasty using three-dimensionally reconstructed CT scans.

This study aims to determine laryngeal dimension in relation to all three transcutaneous injection laryngoplasty (TIL) approaches (thyrohyoid, transthyroid and cricothyroid) using three-dimensionally reconstructed Computed Tomography (CT) scan and compare the measurements between sex, age group and ethnicity. CT scans of the neck of two hundred patients were analysed by two groups of raters. For thyrohyoid approach, mean distance from the superior border of the thyroid cartilage to the laryngeal cavity (THd) and mean angle from the superior border of the thyroid cartilage to mid-true cords (THa) were measured. For transthyroid approach, mean distance from mid-thyroid cartilage to mid-true cords (TTd) and Hounsfield unit (HU) at mid-thyroid cartilage (TTc) were measured. For cricothyroid approach, mean distance from the inferior border of the thyroid cartilage to the laryngeal cavity (CTd) and mean angle from the inferior border of the thyroid cartilage to mid-true cords (CTa) were measured. There were statistically significant differences between males and females for all measurements except for CTa (p < 0.0001). No significant difference across age groups and ethnicities were found for all three approaches (p > 0.05). There was a significant fair positive correlation between age and TTc (p = 0.0002). For all measurements obtained, there were moderate to excellent inter-group consistency and intra-rater reliability. This study demonstrated a significant sex dimorphism that may influence the three TIL approaches except for needle angulation in the cricothyroid approach. The knowledge of laryngeal dimension is important to increase success in TIL procedure.