WHAT IS STATUS CRIBOSUS

Q.All are true regarding space of Virchow-Robin (VRS) except

a. isointense to CSF on all pulse sequences

b. type 2 lacunae

c. lack mass effect

d. round, oval, or curvilinear with well-defined, smooth margins

e.common in relation to anterior commissure

ANS---b

www.ajnr.org

archneur.jamanetwork.com

• Perivascular space of Virchow-Robin (VRS) is an extension of the subarachnoid space that accompanies penetrating vessels into the brain to the level of the capillaries. 
• The VRS at the base of the brain follow the lenticulostriate arteries as they enter the basal ganglia through the anterior perforated substance. On axial images they are typically adjacent to the anterior or posterior surface of the lateral portion of the anterior commissure . In the coronal or sagittal plane they are adjacent to the superior surface of the commissure or just lateral to the putamen.
• Those in the high convexity  follow the course of the penetrating cortical arteries and arterioles from the high-convexity gray matter into the centrum semiovale.
• High signal intensity (i.e., higher intensity than CSF, most notably on proton density–weighted or FLAIR images) foci in the midbrain  can be seen from enlarged perivascular spaces(along  branches of the collicular and accessory collicular arteries)
• Small VR spaces (less than 2 mm) are found in all age groups and probably represent a normal anatomic finding . With advancing age, VR spaces are found with increasing frequency and larger apparent size .
• In one report, lenticulostriate VR spaces had a mild correlation with age, whereas high-convexity VR spaces, although more rare, had a much stronger correlation with age .
• Age, hypertension, dementia, and incidental subcortical white matter lesions were significantly associated with large (greater than 2 mm) VR spaces.
• Migraine patients  have been reported to show prominent perivascular spaces.
• Distinction between dilated perivascular spaces and lacunar infarction is a common problem on clinical MR images. Three criteria must be assessed by the radiologist in these cases: location, morphology, and signal intensity.
• Generally useful guidelines are that lacunar infarctions often are larger than 5 mm, are not symmetric, are located in the upper two thirds of the putamen, and are not isointense to CSF on all imaging sequences
• . Conversely, dilated perivascular spaces usually are isointense to CSF on all pulse sequences, bilaterally symmetric, less than 5 mm in diameter, and located in the inferior one third of the putamen .Size is certainly the weakest discriminator of those mentioned.

New pathologic classification of cerebral lacunae

Type Pathologic criteria 1 Old, small, deep cerebral infarcts with irregular cavities containing macrophages and parenchymal fragments surrounded by gliosis 2 Old, small hemorrhages with hemosiderin-laden macrophages and iron pigmentation of their walls 3 Dilated perivascular spaces; they are round, very regular cavities that always contain one or two sections of an artery with a patent lumen and usually normal walls: the cavity is lined by a single layer of epithelial cells that correspond to the leptomeningeal cells forming the normal lining of the perivacular spaces; according to their number and size, four varieties of types 3 exist. 3a Numerous small, round perivascular spaces (état criblé or status cribosus) 3b Perivascular dilation destroying the adjacent brain (lacunes de désintégration, vaginalite destructive) 3c Solitary subputaminal cavities surrounding the lenticulostriate arteries at their entrance into the lentiform nucleus 3d Expanding perivascular spaces that cause mass effect with possible reactive lesions such as gliosis, spongiosis, swollen oligodendroglia, and myelin loss with edema REF Magnetic Resonance Imaging of the Brain and Spine, 4th Edition,Atlas, Scott W.