MR Imaging of Anisotropically Restricted Diffusion of Water in the Nervous System

Hajnal, Joseph V.; Doran, M.; Hall, Alistair S.; Collins, A. G.; Oatridge, Angela; Pennock, J. M.; Young, I. R.; Gm, Bydder

doi:10.1097/00004728-199101000-00001

Cited by 205 publications

(93 citation statements)

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“…[19][20][21][22] The first systematic study of anisotropic water diffusion in the nervous system by Moseley et al confirmed that water diffusion was anisotropic in normal white matter of cat brain and spinal cord whereas diffusion was isotropic in grey matter. 23 Anisotropy was observed also in human spinal cord, 24 human sciatic nerve, 24 human tibial nerve, 25 cat optic nerve, 25 peripheral nerves in the rabbit forelimb, 26 and rat trigeminal nerve and corpus callosum in vivo. 2,27 The parallel and perpendicular ADC values were around 0.9-1.3 Â 10 À5 cm 2 s À1 and 0.3-0.5 Â 10 À5 cm 2 s À1 , respectively.…”

Section: Early Observationsmentioning

confidence: 90%

The basis of anisotropic water diffusion in the nervous system – a technical review

2002

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Anisotropic water diffusion in neural fibres such as nerve, white matter in spinal cord, or white matter in brain forms the basis for the utilization of diffusion tensor imaging (DTI) to track fibre pathways. The fact that water diffusion is sensitive to the underlying tissue microstructure provides a unique method of assessing the orientation and integrity of these neural fibres, which may be useful in assessing a number of neurological disorders. The purpose of this review is to characterize the relationship of nuclear magnetic resonance measurements of water diffusion and its anisotropy (i.e. directional dependence) with the underlying microstructure of neural fibres. The emphasis of the review will be on model neurological systems both in vitro and in vivo. A systematic discussion of the possible sources of anisotropy and their evaluation will be presented followed by an overview of various studies of restricted diffusion and compartmentation as they relate to anisotropy. Pertinent pathological models, developmental studies and theoretical analyses provide further insight into the basis of anisotropic diffusion and its potential utility in the nervous system.

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Section: Early Observationsmentioning

confidence: 90%

The basis of anisotropic water diffusion in the nervous system – a technical review

2002

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“…It has also been used to evaluate brain tumors (e.g. Le Bihan et al, 1986;Hajnal et al, 1991) and normal and abnormal white matter via diffusion anisotropy (Chien et al, 1990;Doran et al, 1990;Douek et al, 1991;Le Bihan, 1995;Peled et al, 1998).…”

Section: Summary Of Mri Findings and Future Directions For Researchmentioning

confidence: 99%

A review of MRI findings in schizophrenia

Shenton

Dickey

Frumin

et al. 2001

Schizophrenia Research

2,145

121

1,332

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After more than 100 years of research, the neuropathology of schizophrenia remains unknown and this is despite the fact that both Kraepelin (1919/1971: Kraepelin,E., 1919/1971. Dementia praecox. Churchill Livingston Inc., New York) and Bleuler (1911/1950: Bleuler, E., 1911/1950. Dementia praecox or the group of schizophrenias. International Universities Press, New York), who first described 'dementia praecox' and the ' schizophrenias', were convinced that schizophrenia would ultimately be linked to an organic brain disorder. Alzheimer (1897: Alzheimer, A., 1897. Beitrage zur pathologischen anatomie der hirnrinde und zur anatomischen grundlage einiger psychosen. Monatsschrift fur Psychiarie und Neurologie. 2, 82-120) was the first to investigate the neuropathology of schizophrenia, though he went on to study more tractable brain diseases. The results of subsequent neuropathological studies were disappointing because of conflicting findings. Research interest thus waned and did not flourish again until 1976, following the pivotal computer assisted tomography (CT) finding of lateral ventricular enlargement in schizophrenia by Johnstone and colleagues. Since that time significant progress has been made in brain imaging, particularly with the advent of magnetic resonance imaging (MRI), beginning with the first MRI study of schizophrenia by Smith and coworkers in 1984 (Smith, R.C., Calderon, M., Ravichandran, G. K., et al. (1984). Nuclear magnetic resonance in schizophrenia: A preliminary study. Psychiatry Res. 12, 137-147). MR in vivo imaging of the brain now confirms brain abnormalities in schizophrenia.The 193 peer reviewed MRI studies reported in the current review span the period from 1988 to August, 2000. This 12 year period has witnessed a burgeoning of MRI studies and has led to more definitive findings of brain abnormalities in schizophrenia than any other time period in the history of schizophrenia research. Such progress in defining the neuropathology of schizophrenia is largely due to advances in in vivo MRI techniques. These advances have now led to the identification of a number of brain abnormalities in schizophrenia. Some of these abnormalities confirm earlier postmortem findings, and most are small and subtle, rather than large, thus necessitating more advanced and accurate measurement tools. These findings include ventricular enlargement (80% of studies reviewed) and third ventricle enlargement (73% of studies reviewed). There is also preferential involvement of medial temporal lobe structures (74% of studies reviewed), which include the amygdala, hippocampus, and parahippocampal gyrus, and neocortical temporal lobe regions (superior temporal gyrus) (100% of studies reviewed). When gray and white matter of superior temporal gyrus was combined, 67% of studies reported abnormalities. There was also moderate evidence for frontal lobe abnormalities (59% of studies reviewed), particularly prefrontal gray matter and orbitofrontal regions. Similarly, there was moderate evidence for parietal lobe ab...

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“…DTI has been used for detecting changes in myelination in the developing brain (Wimberger et al, 1995;Prayer et al, 1997;Neil et al, 1998) and in demyelinating diseases (Guo et al, 2001;Larsson et al, 2004), although its underlying contrast mechanism remains incompletely understood. There is some evidence that DTI is more sensitive for detecting demyelinating lesions relative to conventional T 1 -and T 2 -weighted imaging (Hajnal et al, 1991;Sukama et al, 1991;Wimberger et al, 1995;Prayer et al, 1997;Guo et al, 2001;Larsson et al, 2004). DTI contrast arises from barriers (such as cell membranes of axons and oligodendrocytes) that hinder water diffusion in some orientations more than others, giving rise to anisotropic diffusion.…”

Section: Introductionmentioning

confidence: 99%

Myelination and long diffusion times alter diffusion-tensor-imaging contrast in myelin-deficient shiverer mice

et al. 2005

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Diffusion tensor imaging (DTI) using variable diffusion times (t diff ) was performed to investigate wild-type (wt) mice, myelin-deficient shiverer (shi) mutant mice and shi mice transplanted with wt neural precursor cells that differentiate and function as oligodendrocytes. At t diff = 30 ms, the diffusion anisotropy "volume ratio" (VR), diffusion perpendicular to the fibers (λ ⊥ ), and mean apparent diffusion coefficient (〈D〉) of the corpus callosum of shi mice were significantly higher than those of wt mice by 12 ± 2%, 13 ± 2%, and 10 ± 1%, respectively; fractional anisotropy (FA) and relative anisotropy (RA) were lower by 10 ± 1% and 11 ± 3%, respectively. Diffusion parallel to the fibers (λ // ) was not statistically different between shi and wt mice. Normalized T 2 -weighted signal intensities showed obvious differences (27 ± 4%) between wt and shi mice in the corpus callosum but surprisingly did not detect transplant-derived myelination. In contrast, diffusion anisotropy maps detected transplant-derived myelination in the corpus callosum and its spatial distribution was consistent with the donor-derived myelination determined by immunohistochemical staining. Anisotropy indices (except λ // ) in the corpus callosum showed strong t diff dependence (30-280 ms), and the differences in λ ⊥ and VR between wt and shi mice became significantly larger at longer t diff , indicative of improved DTI sensitivity at long t diff . In contrast, anisotropy indices in the hippocampus showed very weak t diff dependence and were not significantly different between wt and shi mice across different t diff . This study provides insights into the biological signal sources and measurement parameters influencing DTI contrast, which could lead to developing more sensitive techniques for detection of demyelinating diseases.

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MR Imaging of Anisotropically Restricted Diffusion of Water in the Nervous System

Cited by 205 publications

References 0 publications

The basis of anisotropic water diffusion in the nervous system – a technical review

The basis of anisotropic water diffusion in the nervous system – a technical review

A review of MRI findings in schizophrenia

Myelination and long diffusion times alter diffusion-tensor-imaging contrast in myelin-deficient shiverer mice

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