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Punctate inner choroiditis is one of the so-called White dot syndromes which come under the heading posterior uveitis. The appearance of punctate (punched out) areas is at the level of the inner choroid. These lesions are typically located centrally at the back of the eye, or the posterior pole.
Head CT showing periventricular white matter lesions. Leukoaraiosis is a particular abnormal change in appearance of white matter near the lateral ventricles. It is often seen in aged individuals, but sometimes in young adults. [1] [2] On MRI, leukoaraiosis changes appear as white matter hyperintensities (WMHs) in T2 FLAIR images.
The etiology of multiple evanescent white dot syndrome is currently unknown but two potential origins have been postulated. Gass, et. al. suggests a virus invades retinal photoreceptors through cell-to-cell transmission via either the ora serrata or optic disc margin. [3]
Others classify them as hippocampal, cortical, and WM lesions, [23] and finally, others give seven areas: intracortical, mixed white matter-gray matter, juxtacortical, deep gray matter, periventricular white matter, deep white matter, and infratentorial lesions. [24] The distribution of the lesions could be linked to the clinical evolution [25]
The idea of DAI first came about as a result of studies by Sabina Strich on lesions of the white matter of individuals who had sustained head trauma years before. [37] Strich first proposed the idea in 1956, calling it diffuse degeneration of white matter ; however, the more concise term "diffuse axonal injury" came to be preferred. [ 38 ]
The damaged white matter is known as "Normal-appearing white matter" (NAWM) and is where lesions appear. [10] These lesions form in NAWM before blood–brain barrier breakdown. [64] BBB can be broken centripetally (the most normal) or centrifugally. [65] Several possible biochemical disrupters were proposed.
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]
Disconnection syndrome is a general term for a collection of neurological symptoms caused – via lesions to associational or commissural nerve fibres – by damage to the white matter axons of communication pathways in the cerebrum (not to be confused with the cerebellum), independent of any lesions to the cortex. [1]