55. Patient specific customized cranial implant: “precision makes the difference”

AbstractThe pulse arrival time (PAT), the difference between the R-peak time of electrocardiogram (ECG) signal and the systolic peak of photoplethysmography (PPG) signal, is an indicator that enables noninvasive and continuous blood pressure estimation. However, it is difficult to accurately measure PAT from ECG and PPG signals because they have inconsistent shapes owing to patient-specific physical characteristics, pathological conditions, and movements. Accordingly, complex preprocessing is required to estimate blood pressure based on PAT. In this paper, as an alternative solution, we propose a noninvasive continuous algorithm using the difference between ECG and PPG as a new feature that can include PAT information. The proposed algorithm is a deep CNN–LSTM-based multitasking machine learning model that outputs simultaneous prediction results of systolic (SBP) and diastolic blood pressures (DBP). We used a total of 48 patients on the PhysioNet website by splitting them into 38 patients for training and 10 patients for testing. The prediction accuracies of SBP and DBP were 0.0 ± 1.6 mmHg and 0.2 ± 1.3 mmHg, respectively. Even though the proposed model was assessed with only 10 patients, this result was satisfied with three guidelines, which are the BHS, AAMI, and IEEE standards for blood pressure measurement devices.

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A Computational Analysis of the Influence of a Pressure Wire in Evaluating Coronary Stenosis

Fluids ◽

10.3390/fluids6040165 ◽

2021 ◽

Vol 6 (4) ◽

pp. 165

Author(s):

Jie Yi ◽

Fang-Bao Tian ◽

Anne Simmons ◽

Tracie Barber

Keyword(s):

Coronary Stenosis ◽

Severe Case ◽

Patient Specific ◽

Fractional Flow ◽

Ideal Model ◽

Coronary Pressure ◽

Flow Reserve ◽

Pressure Wire ◽

Physical Presence ◽

The Difference

Cardiovascular disease is one of the world’s leading causes of morbidity and mortality. Fractional flow reserve (FFR) was proposed in the 1990s to more accurately evaluate the functional severity of intermediate coronary stenosis, and it is currently the gold standard in cardiac catheterization laboratories where coronary pressure and flow are routinely obtained. The clinical measurement of FFR relies on a pressure wire for the recording of pressures; however, in computational fluid dynamics studies, an FFR is frequently predicted using a wire-absent model. We aim to investigate the influence of the physical presence of a 0.014-inch (≈0.36 mm) pressure wire in the calculation of virtual FFR. Ideal and patient-specific models were simulated with the absence and presence of a pressure wire. The computed FFR reduced from 0.96 to 0.93 after inserting a wire in a 3-mm non-stenosed (pipe) ideal model. In mild stenotic cases, the difference in FFR between the wire-absent and wire-included models was slight. The overestimation in severe case was large but is of less clinical significance because, in practice, this tight lesion does not require sophisticated measurement to be considered critical. However, an absence of the pressure wire in simulations could contribute to an over-evaluation for an intermediate coronary stenosis.

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Combined Deep CNN–LSTM Network-based Multitasking Learning Architecture for Noninvasive Continuous Blood Pressure Estimation using Difference in ECG-PPG Features

10.21203/rs.3.rs-137994/v1 ◽

2021 ◽

Author(s):

Da Un Jeong ◽

Ki Moo Lim

Keyword(s):

Blood Pressure ◽

Pulse Transit Time ◽

Patient Specific ◽

Peak Time ◽

Simultaneous Prediction ◽

Deep Cnn ◽

Pressure Estimation ◽

The Difference ◽

Blood Pressure Estimation ◽

Continuous Blood Pressure

Abstract The pulse transit time (PTT), which is the difference between the R-peak time of the electrocardiogram (ECG) signal and the systolic peak of the photoplethysmography (PPG) signal, is an indicator that enables noninvasive and continuous blood pressure estimation. However, it is difficult to accurately measure the PTT from the ECG and PPG signals because they have inconsistent shapes owing to patient-specific physical characteristics, pathological conditions, and movements. Accordingly, complex preprocessing is required to estimate blood pressure based on PTT. In this paper, as an alternative solution, we propose a noninvasive continuous algorithm using the difference between the ECG and PPG as a new feature that can include PTT information. The proposed algorithm is a deep CNN–LSTM-based multitasking machine learning model that outputs simultaneous prediction results of systolic (SBP) and diastolic blood pressures (DBP). The prediction accuracies of SBP and DBP using the proposed model were 0.017±1.624 mmHg and 0.164±1.297 mmHg, respectively. This result corresponded to Grade A according to the BHS and AAMI standards, which are the validation standards for blood pressure measuring devices.

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Comparison of the Accuracy and Clinical Parameters of Patient-Specific and Conventionally Bended Plates for Mandibular Reconstruction

Frontiers in Oncology ◽

10.3389/fonc.2021.719028 ◽

2021 ◽

Vol 11 ◽

Author(s):

Henriette L. Möllmann ◽

Laura Apeltrath ◽

Nadia Karnatz ◽

Max Wilkat ◽

Erik Riedel ◽

...

Keyword(s):

Computer Assisted Surgery ◽

Reference Points ◽

Mandibular Reconstruction ◽

Patient Specific ◽

Computer Assisted ◽

Advantages And Disadvantages ◽

Patient Specific Implants ◽

Operative Complications ◽

The Difference ◽

And Training

ObjectivesThis retrospective study compared two mandibular reconstruction procedures—conventional reconstruction plates (CR) and patient-specific implants (PSI)—and evaluated their accuracy of reconstruction and clinical outcome.MethodsOverall, 94 patients had undergone mandibular reconstruction with CR (n = 48) and PSI (n = 46). Six detectable and replicable anatomical reference points, identified via computer tomography, were used for defining the mandibular dimensions. The accuracy of reconstruction was assessed using pre- and postoperative differences.ResultsIn the CR group, the largest difference was at the lateral point of the condyle mandibulae (D2) -1.56 mm (SD = 3.8). In the PSI group, the largest difference between preoperative and postoperative measurement was shown at the processus coronoid (D5) with +1.86 mm (SD = 6.0). Significant differences within the groups in pre- and postoperative measurements were identified at the gonion (D6) [t(56) = -2.217; p = .031 <.05]. In the CR group, the difference was 1.5 (SD = 3.9) and in the PSI group -1.04 (SD = 4.9). CR did not demonstrate a higher risk of plate fractures and post-operative complications compared to PSI.ConclusionFor reconstructing mandibular defects, CR and PSI are eligible. In each case, the advantages and disadvantages of these approaches must be assessed. The functional and esthetic outcome of mandibular reconstruction significantly improves with the experience of the surgeon in conducting microvascular grafts and familiarity with computer-assisted surgery. Interoperator variability can be reduced, and training of younger surgeons involved in planning can be reaching better outcomes in the future.

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A radiological analysis of the difference between MRI- and CT-based patient-specific matched guides for total knee arthroplasty from the same manufacturer

The Bone & Joint Journal ◽

10.1302/0301-620x.98b6.36633 ◽

2016 ◽

Vol 98-B (6) ◽

pp. 786-792 ◽

Cited By ~ 10

Author(s):

M. G. M. Schotanus ◽

R. Sollie ◽

E. H. van Haaren ◽

R. P. M. Hendrickx ◽

E. J. P. Jansen ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Patient Specific ◽

Total Knee ◽

The Difference ◽

Radiological Analysis

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Numerical Parametric Study of Paravalvular Leak Following a Transcatheter Aortic Valve Deployment Into a Patient-Specific Aortic Root

Journal of Biomechanical Engineering ◽

10.1115/1.4040457 ◽

2018 ◽

Vol 140 (10) ◽

Cited By ~ 13

Author(s):

Wenbin Mao ◽

Qian Wang ◽

Susheel Kodali ◽

Wei Sun

Keyword(s):

Aortic Valve ◽

Computational Model ◽

Aortic Root ◽

Paravalvular Leak ◽

Patient Specific ◽

Fe Method ◽

Transcatheter Aortic Valve ◽

Operative Planning ◽

The Difference ◽

The Impact

Paravalvular leak (PVL) is a relatively frequent complication after transcatheter aortic valve replacement (TAVR) with increased mortality. Currently, there is no effective method to pre-operatively predict and prevent PVL. In this study, we developed a computational model to predict the severity of PVL after TAVR. Nonlinear finite element (FE) method was used to simulate a self-expandable CoreValve deployment into a patient-specific aortic root, specified with human material properties of aortic tissues. Subsequently, computational fluid dynamics (CFD) simulations were performed using the post-TAVR geometries from the FE simulation, and a parametric investigation of the impact of the transcatheter aortic valve (TAV) skirt shape, TAV orientation, and deployment height on PVL was conducted. The predicted PVL was in good agreement with the echocardiography data. Due to the scallop shape of CoreValve skirt, the difference of PVL due to TAV orientation can be as large as 40%. Although the stent thickness is small compared to the aortic annulus size, we found that inappropriate modeling of it can lead to an underestimation of PVL up to 10 ml/beat. Moreover, the deployment height could significantly alter the extent and the distribution of regurgitant jets, which results in a change of leaking volume up to 70%. Further investigation in a large cohort of patients is warranted to verify the accuracy of our model. This study demonstrated that a rigorously developed patient-specific computational model can provide useful insights into underlying mechanisms causing PVL and potentially assist in pre-operative planning for TAVR to minimize PVL.

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Effect of pelvic tilt and rotation on cup orientation in standing anteroposterior radiographs

Hip International ◽

10.1177/1120700019831665 ◽

2019 ◽

Vol 30 (1) ◽

pp. 48-55 ◽

Cited By ~ 2

Author(s):

Ho Hyun Yun ◽

William S Murphy ◽

Daniel M Ward ◽

Guoyan Zheng ◽

Brett Hayden ◽

...

Keyword(s):

Computed Tomography ◽

Pelvic Tilt ◽

Patient Specific ◽

Pelvic Rotation ◽

3 Dimensional ◽

Radiographic Measurements ◽

Wide Variability ◽

The Difference ◽

The Right ◽

Cup Positioning

Background: Individual pelvic tilt and rotation have wide variability that can affect the measurement of cup orientation in anteroposterior (AP) radiographs. The purpose of this study was to analyse the effect of pelvic tilt and rotation on radiographic measurements of cup orientation. Methods: A total of 53 patients (63 hips) were included in this study. The patients underwent a computed tomography study with standing AP pelvis radiographs taken both preoperatively and approximately 3 months postoperatively. We used 2-dimensional/3-dimensional matching to measure the pelvic tilt and rotation, and the non-standardised and standardised cup orientation. Results: There was no difference in the pelvic tilt and rotation between the preoperative and postoperative radiographs. The distribution of the differences between the non-standardised and standardised cup anteversion exhibited a change within 5° in only 34/63 (54%) hips. The pelvic tilt correlated with the difference between the non-standardised and standardised cup anteversion, but the pelvic rotation did not. When all 63 hips were separated into the right and left sides, the pelvic rotation inversely correlated with the pelvic tilt-adjusted difference between the non-standardised and standardised cup anteversion of the right side but directly correlated with that of the left side. Conclusions: The current study demonstrated that the measurement of cup anteversion in standing AP radiographs is significantly affected by both the pelvic tilt and pelvic rotation. An improved understanding of the pelvic orientation may eventually allow for desired cup positioning on a patient-specific basis to potentially reduce complications associated with the malposition of the cup.

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Ceramic 3D-Printed Titanium Cranioplasty

Craniomaxillofacial Trauma & Reconstruction ◽

10.1177/1943387520927916 ◽

2020 ◽

Vol 13 (4) ◽

pp. 329-333

Author(s):

Maurice Y. Mommaerts ◽

Paul R. Depauw ◽

Erik Nout

Keyword(s):

Calcium Phosphate ◽

Case Series ◽

Titanium Implants ◽

Border Zone ◽

Implant Design ◽

Patient Specific ◽

Time Range ◽

Free Calcium ◽

Cranial Implant ◽

3D Printed

Study Design: Inlay cranioplasties following partial craniectomy in tumor or trauma cases and onlay cranioplasties for reconstructions of residual developmental skull anomalies are frequently performed using CAD-CAM techniques. Objective: In this case series, we present a novel cranial implant design, being a combination of 3D-printed titanium grade 23 and calcium phosphate paste (CeTi). Methods: The titanium patient-specific implant, manufactured using selective laser melting, has a latticed border with interconnected micropores. The cranioplasty is miniscrew fixed and its border zone subsequently partially filled with calcium phosphate paste to promote osteoinduction and osteoconduction. From April 2017 to April 2019, 8 patients have been treated with such a CeTi implant. The inlay cranioplasties were each time revision surgeries of complicated cases. Results: All implants were successful after a limited follow-up time (range 18-42 months). There were no dehiscences and no infections, and no complaints of thermal conduction. Conclusions: The proposed CeTi cranial implant combines the strength of titanium implants with the biological integration potential of ceramic implants and seems particularly resistant to infection, probably due to the biofunctionalized titanium surface and the antimicrobial activity of elevated intracellular free calcium levels.

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Difference between the biologic and chronologic age as an individualized indicator for the skincare intensity selection: skin cell profile and age difference studies

Biomedical Dermatology ◽

10.1186/s41702-019-0051-1 ◽

2019 ◽

Vol 3 (1) ◽

Cited By ~ 1

Author(s):

Yurij Sukhovei ◽

Elena Kostolomova ◽

Irina Unger ◽

Andrey Koptyug ◽

Denis Kaigorodov

Keyword(s):

Research Question ◽

Treatment Strategies ◽

Skin Aging ◽

Blood Cholesterol ◽

Patient Specific ◽

Age Difference ◽

Skin Cell ◽

The Difference ◽

Study Participants ◽

Cell Profile

Abstract Background The present research addresses the issue of skin aging and corresponding skin treatment individualization. Particular research question was on the development of a simplified criterion supporting patient-specific decisions about the necessity and intensity of skin treatment. Basing on published results and a wide pool of our own experimental data, a hypothesis is formulated that a difference between biologic and chronologic age can be used as a powerful indicator of skin aging. Methods In the present paper, we report the results of studies with 80 volunteers between 15 and 65 years of age linking skin cell profile parameters to biologic and chronologic age. Biologic age was calculated using the empirical expressions based on the forced vital lung capacity, systolic blood pressure, urea concentration, and blood cholesterol level. Epidermis and derma cellular structures were studied using skin biopsy samples taken from the gluteal region. Results The present study supports the conclusion that biologic and chronologic age difference is changing in the progress of life. Our studies are showing that time point when calculated biologic age becomes equal to the chronologic one reflecting the onset of specific changes in the age dependencies of experimentally measured skin cell profile parameters. Thus, it is feasible that a difference between chronologic and individually assessed biologic age indeed reflects the process of skin aging. Conclusions With all reservations to the relatively small number of study participants, it seems feasible that a difference between biologic and chronologic age can be used as an indicator of skin aging. Additional research linking blood immune profile and skin topography to the difference of biologic and chronologic age (reported in the following paper) provides further support for the formulated hypotheses. So, a difference between calculated biologic age and chronologic age can be used as an individualized criterion supporting decisions on skin treatment strategies. Further research involving larger numbers of participants aimed at optimizing the expressions for calculating biologic age could lead to reliable and easily available express criterion supporting the decision for the individualized skin treatment.

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Comparing cost and print time estimates for six commercially-available 3D printers obtained through slicing software for clinically relevant anatomical models

10.21203/rs.3.rs-50148/v2 ◽

2020 ◽

Author(s):

Joshua Vic Chen ◽

Alan BC Dang ◽

Alexis Dang

Keyword(s):

Cost Effective ◽

Patient Specific ◽

Anatomical Models ◽

Worst Case ◽

Layer Height ◽

Orthopaedic Care ◽

Horizontal Orientation ◽

3D Printers ◽

The Difference ◽

Digital Anatomy

Abstract Background3D printed patient-specific anatomical models have been applied clinically to orthopaedic care for surgical planning and patient education. The estimated cost and print time per model for 3D printers have not yet been compared with clinically representative models across multiple printing technologies. This study investigates six commercially-available 3D printers: Prusa i3 MK3S, Formlabs Form 2, Formlabs Form 3, LulzBot TAZ 6, Stratasys F370, and Stratasys J750 Digital Anatomy.MethodsSeven representative orthopaedic standard tessellation models derived from CT scans were imported into the respective slicing software for each 3D printer. For each printer and corresponding print setting, the slicing software provides a print time and material use estimate. Material quantity was used to calculate estimated model cost. Print settings investigated were infill percentage, layer height, and model orientation on the print bed. The slicing software investigated are Cura LulzBot Edition 3.6.20, GrabCAD Print 1.43, PreForm 3.4.6, and PrusaSlicer 2.2.0.ResultsThe effect of changing infill between 15% and 20% on estimated print time and material use was negligible. Orientation of the model has considerable impact on time and cost with worst-case differences being as much as 39.30% added print time and 34.56% added costs. Averaged across all investigated settings, horizontal model orientation on the print bed minimizes estimated print time for all 3D printers, while vertical model orientation minimizes cost with the exception of Stratasys J750 Digital Anatomy, in which horizontal orientation also minimized cost. Decreasing layer height for all investigated printers increased estimated print time and decreased estimated cost with the exception of Stratasys F370, in which cost increased. The difference in material cost was two orders of magnitude between the least and most-expensive printers. The difference in build rate (cm3/min) was one order of magnitude between the fastest and slowest printers.ConclusionsAll investigated 3D printers in this study have the potential for clinical utility. Print time and print cost are dependent on orientation of anatomy and the printers and settings selected. Cost-effective clinical 3D printing of anatomic models should consider an appropriate printer for the complexity of the anatomy and the experience of the printer technicians.

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