On the separation of susceptibility sources in quantitative susceptibility mapping: theory and phantom validation with an in vivo application to multiple sclerosis lesions of different age

2021 ◽  
pp. 107033
Author(s):  
Julian Emmerich ◽  
Peter Bachert ◽  
Mark E. Ladd ◽  
Sina Straub
Keyword(s):  
Multiple Sclerosis ◽  
Susceptibility Mapping ◽  
Quantitative Susceptibility Mapping ◽  
Mapping Theory ◽  
Phantom Validation

scholarly journals Quantitative susceptibility mapping (QSM) of white matter multiple sclerosis lesions: Interpreting positive susceptibility and the presence of iron

2014 ◽  
Vol 74 (2) ◽  
pp. 564-570 ◽  
Author(s):  
Cynthia Wisnieff ◽  
Sriram Ramanan ◽  
John Olesik ◽  
Susan Gauthier ◽  
Yi Wang ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Susceptibility Mapping ◽  
Quantitative Susceptibility Mapping

scholarly journals A comparison of phase imaging and quantitative susceptibility mapping in the imaging of multiple sclerosis lesions at ultrahigh field

2016 ◽  
Vol 29 (3) ◽  
pp. 543-557 ◽  
Author(s):  
Matthew John Cronin ◽  
Samuel Wharton ◽  
Ali Al-Radaideh ◽  
Cris Constantinescu ◽  
Nikos Evangelou ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Susceptibility Mapping ◽  
Phase Imaging ◽  
Quantitative Susceptibility Mapping ◽  
Ultrahigh Field

scholarly journals Longitudinal dentate nuclei iron concentration and atrophy in Friedreich ataxia: IMAGE-FRDA

2018 ◽  
Author(s):  
Phillip G. D. Ward ◽  
Ian H Harding ◽  
Thomas G. Close ◽  
Louise A Corben ◽  
Martin B Delatycki ◽  
...  
Keyword(s):  
Iron Concentration ◽  
Friedreich Ataxia ◽  
Susceptibility Mapping ◽  
Disease Stage ◽  
Healthy Controls ◽  
Quantitative Susceptibility Mapping ◽  
Rates Of Change ◽  
Longitudinal Biomarker ◽  
Baseline Disease Severity

AbstractBackgroundFriedreich ataxia is a recessively inherited, progressive neurological disease characterised by impaired mitochondrial iron metabolism. The dentate nuclei of the cerebellum are characteristic sites of neurodegeneration in the disease, but little is known of the longitudinal progression of pathology in these structures.MethodsUsing in vivo magnetic resonance imaging, including quantitative susceptibility mapping, we investigated changes in iron concentration and volume in the dentate nuclei in individuals with Friedreich ataxia (n=20) and healthy controls (n=18) over a two-year period.ResultsThe longitudinal rate of iron concentration was significantly elevated bilaterally in participants with Friedreich ataxia relative to healthy controls. Atrophy rates did not differ significantly between groups. Change in iron concentration and atrophy both correlated with baseline disease severity or duration, indicating sensitivity of these measures to disease stage. Moreover, atrophy was maximal in individuals early in the disease course, while the rate of iron concentration increased with disease progression.ConclusionsProgressive dentate nuclei pathology is evident in vivo in Friedreich ataxia, and the rates of change of iron concentration and atrophy in these structures are sensitive to the disease stage. The findings are consistent with an increased rate of iron concentration and atrophy early in the disease, followed by iron accumulation and stable volume in later stages. This pattern suggests that iron dysregulation persists after loss of the vulnerable neurons in the dentate. The significant changes observed over a two-year period highlights the utility of quantitative susceptibility mapping as a longitudinal biomarker and staging tool.

scholarly journals DeepQSM - Using Deep Learning to Solve the Dipole Inversion for MRI Susceptibility Mapping

2018 ◽  
Author(s):  
Kasper Gade Bøtker Rasmussen ◽  
Mads Kristensen ◽  
Rasmus Guldhammer Blendal ◽  
Lasse Riis Østergaard ◽  
Maciej Plocharski ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Magnetic Susceptibility ◽  
Iron Homeostasis ◽  
Nerve Fibers ◽  
Susceptibility Mapping ◽  
Source Inversion ◽  
Tissue Properties ◽  
Ill Posed ◽  
Phase Data

Quantitative susceptibility mapping (QSM) aims to extract the magnetic susceptibility of tissue from magnetic resonance imaging (MRI) phase measurements. The mapping of magnetic susceptibility in vivo has gained broad interest in several fields of science and medicine because it yields relevant information on biological tissue properties, predominantly myelin, iron and calcium. Thereby, QSM can also reveal pathological changes of these key components in devastating diseases such as Parkinson’s disease, Multiple Sclerosis, or hepatic iron overload. As QSM requires the solution of an ill-posed field-to-source-inversion, current techniques utilize manual optimization of regularization parameters to balance between smoothing, artifacts and quantification accuracy. We trained a fully convolutional deep neural network - DeepQSM - to invert the magnetic dipole kernel convolution. This network is capable of solving the ill-posed field-to-source inversion on real-world in vivo MRI phase data without the need for manual parameter tuning, which proves that this network has generalized the underlying mathematical principle of the dipole inversion. We demonstrate that DeepQSM’s susceptibility maps enable identification of deep brain substructures that are not visible in MRI phase data and provide information on their respective magnetic tissue properties. We illustrate DeepQSM’s clinical relevance in a patient with multiple sclerosis showing its sensitivity to white matter lesions. In summary, DeepQSM can be used to determine the composition of myelin sheets of nerve fibers in the brain, and to assess quantitative information on iron homeostasis and its dysregulation, and will subsequently contribute to a better understanding of these biological processes in health and disease.

scholarly journals Quantitative Susceptibility Mapping of the Basal Ganglia and Thalamus at 9.4 Tesla

2021 ◽  
Vol 15 ◽  
Author(s):  
Vinod Jangir Kumar ◽  
Klaus Scheffler ◽  
Gisela E. Hagberg ◽  
Wolfgang Grodd
Keyword(s):  
Basal Ganglia ◽  
Functional Anatomy ◽  
Susceptibility Mapping ◽  
Paramagnetic Susceptibility ◽  
Substantial Contribution ◽  
Hemispheric Differences ◽  
Quantitative Susceptibility Mapping ◽  
Ultra High Field

The thalamus (Th) and basal ganglia (BG) are central subcortical connectivity hubs of the human brain, whose functional anatomy is still under intense investigation. Nevertheless, both substructures contain a robust and reproducible functional anatomy. The quantitative susceptibility mapping (QSM) at ultra-high field may facilitate an improved characterization of the underlying functional anatomy in vivo. We acquired high-resolution QSM data at 9.4 Tesla in 21 subjects, and analyzed the thalamic and BG by using a prior defined functional parcellation. We found a more substantial contribution of paramagnetic susceptibility sources such as iron in the pallidum in contrast to the caudate, putamen, and Th in descending order. The diamagnetic susceptibility sources such as myelin and calcium revealed significant contributions in the Th parcels compared with the BG. This study presents a detailed nuclei-specific delineation of QSM-provided diamagnetic and paramagnetic susceptibility sources pronounced in the BG and the Th. We also found a reasonable interindividual variability as well as slight hemispheric differences. The results presented here contribute to the microstructural knowledge of the Th and the BG. In specific, the study illustrates QSM values (myelin, calcium, and iron) in functionally similar subregions of the Th and the BG.

Improved Detection of Cortical Gray Matter Involvement in Multiple Sclerosis with Quantitative Susceptibility Mapping

2015 ◽  
Vol 22 (11) ◽  
pp. 1427-1432 ◽  
Author(s):  
Shingo Kakeda ◽  
Koichiro Futatsuya ◽  
Satoru Ide ◽  
Keita Watanabe ◽  
Mari Miyata ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Gray Matter ◽  
Susceptibility Mapping ◽  
Quantitative Susceptibility Mapping ◽  
Cortical Gray Matter
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