M.S. Theses

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Browsing M.S. Theses by Subject "Ankle -- Diseases."

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    A phantom study :|evaluation of a novel three-lumen balloon catheter for threatment of intractable limb ischemia
    (Thesis (M.S.)-Bogazici University. Institute of Biomedical Engineering, 2019., 2019.) Tatarlar, Efecan.; Kocatürk, Özgür.
    Peripheral artery disease (PAD) is a serious health problem that includes occlusive arterial syndrome. Critical limb ischemia (CLI) which is the most severe form induces extremity gangrene or ulcers extremity rest pain which mostly can lead to limb loss. The most common CLI criteria: (a) 30 mmHg or less toe systolic pressure, (b) 0.4 or less ankle-brachial index (ABI), (c) 50 mmHg or less systolic ankle pressure. In this study, a custom made three lumen catheter (9 Fr) including a distal inflatable balloon in between the inflow and outflow lumen holes was constructed based on Hyper Perfusion Catheter patent (patent no: 2011/07038) owned by Emir Yusuf, MD. The aim of this catheter design is to elevate ankle and/or toe systolic pressures above 50-60 mmHg to promote healing and/or alleviating intractable pain due to intractable ischemia for patients with CLI. To simulate the blood circulation of related anatomy, in vitro CLI model phantom was designed and constructed by using a modified hemodialysis circuit; a hemodialysis pump and a tube set were used in bypass surgery procedures. 10% aqueous glycerol solution (by weight in water) was used to mimic human blood plasma. The data was collected by a custom-made circuit in real time and all measurements were verified with industrial certificated medical devices. In vitro CLI model phantom experiments have shown that it is feasible to elevate the pressure distal to the occlusion (representing ankle pressure) up to 80 mmHg without increasing the systemic pressure in certain conditions.|Keywords : Peripheral Artery Disease (PAD), Critical Limb Ischemia (CLI), Ankle Systolic Pressure, 9 Fr Three Lumen Catheter.
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    Development of a recurrent netural network based estimation algorithms for ankle power by using surface EMG
    (Thesis (M.S.)-Bogazici University. Institute of Biomedical Engineering, 2022., 2022.) Atal, Alper.; Yücesoy, Can A.
    Estimation of ankle power can be used in identification of gait abnormalities and establishing timings of net power generation in powered prosthetic devices. Cur rent inverse dynamics calculations of ankle power rely on gait analysis data collected in specialized, expensive laboratories, which limits its applicability and accessibility for prosthetic device users. The aim of this study is to develop a Recurrent Neural Network system to estimate ankle power during level walking by using only surface electromyography (sEMG) as algorithm inputs. For this purpose, an open access data set which includes 50 participants with 25 males and 25 females aged between 6 to 72. In the dataset there are sEMG data from upper leg muscles: Biceps Femoris (BF), Gas trocnemius Medialis (GM), Gluteus Maximum (GMax), Rectus Femoris (RF), Vastus Medialis (VM) and lower body muscles; Peroneus Longus (PL), Soleus (SO), Tibialis Anterior (TA). Algorithms for combinations of all these muscles have been developed. A correlation coefficient of 0.90 between the actual (result of gait analysis) and predicted ankle power is considered to perform successfully. 25 muscle combinations yielded suc cessful correlations with 1 set of 1 muscle, 3 sets of 2 muscles, 5 sets of 3 muscles, 9 sets of 4 muscles, 5 sets of 5 muscles, 1 set of 6 muscles, 1 set of 7 muscles. Note that, all successful muscle groups include either PL or GM muscle. Our findings sug gest that our system can be used in powered prosthetics control and detection of gait abnormalities.|Keywords : Ankle Power, Electromyography, Walking, Artificial Neural Networks.