Three-dimensional Computed Tomography Research Articles

Study on Dangerous Acupuncture Needling Depth at Yamen (GV15) for Atlantoaxial Dislocation based on MRI and CT

Background: The depth of acupuncture at GV15 significantly changes with atlantoaxial dislocation (AAD). Magnetic resonance imaging (MRI) and computed tomography (CT) are the current methods for assessing acupuncture depth. However, the acupuncture depth in patients with AAD and the best evaluation method for acupuncture have not been thoroughly studied. Objectives: Based on MRI and 3D CT imaging measurements, dangerous needling depths for perpendicular acupuncture and oblique acupuncture in patients with AAD and normal anatomy were obtained. The application value of MRI and 3D CT in evaluating acupuncture depth is discussed. Methods: From January 2018 to December 2021, patients with AAD (120 patients) and control patients without AAD (124 patients) diagnosed and treated at the Upper Cervical Spine Research Center of the China-Japan Friendship Hospital were selected. All patients were enrolled. Both groups included patients with normal body types (BMI 18.5-23.9). The two groups of patients underwent plain cervical MRI scans and three-dimensional plain CT scans, and the dangerous needling depth of the perpendicular spur and the oblique spur were measured on sagittal images. Results: No significant differences were observed between the two measurements (MRI and CT) (P<0.05). The dangerous needling depths in the AAD group were as follows: male straight stab: 45.33±5.17 mm, male oblique stab: 48.58±4.41 mm, female straight thorn: 44.17±7.80 mm, and female oblique thorn: 47.49±7.32 mm. The dangerous needling depths for the control group were as follows: male straight thorn: 47.72±5.06 mm, male oblique thorn: 42.69±5.53 mm, female straight thorn: 44.63±5.85 mm, and female oblique thorn: 39.88 ± 6.18 mm. Conclusions: Acupuncture depth at the dumb point of the AAD changed significantly. The clinical acupuncture depth should not exceed this safe depth. Both CT and MRI can be used to assess dangerous needling depth at GV15.

Evaluation of dose–Volume-based image-guided high-dose-rate brachytherapy in carcinoma uterine cervix: A prospective study

Background: In recent few decades, the evolution in imaging technology, especially computed tomography (CT) and magnetic resonance imaging, results in widespread availability and its use in high-dose-rate (HDR) intracavitary brachytherapy (ICBT) applications. Aim: The present study was aimed to analyze the cumulative dose–volume histogram of the tumor and organs at risk (OARs) in three-dimensional (3D) CT image-based brachytherapy planning and clinical outcomes of the treated patients. Materials and Methods: This prospective observational study included 40 patients with carcinoma cervix. After external beam radiotherapy (EBRT), a dose of 6 Gy per fraction of HDR ICBT in four fractions with a total dose to point “A” approximately 80–85 Gy was given. For planning, the tumor volumes (high-risk clinical target volume [HR-CTV]) and volume of OARs (bladder, rectum, and sigmoid colon) were contoured on each CT slice. The dose–volume parameters, i.e., minimum dose received to 90% and 100% by HR-CTV volume (D90 and D100) for target and the maximum dose received by minimum volume of 2CC (D2CC) for OARs, were calculated and assessed for clinical response in patients. Results: The mean D2CC dose was 18.24 ± 0.93 Gy, 16.44 ± 1.11 Gy, and 16.37 ± 0.67 Gy for bladder, rectum, and sigmoid colon, respectively. The combined (EBRT and HDR ICBT) mean equieffective dose in 2 Gy per fraction (EQD2) dose for bladder was 76.71 ± 2.05 Gy, for rectum was 72.82 ± 2.58 Gy, and for sigmoid colon was 72.71 ± 1.41 Gy, and its comparison with baseline values showing P < 0.01 for bladder, rectum, and sigmoid colon was considered statistically significant. The mean EQD2 dose of HR-CTV D90 was 151 ± 27.3 Gy. Patients who had received HR-CTV D90 of >90 Gy compared with <90 Gy had exceptionally better local control and complete response. Conclusion: The present study suggested that CT is a favorable modality for treatment planning in cervical cancer with limited resources setup in terms of improved tumor coverage, lesser toxicity, confirmation of applicator placement, and accounting dose to OARs.

Intraoperative Chertsey Test, is it a Reliable Alternative to Computed Tomography Scan for Diagnosing Syndesmotic Injuries of the Ankle?

Background:The present study aims to evaluate the diagnostic exactitude of the intraoperative Chertsey test in tibiofibular syndesmotic injuries in patients with malleolar fractures, in comparison with a computed tomography (CT) scan.Materials and Methods:In this study, patients with malleolar fractures operated between 2018 and 2020 were examined. Thirty-nine patients were enrolled in the study. A three-dimensional preoperative CT scan was obtained. The opposite unfractured ankle was also scanned and considered as the control group. The Chertsey test was performed during the operation to assess the syndesmosis injury. Then, patients were partitioned into two distinct groups, considering the condition of their ankle, namely the Chertsey positive (unstable syndesmosis) group and the Chertsey negative (stable syndesmosis) group.Results:The outcomes of the present survey illustrated that the Chertsey test was positive in 16 patients (41.03%) and negative in 23 patients (59.07%). The median of all CT scan parameters (anterior tibiofibular distances (TFD), middle TFD, posterior TFD, and maximal TFD and volume) before surgery in the group of patients with a positive Chertsey test was significantly higher, measured against the unfractured control group (P < 0.001 for all parameters). Furthermore, a comparison of CT scan parameters and syndesmosis space volume before surgery between the two groups of patients with positive and negative Chertsey test results showed that the measurement of parameters in Chertsey-positive patients was significantly higher than the Chertsey-negative patients (P < 0.001).Conclusion:Chertsey test could be used to diagnose syndesmosis injuries in patients with malleolar fractures due to its high importance in the outcome of patients.

Bronchial morphological changes are associated with postoperative intractable cough after right upper lobectomy in lung cancer patients.

To date, postoperative intractable cough (PIC) has not received adequate attention, and the complex perioperative factors when performing pulmonary resection often prevent researchers from addressing this issue. This study aimed to investigate the clinicopathological and radiographic indicators related to PIC in lung cancer patients. In all, 112 patients who had had right upper lobectomy for primary lung cancer from January 2019 to December 2020 were retrospectively reviewed. We collected data via the electronic medical database of our department. Bronchial morphological features were investigated comprehensively via three-dimensional chest computer tomography reconstruction images. During outpatient follow-up visits, 41 (36.6%) patients complained about persistent dry cough after surgery. Compared with the non-cough group, patients in the refractory cough group showed significant differences in smoking history, right upper lobe stump length, changes of right bronchus intermedius (RBI) diameter, changes of right lower lobe (RLL) basal bronchus diameter, changes of RBI/RLL bronchial angle, and bronchial kink. However, according to multivariable regression analysis, stump length, bronchial kink, and diameter change of the right lower lobe basal bronchus were independently associated with postoperative refractory cough. A nebulization drug was prescribed for the 41 patients diagnosed with PIC, and 33 (80.5%) patients had improved by the next visit. After right upper lobectomy, the morphology of the remaining bronchial tree in the residual lung changed significantly. The bronchial morphological alterations were independent risk factors for PIC.

Classification of avulsion fractures of the fifth metatarsal base using three-dimensional CT mapping and anatomical assessment: a retrospective case series study

BackgroundTo clarify the injury mechanism of the avulsion fracture of the fifth metatarsal combining 3-dimensional (3D) fracture mapping with anatomical measurements.MethodsTwo hundred twenty-two patients with the avulsion fractures of the fifth metatarsal base, who were admitted to our hospital from August 2015 to August 2020. The computed tomography (CT) scans were used to generate the 3-D images of all mapped fracture lines for the avulsion fractures of the fifth metatarsal base were compiled in an overall 3D image. The fifth metatarsal base of 8 unpaired lower limbs of adult Asian frozen cadaveric specimens were also dissected to observe and measure the specific locations of the attachment points of the peroneus brevis, lateral band of the plantar fascia, and peroneus tertius to the fifth metatarsal base.ResultsBased on the type of fracture line produced and the specific locations of the attachment points of the tendons or fascia, the avulsion fractures of the fifth metatarsal base can be classified into three types: type I predominantly involves the action of the lateral band of the plantar fascia; type II predominantly involves the action of the peroneus brevis; type IIIA involves the joint action of the peroneus brevis and lateral band of the plantar fascia with one fracture line, and type IIIB involves the joint action of the peroneus brevis and lateral band of the plantar fascia with two fracture lines.ConclusionThe lateral band of the plantar fascia and peroneus brevis play a major role, either separately or together, in avulsion fractures of the fifth metatarsal base. With this knowledge, we propose a novel classification based on the injury mechanism, which can serve as a reference for clinical treatment and diagnosis.Level of evidenceLevel III, retrospective case series.

Investigation of a contributing factor for cervical vertebral stenotic myelopathy using computed tomography for measuring the cervical vertebral volume.

Thoroughbred horses appear to be particularly predisposed to cervical vertebral stenotic myelopathy (CVSM), also known as wobbler syndrome. We hypothesized that variations in the cervical vertebral volumes can affect the dynamic instability of the cervical vertebrae. This observational study aimed to clarify whether cervical vertebral volume could be considered as a contributing factor in CVSM in Thoroughbred horses. Computed tomography (CT) was used to investigate a total of 21 male Thoroughbred horses (age range, 217–1,002 days; mean, 542.3 days). The study population comprised 17 CVSM horses (age range, 217–1,002 days; mean, 549.8 days) and 4 non-CVSM horses (age range, 244–682 days; mean, 510.5 days). The cervical vertebral volumes of three-dimensional CT were measured using the image-processing software. A significant difference in the variation of cervical vertebral volumes among C2 to C4 and C3 to C5 was identified in the CVSM group (P<0.05). While no significant differences were found in the variation in cervical vertebral volumes among C4 to C6. C3 demonstrated a significantly smaller cervical vertebral volume than C2 and C4 (P<0.05). In the non-CVSM group, no significant differences were found in the variation of cervical vertebral volume among C2 to C4, C3 to C5, and C4 to C6. Our findings suggest that variations in cranial cervical vertebral volume in CVSM male horses can be considered as an important contributing factor in CVSM development.

Fourier method for 3-dimensional data fusion of X-ray Computed Tomography and ultrasound

X-ray Computed Tomography (CT) is essential for nondestructive inspection of many manufactured components but is susceptible to various forms of artifacts and noise. In particular, multi-detector row cone-beam CT systems can suffer from so called “cone-beam” artifacts and partial volume effects, particularly on planar edges at the periphery of the field of view in the cone angle dimension. Uni-directional ultrasonic testing methods generally have extremely accurate in-plane depth resolution but poorer lateral resolution due to physical and geometric constraints. This paper presents a novel technique called Computed Tomographic Fusion (CT-F) which uses three-dimensional Fourier filtering to combine x-ray cone-beam CT reconstructions and ultrasound data in the frequency space. The result is a single image with improved accuracy and quality. CT-F mitigates artifacts while allowing for rapid, accurate characterization of large three-dimensional CT volumes. Using simulations and experiments, we demonstrate artifact reduction and edge contrast improvement in volumetric reconstructions.

3D Fourier ghost imaging via semi-calibrated photometric stereo.

We achieved three-dimensional (3D) computational ghost imaging with multiple photoresistors serving as single-pixel detectors using the semi-calibrated lighting approach. We performed imaging in the spatial frequency domain by having each photoresistor obtain the Fourier spectrum of the scene at a low spectral coverage ratio of 5%. To retrieve a depth map of a scene, we inverted, apodized, and applied semi-calibrated photometric stereo (SCPS) to the spectra. At least 93.5% accuracy was achieved for the 3D results of the apodized set of images applied with SCPS in comparison with the ground truth. Furthermore, intensity error map statistics obtained at least 97.0% accuracy for the estimated surface normals using our method. Our system does not need special calibration objects or any additional optical components to perform accurate 3D imaging, making it easily adaptable. Our method can be applied in current imaging systems where multiple detectors operating at any wavelength are used for two-dimensional (2D) imaging, such as imaging cosmological objects. Employing the idea of changing light patterns to illuminate a target scene and having stored information about these patterns, the data retrieved by one detector will give the 2D information while the multiple-detector system can be used to get a 3D profile.

Use of Three-Dimensional Imaging to Assess the Effectiveness of Volume as a Critical Variable in Breast Implant Selection.

In breast augmentation, breast base diameter has been recognized as an important variable in implant selection. However, breast implant volume also has a tremendous impact on the final result. Previous methods of preoperative volume determination have been limited to external devices in a bra. Computer-based three-dimensional simulation technology now allows the physician to effectively communicate with the patient preoperatively regarding volume. A cohort of 40 consecutive patients underwent routine breast augmentation with either anatomically shaped or round implants. Five methods of preoperative volume determination including the Crisalix three-dimensional computer imaging system (Crisalix Virtual Aesthetics, Lausanne, Switzerland), along with an associated virtual reality tool, were used to assess the preoperative desires of the patients. A postoperative questionnaire was used to assess patient satisfaction with each volume determination method. Of the 40 patients, 100 percent were satisfied with their result; however, given the opportunity, 12 percent would have chosen a larger implant. The virtual reality tool and external sizers were shown to be the most effective in choosing an implant. The virtual reality tool was judged to be very helpful (62 percent), very accurate (78 percent), and important (88 percent) in helping patients choose their desired implant size. Prioritizing volume as an implant selection variable in breast augmentation results in a very high rate of patient satisfaction. Therapeutic, IV.

Fusion Visualization Technique to Improve a Three-Dimensional Isotope-Selective CT Image Based on Nuclear Resonance Fluorescence with a Gamma-CT Image

One of the most noteworthy aspects of computed tomography (CT) based on the nuclear resonance fluorescence (NRF) transmission method is the isotope selectivity that makes it possible to discern an isotope of interest from other isotopes within a sample. We experimentally obtained a three-dimensional (3D) isotope-selective CT image based on the NRF transmission method (3D NRF-CT) for the enriched lead isotope distribution of 208Pb in a cylindrical holder in a previous study. The cylindrical holder’s diameter and height are 25 mm and 20 mm, respectively. The NRF-CT imaging technique requires a considerable data accumulation time. It took 48 h to obtain an image with a resolution of 4 mm/pixel in the horizontal plane and 8 mm/pixel in the vertical plane using a laser Compton scattering (LCS) gamma-ray beam with a beam size of 2 mm and a flux density of 10 photons/s/eV. Improving the NRF-CT image resolution with the existing hardware is challenging. Therefore, we proposed an alternative method to improve the NRF-CT image resolution using the fusion visualization (FV) technique by combining the NRF-CT image including isotopic information with a gamma-CT image, which provides better pixel resolution. The 3D gamma-CT image for the same sample was measured at the same beamline BL1U in the ultraviolet synchrotron orbital radiation-III (UVSOR-III) synchrotron radiation facility at the Institute of Molecular Science at the National Institutes of Natural Sciences in Japan under similar experimental conditions except for the LCS gamma-ray beam flux and beam size. Obtaining a 3D gamma-CT image with a resolution of 1 mm/pixel took 5 h using an LCS gamma-ray beam with a beam size of 1 mm and a flux density of 0.7 photons/s/eV. The data processing of the FV technique has been developed, and the 3D NRF-CT image quality was improved.

CT texture analysis-based nomogram for the preoperative prediction of visceral pleural invasion in cT1N0M0 lung adenocarcinoma: an external validation cohort study

To develop a nomogram based on computed tomography (CT) texture analysis for the preoperative prediction of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma. A dataset of chest CT containing lung nodules was collected from two institutions, and all surgically resected nodules were classified pathologically based on the presence of visceral pleural invasion. Each nodule on the CT image was segmented automatically by artificial-intelligence software and its CT texture features were extracted. The dataset was divided into training and external validation cohorts according to the institution, and a nomogram for predicting visceral pleural invasion was developed and validated. Of a total of 313 patients enrolled from two independent institutions, 63 were diagnosed with visceral pleural invasion. Three-dimensional (3D) CT long diameter, skewness, and sphericity, and chronic obstructive pulmonary disease were identified as independent predictors for visceral pleural invasion by multivariable logistic regression. The nomogram based on multivariable logistic regression showed great discriminative ability, as indicated by a C-index of 0.890 (95% confidence interval [CI]: 0.867-0.914) and 0.864 (95% CI: 0.817-0.911) for the training and external validation cohorts, respectively. Additionally, calibration of the nomogram revealed good predictive ability, as indicated by the Brier score (0.108 and 0.100 for the training and external validation cohorts, respectively). A nomogram was developed that could compute the probability of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma with good calibration and discrimination. The nomogram has potential as a reliable tool for clinical evaluation and decision-making.

Evaluation of the reliability of lower extremity alignment measurements using EOS imaging system while standing in an even weight-bearing posture

This study aimed to analyze the reproducibility and reliability of the alignment parameters measured using the EOS image system in both limbs while standing with an even weight-bearing posture. Overall, 104 lower extremities in 52 patients were analyzed retrospectively. The patients stood with an even load over both lower extremities then rotated 15° in both directions. Two EOS images were acquired and 104 pairs of lower extremities were compared according to the position of the indexed lower extremities. Then, the inter-observer reliability of the EOS system and the inter-modality reliability between EOS and computed tomography (CT) were evaluated. Femoro-tibial rotation (FTR) and tibial torsion demonstrated a significant difference between the anterior and posterior positions of the indexed lower extremity. In the inter-observer reliability analysis, all values except for FTR and tibial torsion demonstrated good or very good reliability. In the anterior position, FTR demonstrated moderate, and tibial torsion demonstrated poor reliability. In the posterior position, both FTR and tibial torsion demonstrated poor reliability. In the reliability analysis between the three-dimensional (3D) EOS model and 3D CT images, all measurements of the femur demonstrated very good reliability, but measurements of the tibia did not. For the coronal and sagittal alignment parameters measured by the EOS 3D system with rotated standing posture, except for the measurement including tibial torsion., there were no significant difference for either position of the indexed extremities with high agreement between the observers as well as with the CT 3D model.

A novel method for determining the X-ray beam angulation of the supraspinatus outlet view.

Rapid and accurate quantification of the supraspinatus outlet view (SOV) is a clinical challenge. To quantify the X-ray beam angle of the SOV using the horizontal angle of the subscapular spine line (SSSL) and to further verify the feasibility of this method. A total of 119 patients who underwent shoulder computed tomography (CT) examination were enrolled in the retrospective study. Three-dimensional (3D) CT reconstruction was performed and manually adjusted to provide the position similar to SOV. The rotation angle of the 3D image along the long axis of the human body (marked as β) was obtained. The horizontal angle of SSSL (marked as α) was measured on the anteroposterior localizer image of shoulder CT. Pearson correlation and linear regression correlation analysis were performed. In addition, the first-time success rate between the experience-based group and the measurement-based group were compared to verify the novel method. We found a linear correlation between α and β (r = 0.962; P = 0.000). There was no significant correlation between the experience-based group and the measurement-based group in terms of age (P = 0.500), sex (P = 0.397), and side (P = 0.710), but there was a significant statistical difference in the first success rate between the two validation groups (χ2 = 5.808a, P = 0.016). This novel quantitative measurement method for determining the X-ray beam angle of SOV using the horizontal angle of SSSL is feasible.

Factors Contributing to Graft Matching in a Patellar Osteochondral Allograft Selection Model (211)

Objectives:Patellar osteochondral allograft (OA) transplantation has been shown to be a successful treatment in patients with isolated patellar cartilage injury. Currently, there is minimal guidance in anatomic and sizing factors that portend similar patellar surface topography. The most commonly utilized patellar sizing criteria to match the donor and recipient is radiographic tibial width. Our hypothesis is that specific patella anatomic factors will better predict surface topography matching. To our knowledge, no prior study has investigated the topography of the patella and what intrinsic factors of the graft and the recipient affect matching of the chondral and osseous layers between the graft and defect.Methods:Computed tomography (CT) images of the specimens were acquired and three-dimensional (3D) CT models of the patella were then created and exported into point-cloud models using a 3D reconstruction software program. Circular articular cartilage and subchondral bone defect models were created in each point-cloud model of the recipient patella with a diameter of 18 mm and 22.5 mm at 3 locations: the medial, central, and lateral portions of the patellar surface. Circular articular cartilage and subchondral bone graft models were created on all possible locations on the articular cartilage surface models of the donor patellae (Figure 1). The graft models were virtually placed on the surface of the defect model. Orientation of the graft model was adjusted so that its axis matched that of the defect site. Least distances between the graft and the defect articular surface models were calculated and were defined as the shortest distance from the point in question to the corresponding point in space. A mean value of the least distances was calculated for each position of the graft model. The mean least distance of subchondral bone surface in each point was calculated simultaneously. The graft model was then rotated 360° around the axis perpendicular to the articular cartilage surface in 1° increments, and the least distance of articular cartilage surface and the resulting least distance of subchondral bone surface were calculated at each rotating angle. This procedure was repeated for all points in the articular surface model of the donor patella. Step-off was then calculated as the least mean square difference between the defect and graft along the periphery. Stepwise linear regression was used for each defect location to analyze which variables predict degree of mismatch in millimeters.Results:A total of 16 patella were utilized in analysis. Comparison of cartilage least mean square distances between locations demonstrated that the lateral location had significantly less surface incongruity compared to the other two locations (vs medial: p = .0038, vs central: p = .0046). In addition, significant differences in subchondral bone distances were observed between the locations (lateral vs medial: p = .0007, lateral vs central: p < .0001, medial vs central: p < .0001) (Table 1). The associations of six anatomic and morphologic variables with cartilage mismatch, bone mismatch, and step-off for 18 mm and 22.5 mm defects are presented in Tables 2 and Table 3. All variables were analyzed as the difference in value between the recipient and donor. For both lesion sizes, cartilage step-off was the most susceptible to variable differences. Compared to the 18 mm defect group, the 22.5 mm defects were more affected (higher coefficients) by the same differences in variables. Differences in tibial width were associated mismatch for central lesions (eg. 22.5mm defect coefficient: -0.026, p < .001), while cartilage width was associated with mismatch for lateral lesions. (eg. 22.5 mm defect coefficient: -0.034, p < .023).Conclusions:Multiple clinically relevant factors were found to affect graft and defect chondral mismatch and to a lesser extent osseous mismatch. For all three locations at both defect sizes, step-off was the most susceptible to differences in patellar morphology between the donor and recipient. In addition, differences in tibial width, a commonly used metric for patellar graft matching, did not significantly predict chondral mismatch for lateral and medial sized lesions. These findings should be considered when selecting and preparing the graft in a patella osteochondral allograft procedure.

Tetrahedron beam imaging with a multi-pixel thermionic emission X-ray source and a photon-counting detector: A benchtop experimental study.

A tetrahedron beam (TB) X-ray system with a linear X-ray source array and a linear detector array positioned orthogonal to each other may overcome the X-ray scattering problem of traditional cone-beam X-ray systems. We developed a TB imaging benchtop system using a linear array X-ray source to demonstrate the principle and benefits of TB imaging. A multi-pixel thermionic emission X-ray (MPTEX) source with 48 focal spots in 4-mm spacing was developed in-house. The X-ray beams are collimated to a stack of fan beams that are converged to a 6-mm wide multi-row photon-counting detector (PCD). The data collected with a sequential scan of the sources at a fixed view angle were synthesized to a 2D radiography image by a shift-and-add algorithm. The data collected with a full rotation of the system were reconstructed into 3D TB CT (TBCT) images using an Feldkamp, Davis, and Kress (FDK)-based computed tomography (CT) algorithm modified for the TB geometry. With an 18.8-cm long source array and a 35-cm long detector array, the TB benchtop system provides a 25-cm cross-sectional and 8-cm axial field of view (FOV). The scatter-to-primary ratio (SPR) was approximately 17% for TB, as compared with 120% for cone beam geometry. The TBCT system enables reconstructions in two-dimensional radiography and three-dimensional volumetric CT. The TBCT images were free of "cupping" artifacts and have similar image quality as diagnostic helical CT. A TB imaging benchtop imaging system was successfully developed with MPTEX source and PCD. Phantom and animal cadaver imaging demonstrated that the TB system can produce satisfactory radiographic X-ray images and 3D CT images with image quality comparable to diagnostic helical CTs.

Open osteology: Medical imaging databases as skeletal collections

• Medical imaging datasets can be used as skeletal reference collections • Computed tomography data from TCIA can be accessed via 3D Slicer • Many tools in 3D Slicer support skeletal analyses and dissemination products • 3D bone models can be used for education, research, training, web-based reference • Bone modeling in 3D Slicer will support common workflows and shareable datasets The increasing availability of de-identified medical image databases, especially of computed tomography (CT) scans, presents an opportunity for “open osteology,” or the establishment of new skeletal reference collections. The number of free and/or open-source software packages for generating three-dimensional (3D) CT models, such as 3D Slicer, reduces financial obstacles to working with CT data and encourages the development of common workflows and datasets. The direct link to the Cancer Imaging Archive from 3D Slicer facilitates access to medical imaging datasets to support education and research with virtual skeletal data. Generation of 3D models enables computational methods for skeletal analyses and can also lead to the generation of virtual libraries representing large amounts of human skeletal variation. 3D printing of 3D CT models can supplement physical skeletal collections for the classroom and research beyond the standard commercially available specimens. Web-based technologies support 3D model and CT volume visualization, interaction, and measurement, increasing opportunities for dissemination and collaboration as well as the possible integration of 3D data as references for skeletal analysis tools. Increasing awareness and usage of pre-existing free and open-source resources applicable to forensic anthropology will facilitate method/workflow development, validation, and eventually standardization. This presentation will discuss online sources of skeletal data, outline methods for processing CT scans with free software into 3D digital models and discuss web-based technologies and repositories that allow interaction with 3D skeletal models. The demonstration of these methods will contribute to discussions on the expansion of virtual anthropology and open osteology.

Three-dimensional volume-rendered computed tomography application for follow-up fracture healing and volume measurements pre-surgical rib fixation and post-surgical rib fixation.

Surgical rib fixation (SRF) is being used increasingly in trauma centers for stabilization of chest wall injuries, in line with new and evolving surgical techniques. Our institution has developed a pathway for the management of chest wall injuries and SRF, which includes a follow-up low-volume, noncontrast computed tomography (CT) scan at 12 months. This study was a single-center retrospective study conducted on 25 consecutive patients who underwent SRF between February 2019 and February 2020. All CT measurements were done by a CT radiographer under the supervision of a board-certified radiologist and included the use of three-dimensional volume-rendered images. There were no patients with SRF who experienced hardware failure at 12 months in either flail or nonflail groups. For fractured ribs treated with SRF, complete or partial union occurred in 75 of 76 ribs plated (98.7%). The median ratio for improvement in lung volumes was 1.71 for flail SRF and 1.69 for nonflail SRF in our study. Three-dimensional volume-rendered CT at 12 months post-SRF showed good alignment (no hardware failure) and fracture healing of fixed ribs in both flail and nonflail groups. Lung volumes also improved pre-SRF and post-SRF for both flail and nonflail patients. More studies are needed to define how the pattern of rib fracture healing of fixed and nonfixed ribs affects lung volumes. Therapeutic, Level V.

High-stress distribution in the lateral region of the subtalar joint in the patient with chronic lateral ankle instability.

Chronic lateral ankle instability (CLAI) is associated with osteoarthritis (OA). However, the characteristics of patients with CLAI who progress to OA are not clear. Measurement of Hounsfield Unit (HU) value on computed tomography (CT) is reported to be useful to evaluate the stress distribution. We aimed to evaluate the stress distribution in the ankle and subtalar joints and factors enhancing it in patients with CLAI. Thirty-three ankles with CLAI (CLAI group) and 26 ankles without CLAI (control group) were included. A mean age of CLAI was 35.2years and control was 30.3years. Color map was created in the ankle and subtalar joint according to the HU values using three-dimensional CT to identify the region with high HU values, and HU values in those regions were measured using two-dimensional CT and compared between control and CLAI groups. In CLAI group, the relationships between HU values and ankle activity score (AAS), OA, talar tilting angle (TTA), cartilage injury were assessed. The HU values in the anteromedial region of the talus and lateral region in the subtalar joint were higher than those in the control. In CLAI, patients with an AAS of ≧ 6, over 10° of TTA, cartilage injury, and OA changes in the medial gutter had significantly higher HU values in the lateral region of the subtalar joint than those with an AAS of ≦5, less than 10° of TTA without cartilage injury and OA change. CLAI patients, especially in the patients with high activity level, large TTA, cartilage injury, and OA changes at the medial gutter, have high HU values in the lateral region of the subtalar joint, which suggests that disruption of the subtalar compensation toward OA will occur. For these patients, instability should be completely eliminated to prevent ankle OA. Level III, comparative series.

Evaluation of Sanders Type 2 Joint Depression Calcaneal Fractures in 197 Patients from a Single Center Using Three-Dimensional Mapping.

BackgroundThis study aimed to evaluate Sanders type 2 calcaneal fractures in 197 patients from a single center using the 3D (three-dimensional) CT (computed tomography) mapping method.Material/MethodsA consecutive series of 197 Sanders type 2 joint depression calcaneal fractures was used. The segment and split functions were used to create each calcaneal fragment using Mimics Research 20.0 software. The fracture fragments were reduced in 3-matic Research 12.0 software. In the E-3D Medical 18.01 software, after superimposing the fractured calcaneus entity with the calcaneus template, we drew the fracture line on the template. Finally, the heatmap was obtained by fracture statistical analysis function. Simultaneously, the distribution of the fracture lines in the anterior part of the calcaneus (APC) and middle talar joint was recorded.ResultsThere were 109 cases of Sanders type 2A, 46 cases of Sanders type 2B, and 42 cases of Sanders type 2C. Based on the data, we drew the characteristic fracture map of type 2A 2B and 2C. This study found that the most common types of Sanders type 2A in APC and middle talar articular surface are type AC and type AD. In Sanders type 2B, the most common type is type AC, and in Sanders type 2C it is type ACD.ConclusionsThe findings from this study showed that 3D CT imaging and reconstruction of the calcaneus was a useful diagnostic method to evaluate and classify joint depression calcaneal fractures. The calcaneal fracture map can be used to guide surgical planning and optimize the design of internal fixation.

Facial Dysmorphology in Saethre-Chotzen Syndrome.

Classic features of Saethre-Chotzen syndrome (SCS) described in the literature include a prominent nasal bridge, eyelid ptosis, telorbitism, maxillary hypoplasia, and mandibular prognathism. The purpose of this study was to evaluate objectively the bony features of SCS. Preoperative computer tomography scans of 15 SCS patients, 23 normal controls, 13 bicoronal nonsyndromic, and 7 unicoronal nonsyndromic craniosynostosis patients were included for analysis. Unaffected controls and nonsyndromic patients were age- and sex-matched to SCS patients. Morphometric cephalometrics were analyzed using three-dimensional computer tomography reconstructions. Mann-Whitney U were used to compare facial measurements between SCS and normal and nonsyndromic craniosynostosis controls. Telorbitism was present in bicoronal SCS patients only (P = 0.04) but absent in the unicoronal and bicoronal/metopic cohorts. The angle of the nasal bone relative to the sella was not different between SCS and controls (P = 0.536), although the angle of the nasal bone relative to the forehead was decreased in SCS by 15.5° (P < 0.001). Saethre-Chotzen syndrome had a 2.6° maxillary retrusion relative to controls (P = 0.03). In addition, SCS patients aged 4 to 7 months had a wider (39.34 versus 35.04, P = 0.017) and anteroposteriorly foreshortened (32.12 versus 35.06, P = 0.039) maxilla. There was no difference in mandibular prognathism among SCS patients as measured by the sella-nasion-B point angle compared to controls (P = 0.705). Despite classic descriptions, on morphometric analysis SCS patients did not demonstrate consistency across all suture subtypes in terms of telorbitism, a broad nasal bridge, or mandibular prognathism. Rather, SCS subtypes of SCS based on suture pathology more closely resemble nonsyndromic patients.