ASL-MRI is reported as an option to assess potentially heterogeneous physiological processes important for tumour treatment. Therefore, we explored the heterogeneity in normalised CBF as an imaging biomarker for assessment of treatment effect in pLGG. There is a noticeable effect of chemotherapy observed as a change in texture of healthy appearing brain tissue. A high difference in texture between treated and non-treated patients for non-enhancing tumour part is observed, suggesting that texture, based on co-occurrence matrices, is suitable as an imaging biomarker for assessment of treatment effect in pLGG.
After sentinel lymph nodes are detected using SPIONs and excised, their characterization is important to detect possible metastases. In this research a low-field (0.5T) tabletop MRI scanner was tested for this purpose using 4x accelerated high resolution 3D acquisition. Both simulations and experiments on excised pig lymph nodes showed promising results, with the accelerated scans showing similar image quality with respect to fully sampled datasets. This protocol shows lymph nodes can be imaged at 0.25 mm isotropic resolution within reasonable scan times. Clinical usage should be proven by scanning true metastatic lymph nodes.
APTw imaging is a potential imaging biomarker to assess treatment effects in brain tumours, especially at high field MRI (7T) due to improved signal-to-noise-ratio enabling the assessment of APTw values in heterogenous tumours. Embedding of APTw imaging in clinical decision making requires insight in the repeatability of APTw imaging. Therefore, we evaluated the repeatability of APTw imaging at 7T by using a phantom and in vivo in the human brain subjects. Repeatable and specific APTw maps were obtained at 7T, which facilitate the potential of detecting metabolic changes in brain tumours due to treatment.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors or originators and do not necessarily reflect the views of the National Science Foundation. Abstract Attacks on industrial control systems remain rare overall, yet they may carefully target their victims. A particularly challenging threat consists of adversaries aiming to change a plant's *process flow*. A prominent example of such a threat is Stuxnet, which manipulated the speed of centrifuges to operate outside of their permitted range. Existing intrusion detection approaches fail to address this type of threat. In this paper we propose a novel network monitoring approach that takes process semantics into account by (1) extracting the value of process variables from network traffic, (2) characterizing types of variables based on the behavior of time series, and (3) modeling and monitoring the regularity of variable values over time. We implement a prototype system and evaluate it with real‐world network traffic from two operational water treatment plants. Our approach is a first step towards devising intrusion detection systems that can detect semantic attacks targeting to tamper with a plant's physical processes.
Progression independent of relapse activity (PIRA) has been described in patients with multiple sclerosis (MS) even in the earliest disease stages. Patients with PIRA show increased atrophy rates in multiple brain regions compared to stable patients. Here, we investigated whether patients with PIRA exhibit loss of integrity in WM tracts compared to stable patients. We studied 62 RRMS patients, 27 PIRA and 35 stable patients using a clinical DW-MRI protocol. Our results showed that PIRA patients present smaller FA values in areas of corpus callosum and along corticosprinal tract. These differences suggest neurodegeneration in major WM tracts of PIRA patients.
We performed an extensive assessment of the clinical relevance of a method that we had previously developed, which provides personalized quantitative MRI abnormality maps of individual multiple sclerosis (MS) patients. Specifically, we assessed the relationships between quantitative T1 (qT1), myelin water fraction (MWF), neurite density index (NDI), magnetization transfer saturation (MTsat) abnormality maps and clinical disability in a cohort of 102 MS patients and 98 healthy subjects. We found that qT1 and NDI alterations in white matter lesions were strongly related to patients' clinical disability, supporting the use of those personalized maps for patient stratification and follow-up in clinical practice.
The decision process of artificial intelligence is elusive. We proposed a new method that by combining an attention-based convolutional neural network (GAMER-MRI) with the modified Layer-wise Relevance Propagation could reveal relevant regions on quantitative imaging maps in differentiating multiple sclerosis patients with mild-moderate and severe disabilities. The assessment of the relevant regions included the impact of inverting values within the regions and the heatmap on the MNI152 template. Our results show good network performance and identify brain regions relevant to the corticospinal tract. The proposed method might be useful to further explore patterns of brain microstructural alterations associated with disability.
Damage to the myelin sheath and the neuroaxonal unit are features of multiple sclerosis, as well as reparative processes for both. However, a detailed characterization of the dynamics of those in vivo is challenging. In this longitudinal study, we applied a multi-contrast quantitative MRI approach to disentangle lesion progression in vivo in patients with MS. The microstructural measures were compared between multiple sclerosis groups (55 relapsing-remitting, 24 progressive) and 34 healthy controls. Our results indicate changes in microstructural MRI measures in white matter lesions and normal appearing tissue related to myelin and axonal integrity in RRMS and PMS.
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