On the need for bundle-specific microstructure kernels in diffusion MRI

Publication date: Available online 14 December 2019Source: NeuroImageAuthor(s): Daan Christiaens, Jelle Veraart, Lucilio Cordero-Grande, Anthony N. Price, Jana Hutter, Joseph V. Hajnal, J-Donald TournierAbstractProbing microstructure with diffusion magnetic resonance imaging (dMRI) on a scale orders of magnitude below the imaging resolution relies on biophysical modelling of the signal response in the tissue. The vast majority of these biophysical models of diffusion in white matter assume that the measured dMRI signal is the sum of the signals emanating from each of the constituent compartments, each of which exhibits a distinct behaviour in the b-value and/or orientation domain. Many of these models further assume that the dMRI behaviour of the oriented compartments (e.g. the intra-axonal space) is identical between distinct fibre populations, at least at the level of a single voxel. This implicitly assumes that any potential biological differences between fibre populations are negligible, at least as far as is measurable using dMRI. Here, we validate this assumption by means of a voxel-wise, model-free signal decomposition that, under the assumption above and in the absence of noise, is shown to be rank-1. We evaluate the effect size of signal components beyond this rank-1 representation and use permutation testing to assess their significance. We conclude that in the healthy adult brain, the dMRI signal is adequately represented by a rank-1 model, implying that biological...
Source: NeuroImage - Category: Neuroscience Source Type: research

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Publication date: Available online 18 January 2020Source: NeuroImageAuthor(s): Pei Huang, Johan D. Carlin, Richard N. Henson, Marta M. CorreiaAbstractUltra-high field functional magnetic resonance imaging (fMRI) has allowed us to acquire images with submillimetre voxels. However, in order to interpret the data clearly, we need to accurately correct head motion and the resultant distortions. Here, we present a novel application of Boundary Based Registration (BBR) to realign functional Magnetic Resonance Imaging (fMRI) data and evaluate its effectiveness on a set of 7T submillimetre data, as well as millimetre 3T data for c...
Source: NeuroImage - Category: Neuroscience Source Type: research
Publication date: May 2020Source: Journal of Neurolinguistics, Volume 54Author(s): Mo Chen, Fengyang Ma, Junjie Wu, Shuhua Li, Zhaoqi Zhang, Yongben Fu, Chunming Lu, Taomei GuoAbstractThe present study investigated the effect of language-switching training on the neural correlates of both reactive and proactive control in bilingual language production, as well as the modulating role of the proficiency level of the second language (L2). During the pre-test, Chinese-English bilinguals performed a picture-naming task while being scanned with functional magnetic resonance imaging (fMRI). Participants then took part in an 8-day...
Source: Journal of Neurolinguistics - Category: Speech-Language Pathology Source Type: research
CONCLUSIONS: This study replicates previous findings of smaller medial temporal lobe volumes in CAH patients, and suggests that lateral nucleus of the amygdala, as well as subiculum and subfield CA1 of the hippocampus are particularly affected within the medial temporal lobes in CAH youth. PMID: 31950148 [PubMed - as supplied by publisher]
Source: The Journal of Clinical Endocrinology and Metabolism - Category: Endocrinology Authors: Tags: J Clin Endocrinol Metab Source Type: research
ConclusionGiven its clinical introduction, MPI has the potential to overcome the disadvantages of MRI and CT concerning the visualization of the stent lumen.
Source: CardioVascular and Interventional Radiology - Category: Radiology Source Type: research
Conclusion The integration of PET/MR imaging could be used to efficiently diagnose whether the pancreatic tumor was benign or malignant. The SUVmax/ADC was the most efficient metric, while it could not help in the differentiation of pancreatic cancer.
Source: Nuclear Medicine Communications - Category: Nuclear Medicine Tags: Original Articles Source Type: research
ConclusionsUnequivocal instability is observed with simultaneous transection of the Lisfranc ligament with both plantar ligaments. On CT used as diagnostic tool, plantar injuries at the basis of the second and the third metatarsal are indirect signs of violation of the ligaments and represent an indication for surgical treatment. When using magnetic resonance imaging as diagnostic tool, a ruptured Lisfranc ligament alone without dislocation does not necessarily need surgical intervention.
Source: European Journal of Trauma and Emergency Surgery - Category: Emergency Medicine Source Type: research
Conclusion: MWA is a technically feasible option for melanoma liver metastases with special imaging features on MRI.
Source: Journal of Cancer Research and Therapeutics - Category: Cancer & Oncology Authors: Source Type: research
We present the case of a 55-year-old female who developed cranial nerve symptoms after a 20-year history of HAM/TSP. Although multiple white matter lesions were observed on brain magnetic resonance imaging, no abnormalities were seen on a systemic computed tomography scan. Quantitative flow-cytometric analysis of cell populations in the cerebrospinal fluid (CSF) revealed that most of the infiltrating cells were not inflammatory cells, but HTLV-1-infected CD4+ CADM-1+ T-cells completely lacking CD7 expression. As stepwise downregulation of CD7 is correlated with disease progression fro...
Source: International Journal of Hematology - Category: Hematology Authors: Tags: Int J Hematol Source Type: research
In this study, we investigated the link between AF and senescence markers through the assessment of protein expression in the tissue lysates of human appendages from patients in AF, including paroxysmal (PAF) or permanent AF (PmAF), and in sinus rhythm (SR). The major findings of the study indicated that the progression of AF is strongly related to the human atrial senescence burden as determined by p53 and p16 expression. The stepwise increase of senescence (p53, p16), prothrombotic (TF), and proremodeling (MMP-9) markers observed in the right atrial appendages of patients in SR, PAF, and PmAF points toward multiple inter...
Source: Fight Aging! - Category: Research Authors: Tags: Newsletters Source Type: blogs
Conclusions: MRI is superior to CT scan for detection of structural injuries in children and adolescents with traumatic hip dislocation. The unique structural injuries included entrapment of posterior labrum and posterior unossified acetabular fractures could be seen only at MRI. These findings will impact surgical decision making of these injuries. Level of evidence: Level IV.
Source: Journal of Pediatric Orthopaedics - Category: Orthopaedics Tags: Trauma Source Type: research
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