Digital Imaging And Communications In Medicine Data Research Articles

The retropharyngeal reduction plate for atlantoaxial dislocation: a finite element analysis.

Objective: To investigate the biomechanical properties of the retropharyngeal reduction plate by comparing the traditional posterior pedicle screw-rod fixation by finite element analysis. Methods: Two three-dimensional finite element digital models of the retropharyngeal reduction plate and posterior pedicle screw-rod fixation were constructed and validated based on the DICOM (Digital Imaging and Communications in Medicine) data from C1 to C4. The biomechanical finite element analysis values of two internal fixations were measured and calculated under different conditions, including flexion, extension, bending, and rotation. Results: In addition to the backward extension, there was no significant difference in the maximum von Mises stress between the retropharyngeal reduction plate and posterior pedicle screw fixation under other movement conditions. The retropharyngeal reduction plate has a more uniform distribution under different conditions, such as flexion, extension, bending, and rotation. The stress tolerance of the two internal fixations was basically consistent in flexion, extension, left bending, and right bending. Conclusion: The retropharyngeal reduction plate has a relatively good biomechanical stability without obvious stress concentration under different movement conditions. It shows potential as a fixation option for the treatment of atlantoaxial dislocation.

A novel, end-to-end framework for avoiding collisions between the patient's body and gantry in proton therapy.

Administration of external radiation therapy via proton therapy systems carries a risk of occasional collisions between the patient's body and gantry, which is increased by the snout placed near the patient for better dose distribution. Although treatment planning software (TPS) can simulate controlled collisions, the computed tomography (CT) data used for treatment planning are insufficient given that collisions can occur outside the CT imaging region. Thus, imaging the three-dimensional (3D) surface outside the CT range and combining the data with those obtained by CT are essential for avoiding collisions. To construct a prototype for 3D surface imaging and an end-to-end framework for preventing collisions between the patient's body and the gantry. We obtained 3D surface data using a light sectioning method (LSM). By installing only cameras in front of the CT, we achieved LSM using the CT couch motion and preinstalled patient-positioning lasers. The camera image contained both sagittal and coronal lines, which are unnecessary for LSM and were removed by deep learning. We combined LSM 3D surface data and original CT data to create synthetic Digital Imaging and Communications in Medicine (DICOM) data. Subsequently, we compared the TPS snout auto-optimization using the original CT data with the synthetic DICOM data. The mean positional error for LSM of the arms and head was 0.7±0.8 and 0.8±0.8mm for axial and sagittal imaging, respectively. The TPS snout auto-optimization indicated that the original CT data would cause collisions; however, the synthetic DICOM data prevented these collisions. The prototype system's acquisition accuracy for 3D surface data was approximately 1mm, which was sufficient for the collision simulation. The use of a TPS with collision avoidance can help optimize the snout position using synthetic DICOM data. Our proposed method requires no external software for collision simulation and can be integrated into the clinical workflow to improve treatment planning efficiency.

Initial Experience of 10 Imaging Vendors with the IHE SHARAZONE: a New Multivendor Peer-to-Peer Test Service for DICOM Objects.

Alignment of DICOM (Digital Imaging and Communications in Medicine) capabilities among vendors is crucial to improve interoperability in the healthcare industry and advance medical imaging 2. However, a sustainable model for sharing DICOM samples is not available. To address this issue, Integrating the Healthcare Enterprise (IHE) has introduced the IHE SHARAZONE, a continuous cross-vendor DICOM data sharing test service.IHE is a highly regarded organization known for profiling standards such as DICOM, HL7 v2 (Health Level Seven, version 2), HL7 CDA (Clinical Document Architecture), and HL7 FHIR (Fast Healthcare Interoperability Resources) into practical solutions for clinical practice. The primary goal of the IHE SHARAZONE is to provide a reliable and consistent cross-vendor DICOM data sharing system.To evaluate its effectiveness, a 5-month pilot was conducted with ten imaging vendors. The pilot concluded with a participant survey, which yielded valuable insights into the initial experience with the IHE SHARAZONE. These findings can inform future improvements and developments to this important service.

Smoothing Module for Optimization Cranium Segmentation Using 3D SlicerSmoothing Module for Optimization Cranium Segmentation Using 3D Slicer

Anatomy is the most essential course in health and medical education to study parts of human body and also the function of it. Cadaver is a media used by medical student to study anatomical subject. Because of limited access to cadaver and also due to high prices, this situation makes it necessary to develope an alternative anatomical education media, one of them is the use 3D printing to produce anatomical models. Before 3D Print the cranium, it is necessary to do the segmentation process and often the segmentation result is not good enough and appear a lot of noises. The purpose of this research is to optimize a 3D cranium based on DICOM (digital imaging and communications in medicine) data processing using the smoothing modules on 3D Slicer. The method of this research is to process the Cranium DICOM data using 3D Slicer software by varying the 5 types of smoothing modules. The results with default parameter fill holes and median have better results compared to others. Kernel size variations are performed for smoothing module fill holes and medians. The result is fill holes get optimal segmentation results using a kernel size of 3 mm and the median is 5 mm.

Development of pre-procedure virtual simulation for challenging interventional procedures: an experimental study with clinical application.

BackgroundMost pain management techniques for challenging procedures are still performed under the guidance of the C-arm fluoroscope although it is sometimes difficult for even experienced clinicians to understand the modified three-dimensional anatomy as a two-dimensional X-ray image. To overcome these difficulties, the development of a virtual simulator may be helpful. Therefore, in this study, the authors developed a virtual simulator and presented its clinical application cases.MethodsWe developed a computer program to simulate the actual environment of the procedure. Computed tomography (CT) Digital Imaging and Communications in Medicine (DICOM) data were used for the simulations. Virtual needle placement was simulated at the most appropriate position for a successful block. Using a virtual C-arm, the authors searched for the position of the C-arm at which the needle was visualized as a point. The positional relationships between the anatomy of the patient and the needle were identified.ResultsFor the simulations, the CT DICOM data of patients who visited the outpatient clinic was used. When the patients revisited the clinic, images similar to the simulated images were obtained by manipulating the C-arm. Transforaminal epidural injection, which was difficult to perform due to severe spinal deformity, and the challenging procedures of the superior hypogastric plexus block and Gasserian ganglion block, were successfully performed with the help of the simulation.ConclusionsWe created a pre-procedural virtual simulation and demonstrated its successful application in patients who are expected to undergo challenging procedures.

Evaluation of the short-term curative effect of closed reduction in the treatment of developmental dysplasia of the hip based on three-dimensional magnetic resonance imaging finite element analysis

BackgroundBased on the Digital Imaging and Communications in Medicine (DICOM) data of three-dimensional magnetic resonance imaging (3D-MRI), finite element models of the hip joints of children with developmental dysplasia of the hip were established. The primary objectives included simulation and analysis of the finite element model pre- and post-closed reduction under different stances and loads, and evaluation of the size and distribution of von Mises stress in the acetabulum and femoral head pre- and post-operation and the short-term effects.MethodsAcetabular index measurements of both the unaffected and affected sides were conducted, alongside International Hip Dysplasia Institute (IHDI) classification of the affected hip. Establishing the finite element model of both the affected and unaffected hips was based on the 3D-T1WI sequence DICOM data, using Mimics, 3-matic, and Ansys software, before and after closed reduction surgery. The size and distribution data of von Mises stress on the affected side of the acetabulum and femoral head were collected pre- and post-operation.ResultsThe study indicated that the increasing acetabular index of the affected hip was directly proportional to the increasing severity based on IHDI classification (P < 0.05). Preoperative IHDI classification significantly correlated with the von Mises stress (r = 0.560–0.569, 0.562–0.564, P < 0.05). Under different stances and load conditions, the von Mises stress on the affected side post-operation was lower than that noted pre-operation (P < 0.01), while that on the acetabulum increased proportionally to the load. Although the magnitude and distribution of von Mises stress on the affected side of the acetabulum were similar to those on the healthy side post-operation, there were statistical differences between the two (P < 0.01). The von Mises stress of the lateral column of the femoral head post-operation was significantly lower than that noted pre-operation (P < 0.01). While the high-stress points of the lateral column disappeared post-operation, the von Mises stress was evenly distributed in the femoral head.ConclusionsThe 3D-MRI finite element could provide the von Mises stress value and distribution characteristics of the acetabulum and femoral head pre- and post-operation. Closed reduction can, therefore, improve the size and distribution of von Mises stress on the affected acetabulum and femoral head.

PDCP: A Set of Tools for Extracting, Transforming, and Loading Radiotherapy Data from the Orthanc Research PACS

The Orthanc server is a light-weight open-source picture imaging and archiving system (PACS) used to store digital imaging and communications in medicine (DICOM) data. It is widely used in research environments as it is free, open-source and scalable. To enable the use of Orthanc stored radiotherapy (RT) data in data mining and machine learning tasks, the records need to be extracted, validated, linked, and presented in a usable format. This paper reports patient data collection and processing (PDCP), a set of tools created using python for extracting, transforming, and loading RT data from Orthanc PACs. PDCP enables querying, retrieving, and validating patient imaging summaries; analysing associations between patient DICOM data; retrieving patient imaging data into a local directory; preparing the records for use in various research questions; tracking the patient’s data collection process and identifying reasons behind excluding patient’s data. PDCP targeted simplifying the data preparation process in such applications, and it was made expandable to facilitate additional data preparation tasks.

Evaluation of the accuracy of soft tissue thickness measurements with three different methodologies: An in vitro study.

Soft tissue thickness (STT) influences esthetics, peri-implant, and periodontal health. Non-invasive methods of STT evaluation include cone-beam computed tomography (CBCT) with Digital Imaging and Communications in Medicine (DICOM) files and registration of DICOM files with an intraoral scan or Standard Tessellation Language (STL) files. This study compares three methodologies: bone sounding, DICOM data alone, and DICOM and STL registration to absolute histomorphologic values. Five human maxillas, including teeth numbers 6 to 11, provided 90 sites for analysis. For standardization, reference grooves were placed at the cervical margin and the long axis of each tooth. Direct measurements with a no. 25 K-file were completed at the facial soft tissues at 3.00, 5.00, and 7.00mm from the apical marginal reference. Indirect measures were performed with implant planning software. Histological measurements were rendered with imaging software. One-way analysis of variance (ANOVA) was used to compare the three techniques for the differences from histologic measurements (α=0.05). Seventy-two sites were included for final analysis. The overall mean histological STT (mSTT) was 0.73±0.31mm. Bone sounding overestimated mSTT, 0.22±0.20mm (P&lt;0.001); whereas, DICOM alone underestimated mSTT, -0.23±0.19mm (P&lt;0.001). DICOM and STL registration had non-statistically significant differences, -0.04±0.21mm (P=0.429). Intraclass correlation coefficient (ICC) of DICOM and STL registration achieved the highest agreement with histology (ICC: 0.74). DICOM and STL file registration had the highest agreement with histological STT supporting the use of DICOM and STL registration for the evaluation of STT.

Four-dimensional computed tomographic analysis of screw home movement in patients with anterior cruciate ligament deficient knee - a 3D-3D registration technique.

The tibia externally rotates to the femur during the last 20° of the knee extension motion. This kinematic phenomenon is well known as screw home movement (SHM). The purpose was to clarify the SHM in anterior cruciate ligament deficient (ACLD) knee using four-dimensional computed tomography (4DCT). Six patients with a unilateral isolated ACLD knee participated. In the static position, CT scan of the both limbs of the femur and tibia were performed. Then, 4DCT was performed around knee. In the CT gantry, subjects were positioned in supine position with 45° of knee flexion on a triangle pillow and were asked to extend the knee to full extension within 10s on each limb. The CT data were accumulated in digital imaging and communication in medicine (DICOM) data format. From the static CT and 4DCT DICOM data, three-dimensional surfaces of the knee joint were reconstructed. The whole tibia surface was matched into the partial tibia surface of that frame using 3D-3D registration technique. After the assessment of coordination system of the whole leg, knee flexion, abduction, and external rotation angle were calculated. Knee external rotation angle was significantly smaller on the ACLD side than on the contralateral unaffected side in 0-15° of knee flexion (P < 0.05 in 0, 5, 10, and 15 degrees), while the angle was similar during 15-60° of knee flexion. The absence of SHM in ACLD knee was detected using 3D-3D registration technique based on 4DCT.

A DICOM Framework for Machine Learning and Processing Pipelines Against Real-time Radiology Images

Real-time execution of machine learning (ML) pipelines on radiology images is difficult due to limited computing resources in clinical environments, whereas running them in research clusters requires efficient data transfer capabilities. We developed Niffler, an open-source Digital Imaging and Communications in Medicine (DICOM) framework that enables ML and processing pipelines in research clusters by efficiently retrieving images from the hospitals’ PACS and extracting the metadata from the images. We deployed Niffler at our institution (Emory Healthcare, the largest healthcare network in the state of Georgia) and retrieved data from 715 scanners spanning 12 sites, up to 350 GB/day continuously in real-time as a DICOM data stream over the past 2 years. We also used Niffler to retrieve images bulk on-demand based on user-provided filters to facilitate several research projects. This paper presents the architecture and three such use cases of Niffler. First, we executed an IVC filter detection and segmentation pipeline on abdominal radiographs in real-time, which was able to classify 989 test images with an accuracy of 96.0%. Second, we applied the Niffler Metadata Extractor to understand the operational efficiency of individual MRI systems based on calculated metrics. We benchmarked the accuracy of the calculated exam time windows by comparing Niffler against the Clinical Data Warehouse (CDW). Niffler accurately identified the scanners’ examination timeframes and idling times, whereas CDW falsely depicted several exam overlaps due to human errors. Third, with metadata extracted from the images by Niffler, we identified scanners with misconfigured time and reconfigured five scanners. Our evaluations highlight how Niffler enables real-time ML and processing pipelines in a research cluster.

FAIR‐compliant clinical, radiomics and DICOM metadata of RIDER, interobserver, Lung1 and head‐Neck1 TCIA collections

Purpose One of the most frequently cited radiomics investigations showed that features automatically extracted from routine clinical images could be used in prognostic modeling. These images have been made publicly accessible via The Cancer Imaging Archive (TCIA). There have been numerous requests for additional explanatory metadata on the following datasets — RIDER, Interobserver, Lung1, and Head–Neck1. To support repeatability, reproducibility, generalizability, and transparency in radiomics research, we publish the subjects’ clinical data, extracted radiomics features, and digital imaging and communications in medicine (DICOM) headers of these four datasets with descriptive metadata, in order to be more compliant with findable, accessible, interoperable, and reusable (FAIR) data management principles. Acquisition and validation methods Overall survival time intervals were updated using a national citizens registry after internal ethics board approval. Spatial offsets of the primary gross tumor volume (GTV) regions of interest (ROIs) associated with the Lung1 CT series were improved on the TCIA. GTV radiomics features were extracted using the open-source Ontology-Guided Radiomics Analysis Workflow (O-RAW). We reshaped the output of O-RAW to map features and extraction settings to the latest version of Radiomics Ontology, so as to be consistent with the Image Biomarker Standardization Initiative (IBSI). Digital imaging and communications in medicine metadata was extracted using a research version of Semantic DICOM (SOHARD, GmbH, Fuerth; Germany). Subjects’ clinical data were described with metadata using the Radiation Oncology Ontology. All of the above were published in Resource Descriptor Format (RDF), that is, triples. Example SPARQL queries are shared with the reader to use on the online triples archive, which are intended to illustrate how to exploit this data submission. Data format The accumulated RDF data are publicly accessible through a SPARQL endpoint where the triples are archived. The endpoint is remotely queried through a graph database web application at http://sparql.cancerdata.org. SPARQL queries are intrinsically federated, such that we can efficiently cross-reference clinical, DICOM, and radiomics data within a single query, while being agnostic to the original data format and coding system. The federated queries work in the same way even if the RDF data were partitioned across multiple servers and dispersed physical locations. Potential applications The public availability of these data resources is intended to support radiomics features replication, repeatability, and reproducibility studies by the academic community. The example SPARQL queries may be freely used and modified by readers depending on their research question. Data interoperability and reusability are supported by referencing existing public ontologies. The RDF data are readily findable and accessible through the aforementioned link. Scripts used to create the RDF are made available at a code repository linked to this submission: https://gitlab.com/UM-CDS/FAIR-compliant_clinical_radiomics_and_DICOM_metadata.

The Characteristics of the Favard E4 Glenoid Morphology in Cuff Tear Arthropathy: A CT Study.

Background: Cuff tear arthropathy (CTA) is characterized by superior migration of the humeral head with superior erosion of the glenoid. Rarely, humeral head migration can be anteroinferior with associated anterior erosion of the glenoid, a pattern described by Favard as the type E4 glenoid. The purpose of this retrospective imaging study was to analyze the 2D and 3D characteristics of the E4 glenoid. Methods: A shoulder arthroplasty database of 258 cuff tear arthropathies was examined to identify patients with an E4 type deformity. This resulted in a study cohort of 15 females and 2 males with an average age of 75 years. All patients had radiographs and CT scans available for analysis. CT-scan DICOM (Digital Imaging and Communications in Medicine) data were uploaded to a validated three-dimensional (3D) imaging software. Muscle fatty infiltration, glenoid measurements (anteversion, inclination), and humeral head subluxation according to the scapular plane were determined. Results: The mean anteversion and inclination of the E4 cohort were 32° ± 14° and −5° ± 2, respectively. The mean anterior subluxation was 19% ± 16%. All cases had severe grade 3 or 4 fatty infiltration of the infraspinatus, whereas only 65% had grade 3 or 4 subscapularis fatty infiltration. A significant correlation existed between glenoid anteversion and humeral head subluxation (p < 0.001), but no correlation was found with muscle fatty infiltration. The CT analysis demonstrated an acquired erosive biconcave morphology in 11 patients (65%) and monoconcavity in 6 patients (35%). Conclusion: The E4 type glenoid deformity in cuff tear arthropathy is characterized by an anterior erosion and anteversion associated with anterior subluxation of the humeral head.

Three dimensional modeling method of MIMICS adjacent mask spherical open cell aluminum foam-polyurethane composites based on DICOM data

The complexity and irregularity of the internal structure of aluminum foam and the particularity of the fabricating method make it difficult to establish a three-dimensional model that can accurately reflect the internal structure of aluminum foam-polyurethane composites. This study presents a method of three-dimensional reconstruction of the Materialise’s Interactive Medical Image Control System (MIMICS) adjacent mask based on Digital Imaging and Communications in Medicine (DICOM) data. Firstly, spherical open cell aluminum foam-polyurethane composites with different pore sizes (5 mm, 7 mm, 9 mm) were prepared. Then the corresponding DICOM data of the spherical open cell aluminum foam-polyurethane composites were obtained by CT-scan. Based on adjacent mask, the three-dimensional simulation model of spherical open cell aluminum foam-polyurethane composites was successfully reconstructed in MIMICS. In order to verify the feasibility of this modeling method, a quasi-static compression simulation of the three-dimensional simulation model was carried out by ABAQUS, and the simulated stress-strain curves were acquired. The quasi-static compression experiments were performed on the prepared aluminum foam-polyurethane composites, and the experimental nominal stress-strain curves were obtained. The simulated nominal stress-strain curves were compared with the experimental nominal stress-strain curves. Results show that the two curves are basically the same. The feasibility and accuracy of the three-dimensional modeling method for the aluminum foam-polyurethane composites are verified.

FAIR-compliant clinical, radiomics and DICOM metadata of RIDER, interobserver, Lung1 and head-Neck1 TCIA collections.

PurposeOne of the most frequently cited radiomics investigations showed that features automatically extracted from routine clinical images could be used in prognostic modeling. These images have been made publicly accessible via The Cancer Imaging Archive (TCIA). There have been numerous requests for additional explanatory metadata on the following datasets — RIDER, Interobserver, Lung1, and Head–Neck1. To support repeatability, reproducibility, generalizability, and transparency in radiomics research, we publish the subjects’ clinical data, extracted radiomics features, and digital imaging and communications in medicine (DICOM) headers of these four datasets with descriptive metadata, in order to be more compliant with findable, accessible, interoperable, and reusable (FAIR) data management principles.Acquisition and validation methodsOverall survival time intervals were updated using a national citizens registry after internal ethics board approval. Spatial offsets of the primary gross tumor volume (GTV) regions of interest (ROIs) associated with the Lung1 CT series were improved on the TCIA. GTV radiomics features were extracted using the open‐source Ontology‐Guided Radiomics Analysis Workflow (O‐RAW). We reshaped the output of O‐RAW to map features and extraction settings to the latest version of Radiomics Ontology, so as to be consistent with the Image Biomarker Standardization Initiative (IBSI). Digital imaging and communications in medicine metadata was extracted using a research version of Semantic DICOM (SOHARD, GmbH, Fuerth; Germany). Subjects’ clinical data were described with metadata using the Radiation Oncology Ontology. All of the above were published in Resource Descriptor Format (RDF), that is, triples. Example SPARQL queries are shared with the reader to use on the online triples archive, which are intended to illustrate how to exploit this data submission.Data formatThe accumulated RDF data are publicly accessible through a SPARQL endpoint where the triples are archived. The endpoint is remotely queried through a graph database web application at http://sparql.cancerdata.org. SPARQL queries are intrinsically federated, such that we can efficiently cross‐reference clinical, DICOM, and radiomics data within a single query, while being agnostic to the original data format and coding system. The federated queries work in the same way even if the RDF data were partitioned across multiple servers and dispersed physical locations.Potential applicationsThe public availability of these data resources is intended to support radiomics features replication, repeatability, and reproducibility studies by the academic community. The example SPARQL queries may be freely used and modified by readers depending on their research question. Data interoperability and reusability are supported by referencing existing public ontologies. The RDF data are readily findable and accessible through the aforementioned link. Scripts used to create the RDF are made available at a code repository linked to this submission: https://gitlab.com/UM‐CDS/FAIR‐compliant_clinical_radiomics_and_DICOM_metadata.

Exploring publish/subscribe, multilevel cloud elasticity, and data compression in telemedicine

Background and Objective: Multiple medical specialties rely on image data, typically following the Digital Imaging and Communications in Medicine (DICOM) ISO 12052 standard, to support diagnosis through telemedicine. Remote analysis by different physicians requires the same image to be transmitted simultaneously to different destinations in real-time. This scenario poses a need for a large number of resources to store and transmit DICOM images in real-time, which has been explored using some cloud-based solutions. However, these solutions lack strategies to improve the performance through the cloud elasticity feature. In this context, this article proposes a cloud-based publish/subscribe (PubSub) model, called PS2DICOM, which employs multilevel resource elasticity to improve the performance of DICOM data transmissions.Methods: A prototype is implemented to evaluate PS2DICOM. A PubSub communication model is adopted, considering the coexistence of two classes of users: (i) image data producers (publishers); and (ii) image data consumers (subscribers). PS2DICOM employs a cloud infrastructure to guarantee service availability and performance through resource elasticity in two levels of the cloud: (i) brokers and (ii) data storage. In addition, images are compressed prior to the transmission to reduce the demand for network resources using one of three different algorithms: (i) DEFLATE, (ii) LZMA, and (iii) BZIP2. PS2DICOM employs dynamic data compression levels at the client side to improve network performance according to the current available network throughput.Results: Results indicate that PS2DICOM can improve transmission quality, storage capabilities, querying, and retrieving of DICOM images. The general efficiency gain is approximately 35% in data sending and receiving operations. This gain is resultant from the two levels of elasticity, allowing resources to be scaled up or down automatically in a transparent manner.Conclusions: The contributions of PS2DICOM are twofold: (i) multilevel cloud elasticity to adapt the computing resources on demand; (ii) adaptive data compression to meet the network quality and optimize data transmission. Results suggest that the use of compression in medical image data using PS2DICOM can improve the transmission efficiency, allowing the team of specialists to communicate in real-time, even when they are geographically distant.

In-House Surgeon-Led Virtual Surgical Planning for Maxillofacial Reconstruction

Virtual surgical planning (VSP) and custom fabricated cutting guides for maxillofacial reconstruction have been shown to improve the accuracy of bony reconstruction and overall surgical efficiency and decrease the ischemia time. Our aim was to describe an in-house VSP technique for maxillofacial reconstructive procedures. We used 2 free software applications. 3DSlicer (available at: http://www.3dslicer.org) was used to extract the bones of interest for the recipient and the donor sites from the computed tomography scan's DICOM (digital imaging and communications in medicine) data. The Autodesk Meshmixer (Autodesk Inc, San Rafael, CA) was used to perform VSP and fabrication of the cutting guides. A reconstructed jaw model was printed in-house using a commercially available fused deposition modeling-based desktop 3-dimensional (3D) printer (Qidi Technology, Zhejiang, China) and used to prebend the reconstruction plate. The cutting guides were printed using a commercially available resin-based stereolithography apparatus desktop 3D printer (Form 2, Dental SG Resin; Formlabs, Somerville, MA) to allow for sterilization of the guides. We performed this technique for 19 consecutive patients with maxillofacial benign or malignant tumors requiring microvascular bony reconstruction. We calculated the average time and associated costs using this in-house VSP technique. The technique was found to be simple and repeatable. The average time required for VSP was 158minutes (2hours, 38minutes). The average cost for printing the reconstructed model per case was $5.21 Canadian dollars (CAD), and the average cost for printing the cutting guides per case was $12.80 CAD. Using this technique, in-house VSP and 3D printing can be performed by the treating surgeon, without an engineering background, within a reasonable period.

The feasibility of 3D printing aortic root model by three dimensional transesophageal echocardiography data: a preliminary study compared with CT

Objective To preliminary explore the feasibility of three-dimensional transesophageal echocardiography (3D-TEE) as images data source for 3D printing model by comparing the 3D-TEE with CT of the aortic root Digital Imaging and Communications in Medicine(DICOM) data into 3D printing models respectively. Methods Fifteen patients who underwent surgical aortic valve replacement in the hospital were enrolled, and the aortic root 3D-TEE and CT DICOM data were obtained in perioperative. The images were imported into Mimics software to generate digital model standard tessellation language file, and to print the aortic root models by 3D printer. The structural morphology of both 3D-TEE and CT models were qualitatively evaluated respectively. The aortic annular area, perimeter, maximal diameter and minimal diameter of the original data, digital model, model and aortic valve replacement were quantitatively evaluated, and the consistency of each parameter value were analyzed. The mean diameter of 3D-TEE and CT model were calculated. The correlation of mean diameter with the number of replacement was analyzed. Results ①Both 3D-TEE and CT images data were successfully printed into 3D models, and the positive rate of aortic valve structure were 93.3% (14/15) and 80.0% (12/15) respectively. ②The measured values of the aortic annular 3D-TEE and digital model were smaller than CT, CTdigital model and replacement (P 0.95, P<0.05). Conclusions 3D printing aortic root model based on 3D-TEE image data is of high feasibility. Key words: Echocardiography, three-dimensional, transesophageal; Aortic root; Valve; 3D printing

RELATIONSHIP BETWEEN GRAY LEVELS IN CONE BEAM COMPUTED TOMOGRAPHY AND HOUNSFIELD UNITS IN COMPUTED TOMOGRAPHY

<h3>Background</h3> A deficiency of studies on clinical or close clinical materials of biologic nature exists in the conversion of gray values in cone beam computed tomography (CBCT) to more logically useful Hounsfield units (HU) in multidetector CT. <h3>Objective(s)</h3> The aim of this study was to assess the HU of various tissue materials in CT with their corresponding gray levels in 3 different CBCT units and compare their correlation individually, to compare the actual HU (aHU) values for each material with derived HU (dHU) values from gray levels using the interpolation method, and to evaluate its reliability. <h3>Study Design</h3> An in vitro study was conducted using a human skull model, which was coated with a soft tissue equivalent and embedded with 6 premeasured titanium implants. It was imaged with 3 different CBCT scanners and 1 CT scanner. The exported DICOM (Digital Imaging and Communications in Medicine) data were viewed in Carestream 3-D imaging software. The data were analyzed using Pearson's correlation test to evaluate the correlation between observed aHU values from CT and the corresponding gray levels from each CBCT unit. The method of Mah et al. was used to calculate dHU from gray levels and compare them with aHU. <h3>Results</h3> Among the CBCT machines used, the highest correlation for implants and bone was with Kodak 9500; for teeth, Sirona Galileos; and for soft tissue and air space, Planmeca Promax. The dHU values had significant percentage differences from aHU values. <h3>Discussion/Conclusions</h3> 1. Although there are differences in gray values between same materials in different machines, every CBCT scanner showed good correlation between gray levels and the aHU from CT machine for at least 1 material. 2. For clinical or close clinical materials of a biologic nature, dHU using the current algorithm does not reliably correlate with the aHU of the materials.

In-House Digital Workflow for the Management of Acute Mandible Fractures

Computer-aided design and additive manufacturing are revolutionizing oral and maxillofacial surgery. Current methods use virtual surgical planning sessions and custom plate milling via third-party vendors, which is costly and time-consuming, negating the effectiveness in acute facial trauma. This technical note describes a state-of-the-art in-house expedited digital workflow for computer-aided virtual fracture reduction, 3-dimensional printing, and preoperative reconstruction plate adaptation for the management of an acute mandible fracture. This process uses the computed tomographic scan a patient receives in the emergency department or clinic. The DICOM (Digital Imaging and Communications in Medicine) data are transferred into US Food and Drug Administration-approved software, in which the fracture is segmented and virtually reduced based on condylar position, midline symmetries, and occlusion if present. The reduced mandible is then printed, which serves as a template for preoperative reconstruction plate adaptation. This method facilitates a virtually reduced fractured mandible, 3-dimensionally printed model, and ideally adapted plates ready for sterilization before surgery within 2hours after DICOM upload.

Virtual Orthodontic Surgical Planning to Improve the Accuracy of the Surgery-First Approach: A Prospective Evaluation

We developed an innovative computer-assisted method to increase the accuracy of the surgery-first (SF) approach by linking the virtual orthodontic planning (VOP) with the virtual surgical planning(VSP). Fifteen consecutive patients were enrolled from 2013 to 2015. All 15 patients had initially undergone cone-beam computed tomography (CBCT; 15×15 field-of-view) and intraoral digital scanning of the dental arches. The DICOM (Digital Imaging and Communications in Medicine) data set and STL files were processed using the SimPlant O&O platform (Dentsply-Sirona, York, PA), which facilitates skeletal, dental, and soft tissue modeling and subsequent realization of the VOP/VSP. The VSP was reproduced using computer-aided design and computer-aided manufacturing surgical splints, and the VOP was realized via postoperative orthodontic treatment. At the end of treatment, all the patients underwent repeat CBCT and digital scanning of the dental arches, and the new data sets were compared with the original data sets to determine the deviations. To evaluate skeletal accuracy, we assessed all points within an arbitrary range of -2 to+2mm. To evaluate dental accuracy, the arbitrary range was -0.8 to+0.8mm. The average duration of orthodontic treatment was 17.9months. The accuracy of maxillary treatment averaged 0.0702±2.0724mm and that of mandibular treatment, 0.2811±1.9993mm. The average upper and lower dental arch accuracy was -0.0029±1.125 and -0.0147±1.263mm, respectively. The maxillary surgery accuracy was 75.3% and that of mandibular surgery 74.0%, both within the -2 to+2-mm range. The upper and lower arch accuracy was 58.86 and 51.53%, respectively, both within the -0.8 to+0.8-mm range. The use of the VOP/VSP improved the diagnostic and therapeutic SF preoperative planning. VOP contributed significantly in this context. The accuracy of skeletal repositioning was acceptable; however, the VSP should be rendered more reproducibly in the future to minimize the need for orthodontic compensation and to maximize the advantages of SF.