3D-printed saw guides for lower arm osteotomy, a comparison between a synthetic CT and CT-based workflow

Abstract Background Three-dimensional (3D)-printed saw guides are frequently used to optimize osteotomy results and are usually designed based on computed tomography (CT), despite the radiation burden, as radiation-less alternatives like magnetic resonance imaging (MRI) have inferior bone visualization capabilities. This study investigated the usability of MR-based synthetic-CT (sCT), a novel radiation-less bone visualization technique for 3D planning and design of patient-specific saw guides. Methods Eight human cadaveric lower arms (mean age: 78y) received MRI and CT scans as well as high-resolution micro-CT. From the MRI scans, sCT were generated using a conditional generative adversarial network. Digital 3D bone surface models based on the sCT and general CT were compared to the surface model from the micro-CT that was used as ground truth for image resolution. From both the sCT and CT digital bone models saw guides were designed and 3D-printed in nylon for one proximal and one distal bone position for each radius and ulna. Six blinded observers placed these saw guides as accurately as possible on dissected bones. The position of each guide was assessed by optical 3D-scanning of each bone with positioned saw guide and compared to the preplanning. Eight placement errors were evaluated: three translational errors (along each axis), three rotational errors (around each axis), a total translation (∆T) and a total rotation error (∆R). Results Surface models derived from micro-CT were on average smaller than sCT and CT-based models with average differences of 0.27 ± 0.30 mm for sCT and 0.24 ± 0.12 mm for CT. No statistically significant positioning differences on the bones were found between sCT- and CT-based saw guides for any axis specific translational or rotational errors nor between the ∆T (p = .284) and ∆R (p = .216). On Bland-Altman plots, the ∆T and ∆R limits of agreement (LoA) were within the inter-observer variability LoA. Conclusions This research showed a similar error for sCT and CT digital surface models when comparing to ground truth micro-CT models. Additionally, the saw guide study showed equivalent CT- and sCT-based saw guide placement errors. Therefore, MRI-based synthetic CT is a promising radiation-less alternative to CT for the creation of patient-specific osteotomy surgical saw guides.

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Impact of image reconstruction parameters when using 3D DSA reconstructions to measure intracranial aneurysms

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2017-013080 ◽

2017 ◽

Vol 10 (3) ◽

pp. 285-289 ◽

Cited By ~ 5

Author(s):

Katrina L Ruedinger ◽

David R Rutkowski ◽

Sebastian Schafer ◽

Alejandro Roldán-Alzate ◽

Erick L Oberstar ◽

...

Keyword(s):

Three Dimensional ◽

Hounsfield Unit ◽

Ground Truth ◽

Individual Case ◽

Dome Height ◽

Patient Specific ◽

Analysis Tool ◽

Accuracy Of Measurements ◽

Image Characteristic

Background and purposeSafe and effective use of newly developed devices for aneurysm treatment requires the ability to make accurate measurements in the angiographic suite. Our purpose was to determine the parameters that optimize the geometric accuracy of three-dimensional (3D) vascular reconstructions.MethodsAn in vitro flow model consisting of a peristaltic pump, plastic tubing, and 3D printed patient-specific aneurysm models was used to simulate blood flow in an intracranial aneurysm. Flow rates were adjusted to match values reported in the literature for the internal carotid artery. 3D digital subtraction angiography acquisitions were obtained using a commercially available biplane angiographic system. Reconstructions were done using Edge Enhancement (EE) or Hounsfield Unit (HU) kernels and a Normal or Smooth image characteristic. Reconstructed images were analyzed using the vendor's aneurysm analysis tool. Ground truth measurements were derived from metrological scans of the models with a microCT. Aneurysm volume, surface area, dome height, minimum and maximum ostium diameter were determined for the five models.ResultsIn all cases, measurements made with the EE kernel most closely matched ground truth values. Differences in values derived from reconstructions displayed with Smooth or Normal image characteristics were small and had only little impact on the geometric parameters considered.ConclusionsReconstruction parameters impact the accuracy of measurements made using the aneurysm analysis tool of a commercially available angiographic system. Absolute differences between measurements made using reconstruction parameters determined as optimal in this study were, overall, very small. The significance of these differences, if any, will depend on the details of each individual case.

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Investigation of three-dimensional printing materials for printing aorta model replicating Type B aortic dissection

Current Medical Imaging Formerly Current Medical Imaging Reviews ◽

10.2174/1573405617666210218102046 ◽

2021 ◽

Vol 17 ◽

Author(s):

Chia-An Wu ◽

Andrew Squelch ◽

Zhonghua Sun

Keyword(s):

3D Printing ◽

Aortic Dissection ◽

Three Dimensional ◽

Ct Images ◽

Patient Specific ◽

Type B ◽

Type B Aortic Dissection ◽

Ct Attenuation ◽

Significant Difference ◽

3D Printed

Aim: To determine a printing material that has both elastic property and radiology equivalence close to real aorta for simulation of endovascular stent graft repair of aortic dissection. Background: With the rapid development of three-dimensional (3D) printing technology, a patient-specific 3D printed model is able to help surgeons to make better treatment plan for Type B aortic dissection patients. However, the radiological properties of most 3D printing materials have not been well characterized. This study aims to investigate the appropriate materials for printing human aorta with mechanical and radiological properties similar to the real aortic computed tomography (CT) attenuation. Objective: Quantitative assessment of CT attenuation of different materials used in 3D printed models of aortic dissection for developing patient-specific 3D printed aorta models to simulate type B aortic dissection. Method: A 25-mm length of aorta model was segmented from a patient’s image dataset with diagnosis of type B aortic dissection. Four different elastic commercial 3D printing materials, namely Agilus A40 and A50, Visijet CE-NT A30 and A70 were selected and printed with different hardness. Totally four models were printed out and conducted CT scanned twice on a 192-slice CT scanner using the standard aortic CT angiography protocol, with and without contrast inside the lumen.Five reference points with region of interest (ROI) of 1.77 mm2 were selected at the aortic wall and intimal flap and their Hounsfield units (HU) were measured and compared with the CT attenuation of original CT images. The comparison between the patient’s aorta and models was performed through a paired-sample t-test to determine if there is any significant difference. Result: The mean CT attenuation of aortic wall of the original CT images was 80.7 HU. Analysis of images without using contrast medium showed that the material of Agilus A50 produced the mean CT attenuation of 82.6 HU, which is similar to that of original CT images. The CT attenuation measured at images acquired with other three materials was significantly lower than that of original images (p<0.05). After adding contrast medium, Visijet CE-NT A30 had an average CT attenuation of 90.6 HU, which is close to that of the original images with statistically significant difference (p>0.05). In contrast, the CT attenuation measured at images acquired with other three materials (Agilus A40, A50 and Visiject CE-NT A70) was 129 HU, 135 HU and 129.6 HU, respectively, which is significantly higher than that of original CT images (p<0.05). Conclusion: Both Visijet CE-NT and Agilus have tensile strength and elongation close to real patient’s tissue properties producing similar CT attenuation. Visijet CE-NT A30 is considered the appropriate material for printing aorta to simulate contrast-enhanced CT imaging of type B aortic dissection. Due to lack of body phantom in the experiments, further research with simulation of realistic anatomical body environment should be conducted.

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Accuracy Assessment of Molded, Patient-Specific Polymethylmethacrylate Craniofacial Implants Compared to Their 3D Printed Originals

Journal of Clinical Medicine ◽

10.3390/jcm9030832 ◽

2020 ◽

Vol 9 (3) ◽

pp. 832 ◽

Cited By ~ 1

Author(s):

Dave Chamo ◽

Bilal Msallem ◽

Neha Sharma ◽

Soheila Aghlmandi ◽

Christoph Kunz ◽

...

Keyword(s):

Computer Aided Design ◽

Accuracy Assessment ◽

Three Dimensional ◽

Production Costs ◽

Patient Specific ◽

Patient Specific Implants ◽

3D Printed ◽

Cost Efficient ◽

Craniofacial Implants ◽

Aided Design

The use of patient-specific implants (PSIs) in craniofacial surgery is often limited due to a lack of expertise and/or production costs. Therefore, a simple and cost-efficient template-based fabrication workflow has been developed to overcome these disadvantages. The aim of this study is to assess the accuracy of PSIs made from their original templates. For a representative cranial defect (CRD) and a temporo-orbital defect (TOD), ten PSIs were made from polymethylmethacrylate (PMMA) using computer-aided design (CAD) and three-dimensional (3D) printing technology. These customized implants were measured and compared with their original 3D printed templates. The implants for the CRD revealed a root mean square (RMS) value ranging from 1.128 to 0.469 mm with a median RMS (Q1 to Q3) of 0.574 (0.528 to 0.701) mm. Those for the TOD revealed an RMS value ranging from 1.079 to 0.630 mm with a median RMS (Q1 to Q3) of 0.843 (0.635 to 0.943) mm. This study demonstrates that a highly precise duplication of PSIs can be achieved using this template-molding workflow. Thus, virtually planned implants can be accurately transferred into haptic PSIs. This workflow appears to offer a sophisticated solution for craniofacial reconstruction and continues to prove itself in daily clinical practice.

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Custom Patient-Specific Three-Dimensional Printed Mitral Valve Models for Pre-Operative Patient Education Enhance Patient Satisfaction and Understanding

Journal of Medical Devices ◽

10.1115/1.4043737 ◽

2019 ◽

Vol 13 (3) ◽

Author(s):

Kay S. Hung ◽

Michael J. Paulsen ◽

Hanjay Wang ◽

Camille Hironaka ◽

Y. Joseph Woo

Keyword(s):

Patient Education ◽

Mitral Valve ◽

Three Dimensional ◽

3D Models ◽

Patient Specific ◽

Imaging Data ◽

Anatomical Models ◽

Mitral Valves ◽

Flexible Polymer ◽

3D Printed

In recent years, advances in medical imaging and three-dimensional (3D) additive manufacturing techniques have increased the use of 3D-printed anatomical models for surgical planning, device design and testing, customization of prostheses, and medical education. Using 3D-printing technology, we generated patient-specific models of mitral valves from their pre-operative cardiac imaging data and utilized these custom models to educate patients about their anatomy, disease, and treatment. Clinical 3D transthoracic and transesophageal echocardiography images were acquired from patients referred for mitral valve repair surgery and segmented using 3D modeling software. Patient-specific mitral valves were 3D-printed using a flexible polymer material to mimic the precise geometry and tissue texture of the relevant anatomy. 3D models were presented to patients at their pre-operative clinic visit and patient education was performed using either the 3D model or the standard anatomic illustrations. Afterward, patients completed questionnaires assessing knowledge and satisfaction. Responses were calculated based on a 1–5 Likert scale and analyzed using a nonparametric Mann–Whitney test. Twelve patients were presented with a patient-specific 3D-printed mitral valve model in addition to standard education materials and twelve patients were presented with only standard educational materials. The mean survey scores were 64.2 (±1.7) and 60.1 (±5.9), respectively (p = 0.008). The use of patient-specific anatomical models positively impacts patient education and satisfaction, and is a feasible method to open new opportunities in precision medicine.

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Personalized Three-Dimensional Printed Models in Congenital Heart Disease

Journal of Clinical Medicine ◽

10.3390/jcm8040522 ◽

2019 ◽

Vol 8 (4) ◽

pp. 522 ◽

Cited By ~ 13

Author(s):

Sun ◽

Lau ◽

Wong ◽

Yeong

Keyword(s):

Congenital Heart Disease ◽

Heart Disease ◽

Congenital Heart ◽

Three Dimensional ◽

Patient Specific ◽

Future Research ◽

Imaging Data ◽

Doctor Patient Communication ◽

Medical Education And Training ◽

3D Printed

Patient-specific three-dimensional (3D) printed models have been increasingly used in cardiology and cardiac surgery, in particular, showing great value in the domain of congenital heart disease (CHD). CHD is characterized by complex cardiac anomalies with disease variations between individuals; thus, it is difficult to obtain comprehensive spatial conceptualization of the cardiac structures based on the current imaging visualizations. 3D printed models derived from patient’s cardiac imaging data overcome this limitation by creating personalized 3D heart models, which not only improve spatial visualization, but also assist preoperative planning and simulation of cardiac procedures, serve as a useful tool in medical education and training, and improve doctor–patient communication. This review article provides an overall view of the clinical applications and usefulness of 3D printed models in CHD. Current limitations and future research directions of 3D printed heart models are highlighted.

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Three-Dimensional Reconstruction of Structural Surface Model of Heritage Bridges Using UAV-Based Photogrammetric Point Clouds

Remote Sensing ◽

10.3390/rs11101204 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1204 ◽

Cited By ~ 17

Author(s):

Yue Pan ◽

Yiqing Dong ◽

Dalei Wang ◽

Airong Chen ◽

Zhen Ye

Keyword(s):

Classification Tree ◽

Three Dimensional ◽

Point Clouds ◽

3D Models ◽

Surface Model ◽

Reconstruction Method ◽

3D Point Clouds ◽

Surface Models ◽

Structural Surface ◽

Better Than

Three-dimensional (3D) digital technology is essential to the maintenance and monitoring of cultural heritage sites. In the field of bridge engineering, 3D models generated from point clouds of existing bridges is drawing increasing attention. Currently, the widespread use of the unmanned aerial vehicle (UAV) provides a practical solution for generating 3D point clouds as well as models, which can drastically reduce the manual effort and cost involved. In this study, we present a semi-automated framework for generating structural surface models of heritage bridges. To be specific, we propose to tackle this challenge via a novel top-down method for segmenting main bridge components, combined with rule-based classification, to produce labeled 3D models from UAV photogrammetric point clouds. The point clouds of the heritage bridge are generated from the captured UAV images through the structure-from-motion workflow. A segmentation method is developed based on the supervoxel structure and global graph optimization, which can effectively separate bridge components based on geometric features. Then, recognition by the use of a classification tree and bridge geometry is utilized to recognize different structural elements from the obtained segments. Finally, surface modeling is conducted to generate surface models of the recognized elements. Experiments using two bridges in China demonstrate the potential of the presented structural model reconstruction method using UAV photogrammetry and point cloud processing in 3D digital documentation of heritage bridges. By using given markers, the reconstruction error of point clouds can be as small as 0.4%. Moreover, the precision and recall of segmentation results using testing date are better than 0.8, and a recognition accuracy better than 0.8 is achieved.

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Revision of the Highly Specialized Ant Genus Discothyrea (Hymenoptera: Formicidae) in the Afrotropics with X-Ray Microtomography and 3D Cybertaxonomy

Insect Systematics and Diversity ◽

10.1093/isd/ixz015 ◽

2019 ◽

Vol 3 (6) ◽

Cited By ~ 1

Author(s):

Francisco Hita-Garcia ◽

Ziv Lieberman ◽

Tracy L Audisio ◽

Cong Liu ◽

Evan P Economo

Keyword(s):

Three Dimensional ◽

Junior Synonym ◽

Micro Ct ◽

Still Images ◽

Distribution Maps ◽

3D Surface ◽

Species Complexes ◽

Key Species ◽

Surface Models ◽

Ct Data

Abstract Discothyrea Roger, 1863 is a small genus of proceratiine ants with remarkable morphology and biology. However, due to cryptic lifestyle, Discothyrea are poorly represented in museum collections and their taxonomy has been severely neglected. We perform the first comprehensive revision of Discothyrea in the Afrotropical region through a combination of traditional and three-dimensional (3D) cybertaxonomy based on microtomography (micro-CT). Species diagnostics and morphological character evaluations are based on examinations of all physical specimens and virtual analyses of 3D surface models generated from micro-CT data. Additionally, we applied virtual dissections for detailed examinations of cephalic structures to establish terminology based on homology for the first time in Discothyrea. The complete datasets comprising micro-CT data, 3D surface models and videos, still images of volume renderings, and colored stacked images are available online as cybertype datasets (Hita Garcia et al. 2019, http://doi.org/10.5061/dryad.3qm4183). We define two species complexes (D. oculata and D. traegaordhi complexes) and revise the taxonomy of all species through detailed illustrated diagnostic character plates, a newly developed identification key, species descriptions, and distribution maps. In total, we recognize 20 species; of which, 15 are described as new. We also propose D. hewitti Arnold, 1916 as junior synonym of D. traegaordhi Santschi, 1914 and D. sculptior Santschi, 1913 as junior synonym of D. oculata Emery, 1901. Also, we designate a neotype for D. traegaordhi to stabilize its status and identity, and we designate a lectotype for D. oculata. The observed diversity and endemism are discussed within the context of Afrotropical biogeography and the oophagous lifestyle.

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Patient-Specific Quality Assurance Using a 3D-Printed Chest Phantom for Intraoperative Radiotherapy in Breast Cancer

Frontiers in Oncology ◽

10.3389/fonc.2021.629927 ◽

2021 ◽

Vol 11 ◽

Author(s):

Yeonho Choi ◽

Ik Jae Lee ◽

Kwangwoo Park ◽

Kyung Ran Park ◽

Yeona Cho ◽

...

Keyword(s):

Quality Assurance ◽

Soft Tissue ◽

Three Dimensional ◽

Intraoperative Radiotherapy ◽

Hounsfield Unit ◽

Patient Specific ◽

Depth Dose ◽

Dose Comparison ◽

3D Printed ◽

The Mean

This study aims to confirm the usefulness of patient-specific quality assurance (PSQA) using three-dimensional (3D)-printed phantoms in ensuring the stability of IORT and the precision of the treatment administered. In this study, five patient-specific chest phantoms were fabricated using a 3D printer such that they were dosimetrically equivalent to the chests of actual patients in terms of organ density and shape around the given target, where a spherical applicator was inserted for breast IORT treatment via the INTRABEAM™ system. Models of lungs and soft tissue were fabricated by applying infill ratios corresponding to the mean Hounsfield unit (HU) values calculated from CT scans of the patients. The two models were then assembled into one. A 3D-printed water-equivalent phantom was also fabricated to verify the vendor-provided depth dose curve. Pieces of an EBT3 film were inserted into the 3D-printed customized phantoms to measure the doses. A 10 Gy prescription dose based on the surface of the spherical applicator was delivered and measured through EBT3 films parallel and perpendicular to the axis of the beam. The shapes of the phantoms, CT values, and absorbed doses were compared between the expected and printed ones. The morphological agreement among the five patient-specific 3D chest phantoms was assessed. The mean differences in terms of HU between the patients and the phantoms was 2.2 HU for soft tissue and −26.2 HU for the lungs. The dose irradiated on the surface of the spherical applicator yielded a percent error of −2.16% ± 3.91% between the measured and prescribed doses. In a depth dose comparison using a 3D-printed water phantom, the uncertainty in the measurements based on the EBT3 film decreased as the depth increased beyond 5 mm, and a good agreement in terms of the absolute dose was noted between the EBT3 film and the vendor data. These results demonstrate the applicability of the 3D-printed chest phantom for PSQA in breast IORT. This enhanced precision offers new opportunities for advancements in IORT.

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Pelvic Reconstruction With a Novel Three-Dimensional-Printed, Multimodality Imaging Based Endoprosthesis Following Enneking Type I + IV Resection

Frontiers in Oncology ◽

10.3389/fonc.2021.629582 ◽

2021 ◽

Vol 11 ◽

Author(s):

Zeping Yu ◽

Wenli Zhang ◽

Xiang Fang ◽

Chongqi Tu ◽

Hong Duan

Keyword(s):

Multimodality Imaging ◽

Three Dimensional ◽

Patient Specific ◽

Surgical Trauma ◽

Type I ◽

Complication Rates ◽

Pelvic Tumor ◽

Musculoskeletal Tumor Society ◽

Rod System ◽

3D Printed

Background and PurposePelvic tumor involving Type I + IV resections are technically challenging, along with various reconstructions methods presenting unsatisfactory outcomes and high complication rates. Since predominating studies preferred adopting pedicle screw-rod system (PRSS) to address this issue, we designed a novel three-dimensional-printed, multimodality imaging (3DMMI) based endoprosthesis with patient-specific instrument (PSI) assistance to facilitate the surgical reconstruction of pelvic tumor involving Enneking Type I + IV resection. We aimed to investigate the clinical effectiveness of this novel endoprosthesis and compare it with PRSS in Type I + IV reconstruction.MethodsWe retrospective studied 28 patients for a median follow-up of 47 months (range, 10 to 128 months) in this study with either 3D-printed endoprosthesis reconstruction (n = 10) or PRSS reconstruction (n = 18) between January 2000 and December 2017. Preoperative 3DMMI technique was used for tumor evaluation, PSI design, virtual surgery, and endoprosthesis fabrication. Clinical, oncological outcomes, functional assessments, and complications were analyzed between the two groups.ResultsMinor surgical trauma with mean operative duration of 251 ± 52.16 minutes (p = 0.034) and median intraoperative hemorrhage of 2000ml (range, 1600, 4000ml) (p = 0.032) was observed in endoprosthesis group. Wide margins were achieved in 9 patients of the endoprosthesis group compared with 10 in the PRSS group (p = 0.09). The 1993 version of the Musculoskeletal Tumor Society score (MSTS-93) was 23.9 ± 3.76 in endoprosthesis group, which was higher than PRSS group (p = 0.012). No statistical significance was found in relapse between two groups (p = 0.36). Complications were observed in two patients in endoprosthesis group compared with 12 patients in PRSS group (p = 0.046).ConclusionThe novel design of this 3D-printed endoprosthesis, together with 3DMMI and PSI assisted, is technically accessible with favorable clinical outcomes compared with PRSS. Further study is essential to identify its long-term outcomes.

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Accuracy and Safety of In-House Surgeon-Designed Three-Dimensional Printed Patient Specific Implants for Wafer-Less Le Fort I Osteotomy

10.21203/rs.3.rs-858174/v1 ◽

2021 ◽

Author(s):

Yiu Yan LEUNG ◽

Jasper Ka Chai LEUNG ◽

Alvin Tsz Choi LI ◽

Nathan En Zuo TEO ◽

Karen Pui Yan LEUNG ◽

...

Keyword(s):

Orthognathic Surgery ◽

Three Dimensional ◽

Patient Specific ◽

Le Fort I Osteotomy ◽

Le Fort ◽

Patient Specific Implants ◽

Principal Axes ◽

Operative Complications ◽

3D Printed ◽

Le Fort I

Abstract The design and fabrication of three-dimensional (3D) -printed patient-specific implants (PSIs) for orthognathic surgery are customarily outsourced to commercial companies. We propose a protocol of designing PSIs and surgical guides by orthognathic surgeons-in-charge instead for wafer-less Le Fort I osteotomy. The aim of this prospective study was to evaluate the accuracy and post-operative complications of PSIs that are designed in-house for Le Fort I osteotomy. The post-operative cone beam computer tomography (CBCT) model of the maxilla was superimposed to the virtual surgical planning to compare the discrepancies of pre-determined landmarks, lines and principal axes between the two models. Twenty-five patients (12 males, 13 females) were included. The median linear deviations of the post-operative maxilla of the x, y and z axes were 0.74 mm, 0.75 mm and 0.72 mm, respectively. The deviations in the principal axes for pitch, yaw and roll were 1.40°, 0.90° and 0.60°, respectively. There were no post-operative complications related to the PSIs in the follow-up period. The 3D-printed PSIs designed in-house for wafer-less Le Fort I osteotomy are accurate and safe. Its clinical outcomes and accuracy are comparable to commercial PSIs for orthognathic surgery.

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