نوع مقاله: مقاله کامل پژوهشی

نویسندگان

1 استادیار دانشکده مهندسی مکانیک، دانشگاه علم و صنعت ایران

2 استاد دانشکده مهندسی پزشکی، دانشگاه صنعتی امیر کبیر

3 استاد دانشکده مهندسی مکانیک، دانشگاه صنعتی امیر کبیر

4 استادیار دانشگاه شهید بهشتی، بیمارستان شهدای تجریش

10.22041/ijbme.2008.13547

چکیده

به منظور دستیابی به مدل مناسب برای توجیه رفتار بیومکانیکی مغز و تغییر شکل و جابجایی بطن ها، دو نوع مدلسازی کامپیوتری کرنش صفحه ای الاستیک و هایپرالاستیک بافت مغز بر اساس تحلیل المان محدود به کار گرفته شده و مورد مقایسه قرار گرفته اند. اسکن بیمار مبتلا به هماتوم اپی دورال، با فرض کرنش صفحه ای الاستیک و هایپرالاستیک مدلسازی شد. سپس با اعمال پارامترهای مکانیکی نسجν) ، E، C01 و (C10 و تغییر فشار داخل بطنی، میزان جابجایی نقاط مشابه در بطن مدلسازی شده، با بطن واقعی مقایسه شد و نهایتا مقادیری با کمترین میزان خطا را به دست می داد، مشخص گردید. این شبیه سازی ها در بارگذاری های متفاوت با فشار داخل بطنی مختلف نشان داد که عدم توجه به افزایش فشار داخل بطنی نتایج غیر قابل قبولی خواهد داشت. به طور خاص، در بارگذاری کرنشی یک طرفه با ΔP=0 دیواره های بطن سمت هماتوم به نحو قابل ملاحظه ای روی هم قرار می گیرد. بهترین نتایج برای مدل الاستیک با افزایش فشارΔP=1.25 kpa و برای مدل هایپرالاستیک با ΔP=1.00 kpa به دست آمد که با شرایط بالینی بیمار مورد مطالعه سازگار بود. بنابراین مدلسازی بیومکانیکی کرنش صفحه ای در بارگذاری های کرنشی یک طرفه (شرایطی که مشابه کاربرد سیستم های ناوبری در جراحی است)، بدون توجه به هندسه و تغییرات فشار داخل بطن ها نتایج قابل قبولی به دست نمی دهد. با در نظر گرفتن پارامترهای فوق، استفاده از مدل های الاستیک (با دقت نسبی متوسط 88.7%) در مقایسه با هایپرالاستیک (با دقت نسبی متوسط 86.9%) نتایج بهتری در توجیه رفتار مکانیکی مغز در ضایعه هماتوم اپی دورال به همراه خواهد داشت.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Studying The Biomechanical Behavior Of Brain Tissue Comparing Elastic And Hyperelastic Models

نویسندگان [English]

  • Farhad Farmanzad 1
  • Siamak Najarian 2
  • Mohammad Reza Eslami 3
  • Amir Saeed Seddighi 4

1 Associated Professor, Mechanical Engineering School, Iran University of Science & Technology

2 Professor, Biomedical Engineering School, Amirkabir University of Technology

3 Professor, Biomedical Engineering School, Amirkabir University of Technology

4 Associated Professor, Shahid Beheshti University, Shohada Hospital (Tajrish)

چکیده [English]

Two different types of computer modeling, i.e., the elastic and hyperelastic plane strain models were employed and compared with each other. Using finite element analysis, we determined a suitable model for describing the biomechanical behavior of the brain, especially the deformation and displacement of the brain ventricles. The CT-Scan of an epidural hematoma patient was modeled using both approaches. Then, by varying the mechanical parameters of the tissue (i.e., C10, C01, E, and v) and the internal ventricular pressure, the displacement rate of the corresponding points in the ventricles was simulated. Finally, the results of the simulation were compared with those of the actual ventricles, and then, the data set with the least amount of error was identified. For various types of loadings and with different pressure gradients, the results of the simulation show that if the effect of an increase in the internal pressure of the ventricles is neglected, it will lead to unrealistic results. Particularly, in unidirectional strain loading with a pressure gradient of zero (AP= 0), the walls of the ventricle adjacent to the hematoma will collapse completely. The best results were obtained for the elastic model where ΔP = 9.4 mmHg (1.25 kPa) and for the hyperelastic model where ΔP = 7.5 mmHg (1.00 kPa). These findings are consistent with the clinical conditions of the patient. In the plane strain biomechanical modeling, for unidirectional strain loading (conditions which are similar to the application of navigation systems in surgeries), neglecting the geometry and the variation of the internal pressure of the ventricles will not lead to acceptable results. Taking into account the above­mentioned parameters in describing the mechanical behavior of the brain (for epidural hematoma lesions), the elastic model (88.7% average relative accuracy) brings about better results compared with those of the hyperclastic model (86.9% average relative accuracy). 

کلیدواژه‌ها [English]

  • Brain tissue
  • Biomechanical modeling
  • elastic
  • Hyperelastic
  • Epidural Hematoma
  • Finite Elements Analysis

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