medicine and biology
Physical knowledge improves prediction of EM Fields
Dulny, Andrzej, Jabbarigargari, Farzad, Hotho, Andreas, Schreiber, Laura Maria, Terekhov, Maxim, Krause, Anna
We propose a 3D U-Net model to predict the spatial distribution of electromagnetic fields inside a radio-frequency (RF) coil with a subject present, using the phase, amplitude, and position of the coils, along with the density, permittivity, and conductivity of the surrounding medium as inputs. To improve accuracy, we introduce a physics-augmented variant, U-Net Phys, which incorporates Gauss's law of magnetism into the loss function using finite differences. We train our models on electromagnetic field simulations from CST Studio Suite for an eight-channel dipole array RF coil at 7T MRI. Experimental results show that U-Net Phys significantly outperforms the standard U-Net, particularly in predicting fields within the subject, demonstrating the advantage of integrating physical constraints into deep learning-based field prediction.
Non-Uniform Conductivity Estimation for Personalized Brain Stimulation using Deep Learning
Rashed, Essam A., Gomez-Tames, Jose, Hirata, Akimasa
--Electromagnetic stimulation of the human brain is a key tool for the neurophysiological characterization and diagnosis of several neurological disorders. Transcranial magnetic stimulation (TMS) is one procedure that is commonly used clinically. However, personalized TMS requires a pipeline for accurate head model generation to provide target-specific stimulation. This process includes intensive segmentation of several head tissues based on magnetic resonance imaging (MRI), which has significant potential for segmentation error, especially for low-contrast tissues. Additionally, a uniform electrical conductivity is assigned to each tissue in the model, which is an unrealistic assumption based on conventional volume conductor modeling. This paper proposes a novel approach to the automatic estimation of electric conductivity in the human head for volume conductor models without anatomical segmentation. A convolutional neural network is designed to estimate personalized electrical conductivity values based on anatomical information obtained from T1-and T2-weighted MRI scans. This approach can avoid the time-consuming process of tissue segmentation and maximize the advantages of position-dependent conductivity assignment based on water content values estimated from MRI intensity values. The computational results of the proposed approach provide similar but smoother electric field results for the brain when compared to conventional approaches. In electromagnetic dosimetry applications, the use of computational models that imitate human anatomy is an essential process [1].
Impact of Artificial Intelligence (AI) In Medicine and Biology
The broad uses of Artificial Intelligence (AI) Technologies applications have been already been noticed by all of us in several areas of developments with main impacts on technology-based stuff including machine learning devices, robotics etc to name a few. Artificial Intelligence (AI) is one of the most famously used cutting-edge technologies whose importance major to exhibit human intelligence kind of behavior has been noticed and accordingly almost all the fields have been seen to implement the uses of artificial intelligence based systems. The technology makes any operating device equipped enough to expose human-like behavior with self-understanding and decision-making capabilities and accordingly putting the stuff in front of us. Following the wide versatility of this cutting-edge technology extremely famous with the name Artificial Intelligence, health care based sectors associated with the fields of medicine and biology have also attempted to implement the use of artificial intelligence in the developmental procedures. The implementations and benefits of Artificial Intelligence (AI) in medicine and biology can be understood with the help of following bullet points.
Iterative PET Image Reconstruction Using Convolutional Neural Network Representation
Gong, Kuang, Guan, Jiahui, Kim, Kyungsang, Zhang, Xuezhu, Fakhri, Georges El, Qi, Jinyi, Li, Quanzheng
PET image reconstruction is challenging due to the ill-poseness of the inverse problem and limited number of detected photons. Recently deep neural networks have been widely and successfully used in computer vision tasks and attracted growing interests in medical imaging. In this work, we trained a deep residual convolutional neural network to improve PET image quality by using the existing inter-patient information. An innovative feature of the proposed method is that we embed the neural network in the iterative reconstruction framework for image representation, rather than using it as a post-processing tool. We formulate the objective function as a constraint optimization problem and solve it using the alternating direction method of multipliers (ADMM) algorithm. Both simulation data and hybrid real data are used to evaluate the proposed method. Quantification results show that our proposed iterative neural network method can outperform the neural network denoising and conventional penalized maximum likelihood methods.