Materialise's Interactive Medical Image Control System Research Articles

Effect of a Percutaneous Screw Guide on Screw Placement for Posterior Talar Fractures.

This study aimed to evaluate the hypothesis that the utilization of percutaneous screw guides enhances the precision of screw placement in the surgical fixation of talar fractures. Computed tomography (CT) scans of ankle joints were obtained from 40 healthy adults and 10 cadaveric specimens between April 2019 and August 2020 at Ningbo No. 6 Hospital. The acquired CT data were imported into Materialise Interactive Medical Image Control System (MIMICS) software for processing. Three-dimensional (3D) digital models of the ankle joints were reconstructed, and relevant anatomical parameters were measured. A percutaneous screw guide (PSG) was designed and fabricated to facilitate accurate screw placement in the posterior talar process. Ten eligible cadaveric ankle joints were selected for further analysis and their 3D models were reconstructed using the MIMICS software. Screw trajectory parameters were then measured and analyzed based on these cadaveric models, forming the model group for comparative analyses. Ten cadaveric specimens were utilized in this study, equally divided into two groups: a guider group (n = 5) and a free-hand group (n = 5). In the guider group, talar posterior process screws were inserted using percutaneous screw guidance. In the free-hand group, screws were inserted into the talar posterior process without guidance. Post-operative CT scans were performed on all specimens. The following parameters were quantitatively compared between the two groups: screw trajectories, entry point distances in specimens with preselected screws, entry point distance trajectories in the 3D model, operation time, frequency of fluoroscopic imaging, and number of drilling attempts. Following the generation of the 3D models from 10 cadavers, a virtual screw was digitally inserted into each model. In the model group, the preselected screw trajectory was oriented towards the medial aspect of the talar neck base, with a cephalad inclination angle (CIA) of 3.1° ± 1.5° in the transverse~plane and a medial diverge angle (MDA) of 12.0° ± 1.4° in the coronal plane. The CIA and MDA of the screw trajectory in the guider group were 2.1° ± 1.7° and 11.2° ± 1.6°, respectively, whereas the CIA and MDA in the free-hand group were 6.0° ± 2.2° and 18.8° ± 1.6°, respectively. Statistical analysis revealed significant differences in both CIA and MDA between the two groups (p < 0.05). Furthermore, the guider group yielded superior outcomes in terms of entry point distance, operation time, fluoroscopic exposure time, and number of drilling attempts compared to the free-hand group (p < 0.05). Percutaneous screw guidance can improve the accuracy and safety of the posterior process of the talar screws, which can be feasible for percutaneous fixation. Further studies are required to confirm the efficacy and clinical outcomes of percutaneous screw guidance.

Intradiscal cement leakage (ICL) increases the stress on adjacent vertebrae after kyphoplasty for osteoporotic vertebra compression fracture (OVCF): a finite-element study

This study aimed to explore the biomechanical effects on adjacent vertebra of thoracolumbar Osteoporotic Vertebra Compression Fracture (OVCF) after Percutaneous Kyphoplasty (PKP) with intraoperative intradiscal cement leakage (ICL) by applying a Finite-Element Analysis. We collected pre- and post-operative computer tomography (CT) images of a 71-year-old female patient with single T12 OVCF, who underwent an intraoperative cement leakage into the T12–L1 disc. Three-dimensional finite element models of thoracolumbar spine (T10–L2) were built with the support of Materialise Interactive Medical Image Control System (MIMICS) and ABAQUS software. The stress on adjacent vertebrae and endplates under the uniform compressive pressure (0.3 MPa) and during different loading moments were analyzed. The three-dimensional finite element models reveal an asymmetrical distribution of von Mises stresses on the adjacent endplate unaffected by the surgical intervention. The maximum von Mises stress on adjacent vertebral bodies increased during different loading conditions, especially for lateral bending and rotation loading conditions, whereas the maximum von Mises stress on distal non-treated vertebrae decreased on anteflexion and backward extension loading conditions. Post-operative adjacent vertebra compression fractures after PKP with intraoperative intradiscal cement leakage (ICL) may be closely related to the biomechanical changes of adjacent vertebrae of thoracolumbar OVCF, and it may increase the risk of postoperative fracture.

Turbulent Kinetic Energy of Flow during Inhale and Exhale to Characterize the Severity of Obstructive Sleep Apnea Patient

This paper aims to investigate and present the numerical investigation of airflow characteristics using Turbulent Kinetic Energy (TKE) to characterize the upper airway with obstructive sleep apnea (OSA) under inhale and exhale breathing conditions. The importance of TKE under both breathing conditions is that it show an accurate method in expressing the severity of flow in sleep disorder. Computational fluid dynamics simulate the upper airway’s airflow via steady-state Reynolds-averaged Navier-Stokes (RANS) with k–ω shear stress transport (SST) turbulence model. The three-dimensional (3D) airway model is created based on the CT scan images of an actual patient, meshed with 1.29 million elements using Materialise Interactive Medical Image Control System (MIMICS) and ANSYS software, respectively. High TKE were noticed around the region after the necking (smaller cross-sectional area) during the inhale and exhale breathing. The turbulent kinetic energy could be used as a valuable measure to identify the severity of OSA. This study is expected to provide a better understanding and clear visualization of the airflow characteristics during the inhale and exhale breathing in the upper airway of patients for medical practitioners in the OSA research field.

Optic canal characteristics in pediatric syndromic craniosynostosis

The aim of this study was to compare optic canal parameters of syndromic craniosynostosis patients with those of normal patients to visit the possibility of optic nerve impingement as a cause of visual impairment.Computed tomography scan images were processed using the Materialise Interactive Medical Image Control System (MIMICS) Research 21.0 software (Materialise NV, Leuven, Belgium). Eleven optic canal parameters were measured: 1) height of optic canal on the cranial side, 2) height of optic canal on the orbital side 3) length of the medial wall of the optic canal, 4) length of the lateral canal wall of the optic canal, 5) diameter of the optic canal at five points (Q1-Q4 and mid canal), and 6) area and perimeter of optic canal. These measurements were obtained for both the right and left optic canals.The study sample comprised four Crouzon syndrome, five Apert syndrome, and three Pfeiffer syndrome patients. The age of these syndromic craniosynostosis patients ranged from 2 to 63 months. The height of the optic canal on the orbital side (p = 0.041), diameter of the mid canal (p = 0.040), and diameter between the mid-canal and the cranial opening (Q3) (p = 0.079) for syndromic craniosynostosis patients were statistically narrower compared with those of normal patients when a significance level of 0.1 was considered. Scatter plots for the ages of patients versus the above parameters gave three separated clusters that suggested the arresting of optic canal development with age.The findings from this study demonstrated a narrowing of the optic canal in syndromic craniosynostosis patients, and indicate that optic canal anatomical characteristics may have an association with visual impairment among pediatric syndromic craniosynostosis patients.

Optic Canal Analysis in Syndromic Craniosynostosis: Volumetric and Surface Area Validation Study Using Different Measurement Modalities.

In syndromic craniosynostosis (SC), unlike persistent corneal irritation due to severe exophthalmos and increased intracranial pressure, optic canal (OC) stenosis has been scarcely reported to cause visual impairment. This study aimed to validate the OC volumetric and surface area measurement among SC patients. Sixteen computed tomography scan of SC patients (8 months-6 years old) were imported to Materialise Interactive Medical Image Control System (MIMICS) and Materialise 3-matics software. Three-dimensional (3D) OC models were fabricated, and linear measurements were obtained. Mathematical formulas were used for calculation of OC volume and surface area from the 3D model. The same measurements were obtained from the software and used as ground truth. Data normality was investigated before statistical analyses were performed. Wilcoxon test was used to validate differences of OC volume and surface area between 3D model and software. The mean values for OC surface area for 3D model and MIMICS software were 103.19 mm2 and 31.27 mm2, respectively, whereas the mean for OC volume for 3D model and MIMICS software were 184.37 mm2 and 147.07 mm2, respectively. Significant difference was found between OC volume (P = 0.0681) and surface area (P = 0.0002) between 3D model and software. Optic canal in SC is not a perfect conical frustum thus making 3D model measurement and mathematical formula for surface area and volume estimation not ideal. Computer software remains the best modality to gauge dimensional parameter and is useful to elucidates the relationship of OC and eye function as well as aiding intervention in SC patients.

A Novel Framework on Abdominal Aortic Aneurysm Analysis Based on Biomedical Simulation Tools

Nowadays, the mortality rate due to cardiovascular diseases is significant due to noticed critical aneurysm cases. Abnormal swelling at the aorta causes Abdominal Aortic Aneurysm (AAA). They are usually saccular, fusiform according to their shape statistics. Hence it’s better to analyze, segment and model them to aid physicians/surgeons in various aspects of nonsurgical and surgical treatments. Morphological study provides approximate dimensions and risk of rupture. The objective of this work is to provide an extensive study on AAA segmentation, modeling and analysis with individual frameworks in sequence using tools like MATrix LABoratory (MATLAB), Materialise's Interactive Medical Image Control System (MIMICS), 3-matic and Finite Element Biomechanics (FEBio). The ultimate goal is to develop a 3D printed aneurysm replica for further evaluation and analysis using Ultimaker Cura Slicer Software. MATLAB is used to segment the Aorta irrespective of intensity/contrast inhomogeneities using Solidity feature. MIMICS software is used for modeling the aneurysms using three types of Axial, Coronal, and Saggital views. 3-matic provides an easy interface to do the dimensional analysis using imported aneurysm morphology. FEBio with PreView, PostView plugins is a nonlinear finite element solver which offers a chance to study it and to predict the future regions of rupture to some extent via Computational Fluid Dynamics (CFD) features. 3D printing of aneurysm offers the flexibility of knowing their epithelial characteristics and hands-on experience. The main merit of this novel and efficient framework is non-invasive studies of Aneurysm Segmentation, Analysis, and Modeling using five tools which addresses the complete study of AAA.

Biomechanical analysis of the computer-assisted internal fixation of a femoral neck fracture

The number and spatial configuration of the screws will affect the stability and prognosis of the fractures. In our study, we assessed the biomechanical effects of the double-head cannulated compression screw (DhCCS) and ordinary cannulated compression screw (OCCS) for the treatment of femoral neck fractures by using computer finite element analysis. The original digital imaging and communications in medicine (DICOM)data of a proximal femur were imported into Materialise's interactive medical image control system (MIMICS)software for modeling. Both DhCCS and OCCS 3D-models were obtained by using the 3D scan technique. Using the fracture model and internal fixation assembly model with an inverted triangle, two horizontal and vertical distribution were established in UG software. Next, the displacement and stress distribution were calculated in ANSYS software. The displacement value of the femoral head in the DhCCS group was smaller than that in the OCCS group, and the displacement value in the two horizontal groups was smaller than that in the vertical group. The stress distribution in the DhCCS group was concentrated on the screw rod at the fracture block and thread end, while only at the fracture block in the OCCS group. The stress in the horizontal group was more dispersed on the screws than that in the vertical group. DhCCS has reliable stability for the fixation of femoral neck fractures and applied in the clinical work and 2 horizontal fixation can be used when two screws are selected.

Persistent first intersegmental artery (PFIA) visualized by three-dimensional computed tomography angiography in Chinese population

BackgroundPersistent first intersegmental artery (PFIA) is one of the most frequently vertebral artery (VA) variations. The presence of PFIA obviously increases the complexity and difficulty of vertebral lesion treatment. Thus, preoperative detection of PFIA is necessary to increase the successful rate of surgeries. We attempted to evaluate the utility value of three-dimension (3D) computed tomography angiography (CTA) for detecting PFIA in the north Chinese population. Materials and methodsConsecutive patients subjected to CTA between June 2012 and March 2014 were recruited from 5 clinical centers in the north of China. . The VA-cervical atlas complexus were observed by CTA. The assessment of PFIA was performed by reconstructing the images via Materialise's interactive medical image control system (MIMICS) and the measurement of VA diameter was performed on the source images. PFIA including unilateral and bilateral was calculated. The dominant side was defined as the unilateral VA with 130% fold larger diameter than the other side. ResultsA total of 200 north Chinese patients with mean age of 57.8 ± 9.3 years old were enrolled in the present study. Total 400 VA-cervical atlas complexus were observed by 3D-CTA, among which 9 complexus (2.25%) were diagnosed with PFIA, and 3 complexus (0.75%) were presented with the dominant VA. The spinal surgical procedures were performed successfully in all the patients with no injury and complications to the VA. ConclusionsThe incidence of PFIA in 400 VA-cervical atlas complexus are relatively high (2.25%) in our patient population. On the basis of relatively high prevalence of this anomaly, the preoperative detection of PFIA by 3D-CTA is recommended for the north Chinese population.

Implant Insertion Torque Load Analysis for Mandible using CBCT Images

ABSTRACT Introduction Osteoporotic patients require particular attention to their implant site bone quality as an indication of prognosis and may require modified surgical technique Insertion Torque (IT). Aim It is the purpose of this study to test whether IT is significantly correlated with bone density or not, as assessed by the cone-beam computed tomography (CBCT) in a group of osteopenic and osteoporotic patients. Materials and methods A total of 30 patients were included in the study. The mandibular second premolar region was chosen as the site of investigation to prevent variability in surgical implant placement technique in different locations affecting bone mineral density (BMD). Partially, edentulous female patients between 51 and 60 years of age who were scheduled to receive implant placement were recruited for the study. CBCT (Master Series 3D Dental Imaging) was used for preoperative evaluation of the jaws for each patient. Materialise's Interactive Medical Image Control System (MIMICS) was used to process stacks of 2D images from CBCT. Finite element analysis were carried out on bone using Ansys software. Maximum displacement and maximum stress—strain patterns were compared in normal, osteoporotic, and osteopenic groups. Results The difference in mean bone density in all three groups were statistically significant (p &lt; 0.05) (Table 1). FEA at 32, 36, 40 N in all 3 groups was statistically significant. (Table 2). Conclusion Within the limitations of the study, the amount of stress—strain that exhibits at 40 N load in normal bone will be almost the same stress—strain given at 32 N load in osteoporotic bone. Normal IT load analysis exhibits more stress/strain in osteoporotic patients when compared with other groups, showing that IT must be achieved to an optimum level to avoid further complication and failures. How to cite this article Venkatakrishnan CJ, Bhuminathan S, Chandran CR. Implant Insertion Torque Load Analysis for Mandible using CBCT Images. World J Dent 2017;8(3):183-189.

Dorsolateral musculocutaneous perforators of posterior intercostal artery: An anatomical study

The posterior intercostal artery (PICA) is divided into four segments, vertebral, costal, intermuscular, and rectus, based on the neurovascular branching pattern. Dorsal branches arise from the vertebral segment. Several musculocutaneous perforators and a lateral branch originate from the costal segment. Musculocutaneous branches arise from the intermuscular and rectus segments. The purpose of this study is to describe in detail the musculocutaneous perforators of the costal segment of the posterior intercostal artery. Fresh cadavers were injected with a modified lead oxide-gelatin mixture. Intercostal spaces (8-11) were dissected in twelve cadavers (six preserved cadavers and six fresh cadavers). Angiograms were assembled with Adobe Photoshop. Two fresh cadavers underwent CT angiography and three dimensional reconstructions of the intercostal perforators were performed using Materialise's Interactive Medical Image Control System (MIMICS). In twelve cadavers, a total of 356 perforators (size > 0.5 mm) were found to arise from the posterior intercostal arteries in 96 intercostal (IC) spaces. 154 perforators (>0.5 mm) were found in the costal segment of the PICA. An average of 6.4 perforators was found in each hemithorax. All perforators were found within 2 cm of the midscapular line. At least one perforator was found in all intercostal spaces. Two or more perforators were found in 40% of the 8th and 9th IC spaces and 60% of the 10th and 11th IC spaces. Perforators were oriented perpendicular to the direction of the muscle fibres of the latissimus dorsi and were usually present one or two intercostal spaces below their origin from the PICA. Perforators of the costal segment of the PICA are described in detail. We propose to call these currently unnamed musculocutaneous perforators "dorsolateral" branches of the PICA, as they are located between dorsal and lateral branches of PICA.

Three‐dimensional visualization of the cutaneous angiosome using angiography

The purpose of this study was to establish the three-dimensional (3D) architecture of the cutaneous angiosome for assessment and design of the perforator flaps. Two fresh cadavers were injected with carboxymethyl cellulose (CMC)/lead oxide and computed tomography (CT) scanned before and after the injection. The various parts of the cutaneous and subcutaneous tissue derived from one of the injected cadavers were also CT scanned. Three-dimensional reconstruction of the cutaneous angiosome and the two flap designs were performed using Materialise's Interactive Medical Image Control System (MIMICS). Both the reconstructed cutaneous angiosomes and the digital flaps can be displayed independently or in conjunction with bones, source arteries, and skin. The 3D architecture of the cutaneous angiosome ensures clear display of the spatial location, distribution range, and anastomoses relationship of the cutaneous perforators. In addition, the caliber, length, and position of a particular source artery are illustrated in the exact spatial location. As a result, the technique provides visualization of the general area and the expandable direction of a respective flap. This technique has the potential to play an important role in assessing perforator blood supply territory and in the design of new flaps.

Application of Materialise's interactive medical image control system in orthognathic surgery

Objective To evaluate the value of Materialise's interactive medical image control system (MIMICS) in the computer aided surgery, and to offer a reliable system for precise surgical planning and good effect of orthognathic surgery. Methods Based on CT images, geometric characteristics of 2 patients' head were collected for a 3D reconstruction of the human head. Skull, skin, and submucous tissue were reconstructed and optimized separately by MIMICS 10.01. Surgeries were simulated and the soft tissue deformation was predicted according to the surgical planning of experienced surgeons. Results Mesh of skull, skin and submucous tissue were constructed manually for 2 patients. Surgical procedures were simulated and the prediction of soft tissue deformation was realized by MIMICS, which could be visualized in any angle. Conclusion MIMICS is a helpful digital tool for computer aided surgery and the prediction of soft tissue deformation. MIMICS is also a 3D visualization system for orthognathic surgeries, by which surgeons could realize the surgical planning, revising,and the patient-doctor communication on the computer screen. Key words: Materialise's interactive medical image control system; Orthognathic surgery; Visualization

Haptic model fabrication for undergraduate and postgraduate teaching

Three series of cone-beam computed tomography (CBCT) patient data sets were obtained. These data were exported into DICOM and MIMICS (Materialise's Interactive Medical Image Control System; Materialise, Leuven, Belgium) and were imported for differentiation of various tissues (bone, teeth, and nerve). After transferring the data to an additive manufacturing machine, three-dimensional (3D) haptic models were fabricated using clear and opaque materials. These models were integrated into phantom heads normally used for education in undergraduate dental education. 3D prototype CBCT-based haptic patient models can be used in undergraduate and postgraduate education. Students can simulate routine standard oral surgical procedures with supervision under 'dry conditions'. Residents can simulate advanced and complex cases before performing the real operation.

Biomechanics of the Cricoarytenoid Joint: Three-Dimensional Imaging and Vector Analysis

Laryngeal framework surgery requires a good understanding of the biomechanics of the cricoarytenoid (CA) joint, the precise function of which is still only poorly understood. The aim of the study was (1) to show that, by superimposing two or more three-dimensional (3D) images, we can visualize the exact position of the arytenoid cartilages within the larynx at different phases of their movement; and (2) to demonstrate that it is possible to analyze the arytenoid cartilage movements mathematically with the help of vector analysis. In vitro cadaver study. Twenty fresh and intact cadaver larynges were scanned by high-resolution computerized tomography with the arytenoid cartilages in "respiratory" position and in "phonatory" position. The two positions were superimposed and rendered in 3D with MIMICS (Materialise Interactive Medical Image Control System, Leuven, Belgium). The spatial trajectory of the arytenoid cartilage movements was calculated with vector analysis. The movement from the "respiratory" to the "phonatory" position has three components: (1) an inward rocking action around the longitudinal CA joint; (2) a forward sliding movement along the longitudinal axis of the CA joint; and (3) an inward rotation around a virtual axis that runs perpendicular to the CA joint axis. Superimposing 3D images of the larynx with the help of the software package MIMICS allows us to visualize and to analyze mathematically the trajectory of the arytenoid cartilage. The arytenoid cartilages rock inward, slide forward, and rotate inward when they move from the "respiratory" to the "phonatory" position.