نتایج جستجو برای: t2 relaxometry
تعداد نتایج: 31231 فیلتر نتایج به سال:
conclusion in breast cancer after nac, the lesion t2 relaxation time was reduced in the responders, and this finding is potentially useful to assess the response to nac. results in 26 cases with nac, the mean lesion t2 relaxation time before nac was 81.34 ± 13.68 ms, compared with 64.50 ± 8.71 ms after nac. significant differences in the lesion t2 relaxation times existed between the pre- and p...
PURPOSE To evaluate neurochemical and structural changes in the patients with newly diagnosed obstructive sleep apnea syndrome (OSAS) by MR spectroscopy (MRS), T2 relaxometry, and diffusion weighted imaging (DWI). MATERIAL AND METHODS Following the acquisition of routine cranial MR, MRS, T2 relaxometry, and DWI images; spectroscopic metabolite ratios and DWI-T2 relaxometry findings of the tha...
OBJECTIVES The aims of the study were (i) to examine the localizing value of three MRI quantitative modalities (qMRI) currently used for the analysis of the hippocampus and amygdala in the context of pre-surgical screening and (ii) to propose a step-by-step protocol based on the sensitivity and performance of the different MR techniques. METHODS Ninety-two adults with chronic mesial temporal ...
INTRODUCTION T2 relaxometry has become an important tool in quantitative MRI. Little focus has been put on the effect of the refocusing flip angle upon the offset parameter, which was introduced to account for a signal floor due to noise or to long T2 components. The aim of this study was to show that B1 imperfections contribute significantly to the offset. We further introduce a simple method ...
Nuclear magnetic resonance relaxometry is a uniquely practical and versatile implementation of NMR technology. Because it does not depend on chemical shift resolution, it can be performed using low-field compact instruments deployed in atypical settings. Early relaxometry studies of human blood were focused on developing a diagnostic test for cancer. Those efforts were misplaced, as the measure...
We introduce a new approach to characterise brain tissue microstructure combining diffusion MRI and relaxometry. The tissue is modelled as a composition of water pools with distinct T2 and diffusivities. Mathematically, we establish a blind source separation framework that we solve using sparse component analysis. Results show that this technique is able to extract distinct diffusion and relaxo...
BACKGROUND AND PURPOSE Increased T2 relaxation times in the ipsilateral hippocampus are present in patients with hippocampal sclerosis. Visual assessment of T2-weighted images of these patients suggests increased signal intensity in the anterior temporal lobe as well. Our aim was to assess hippocampal and anterior temporal T2 relaxation times in patients with partial epilepsy by using a new T2-...
OBJECTIVE Hippocampal sclerosis (HS), the most common cause of refractory temporal lobe epilepsy, is associated with hippocampal volume loss and increased T2 signal. These can be identified on quantitative imaging with hippocampal volumetry and T2 relaxometry. Although hippocampal segmentation for volumetry has been automated, T2 relaxometry currently involves subjective and time-consuming manu...
Introduction & Objective : The aim of this study was to optimize MRI conventional protocols for BMD(Bone Mineral Density) measurements using MRI Relaxometry in systems not facilitated with special multi echo protocols. Since, cortical and trabecular bone separation can not be performed in DEXA, so the results might lead to erroneous interpretation of BMD values. One method for bone quality dete...
Background T2* relaxometry offers a non-invasive method to accurately quantify myocardial iron levels, thus aiding the diagnosis and assessment of prognosis of patients. Two T2* sequences are used clinically: the single breathhold multi-echo gradient echo white blood (WB) and black blood (BB) techniques. At 1.5T, BB T2* has superior reproducibility and fewer artefacts than WB T2*. We compared B...
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