Hyperintensity

MRI scans showing hyperintensities

A hyperintensity or T2 hyperintensity is an area of high intensity on types of magnetic resonance imaging (MRI) scans of the brain of a human or of another mammal that reflect lesions produced largely by demyelination and axonal loss. 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][2] or subcortical gray matter (gray matter hyperintensities or GMH). The volume and frequency is strongly associated with increasing age.[2] They are also seen in a number of neurological disorders and psychiatric illnesses. For example, deep white matter hyperintensities are 2.5 to 3 times more likely to occur in bipolar disorder and major depressive disorder than control subjects.[3][4] WMH volume, calculated as a potential diagnostic measure, has been shown to correlate to certain cognitive factors.[5] 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.

A hyperintensity or T2 hyperintensity is an area of high intensity on types of magnetic resonance imaging (MRI) scans of the brain of a human or of another mammal that reflect lesions produced largely by demyelination and axonal loss. 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][2] or subcortical gray matter (gray matter hyperintensities or GMH). The volume and frequency is strongly associated with increasing age.[2] They are also seen in a number of neurological disorders and psychiatric illnesses. For example, deep white matter hyperintensities are 2.5 to 3 times more likely to occur in bipolar disorder and major depressive disorder than control subjects.[6][7] WMH volume, calculated as a potential diagnostic measure, has been shown to correlate to certain cognitive factors.[8] 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 hyperintensities 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 effects on the brain.[9]

Postmortem studies combined with MRI suggest that hyperintensities are dilated perivascular spaces, or demyelination caused by reduced local blood flow.[10]

  1. ^ a b 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.
  2. ^ a b c d Habes M, Erus G, Toledo JB, Zhang T, Bryan N, Launer LJ, Rosseel Y, Janowitz D, Doshi J, Van der Auwera S, von Sarnowski B, Hegenscheid K, Hosten N, Homuth G, Völzke H, Schminke U, Hoffmann W, Grabe H, Davatzikos C (2016). "White matter hyperintensities and imaging patterns of brain ageing in the general population". Brain. 139 (Pt 4): 1164–1179. doi:10.1093/brain/aww008. PMC 5006227. PMID 26912649.
  3. ^ 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.
  4. ^ 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. S2CID 46065841.
  5. ^ 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.
  6. ^ 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.
  7. ^ 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. S2CID 46065841.
  8. ^ 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.
  9. ^ Theodoridou A, Settas L (2006). "Demyelination in rheumatic diseases". J. Neurol. Neurosurg. Psychiatry. 77 (989): 290–5. doi:10.1136/jnnp.2005.075861. PMC 2077679. PMID 16484634.
  10. ^ 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 (1): 333–9. Bibcode:2002NYASA.977..333T. doi:10.1111/j.1749-6632.2002.tb04835.x. PMID 12480770. S2CID 22163039.