A study of machine learning and deep learning models for solving medical imaging problems

Application of machine learning and deep learning methods on medical imaging aims to create systems that can help in the diagnosis of disease and the automation of analyzing medical images in order to facilitate treatment planning. Deep learning methods do well in image recognition, but medical images present unique challenges. The lack of large amounts of data, the image size, and the high class-imbalance in most datasets, makes training a machine learning model to recognize a particular pattern that is typically present only in case images a formidable task. Experiments are conducted to classify breast cancer images as healthy or non-healthy, and to detect lesions in damaged brain MRI (Magnetic Resonance Imaging) scans. Random Forest, Logistic Regression and Support Vector Machine perform competitively in the classification experiments, but in general, deep neural networks beat all conventional methods. Gaussian Naïve Bayes (GNB) and the Lesion Identification with Neighborhood Data Analysis (LINDA) methods produce better lesion detection results than single path neural networks, but a multi-modal, multi-path deep neural network beats all other methods. The importance of pre-processing training data is also highlighted and demonstrated, especially for medical images, which require extensive preparation to improve classifier and detector performance. Only a more complex and deeper neural network combined with properly pre-processed data can produce the desired accuracy levels that can rival and maybe exceed those of human experts

Prediction of fluid responsiveness using respiratory variations in left ventricular stroke area by transoesophageal echocardiographic automated border detection in mechanically ventilated patients.

BackgroundLeft ventricular stroke area by transoesophageal echocardiographic automated border detection has been shown to be strongly correlated to left ventricular stroke volume. Respiratory variations in left ventricular stroke volume or its surrogates are good predictors of fluid responsiveness in mechanically ventilated patients. We hypothesised that respiratory variations in left ventricular stroke area (DeltaSA) can predict fluid responsiveness.MethodsEighteen mechanically ventilated patients undergoing coronary artery bypass grafting were studied immediately after induction of anaesthesia. Stroke area was measured on a beat-to-beat basis using transoesophageal echocardiographic automated border detection. Haemodynamic and echocardiographic data were measured at baseline and after volume expansion induced by a passive leg raising manoeuvre. Responders to passive leg raising manoeuvre were defined as patients presenting a more than 15% increase in cardiac output.ResultsCardiac output increased significantly in response to volume expansion induced by passive leg raising (from 2.16 +/- 0.79 litres per minute to 2.78 +/- 1.08 litres per minute; p < 0.01). DeltaSA decreased significantly in response to volume expansion (from 17% +/- 7% to 8% +/- 6%; p < 0.01). DeltaSA was higher in responders than in non-responders (20% +/- 5% versus 10% +/- 5%; p < 0.01). A cutoff DeltaSA value of 16% allowed fluid responsiveness prediction with a sensitivity of 92% and a specificity of 83%. DeltaSA at baseline was related to the percentage increase in cardiac output in response to volume expansion (r = 0.53, p < 0.01).ConclusionDeltaSA by transoesophageal echocardiographic automated border detection is sensitive to changes in preload, can predict fluid responsiveness, and can quantify the effects of volume expansion on cardiac output. It has potential clinical applications

Extensive Repair in Type A Aortic Dissection: To Save the Patient or to Ensure a Durable Repair?

Type A aortic dissection (TAAD) is a serious condition requiring emergency surgical management. The main objective of the treatment is the patient survival. Thus, the surgeon has to perform a well-mastered surgical technique without extending the operative time and emphasizing operative risk. Nevertheless, patients with history of TAAD present long-term complications on the aorta, mainly aneurysmal evolution and dissection recurrence. In order to decrease the long-term excess mortality of this population, it is necessary to respect some rules during the surgery. Concerning the proximal segment of the ascending aorta, the aortic root has to be replaced by a composite graft (Bentall technique) or a valve sparing inclusion (David technique) when the dissection reaches the sinuses of Valsalva or when aortic valve regurgitation is observed. Concerning the distal segment of the ascending aorta, the distal anastomosis has to be performed without aortic clamping. Concerning the descending thoracic aorta, hybrid surgery should be performed on patients with malperfusion syndrome and patients with high risk factors for aneurysmal evolution

دراسة لقياس تراكيز الغازات ضعيفة التركيز باستخدام حساس MQ-2

   قمنا في هذا البحث بدراسة تمكننا من حساب عدد جزئيات غاز بدلالة جهد مخرج حساس الغاز MQ-2  حيث يستطيع الحساس MQ-2 استشعار عدد من الغازات مثل: (أحادي أكسيد الكربون CO، النفط المسال LPG،  الميثان CH4، الدخان Smoke، الكحول Alcohol، الهيدروجين H2 ، البروبان C3H8) في الوسط المحيط به.     إن لحساس الغاز مقاومة تتغير قيمتها حسب تركيز الغاز ويتغير تبعاً لذلك جهد مخرج ذلك الحساس ولكن القراءات المباشرة التي يعطيها الحساس لا تفيد بشكل كبير وسنستنتج باستخدام عدد من العلاقات قيمة تركيز الغاز في أي مكان.     قمنا بتصميم دارة إلكترونية تقوم بحساب جهد مخرج الحساس ومقاومته وتركيز الغاز وإظهار قيمتها على شاشة LCD وإرسال إنذار في حال وجود تسرب غاز إلى الهاتف المحمول عبر الإنترنت. بالإضافة لإنذار صوتي في مكان التسرب باستخدام طنان كهربائي Buzzer، وقد أظهرت نتائج إختبار الدارة صِحّة وقدرها 92.5% وكانت الحساسية 95% أما النوعية فكانت 90%

Is there an optimal minimally invasive technique for left anterior descending coronary artery bypass?

<p>Abstract</p> <p>Background</p> <p>The aim of this retrospective study was to evaluate the clinical outcome of three different minimally invasive surgical techniques for left anterior descending (LAD) coronary artery bypass grafting (CABG): Port-Access surgery (PA-CABG), minimally invasive direct CABG (MIDCAB) and off-pump totally endoscopic CABG (TECAB).</p> <p>Methods</p> <p>Over a decade, 160 eligible patients for elective LAD bypass were referred to one of the three techniques: 48 PA-CABG, 53 MIDCAB and 59 TECAB. In MIDCAB group, Euroscore was higher and target vessel quality was worse. In TECAB group, early patency was systematically evaluated using coronary CT scan. During follow-up (mean 2.7 ± 0.1 years, cumulated 438 years) symptom-based angiography was performed.</p> <p>Results</p> <p>There was no conversion from off-pump to on-pump procedure or to sternotomy approach. In TECAB group, there was one hospital cardiac death (1.7%), reoperation for bleeding was higher (8.5% vs 3.7% in MIDCAB and 2% in PA-CABG) and 3-month LAD reintervention was significantly higher (10% vs 1.8% in MIDCAB and 0% in PA-CABG). There was no difference between MIDCAB and PA-CABG groups. During follow-up, symptom-based angiography (n = 12) demonstrated a good patency of LAD bypass in all groups and 4 patients underwent a no LAD reintervention. At 3 years, there was no difference in survival; 3-year angina-free survival and reintervention-free survival were significantly lower in TECAB group (TECAB, 85 ± 12%, 88 ± 8%; MIDCAB, 100%, 98 ± 5%; PA-CABG, 94 ± 8%, 100%; respectively).</p> <p>Conclusions</p> <p>Our study confirmed that minimally invasive LAD grafting was safe and effective. TECAB is associated with a higher rate of early bypass failure and reintervention. MIDCAB is still the most reliable surgical technique for isolated LAD grafting and the least cost effective.</p

Fundamental study on embedded crack identification by genetic algorithm and FE analysis

Simple and sufficiently accurate fatigue crack detection technique is necessary to evaluate the fatigue performance of existing structures. Recently, measurement of two-dimensional displacement or stain distribution on the surface of plates becomes possible and this technique is considered to be applicable to estimate the initiation and propagation of embedded crack. In this study, possibility to estimate the position and size of embedded crack based on the measured surface displacement distribution by combining finite element analysis and optimization technique (Genetic Algorithm) is examined

A new ultrasonic process for a renewal of aortic valve decalcification

BACKGROUND: Aortic valve decalcification by ultrasound was given up. We evaluated a new ultrasound microhandpiece (Dissectron Penstyle(®)) to rehabilitate this alternative treatment. METHODS: We used under magnifying lenses the ultrasound microhandpiece to decalcify 30 explanted aortic valves. In the cases with embedded calcifications the thin top of the probe could be introduced into the thickness of the leaflet preserving covering layers. RESULTS: The leaflets were totally decalcified and flexible, and surrounding structures were preserved as assessed by histological examination. CONCLUSION: This new approach of ultrasonic aortic valve decalcification gives good in vitro results which allow to consider a clinical evaluation of this procedure