scholarly journals Automated slice-specific z-shimming for fMRI of the human spinal cord

2021 ◽  
Author(s):  
Merve Kaptan ◽  
S. Johanna Vannesjo ◽  
Toralf Mildner ◽  
Ulrike Horn ◽  
Ronald Hartley-Davies ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Gray Matter ◽  
The Other ◽  
Local Magnetic Field ◽  
Series Data ◽  
Human Spinal Cord ◽  
Beneficial Effects ◽  
Spinal Fmri ◽  
Manual Selection ◽  
Selection Of

Functional magnetic resonance imaging (fMRI) of the human spinal cord faces many challenges, one of which is signal loss due to local magnetic field inhomogeneities. This issue can be addressed with slice-specific z-shimming, which compensates for the dephasing effect of the inhomogeneities using a single, slice-specific gradient pulse. Since the original demonstration of its utility, this technique has already been employed in several spinal fMRI studies. Here, we aim to address two outstanding issues regarding this technique: on the one hand, we evaluate its effects on several parameters that are directly relevant for spinal fMRI (but have not yet been assessed) and on the other hand, we improve upon the manual selection of slice-specific z-shims by developing automated procedures. First, we demonstrate that the beneficial effects of z-shimming i) are apparent across a large range of echo times, ii) hold true for both the dorsal and ventral horn gray matter, and iii) are also clearly apparent in the temporal signal-to-noise ratio (tSNR) of gradient-echo EPI time-series data. Second, and more importantly, we address the time-consuming and subjective nature of manual selection of slice-specific z-shims by developing two automated approaches: one is based on finding the z-shim that maximizes spinal cord signal intensity in each slice of an EPI z-shim reference-scan and the other is based on finding the strength of the gradient-field that compensates the through-slice inhomogeneity in field map data. Both automated approaches i) were much faster than the manual approach, ii) lead to significant improvements in spinal cord gray matter tSNR compared to no z-shimming and iii) resulted in beneficial effects that were stable across time. While the field map-based approach performed slightly worse than the manual approach, the EPI-based approach performed at least as well as the manual one and was furthermore validated on an independently acquired corticospinal data-set (N > 100). Together, we believe that automated z-shimming will improve the data quality of future spinal fMRI studies and — by removing the subjective step of manual z-shim selection — may also lead to increased reproducibility in longitudinal studies.

DISTRIBUTION OF ELEMENTS IN HUMAN SPINAL CORD

1992 ◽  
Vol 02 (04) ◽  
pp. 433-440 ◽  
Author(s):  
MASAE YUKAWA ◽  
T. KOBAYASHI ◽  
Y. QIU ◽  
N. KAMEDA ◽  
Y. ITO ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Cross Section ◽  
The Other ◽  
Current Understanding ◽  
Human Spinal Cord ◽  
Lumbar Level ◽  
Distribution Of Elements ◽  
The Cross

The distribution of elements in human spinal cord was investigated on unfixed frozen cord material using PIXE technique. Distribution of Cu, Zn and Fe were not uniform in the cross section of the spinal cord and concentrations of these elements were higher in the anterior gray horn than in the other areas, while K and Cl distributed uniformly. The content of K changed along the spinsl cord from the cervical to the lumbar level. These findings are discussed in relation to current understanding of the physiology of the spinal cord.

scholarly journals Assessing Nociception by Fmri of the Human Spinal Cord: A Systematic Review

2015 ◽  
Vol 8s1 ◽  
pp. MRI.S23556 ◽  
Author(s):  
Tiffany A. Kolesar ◽  
Kirsten M. Fiest ◽  
Stephen D. Smith ◽  
Jennifer Kornelsen
Keyword(s):  
Systematic Review ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Reference Lists ◽  
Web Of Science ◽  
Original Research ◽  
Noxious Stimulation ◽  
Human Spinal Cord ◽  
Cord Injury ◽  
Spinal Fmri

Objective To assess the use of fMRI of the spinal cord in measuring noxious stimulation. Methods The Scopus, Medline, EMBASE, and Web of Science databases were searched, along with the reference lists of included articles. Two independent reviewers screened abstracts, full-text articles, and extracted data. Original research was included if fMRI of the human spinal cord was used to measure responses to noxious stimulation. Results Of the 192 abstracts screened, 19 met the search criteria and were divided according to their focus: investigating pain responses ( n = 6), methodology ( n = 6), spinal cord injury ( n = 2), or cognition–pain interactions ( n = 5). All but one study appear to have observed activity in ipsilateral and dorsal gray matter regions in response to noxious stimuli, although contralateral or ventral activity was also widely observed. Conclusions Although nociception can be investigated using spinal fMRI, establishing reliability, standardizing methodology, and reporting of results will greatly advance this field.

scholarly journals Vascular mechanisms in the pathophysiology of human spinal cord injury

1997 ◽  
Vol 2 (1) ◽  
pp. E2
Author(s):  
Charles H. Tator ◽  
Izumi Koyanagi
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
White Matter ◽  
Gray Matter ◽  
White Matter Lesions ◽  
Arterial System ◽  
Secondary Injury ◽  
Human Spinal Cord ◽  
Injury Mechanisms ◽  
Cord Injury

Vascular injury plays an important role in the primary and secondary injury mechanisms that cause damage to the acutely traumatized spinal cord. To understand the pathophysiology of human spinal cord injury, the authors investigated the vascular system in three uninjured human spinal cords using silicone rubber microangiography and analyzed the histological findings related to vascular injury in nine acutely traumatized human spinal cords obtained at autopsy. The interval from spinal cord injury to death ranged from 20 minutes to 9 months. The microangiograms of the uninjured human cervical cords demonstrated new information about the sulcal arterial system and the pial arteries. The centrifugal sulcal arterial system was found to supply all of the anterior gray matter, the anterior half of the posterior gray matter, approximately the inner half of the anterior and lateral white columns, and the anterior half of the posterior white columns. Traumatized spinal cord specimens in the acute stage (3-5 days postinjury) showed severe hemorrhages predominantly in the gray matter, but also in the white matter. The white matter surrounding the hemorrhagic gray matter showed a variety of lesions, including decreased staining, disrupted myelin, and axonal and periaxonal swelling. The white matter lesions extended far from the injury site, especially in the posterior columns. There was no evidence of complete occlusion of any of the larger arteries, including the anterior and posterior spinal arteries and the sulcal arteries. However, occluded intramedullary veins were identified in the degenerated posterior white columns. In the chronic stage (3-9 months postinjury), the injured segments showed major tissue loss with large cavitations, whereas both rostral and caudal remote sites showed well-demarcated necrotic areas indicative of infarction mainly in the posterior white columns. Obstruction of small intramedullary arteries and veins by the initial mechanical stress or secondary injury mechanisms most likely produced these extensive white matter lesions. Our studies implicate damage to the anterior sulcal arteries in causing the hemorrhagic necrosis and subsequent central myelomalacia at the injury site in acute spinal cord injury in humans.

scholarly journals FETAL ANATOMY OF THE HUMAN SPINAL CORD

2020 ◽  
Vol 19 (3) ◽  
pp. 5-12
Author(s):  
V. Shkolnikov
Keyword(s):  
Spinal Cord ◽  
White Matter ◽  
Glial Cells ◽  
Motor Neurons ◽  
Gray Matter ◽  
The Body ◽  
Diagnostic Methods ◽  
Large Area ◽  
Intrauterine Development ◽  
Human Spinal Cord

Due to the development and improvement of medical technologies and diagnostic methods, in recent years, the interest of neuromorphologists, neuropathologists, neurosurgeons and reproductive specialists in the histogenesis of the structures of the central nervous system, in particular, the spinal cord, has increased. In the process of macro- and microscopic examination of the spinal cord of human fetuses of 20-21 weeks of intrauterine development, the topography of the thickenings in relation to the parts of the spinal column was established according to our own method, the morphometric parameters of the structures of the spinal cord segments and the regularities of cytoarchitectonics were determined. In 20-21 week old fetuses, the ratio of the length of the spine to the parietococcygeal length of the fetus is 65.0%, and the ratio of the length of the spinal cord to the parietococcygeal length of the fetus is 54.0 %. The border between the cervical and thoracic spine is projected onto a conditional line that connects the spine of the scapula. The border between the thoracic and lumbar regions of the spine is the line between the upper three quarters and the lower one quarter of the body length. The border between the lumbar and sacral parts runs along a conventionally drawn line that connects the posterior lower iliac spines, and the border of the transition of the sacral to the coccygeal is the level of the lower third of the gluteal region. The structure of the gray matter of the spinal cord segments in this age period corresponds to that in people of mature age – the presence of anterior, lateral and posterior horns. A large area of gray matter is observed in the cervical and lumbar segments, a smaller area in the thoracic and sacral segments. The structuredness of the white matter of the spinal cord segments in this age period corresponds to that in adults – the presence of anterior, lateral and posterior cords. The cervical and lumbar segments have a large area of white matter, and in magnitude they are the same. The nuclei of radial glial cells are relatively equal in size in all segments. The thickness of the matrix layer varies throughout the entire spinal cord, but reaches its greatest size in the ventral parts. The sizes of the nuclei of neuroblasts also fluctuate: the nuclei of motor neurons have large sizes, and the smaller ones are inserted and vegetative. The nuclei of glial cells have relatively identical sizes of different segments of the spinal cord, but 2-3 times less than the nuclei of neuroblasts.

scholarly journals Lateralized Brainstem and Cervical Spinal Cord Responses to Aversive Sounds: A Spinal fMRI Study

2018 ◽  
Vol 8 (9) ◽  
pp. 165 ◽  
Author(s):  
Stephen Smith ◽  
Tiffany Kolesar ◽  
Jennifer Kornelsen
Keyword(s):  
Spinal Cord ◽  
Cervical Spinal Cord ◽  
Brain Structures ◽  
The Other ◽  
Auditory Stimuli ◽  
Fmri Study ◽  
Spinal Fmri ◽  
Auditory Cortices ◽  
The Right ◽  
Influence Activity

Previous research has delineated the networks of brain structures involved in the perception of emotional auditory stimuli. These include the amygdala, insula, and auditory cortices, as well as frontal-lobe, basal ganglia, and cerebellar structures involved in the planning and execution of motoric behaviors. The aim of the current research was to examine whether emotional sounds also influence activity in the brainstem and cervical spinal cord. Seventeen undergraduate participants completed a spinal functional magnetic resonance imaging (fMRI) study consisting of two fMRI runs. One run consisted of three one-minute blocks of aversive sounds taken from the International Affective Digitized Sounds (IADS) stimulus set; these blocks were interleaved by 40-s rest periods. The other block consisted of emotionally neutral stimuli also drawn from the IADS. The results indicated a stark pattern of lateralization. Aversive sounds elicited greater activity than neutral sounds in the right midbrain and brainstem, and in right dorsal and ventral regions of the cervical spinal cord. Neutral stimuli, on the other hand, elicited less neural activity than aversive sounds overall; these responses were left lateralized and were found in the medial midbrain and the dorsal sensory regions of the cervical spinal cord. Together, these results demonstrate that aversive auditory stimuli elicit increased sensorimotor responses in brainstem and cervical spinal cord structures.

Vascular mechanisms in the pathophysiology of human spinal cord injury

1997 ◽  
Vol 86 (3) ◽  
pp. 483-492 ◽  
Author(s):  
Charles H. Tator ◽  
Izumi Koyanagi
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
White Matter ◽  
Gray Matter ◽  
White Matter Lesions ◽  
Arterial System ◽  
Secondary Injury ◽  
Human Spinal Cord ◽  
Injury Mechanisms ◽  
Cord Injury

✓ Vascular injury plays an important role in the primary and secondary injury mechanisms that cause damage to the acutely traumatized spinal cord. To understand the pathophysiology of human spinal cord injury, the authors investigated the vascular system in three uninjured human spinal cords using silicone rubber microangiography and analyzed the histological findings related to vascular injury in nine acutely traumatized human spinal cords obtained at autopsy. The interval from spinal cord injury to death ranged from 20 minutes to 9 months. The microangiograms of the uninjured human cervical cords demonstrated new information about the sulcal arterial system and the pial arteries. The centrifugal sulcal arterial system was found to supply all of the anterior gray matter, the anterior half of the posterior gray matter, approximately the inner half of the anterior and lateral white columns, and the anterior half of the posterior white columns. Traumatized spinal cord specimens in the acute stage (3–5 days postinjury) showed severe hemorrhages predominantly in the gray matter, but also in the white matter. The white matter surrounding the hemorrhagic gray matter showed a variety of lesions, including decreased staining, disrupted myelin, and axonal and periaxonal swelling. The white matter lesions extended far from the injury site, especially in the posterior columns. There was no evidence of complete occlusion of any of the larger arteries, including the anterior and posterior spinal arteries and the sulcal arteries. However, occluded intramedullary veins were identified in the degenerated posterior white columns. In the chronic stage (3–9 months postinjury), the injured segments showed major tissue loss with large cavitations, whereas both rostral and caudal remote sites showed well-demarcated necrotic areas indicative of infarction mainly in the posterior white columns. Obstruction of small intramedullary arteries and veins by the initial mechanical stress or secondary injury mechanisms most likely produced these extensive white matter lesions. Our studies implicate damage to the anterior sulcal arteries in causing the hemorrhagic necrosis and subsequent central myelomalacia at the injury site in acute spinal cord injury in humans.

A systematic review of spinal fMRI research: outlining the elements of experimental design

2012 ◽  
Vol 17 (Suppl1) ◽  
pp. 102-118 ◽  
Author(s):  
David W. Cadotte ◽  
Patrick W. Stroman ◽  
David Mikulis ◽  
Michael G. Fehlings
Keyword(s):  
Systematic Review ◽  
Spinal Cord ◽  
Sensory Stimulation ◽  
Healthy Individuals ◽  
Human Spinal Cord ◽  
Published Report ◽  
Cord Injury ◽  
Spinal Fmri ◽  
Injury Research ◽  
Stimulation Paradigm

Object Since the first published report of spinal functional MRI (fMRI) in humans in 1996, this body of literature has grown substantially. In the present article, the authors systematically review all spinal fMRI studies conducted in healthy individuals with a focus on the different motor and sensory paradigms used and the results acquired. Methods The authors conducted a systematic search of MEDLINE for literature published from 1990 through November 2011 reporting on stimulation paradigms used to assess spinal fMRI scans in healthy individuals. Results They identified 19 peer-reviewed studies from 1996 to the present in which a combination of different spinal fMRI methods were used to investigate the spinal cord in healthy individuals. Eight of the studies used a motor stimulation paradigm, 10 used a sensory stimulation paradigm, and 1 compared motor and sensory stimulation paradigms. Conclusions Despite differences in the results of various studies, even when similar stimulation paradigms were used, this body of literature underscores that spinal fMRI signals can be obtained from the human spinal cord. The authors intend this review to serve as an introduction to spinal fMRI research and what it may offer the field of spinal cord injury research.

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