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出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/10/07 00:26:38」(JST)
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MRI scans showing hyperintensities
Hyperintensities refer to areas of high intensity on types of magnetic resonance imaging (MRI) scans of the human brain or that of other mammals. These small regions of high intensity are observed on T2 weighted MRI images (typically created using 3D FLAIR) within cerebral white matter (white matter lesions, white matter hyperintensities or WMH)[1] or subcortical gray matter (gray matter hyperintensities or GMH). They are usually seen in normal aging but also in a number of neurological disorders and psychiatric illnesses. For example deep white matter hyperintensites are 2.5 to 3 times more likely to occur in bipolar disorder and major depressive disorder than control subjects.[2][3] WMH volume, calculated as a potential diagnostic measure, has been shown to correlate to certain cognitive factors.[4] Hyperintensities appear as "bright signals" (bright areas) on an MRI image and the term "bright signal" is occasionally used as a synonym for a hyperintensity.
Hyperintensities are commonly divided into 3 types depending on the region of the brain where they are found. Deep white matter hyperintensites occur deep within white matter, periventricular white matter hyperintensities occur adjacent to the lateral ventricles and subcortical hyperintensities occur in the basal ganglia.[citation needed]
Hyperintensities are often seen in auto immune diseases that have effect on the brain.[5]
Postmortem studies combined with MRI suggest that hyperintensities are dilated perivascular spaces, or demyelination caused by reduced local blood flow.[6]
Contents
- 1 Causes
- 2 Cognitive Effects
- 3 See also
- 4 References
- 5 External links
Causes
White matter hyperintensities can be caused by a variety of factors including ischemia, micro-hemorrhages, gliosis, damage to small blood vessel walls, breaches of the barrier between the barrier between the cerebrospinal fluid and the brain, or loss and deformation of the myelin sheath.[7]
Cognitive Effects
In most elderly people, presence of severe WMH and medial temporal lobe atrophy MTA was linked with an increase in frequency of mild cognitive deficits. Studies suggest that a combination of MTA and severe WMH showed more than a fourfold increase in the frequency of mild cognitive deficits.[8] It's also been consistently shown that severe WMH is known to be associated with gait disorders, impaired balance and cognitive disturbances. Certain features of gait pattern associated with WMH are: slight widening of the base, slowing and shortening of stride length and turning en bloc. Speed of cognitive processes and frontal skills may also be impaired in people with WMH.[9][10] Pathological signs of oligodendritic apoptosis and damage to axonal projections have been evident. Sufficient damage to the axons that course through WMH can cause adequate interference with normal neuronal functions.[11]
It is also thought that WMH patients have a negative impact on cognition in Alzheimer's disease population. In Alzheimer's patients, higher WHM are associated with higher amyloid beta deposits, possibly associated with small vessel disease and reduced amyloid beta clearance.[10]
See also
- Leukoaraiosis
- Hypertensive leukoencephalopathy
- Virchow-Robin spaces
- Subcortical ischemic depression
References
- ^ Debette S, Markus HS (2010). "The clinical importance of white matter hyperintensities on brain magnetic resonance imaging: systematic review and meta-analysis". BMJ 341: c3666. doi:10.1136/bmj.c3666. PMC 2910261. PMID 20660506.
- ^ Kempton, Matthew J.; Geddes, JR; Ettinger, U; Williams, SC; Grasby, PM (2008). "Meta-analysis, Database, and Meta-regression of 98 Structural Imaging Studies in Bipolar Disorder". Archives of General Psychiatry 65 (9): 1017–32. doi:10.1001/archpsyc.65.9.1017. PMID 18762588.
- ^ Videbech, P. (1997). "MRI findings in patients with affective disorder: A meta-analysis". Acta Psychiatrica Scandinavica 96 (3): 157–68. doi:10.1111/j.1600-0447.1997.tb10146.x. PMID 9296545.
- ^ Brickman, Adam M.; Meier, Irene B.; Korgaonkar, Mayuresh S.; Provenzano, Frank A.; Grieve, Stuart M.; Siedlecki, Karen L.; Wasserman, Ben T.; Williams, Leanne M.; Zimmerman, Molly E. (2012). "Testing the white matter retrogenesis hypothesis of cognitive aging". Neurobiology of Aging 33 (8): 1699–715. doi:10.1016/j.neurobiolaging.2011.06.001. PMC 3222729. PMID 21783280.
- ^ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2077679/
- ^ Thomas, Alan J.; Perry, Robert; Barber, Robert; Kalaria, RAJ N.; O'Brien, John T. (2002). "Pathologies and Pathological Mechanisms for White Matter Hyperintensities in Depression". Annals of the New York Academy of Sciences 977: 333–9. doi:10.1111/j.1749-6632.2002.tb04835.x. PMID 12480770.
- ^ Raz N, Yang Y, Dahle CL, Land S (2012). "Volume of white matter hyperintensities in healthy adults: contribution of age, vascular risk factors, and inflammation-related genetic variants". Biochimica et Biophysica Acta 1822 (3): 361–369. doi:10.1016/j.bbadis.2011.08.007. PMC 3245802. PMID 21889590.
- ^ Van Der Flier, W M; Van Straaten, EC; Barkhof, F; Ferro, JM; Pantoni, L; Basile, AM; Inzitari, D; Erkinjuntti, T; et al. (2005). "Medial temporal lobe atrophy and white matter hyperintensities are associated with mild cognitive deficits in non-disabled elderly people: The LADIS study". Journal of Neurology, Neurosurgery & Psychiatry 76 (11): 1497–500. doi:10.1136/jnnp.2005.064998. PMC 1739423. PMID 16227537.
- ^ Gouw, A.A.; Flier, W.M.; Straaten, E.C.W.; Barkhof, F.; Ferro, J.M.; Baezner, H.; Pantoni, L.; Inzitari, D.; et al. (2006). "Simple versus complex assessment of white matter hyperintensities in relation to physical performance and cognition: The LADIS study". Journal of Neurology 253 (9): 1189–96. doi:10.1007/s00415-006-0193-5. PMID 16998647.
- ^ a b Birdsill AC, Koscik RL, Jonaitis EM, Johnson SC, Okonkwo OC, Hermann BP, Larue A2, Sager MA, Bendlin BB (2014). "Regional white matter hyperintensities: aging, Alzheimer's disease risk, and cognitive function" (PDF). Neurobiology of Aging 35 (4): 769–776. doi:10.1016/j.neurobiolaging.2013.10.072. PMID 24199958.
- ^ Bocti, C.; Swartz, R. H.; Gao, F.-Q.; Sahlas, D. J.; Behl, P.; Black, S. E. (2005). "A New Visual Rating Scale to Assess Strategic White Matter Hyperintensities Within Cholinergic Pathways in Dementia". Stroke 36 (10): 2126–31. doi:10.1161/01.STR.0000183615.07936.b6. PMID 16179569.
External links
- MRI database at www.bipolardatabase.org.
UpToDate Contents
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English Journal
- Imaging features of small hepatocellular carcinomas with microvascular invasion on gadoxetic acid-enhanced MR imaging.
- Kim MJ, Lee M, Choi JY, Park YN.SourceDepartment of Radiology and Research Institute of Radiological Science, Yonsei University Severance Hospital, Seoul, South Korea.
- European journal of radiology.Eur J Radiol.2012 Oct;81(10):2507-12. Epub 2011 Dec 3.
- OBJECTIVES: Detection of hepatocellular carcinomas (HCCs) before microvascular invasion (MVI) occurs is important due to the poor outcomes associated with MVI. We retrospectively investigated the imaging features of small HCCs with MVI on gadoxetic acid-enhanced MR imaging.METHODS: Fifty patients (4
- PMID 22137613
- Sandwich sign of Borrmann type 4 gastric cancer on diffusion-weighted magnetic resonance imaging.
- Zhang XP, Tang L, Sun YS, Li ZY, Ji JF, Li XT, Liu YQ, Wu Q.SourceKey Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University School of Oncology, Beijing Cancer Hospital & Institute, No. 52 Fu Cheng Road, Hai Dian District, Beijing 100142, China.
- European journal of radiology.Eur J Radiol.2012 Oct;81(10):2481-6. Epub 2011 Nov 17.
- OBJECTIVE: To assess the appearance of Borrmann type 4 (BT-4) gastric cancer on diffusion-weighted magnetic resonance imaging (DWI) and to investigate the potential of qualitative and quantitative DW images analysis to differentiate BT-4 gastric cancer from poorly distended normal stomach wall.MATER
- PMID 22099950
Japanese Journal
- Chronic Graft-versus-host Disease Presenting with Multiple Punctate Intracranial Lesions on Contrast-enhanced Magnetic Resonance Imaging
- Image Non-Uniformity Correction for 3-T Gd-EOB-DTPA-Enhanced MR Imaging of the Liver
- 6ヶ月間に4回の脳梗塞を繰り返し,脳底動脈の急速な拡張を認めたintracranial arterial dolichoectasiaの1例
Related Links
- Definition of hyperintensity in the Definitions.net dictionary. Meaning of hyperintensity. What does hyperintensity mean? Information and translations of hyperintensity in the most comprehensive dictionary definitions resource on the ...
- the right frontal lobe likely from prior resection with some hyperintensity in the adjacent brain parenchyma Additionally note the abnormal high signal in the medial right thalamus Legend Additional FLAIR sequences left and middle ...
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