KEY FACTS Terminology Congenital anomalies of pituitary stalk → potential hypothalamic/pituitary axis malfunction Imaging Posterior pituitary ectopia (PPE) Duplicated pituitary gland/stalk (DP) PPE: No (or tiny) pituitary stalk, ectopic posterior pituitary on midline sagittal T1WI MR Look for associated anomalies:…
Gross Anatomy Sella Bony anatomy : The sella turcica (“Turkish saddle”) is a concave, midline depression in the basisphenoid that contains the pituitary gland (also called the hypophysis). The anterior borders of the sella are formed by the anterior clinoid…
KEY FACTS Terminology Hydrocephalus Enlargement of cerebral ventricles secondary to abnormal cerebrospinal fluid (CSF) formation, flow, or absorption resulting in ↑ CSF volume Imaging Shunt failure → dilated ventricles + edema around ventricles, along catheter and reservoir Use CT or…
KEY FACTS Terminology Normal pressure hydrocephalus (NPH) Ventriculomegaly with normal cerebrospinal fluid (CSF) pressure, altered CSF dynamics Imaging Enlarged lateral & 3rd ventricles, 4th ventricle relatively normal Disproportionately large ventricles compared with subarachnoid spaces (particularly sylvian fissures and basal cisterns)…
KEY FACTS Terminology Focal reduction of cerebral aqueduct diameter Imaging Ventriculomegaly of lateral and 3rd ventricles with normal-sized 4th ventricle ± periventricular interstitial edema (uncompensated hydrocephalus) Multiplanar MR with sagittal 3D-heavy T2WI sequences and sagittal cardiac-gated cine MR Top Differential…
KEY FACTS Terminology Extraventricular obstructive hydrocephalus (EVOH): Enlarged ventricles due to mismatch between cerebrospinal fluid (CSF) formation, absorption Synonym: “Communicating” hydrocephalus Imaging Impaired absorption of CSF distal to 4th ventricle outlet foramina Ventricular size varies with duration of obstruction All…
KEY FACTS Terminology Intraventricular obstructive hydrocephalus (IVOH) = obstruction proximal to foramina of Luschka, Magendie Acute (aIVOH) Chronic “compensated” (cIVOH) Imaging aIVOH = “ballooned” ventricles plus indistinct (“blurred”) margins “Fingers” of CSF extend into periventricular white matter Most striking around…
KEY FACTS Terminology Cystic CSF cavity of septum pellucidum (SP) Occurs ± cavum vergae (CV) Imaging Elongated finger-shaped CSF collection between lateral ventricles Cavum septi pellucidi (CSP): Between frontal horns of lateral ventricles CV: Posterior extension between fornices CV is…
Gross and Imaging Anatomy Ventricles and Choroid Plexus Basic embryology : Early in embryonic development, the forebrain cavity divides into 2 lateral ventricles, which develop as outpouchings from the rostral 3rd ventricle and are connected to it by the interventricular…
KEY FACTS Terminology Inferior olivary nucleus (ION) degeneration Unique type of transsynaptic neuronal degeneration Olivary deafferentation thought to be source of ensuing hypertrophic olivary degeneration (HOD) Usually caused by primary lesions in dento-rubro-olivary pathway (anatomical triangle of Guillain-Mollaret) Triangle of…