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1.
Int J Cardiovasc Imaging ; 36(1): 123-129, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31515695

RESUMO

Valve size selection for transcatheter aortic valve replacement (TAVR) is currently based on cardiac CT-scan. At variance with patient-specific computer simulation, this does not allow the assessment of the valve-host interaction. We aimed to compare clinical valve size selection and valve size selection by an independent expert for computer simulation. A multicenter retrospective analysis of valve size selection by the physician and the independent expert in 141 patients who underwent TAVR with the self-expanding CoreValve or Evolut R. Baseline CT-scan was used for clinical valve size selection and for patient-specific computer simulation. Simulation results were not available for clinical use. Overall true concordance between clinical and simulated valve size selection was observed in 47 patients (33%), true discordance in 15 (11%) and ambiguity in 79 (56%). In 62 (44%, cohort A) one valve size was simulated whereas two valve sizes were simulated in 79 (56%, cohort B). In cohort A, concordance was 76% and discordance was 24%; a smaller valve size was selected for simulation in 10 patients and a larger in 5. In cohort B, a different valve size was selected for simulation in all patients in addition to the valve size that was used for TAVR. The different valve size concerned a smaller valve in 45 patients (57%) and a larger in 34 (43%). Selection of the valve size differs between the physician and the independent computer simulation expert who used the same source of information. These findings indicate that valve sizing in TAVR is still more intricate than generally assumed.


Assuntos
Estenose da Valva Aórtica/diagnóstico por imagem , Estenose da Valva Aórtica/cirurgia , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/cirurgia , Próteses Valvulares Cardíacas , Modelagem Computacional Específica para o Paciente , Cirurgiões/psicologia , Tomografia Computadorizada por Raios X , Substituição da Valva Aórtica Transcateter/instrumentação , Idoso , Idoso de 80 Anos ou mais , Valva Aórtica/fisiopatologia , Estenose da Valva Aórtica/fisiopatologia , Competência Clínica , Tomada de Decisão Clínica , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Modelos Cardiovasculares , Variações Dependentes do Observador , Seleção de Pacientes , Valor Preditivo dos Testes , Desenho de Prótese , Interpretação de Imagem Radiográfica Assistida por Computador , Reprodutibilidade dos Testes , Estudos Retrospectivos
2.
BMC Bioinformatics ; 20(1): 457, 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31492098

RESUMO

BACKGROUND: Mathematics and Phy sics-based simulation models have the potential to help interpret and encapsulate biological phenomena in a computable and reproducible form. Similarly, comprehensive descriptions of such models help to ensure that such models are accessible, discoverable, and reusable. To this end, researchers have developed tools and standards to encode mathematical models of biological systems enabling reproducibility and reuse, tools and guidelines to facilitate semantic description of mathematical models, and repositories in which to archive, share, and discover models. Scientists can leverage these resources to investigate specific questions and hypotheses in a more efficient manner. RESULTS: We have comprehensively annotated a cohort of models with biological semantics. These annotated models are freely available in the Physiome Model Repository (PMR). To demonstrate the benefits of this approach, we have developed a web-based tool which enables users to discover models relevant to their work, with a particular focus on epithelial transport. Based on a semantic query, this tool will help users discover relevant models, suggesting similar or alternative models that the user may wish to explore or use. CONCLUSION: The semantic annotation and the web tool we have developed is a new contribution enabling scientists to discover relevant models in the PMR as candidates for reuse in their own scientific endeavours. This approach demonstrates how semantic web technologies and methodologies can contribute to biomedical and clinical research. The source code and links to the web tool are available at https://github.com/dewancse/model-discovery-tool.


Assuntos
Modelos Biológicos , Semântica , Humanos , Modelagem Computacional Específica para o Paciente , Reprodutibilidade dos Testes , Software
3.
Vasc Endovascular Surg ; 53(7): 572-582, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31382837

RESUMO

BACKGROUND-AIM: Limited data exist concerning the fluid dynamic changes induced by endovascular aortic repair with fenestrated and chimney graft modalities in pararenal aneurysms. We aimed to investigate and compare the wall shear stress (WSS) and flow dynamics for the branch vessels before and after endovascular aortic repair with fenestrated and chimney techniques. METHODS: Modeling was done for patient specific pararenal aortic aneurysms employing fenestrated and chimney grafts (Materialise Mimics 10.0) before and after the endovascular procedure, using computed tomography scans of patients. Surface and spatial grids were created using the ANSYS CFD meshing software 2019 R2. Assessment of blood flow, streamlines, and WSS before and after aneurysm repair was performed. RESULTS: The endovascular repair with chimney grafts leaded to a 43% to 53% reduction in perfusion in renal arteries. In fenestrated reconstruction, we observed a 15% reduced perfusion in both renal arteries. In both cases, we observed a decrease in the recirculation phenomena of the aorta after endovascular repair. Concerning the grafts of the renal arteries, we observed in both the transverse and longitudinal axes low WSS regions with simultaneous recirculation of the flow 1 cm distal to the ostium sites in both aortic graft models. High WSS regions appeared in the sites of ostium. CONCLUSIONS: We observed reduced renal perfusion in chimney grafts compared to fenestrated grafts, probably caused by the long and kinked characteristics of these devices.


Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Implante de Prótese Vascular/instrumentação , Prótese Vascular , Tomada de Decisão Clínica , Procedimentos Endovasculares/instrumentação , Modelos Cardiovasculares , Modelagem Computacional Específica para o Paciente , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/fisiopatologia , Aortografia/métodos , Implante de Prótese Vascular/efeitos adversos , Angiografia por Tomografia Computadorizada , Procedimentos Endovasculares/efeitos adversos , Hemodinâmica , Humanos , Hidrodinâmica , Seleção de Pacientes , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/fisiopatologia , Valor Preditivo dos Testes , Desenho de Prótese , Interpretação de Imagem Radiográfica Assistida por Computador , Circulação Renal , Estresse Mecânico , Resultado do Tratamento
4.
Comput Methods Programs Biomed ; 179: 104993, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31443866

RESUMO

Twin-to-twin transfusion syndrome (TTTS) is a serious condition that may occur in pregnancies when two or more fetuses share the same placenta. It is characterized by abnormal vascular connections in the placenta that cause blood to flow unevenly between the babies. If left untreated, perinatal mortality occurs in 90% of cases, whilst neurological injuries are still present in TTTS survivors. Minimally invasive fetoscopic laser surgery is the standard and optimal treatment for this condition, but is technically challenging and can lead to complications. Acquiring and maintaining the required surgical skills need consistent practice, and a steep learning curve. An accurate preoperative planning is thus vital for complex TTTS cases. To this end, we propose the first TTTS fetal surgery planning and simulation platform. The soft tissue of the mother, the uterus, the umbilical cords, the placenta and its vascular tree are segmented and registered automatically from magnetic resonance imaging and 3D ultrasound using computer vision and deep learning techniques. The proposed state-of-the-art technology is integrated into a flexible C++ and MITK-based application to provide a full exploration of the intrauterine environment by simulating the fetoscope camera as well as the laser ablation, determining the correct entry point, training doctors' movements and trajectory ahead of operation, which allows improving upon current practice. A comprehensive usability study is reported. Experienced surgeons rated highly our TTTS planner and simulator, thus being a potential tool to be implemented in real and complex TTTS surgeries.


Assuntos
Transfusão Feto-Fetal/cirurgia , Fetoscopia/métodos , Modelos Anatômicos , Algoritmos , Gráficos por Computador , Simulação por Computador , Feminino , Transfusão Feto-Fetal/diagnóstico por imagem , Fetoscopia/estatística & dados numéricos , Humanos , Imagem Tridimensional , Recém-Nascido , Terapia a Laser/métodos , Terapia a Laser/estatística & dados numéricos , Imagem por Ressonância Magnética/estatística & dados numéricos , Modelagem Computacional Específica para o Paciente/estatística & dados numéricos , Placenta/diagnóstico por imagem , Gravidez , Interface Usuário-Computador , Útero/diagnóstico por imagem
5.
Int J Hyperthermia ; 36(1): 801-811, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31450989

RESUMO

Purpose: To investigate the effect of patient specific vessel cooling on head and neck hyperthermia treatment planning (HTP). Methods and materials: Twelve patients undergoing radiotherapy were scanned using computed tomography (CT), magnetic resonance imaging (MRI) and contrast enhanced MR angiography (CEMRA). 3D patient models were constructed using the CT and MRI data. The arterial vessel tree was constructed from the MRA images using the 'graph-cut' method, combining information from Frangi vesselness filtering and region growing, and the results were validated against manually placed markers in/outside the vessels. Patient specific HTP was performed and the change in thermal distribution prediction caused by arterial cooling was evaluated by adding discrete vasculature (DIVA) modeling to the Pennes bioheat equation (PBHE). Results: Inclusion of arterial cooling showed a relevant impact, i.e., DIVA modeling predicts a decreased treatment quality by on average 0.19 °C (T90), 0.32 °C (T50) and 0.35 °C (T20) that is robust against variations in the inflow blood rate (|ΔT| < 0.01 °C). In three cases, where the major vessels transverse target volume, notable drops (|ΔT| > 0.5 °C) were observed. Conclusion: Addition of patient-specific DIVA into the thermal modeling can significantly change predicted treatment quality. In cases where clinically detectable vessels pass the heated region, we advise to perform DIVA modeling.


Assuntos
Vasos Sanguíneos/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/irrigação sanguínea , Hipertermia Induzida , Modelagem Computacional Específica para o Paciente , Vasos Sanguíneos/anatomia & histologia , Estudos de Viabilidade , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Imagem por Ressonância Magnética , Temperatura Ambiente , Terapia Assistida por Computador , Tomografia Computadorizada por Raios X
6.
J Stroke Cerebrovasc Dis ; 28(11): 104339, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31451338

RESUMO

BACKGROUND: Infarcts in the lateral striate artery (LSA) territory can be caused by several pathological changes, including lipohyalinosis and microatheroma. However, fluid dynamic effects on these changes remain unknown. Thus, we investigated whether the fluid dynamic metrics of the LSAs were altered in patients with acute ischemic stroke using computational fluid dynamics (CFD) analysis. METHODS: Fifty-one patients with acute ischemic stroke confined in the basal ganglia and/or corona radiata underwent high-resolution magnetic resonance angiography (HR-MRA) at 7T. We performed CFD analyses to obtain indices including the wall shear stress (WSS), WSS gradient (WSSG), and flow velocity (FV) and compared these values between the ipsilesional and contralesional sides in the patients with infarcts in the LSA or non-LSA territories. RESULTS: In patients with LSA-territory infarcts, the WSS, WSSG, and FV values were significantly lower in the ipsilesional LSAs than in the contralesional LSAs (P = .01-.03), while these values in the proximal middle cerebral arteries showed no significant lateralities. In contrast, in patients with non-LSA-territory infarcts, there were no significant lateralities in the metrics between the ipsilesional and contralesional sides. CONCLUSIONS: The CFD analyses using HR-MRA revealed significantly low WSS and WSSG values of the ipsilesional LSAs compared with that of the contralesional side in patients with LSA-territory infarcts, suggesting that fluid dynamic factors of LSAs can be one of the risk factors for LSA-territory infarctions.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Angiografia Cerebral/métodos , Artérias Cerebrais/diagnóstico por imagem , Circulação Cerebrovascular , Angiografia por Ressonância Magnética , Modelos Cardiovasculares , Modelagem Computacional Específica para o Paciente , Acidente Vascular Cerebral/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo , Isquemia Encefálica/fisiopatologia , Artérias Cerebrais/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Estresse Mecânico , Acidente Vascular Cerebral/fisiopatologia
7.
World Neurosurg ; 132: 75-80, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31470159

RESUMO

BACKGROUND: Incomplete ossification of the pars interarticularis will result in a pars defect, a common cause of low back pain in youth and strongly associated with participation in high-impact sports. If left untreated, it can result in spondylolisthesis, causing dynamic canal stenosis, low back pain, and radiculopathy. The treatment of pars defect was first described by Bucks in 1970, who used screws in the lamina placed through an upward and outward direction. However, because of the multiple inclusion and exclusion criteria and narrow margin of error, the Bucks pars repair technique is not commonly performed. METHODS: A 28-year-old woman had with low back pain that she had been experiencing since mid-adolescence. Computed tomography revealed a bilateral L5 pars defect without spondylolisthesis. Her L5 vertebra was reconstructed virtually. The screw trajectories, a 3-dimensional (3D) model of the vertebra, and a patient-specific drill guide (PSDG) were designed and printed using positioning guide software (MySpine MC Guides [Medacta International SA, Castel San Petro, Switzerland]). A modified Bucks procedure using cannulated compression screws and the PSDG was performed. RESULTS: Follow-up computed tomography revealed accurate placement of the compression screws, mirroring the planned trajectory. The patient was pain free at 3 months postoperatively, and early union across the defect was visualized on the 5-month radiographic imaging study. CONCLUSION: Using 3D planning software, complex surgical procedures can be planned using the patient's anatomy and computed tomography. With the aid of 3D-printed PSDGs, screw placement in narrow corridors, such as was shown in our case, is safe, efficient, and achievable.


Assuntos
Vértebras Lombares/cirurgia , Modelos Anatômicos , Espondilólise/cirurgia , Adulto , Parafusos Ósseos , Transplante Ósseo , Fios Ortopédicos , Feminino , Humanos , Imagem Tridimensional , Vértebras Lombares/anormalidades , Vértebras Lombares/anatomia & histologia , Vértebras Lombares/diagnóstico por imagem , Tamanho do Órgão , Modelagem Computacional Específica para o Paciente , Impressão Tridimensional
8.
J Cardiovasc Med (Hagerstown) ; 20(9): 584-596, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31369473

RESUMO

: In recent years, three-dimensional modelling and printing techniques have improved diagnosis and preprocedural planning during percutaneous interventions or surgery in cardiovascular disease. The raw data for the whole process are obtained through medical imaging, where regions of interest, that is heart chambers, valves, aorta, coronary vessels etc., are segmented and converted into three-dimensional digital models, which are then reproduced in physical replica by a three-dimensional printer. In the current article, a freeware patient-specific three-dimensional modelling and printing step-by-step procedure for preprocedural planning for complex heart diseases is presented and applied on four patients. Finally, a general discussion on the potential and future developments of personalized three-dimensional modelling and rapid prototyping for preprocedural planning is also presented.


Assuntos
Doenças Cardiovasculares/diagnóstico por imagem , Doenças Cardiovasculares/terapia , Tomada de Decisão Clínica , Modelos Anatômicos , Modelos Cardiovasculares , Modelagem Computacional Específica para o Paciente , Impressão Tridimensional , Idoso , Idoso de 80 Anos ou mais , Desenho de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Impressão Tridimensional/instrumentação , Desenho de Programas de Computador
9.
J Cardiovasc Surg (Torino) ; 60(5): 582-588, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31256581

RESUMO

BACKGROUND: A geometrical understanding of the individual patient's disease morphology is crucial in aortic surgery. The aim of our study was to validate a questionnaire addressing understanding of aortic disease and use this questionnaire to investigate the value of 3D printing as a teaching tool for surgical trainees. METHODS: Anonymized CT-angiography images of six different patients were selected as didactic cases of aortic disease and made into 3D models of transparent rigid resin with the Vat-photopolymerization technique. The 3D aortic models, which could be disassembled and reassembled, were displayed to 37 surgical trainees, immediately after a seminar on aortic disease. A questionnaire was developed to compare the trainees' understanding before (T0) and after (T1) demonstration of the 3D printed models. RESULTS: A panel of 15 experts participated in evaluating face and content validity of the questionnaire. The questionnaire validity was established and therefore the information investigated by the questionnaire could be synthetized using the mean of the items to indicate the understanding. The participants (mean age 28 years, range 26-34, male 59%) showed a significant improvement in understanding from T0 (median=7.25; IQR=1.50) to T1 (median=8.00; IQR=1.50; P=0.002). CONCLUSIONS: Preliminary data suggest that the use of 3D-printed aortic models as a teaching tool was feasible and improved the understanding of aortic disease among surgical trainees.


Assuntos
Aorta/diagnóstico por imagem , Doenças da Aorta/diagnóstico por imagem , Aortografia/métodos , Angiografia por Tomografia Computadorizada , Educação de Pós-Graduação em Medicina/métodos , Impressão Tridimensional , Cirurgiões/educação , Inquéritos e Questionários , Procedimentos Cirúrgicos Vasculares/educação , Adulto , Aorta/cirurgia , Doenças da Aorta/cirurgia , Compreensão , Escolaridade , Estudos de Viabilidade , Feminino , Humanos , Masculino , Modelos Anatômicos , Modelos Cardiovasculares , Modelagem Computacional Específica para o Paciente , Valor Preditivo dos Testes , Dados Preliminares , Interpretação de Imagem Radiográfica Assistida por Computador , Reprodutibilidade dos Testes
10.
J Thorac Cardiovasc Surg ; 157(3): 1146-1155, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-31264966

RESUMO

OBJECTIVE: Fontan surgical planning is an image-based, collaborative effort, which is hypothesized to result in improved patient outcomes. A common motivation for Fontan surgical planning is the progression (or concern for progression) of pulmonary arteriovenous malformations. The purpose of this study was to evaluate the accuracy of surgical planning predictions, specifically hepatic flow distribution (HFD), a known factor in pulmonary arteriovenous malformation progression, and identify methodological improvements needed to increase prediction accuracy. METHODS: Twelve single-ventricle patients who were enrolled in a surgical planning protocol for Fontan surgery with pre- and postoperative cardiac imaging were included in this study. Computational fluid dynamics were used to compare HFD in the surgical planning prediction and actual postoperative conditions. RESULTS: Overall, HFD prediction error was 17 ± 13%. This error was similar between surgery types (15 ± 18% and 18 ± 10% for revisions vs Fontan completions respectively; P = .73), but was significantly lower (6 ± 7%; P = .05) for hepatic to azygous shunts. Y-grafts and extracardiac conduits showed a strong correlation between prediction error and discrepancies in graft insertion points (r = 0.99; P < .001). Improving postoperative anatomy prediction significantly reduced overall HFD prediction error to 9 ± 6% (P = .03). CONCLUSIONS: Although Fontan surgical planning can offer accurate HFD predictions for specific graft types, methodological improvements are needed to increase overall accuracy. Specifically, improving postoperative anatomy prediction was shown to be an important target for future work. Future efforts and refinements to the surgical planning process will benefit from an improved understanding of the current state and will rely heavily on increased follow-up data.


Assuntos
Tomada de Decisão Clínica , Técnicas de Apoio para a Decisão , Técnica de Fontan , Cardiopatias Congênitas/cirurgia , Circulação Hepática , Imagem por Ressonância Magnética , Modelagem Computacional Específica para o Paciente , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Técnica de Fontan/efeitos adversos , Georgia , Cardiopatias Congênitas/diagnóstico por imagem , Cardiopatias Congênitas/fisiopatologia , Humanos , Hidrodinâmica , Lactente , Masculino , Modelos Cardiovasculares , Seleção de Pacientes , Philadelphia , Complicações Pós-Operatórias/etiologia , Valor Preditivo dos Testes , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
11.
J Craniofac Surg ; 30(8): e720-e723, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31261343

RESUMO

PURPOSE: Decompressive craniectomy is a life-saving procedure in the setting of malignant brain swelling. Patients who survive require cranioplasty for anatomical reconstruction and cerebral protection. Autologous cranioplasty remains the commonest practice nowadays, but partial bone flap defects are frequently encountered. The authors, therefore, seek to develop a new technique of reconstruction for cranioplasty candidate with partial bone flap defect utilizing computer-assisted 3D modeling and printing. METHODS: A prospective study was conducted to evaluate the outcome of a new reconstruction technique that produces patient-specific hybrid polymethyl methacrylate-autologous cranial implant. Computer-assisted 3D modeling and printing was utilized to produce patient-specific molds, which allowed real-time reconstruction of bone flap with partial defect intra-operatively. RESULTS: Outcome assessment for 11 patients at 6 weeks and 3 months post-operatively revealed satisfactory implant alignment with favorable cosmesis. The mean visual analog scale for cosmesis was 91. Mean implant size was 50cm, and the mean duration of intra-operative reconstruction was 30 minutes. All of them revealed improvement in quality of life following surgery as measured by the SF-36 score. Cost analysis revealed that this technique is more cost-effective compared to customized cranial prosthesis. CONCLUSION: This new technique and approach produce hybrid autologous-alloplastic bone flap that resulted in satisfactory implant alignment and favorable cosmetic outcome with relatively low costs.


Assuntos
Crânio/cirurgia , Retalhos Cirúrgicos , Adolescente , Adulto , Craniectomia Descompressiva/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelagem Computacional Específica para o Paciente , Impressão Tridimensional , Estudos Prospectivos , Qualidade de Vida , Procedimentos Cirúrgicos Reconstrutivos , Resultado do Tratamento , Adulto Jovem
12.
J Therm Biol ; 83: 119-133, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31331510

RESUMO

Focused ultrasound surgery (FUS) is a non-invasive thermal therapeutic method which has been emerged in the field of brain tumors treatment. During intraoperative brain surgery, application of FUS can significantly increase the accuracy of thermal ablation of tumor while reducing undesirable damage to healthy brain tissue. The main objective of this study is acquiring acoustic transducer specifications to achieve optimum thermal treatment in the tumoral tissue. 2D and 3D models are constructed from patient-specific brain MRI images which consist of a malignant vascular tumor. Acoustic pressure and temperature are obtained by using homogenous Helmholtz and bio-heat transfer equations according to insignificant nonlinear effect. Besides that, thermal lesion induced by FUS is obtained by the thermal dose function. Results show the significance of blood vessels' cooling effect on the temperature profile. Moreover, correlation between temperature profile and transducer's operating parameter including power, frequency and duty cycle is obtained. Artificial neural network analysis is conducted to estimate required transducer parameters for optimum temperature rise.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Modelagem Computacional Específica para o Paciente , Neoplasias Encefálicas , Circulação Cerebrovascular , Glioblastoma , Ablação por Ultrassom Focalizado de Alta Intensidade/instrumentação , Temperatura Alta , Humanos , Imagem Tridimensional/métodos , Imagem por Ressonância Magnética/métodos
13.
PLoS One ; 14(6): e0218612, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31216346

RESUMO

INTRODUCTION: Acetabular fractures consist of complex fracture patterns whereby bone fragments are displaced in different directions. Two-dimensional computed tomography (2DCT) gap and step-off measurements tend to underestimate the multidirectional features of these fractures. The aim was to develop a three-dimensional computed tomography (3DCT) measurement method for acetabular fractures and validate whether this method will provide an observer independent fracture characterization. MATERIALS AND METHODS: Sixty patients, operated for an acetabular fracture between 2007 and 2018, were included. The displacement was measured on the pre- and postoperative CT scans. Pre- and postoperative CT-based 3D models were made for each patient. Multiple 3D measurements, namely the 3D step-off, gap and the total gap area were introduced to quantify the preoperative and postoperative displacement. The Wilcoxon signed rank analysis was used to compare the 2DCT and 3DCT measurements. RESULTS: The preoperative displacement was significantly underestimated by 2DCT measurements in comparison with 3DCT measurements (2D vs. 3D; step-off 8 vs. 16 mm with P < 0.001; gap 19 vs. 21 mm with P = 0.001). The same applies to the postoperative residual displacement (2D vs. 3D; step-off 0 vs. 6 mm; gap 3 vs. 8 mm; P < 0.001). The total gap area, defined as the surface area between all fracture lines in the 3D model, was measured for each patient, resulting in a median value of 722 mm2 preoperatively and 168 mm2 postoperatively, with excellent inter- and intra-rater reliability. CONCLUSION: 2DCT measurements tend to underestimate the initial and residual displacement in complex acetabular fractures. A 3DCT analysis of these injuries was developed to overcome this and should be used in addition to the Judet/Letournel and AO/OTA classification systems, in order to provide an observer independent quantifiable fracture description and accurate assessment of the fracture reduction.


Assuntos
Acetábulo/diagnóstico por imagem , Fraturas Ósseas/diagnóstico por imagem , Modelagem Computacional Específica para o Paciente , Tomografia Computadorizada por Raios X/métodos , Acetábulo/lesões , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
14.
Int J Cardiovasc Imaging ; 35(11): 2067-2076, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31203535

RESUMO

The use of 3D printed models of the right ventricular outflow tract (RVOT) for surgical and interventional planning is growing and often requires image segmentation of cardiac magnetic resonance (CMR) images. Segmentation results may vary based on contrast, image sequence, signal threshold chosen by the operator, and manual post-processing. The purpose of this study was to determine potential biases and post-processing errors in image segmentation to enable informed decisions. Models of the RVOT and pulmonary arteries from twelve patients who had contrast enhanced CMR angiography with gadopentetate dimeglumine (GPD), gadofosveset trisodium (GFT), and a post-GFT inversion-recovery (IR) whole heart sequence were segmented, trimmed, and aligned by three operators. Geometric agreement and minimal RVOT diameters were compared between sequences and operators. To determine the contribution of threshold, interoperator variability was compared between models created by the same two operators using the same versus different thresholds. Geometric agreement by Dice between objects was high (intraoperator: 0.89-0.95; interoperator: 0.95-0.97), without differences between sequences. Minimal RVOT diameters differed on average by - 1.9 to - 1.3 mm (intraoperator) and by 0.4 to 1.4 mm (interoperator). The contribution of threshold to interoperator geometric agreement was not significant (same threshold: 0.96 ± 0.06, different threshold: 0.93 ± 0.05; p = 0.181), but minimal RVOT diameters were more variable with different versus constant thresholds (- 9.12% vs. 2.42%; p < 0.05). Thresholding does not significantly change interoperator variability for geometric agreement, but does for minimal RVOT diameter. Minimal RVOT diameters showed clinically relevant variation within and between operators.


Assuntos
Meios de Contraste/administração & dosagem , Gadolínio DTPA/administração & dosagem , Gadolínio/administração & dosagem , Cardiopatias Congênitas/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Imagem Tridimensional , Angiografia por Ressonância Magnética , Modelos Cardiovasculares , Compostos Organometálicos/administração & dosagem , Modelagem Computacional Específica para o Paciente , Artéria Pulmonar/diagnóstico por imagem , Cardiopatias Congênitas/fisiopatologia , Ventrículos do Coração/fisiopatologia , Humanos , Variações Dependentes do Observador , Valor Preditivo dos Testes , Artéria Pulmonar/fisiopatologia , Reprodutibilidade dos Testes
16.
J Vasc Interv Radiol ; 30(7): 987-994.e4, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31109852

RESUMO

PURPOSE: To evaluate whether the biomechanical marker known as rupture risk equivalent diameter (RRED) was superior to the actual abdominal aortic aneurysm (AAA) diameter in estimating future rupture risk in patients who had undergone pre-rupture computed tomography (CT) angiography. MATERIALS AND METHODS: A retrospective study was conducted in 13 patients with ruptured AAAs who had undergone CT angiography before and after rupture between 2001 and 2015. The median time between the 2 scans was 731 days. Biomechanical and geometrical markers such as maximal AAA diameter, peak wall stress (PWS), and RRED were calculated with AAA-dedicated software. The main analyses determined whether RRED was higher than the actual diameter and the threshold diameter for elective surgery (55 mm for men, 50 mm for women) in AAAs before and after rupture. Differences between diameter and biomechanical markers before and after rupture were tested with appropriate statistical tests. RESULTS: RRED before and after rupture was smaller than the actual diameter in 7 of 13 cases. Post-rupture RRED was estimated to be smaller than the threshold diameter for elective repair in 4 cases, again suggesting a low rupture risk. The median PWS before and after rupture was 181.7 kPa (interquartile range [IQR], 152.1-244.2 kPa) and 274.1 kPa (IQR, 172.2-377.2 kPa), respectively. CONCLUSIONS: RRED was smaller than the actual diameter in more than half of pre-rupture AAAs, suggesting a lower rupture risk than estimated with the actual diameter. The results suggest that the currently available biomechanical imaging markers might not be ready for use in clinical practice.


Assuntos
Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Ruptura Aórtica/etiologia , Aortografia/métodos , Angiografia por Tomografia Computadorizada , Tomografia Computadorizada Multidetectores , Idoso , Idoso de 80 Anos ou mais , Aorta Abdominal/fisiopatologia , Aneurisma da Aorta Abdominal/complicações , Aneurisma da Aorta Abdominal/fisiopatologia , Ruptura Aórtica/diagnóstico por imagem , Ruptura Aórtica/fisiopatologia , Fenômenos Biomecânicos , Bases de Dados Factuais , Feminino , Humanos , Masculino , Países Baixos , Modelagem Computacional Específica para o Paciente , Valor Preditivo dos Testes , Prognóstico , Interpretação de Imagem Radiográfica Assistida por Computador , Fluxo Sanguíneo Regional , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Estresse Mecânico
17.
Int J Comput Assist Radiol Surg ; 14(7): 1227-1235, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31115756

RESUMO

PURPOSE: Transcatheter, beating heart repair techniques for mitral valve regurgitation is a very active area of development. However, it is difficult to both simulate and predict the clinical outcomes of mitral repairs, owing to the complexity of mitral valve geometry and the influence of hemodynamics. We aim to produce a workflow for manufacturing dynamic patient-specific models to simulate the mitral valve for transcatheter repair applications. METHODS: In this paper, we present technology and associated workflow, for using transesophageal echocardiography to generate dynamic physical replicas of patient valves. We validate our workflow using six patient datasets representing patients with unique or particularly challenging pathologies as selected by a cardiologist. The dynamic component of the models and their resultant potential as procedure planning tools is due to a dynamic pulse duplicator that permits the evaluation of the valve models experiencing realistic hemodynamics. RESULTS: Early results indicate the workflow has excellent anatomical accuracy and the ability to replicate regurgitation pathologies, as shown by colour Doppler ultrasound and anatomical measurements comparing patients and models. Analysis of all measurements successfully resulted in t critical two-tail > t stat and p values > 0.05, thus demonstrating no statistical difference between the patients and models, owing to high fidelity morphological replication. CONCLUSIONS: Due to the combination of a dynamic environment and patient-specific modelling, this workflow demonstrates a promising technology for simulating the complete morphology of mitral valves undergoing transcatheter repairs.


Assuntos
Ecocardiografia Transesofagiana/métodos , Próteses Valvulares Cardíacas , Insuficiência da Valva Mitral/cirurgia , Valva Mitral/diagnóstico por imagem , Modelagem Computacional Específica para o Paciente , Hemodinâmica , Humanos , Insuficiência da Valva Mitral/diagnóstico por imagem
18.
Ann Vasc Surg ; 59: 308.e1-308.e8, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31075464

RESUMO

BACKGROUND: Pancreaticoduodenal artery aneurysms (PDAAs) with occlusion of the superior mesenteric artery (SMA) are extremely rare. In the present study, we used computational fluid dynamics (CFD) to analyze the hemodynamics of a patient-specific PDAA with occlusion of the SMA preoperatively and then decide the treatment strategy in terms of the potential postoperative hemodynamics. METHODS: A 3D model of a 69-old-year female with PDAA was reconstructed based on CT images. The virtual postoperative models of the aneurysmectomy with or without revascularization were numerically simulated in terms of hemodynamics including the flow field and wall shear stress (WSS). RESULTS: Aneurysmectomy with revascularization would result in the original aneurysm site experiencing abnormally high WSS and pressure, which may possibly lead to the recurrence of PDAA. However, aneurysmectomy without revascularization would lead to stagnant flow in the blocked posterior-inferior pancreaticoduodenal artery (PIPDA). As a result, the PIPDA may soon be completely occluded after surgery and the SMA perfusion would be guaranteed. Finally, aneurysmectomy without revascularization was performed in this patient. The postoperative six-month computed tomography angiography result finely matched to the preoperative CFD simulation result. CONCLUSIONS: This study gained insights into hemodynamics of PDAA. In addition, it demonstrated that utilization of CFD analysis also possibly helps assist the operation strategies for vascular diseases.


Assuntos
Aneurisma/cirurgia , Duodeno/irrigação sanguínea , Hemodinâmica , Artéria Mesentérica Superior/cirurgia , Oclusão Vascular Mesentérica/cirurgia , Pâncreas/irrigação sanguínea , Modelagem Computacional Específica para o Paciente , Circulação Esplâncnica , Idoso , Aneurisma/complicações , Aneurisma/diagnóstico por imagem , Aneurisma/fisiopatologia , Tomada de Decisão Clínica , Angiografia por Tomografia Computadorizada , Feminino , Humanos , Artéria Mesentérica Superior/diagnóstico por imagem , Artéria Mesentérica Superior/fisiopatologia , Oclusão Vascular Mesentérica/complicações , Oclusão Vascular Mesentérica/diagnóstico por imagem , Oclusão Vascular Mesentérica/fisiopatologia , Modelos Cardiovasculares , Valor Preditivo dos Testes , Resultado do Tratamento , Grau de Desobstrução Vascular
19.
J Orthop Res ; 37(10): 2197-2203, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31144729

RESUMO

To manage osteoporotic hip fracture risk, it is necessary to understand failure mechanisms of bone at both the material and organ level. The structural response of bone is dependent on load history. Repeated loading causes progressive microstructural cracking, resulting in reduced apparent-level stiffness and, if damage is significant, reductions to peak load bearing capability. However, the effect of previous damage accumulation has not been well explored at the organ level. It was hypothesized that femoral fracture load and fracture pattern may be sensitive to damage accumulation from previous loading events. Six cadaveric specimens were used to develop patient specific finite element (FE) models from quantitative tomographic (qCT) scans. Material properties were assigned from qCT intensity at each element location, and damage evolution was predicted using a previously validated quasi-brittle FE model. Three scenarios were investigated: stumble followed by another stumble (S-S), fall followed by another fall (F-F), and stumble followed by a fall (S-F). Fracture load and pattern were compared to FE predictions for a single stumble (S) or single fall (F) loading event. Most specimens were resilient to accumulated damage, showing little (<5%) change in fracture load from the multiple-load scenarios (S-S, F-F, and S-F) compared to an equivalent single load scenario (S or F). Only one specimen demonstrated moderate (5-15%) reductions in strength from all three multiple-load scenarios. However, two specimens experienced moderate (20-30%) increase in fracture load in some load cases. In these cases, initial damage caused the load to be more evenly distributed upon subsequent loading events. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2197-2203, 2019.


Assuntos
Fraturas do Fêmur/etiologia , Fêmur/fisiologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Análise de Elementos Finitos , Humanos , Masculino , Pessoa de Meia-Idade , Modelagem Computacional Específica para o Paciente , Suporte de Carga
20.
Appl Radiat Isot ; 150: 135-140, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31146217

RESUMO

The use of radiolabeled molecules for tumor targeting constitutes a remarkable technique for the treatment of systemic malignancies. An accurate patient-specific dosimetry in nuclear medicine procedures should be a relevant pre-requisite in order to achieve the required lethal damage to tumor cells while maintaining possible side-effects to normal tissues at tolerable levels. It is desired to assess in vivo the radiopharmaceutical distribution for further estimation of absorbed dose released to target and involved organs. In this context, it was developed a computational toolkit, called DOSIS, in order to perform patient-specific dosimetry based on personalized patient anatomy and biodistribution of radionuclides both obtained by currently available dual PET/CT or SPECT/CT facilities. This work is focused on comparing 3D dose distributions obtained by DOSIS performing full stochastic Monte Carlo simulations versus analogue distributions obtained with analytical approaches like dose point kernel convolution and local energy deposition, when considering non-homogeneous activity or density distributions at different scales. Mathematical virtual phantoms were created for this study in order to compare results with other calculation methods. Some of the beta-emitters radionuclides commonly used for therapy (90Y, 131I, 177Lu) were investigated, and emissions of beta-particles, conversion electrons, gamma radiation, and characteristic X-rays were considered. DOSIS implements a novel code devoted to managing radiation transport simulation by means of PENELOPE Monte Carlo general-purpose routines on voxelized geometries defined by 3D mass and activity distributions. Both distributions can be defined through patients-specific images, or pre-defined virtual phantoms. Results preliminary confirmed DOSIS as a reliable and accurate toolkit for personalized internal dosimetry along with highlighting advantages/drawbacks of the different calculation schemes proposed.


Assuntos
Modelagem Computacional Específica para o Paciente/estatística & dados numéricos , Radiometria/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Simulação por Computador , Humanos , Método de Monte Carlo , Neoplasias/diagnóstico por imagem , Neoplasias/radioterapia , Medicina Nuclear/métodos , Medicina Nuclear/estatística & dados numéricos , Imagens de Fantasmas , Radiometria/estatística & dados numéricos , Compostos Radiofarmacêuticos/uso terapêutico , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único , Software , Processos Estocásticos , Distribuição Tecidual
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