In a study by Galarza et al, the posterior fossa arachnoid cysts were located at the vermis-cisterna magna (n=4), the cerebellar hemispheres (n=2), the cerebellopontine angle (n=3) and the quadrigeminal
Brain computed tomography (CT) and magnetic resonance imaging (MRI) showed right cystic lesion rising from the quadrigeminal
cistern on the left side and extending supratentorially, indenting the third ventricle causing obstructive hydrocephalus.
cyst management by cystoperitoneal shunt in a 4-year-old Persian cat.
While hyperintensity is seen in medial thalamic and periacuaductal gray matter on T2 and FLAIR sequences of cranial Magnetic Resonance Imaging (MRI) in acute cases, atrophy in mamillary bodies, enhanced signaling in the base of fourth ventricle, midline of cerebellum may be seen in chronic cases and contrast enhancement may occur in mamillary bodies and inferior quadrigeminal
The pericallosal region as well as the quadrigeminal
and suprasellar cisterns is the common location for intracranial lipomas.
Contraindications to lumbar puncture [7-9] * Major contraindication is raised intracranial pressure * Focal neurological deficit * Papilloedema * Significantly altered level of consciousness * Computed tomography (CT) findings * lateral midline shift * loss of suprachiasmatic or basal cisterns * fourth ventricle effacement * obliteration of supracerebellar or quadrigeminal
plate cisterns with patent ambient cisterns * Presence of local infection at lumbar puncture site * Coagulopathy * Thrombocytopenia (platelet count <50 000)
Characteristic imaging appearances of asymmetric narrowing of the internal carotid arteries (especially the supraclinoid portion) with numerous collateral vessels around the brainstem, especially within the ambient and quadrigeminal
plate cisterns, are demonstrated with progression.
Because patients are usually scanned in the supine position, particularly important locations include the interpeduncular cistern, the occipital horns of the lateral ventricles, the quadrigeminal
plate cistern, and the dependent portions of the Sylvian fissures (Figure 1).
Identification of arachnoid cysts in the quadrigeminal
cistern using ultrasonography.