An alternative explanation of the origin of the signal in diffusion-weighted MRI

Branco, Gabriel

doi:10.1007/s002340050022

Cited by 15 publications

(8 citation statements)

References 8 publications

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“…The patient with restricted diffusion (with low ADC values ranging from 0.46 to 0.57×10 −3 mm 2 /s) likely reflected presence of impaired myelination associated with a restriction of mobility of the water molecules in the partially destroyed portions of myelin sheath, as suggested by Phillips et al [1]. In a recent experiment it was shown that transition of water from the sol to the gel state contributes to the signal on diffusion MRI, and in gel state high signal is observed on b=1000 s/mm 2 images (which should result in low ADC values) [16]. In light of that experiment, an alternative explanation could be the existence of water in some kind of a gel status in the regions with impaired myelination.…”

Section: Discussionmentioning

confidence: 79%

Diffusion MRI findings in phenylketonuria

Şener

2003

Eur Radiol

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Two patients with phenylketonuria were studied who were under dietary control since infancy, and who were mentally normal. Diffusion MRI was obtained using a spin-echo, echo-planar sequence with a gradient strength of 30 mT/m at 1.5 T. A trace sequence (TR=5700 ms, and TE=139 ms) was used, acquired in 22 s. Heavily diffusion-weighted (b=1000 mm2/s) images, and the apparent diffusion coefficient (ADC) values from automatically generated ADC maps were studied. There were two different patterns in these two patients, restricted and increased diffusion patterns. Restricted diffusion pattern consisted of high-signal on b=1000 s/mm2 images with low ADC values ranging from 0.46 to 0.57x10(-3) mm2/s. Increased diffusion pattern consisted of normal b=1000 s/mm2 images with high ADC values ranging from 1.37 to 1.63x10(-3) mm2/s. It is likely that these values reflected presence of two different histopathological changes in phenylketonuria or reflected different stages of the same disease.

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Section: Discussionmentioning

confidence: 79%

Diffusion MRI findings in phenylketonuria

Şener

2003

Eur Radiol

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“…[10][11][12][13][14] The investigators suggested that the restricted diŠusion pattern might be consistent with some disintegration of the white matter secondary to impaired myelination and that restriction of mobility of the water molecules within abnormal portions of the myelin sheath resulted in a pattern in diŠusion MR imaging similar to that of cytotoxic edema. 10,14,15 In Cockayne syndrome, early cell death caused by deˆcient DNA repair might produce disintegration of the white matter, which in turn, restricts diŠu-sion of water. Nishio's group described myelin staining visualized as numerous patchy losses of myelination in the subcortical white matter in an autopsy study of a severe form of the syndrome.…”

Section: Magnetic Resonance In Medical Sciencesmentioning

confidence: 99%

MR Findings of Cerebral White Matter in Cockayne Syndrome

Adachi¹,

Kawanami

Ohshima³

et al. 2006

magn reson med sci

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The characteristic magnetic resonance (MR)ˆndings of Cockayne syndrome have been reported; however, the corresponding characteristics on diŠusion-weighted and ‰uid-attenuated inversion recovery (FLAIR) imaging are yet to be documented. In this adult case with Cockayne syndrome, we identiˆed small patchy subcortical lesions visualized as areas of high intensity on diŠusion-weighted images and low intensity on FLAIR images. It is possible that theseˆndings re‰ect active demyelinating lesions.

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“…In effetti in generale un maggior contenuto idrico, quale si verifica ad esempio nell'edema extracellulare 7-10,15 provoca un incremento della diffusione, probabilmente do-vuto alla minor concentrazione proteica. Recentemente è stato proposto che la restrizione alla diffusione sia dovuta ad un cambiamento di stato del citoplasma (transizione sol-gel) 13 . Questa ipotesi spiegherebbe anche l'irreversibilità delle lesioni in DWI.…”

Section: Sensibilità Delle Sequenze Dwi Significato Delle Lesioniunclassified

La RM funzionale, studi di diffusione nell'ischemia acuta

Bergui

Zhong

Bradač

2001

Rivista di Neuroradiologia

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RIASSUNTO -Abbiamo studiato con sequenze convenzionali e pesate in diffusione 12 pazienti con sintomi clinici di ischemia acuta, per valutare la sensibilità delle varie sequenze in acuto, e l'evoluzione delle lesioni visibili in diffusione. Le sequenze pesate in diffusione si sono dimostrate più sensibili delle sequenze convenzionali in acuto, ed hanno permesso in tutti i casi di identificare la lesione responsabile dei sintomi nei pazienti con stroke; nell'unico paziente con TIA sia gli esami in acuto che il controllo a distanza sono risultati normali. Le lesioni evidenziate in diffusione in acuto sono evolute in tutti i casi in lesioni iperintense in T2 nel controllo a distanza, confermando l'ipotesi che un'alterazione in diffusione indichi un danno cellulare irreversibile. Lo studio con diffusione nell'ischemia acuta può fornire elementi diagnostici aggiuntivi. SUMMARY -Conventional and diffusion-weighted MR imaging was carried out in 12 patients with clinical symptoms of acute ischaemia to assess the sensitivity of different MR sequences in acute illness and during the evolution of lesions visible in diffusion weighted images.Diffusion-weighted images were more sensitive than conventional scans in acute illness and identified the lesion responsible for symptoms in all patients with stroke. Imaging results in the acute condition and during long-term follow-up were normal in the only patient with transient ischaemic attack. Lesions disclosed by diffusion-weighted imaging in acute stroke evolved into hyperintense lesions in follow-up T2-weighted scans, confirming the hypothesis that a change in diffusion indicates irreversible cell damage. Diffusion-weighted imaging in acute ischaemia may provide additional diagnostic information.

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An alternative explanation of the origin of the signal in diffusion-weighted MRI

Cited by 15 publications

References 8 publications

Diffusion MRI findings in phenylketonuria

Diffusion MRI findings in phenylketonuria

MR Findings of Cerebral White Matter in Cockayne Syndrome

La RM funzionale, studi di diffusione nell'ischemia acuta

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