NEURORADIOLOGY (Demyelinating and Inflammatory Disease (ADEM:
POSTERIOR FOSSA MASSES
- Think VHL, most ommon mrohpoogy is periotumoral cyst w/ intensely enhancing tumor nodule. Usually CEREBELLUM
- Infiltrative pontine mass
-See >> Choline > NAA (normal is to see NAA > Choline
- 2 types (Diffusely infiltrating and Focal)
- Infiltrating PONTINE = WORSE PROGNOSIS, focal pontine is better prognosis
- midbrain glioma (tectal or tegmental) are low grade, watched w/ surveillance.
- Most common MALIGNANT pediatric brain tumor(peaks at 5-7yrs),
-Midline, cerebellar vermis
-LOTS of restricted diffusion
- Tx is surgical resection and radiotherapy
- Must check total spine for CSF spread
- Most common brain neoplasm in pedsiatric pts
-Imaging characteristics vary by loation
-Cerebellum = classic cyst and nodule, Optic-hypothalamic = more infiltrative and a/w NF1
-TX: Surgery, not really radiation in younger kids due to morbidity.
Lhermitte-Duclos Disease (Dysplastic Gangliocytoma):
- Tigroid appearance of cerebellum.
a/w COWDEN syndrome --> AD neoplastic syndrome that has systemic hamartomas, phakomatoses, malignancies in the breasts, thyroid, GU/GI system.
CP ANGLE MASSES
Vestibular Schwanomma = Most common
- benign, SLOW GROWING, MOST COMMONLY INVOLVES CN8
- treat w/ observation, gamma knife, or microsurgical resection.
-AVIDLY ENHANCES, Iso on T1, NO RESTRICTED DIFFUSION
- Has DUMBBELL SHAPE and scallops the bone, non-permeative (like paraganglioma) nor hyperostotic (like meningioma)
- Dural tail, reactive hyperostosis in underlying bone, possible restricted diffusion.
- Congintal inclusion cysts of ECTODERMAL TISSUES
- Well Marginated w/ irregular modular surface made of stratified keratinized squamous epithelium.
- MC LOCATIONS = CP Angle (~50%, 4th ventricle, sellar region, maybe intraparenchymal,
- On ct = hypodense similar to CSF, on flair = incomplete signal suppression, DWI = RESTRICTED DIFFUSION (most helpful imaging feature).
- Usually in jugular foramen, with glossopharyngeal nerve
- Will have salt and pepper appearance w/ flow voids
- Typically inferior 4th ventricle, soft tumor it squeezes through formane of lushka, magendie, an magnum
- Calcifications, hemorrhage, and cystic components are common,
-doesn't relaly restrict on DWI
- young ADULTS/adolescents,
- Predominnatnly lateral ventricle, attached to septum pellucidium.
-TX: Surgical resection
- See in TS
- See calcs and enhancement in subependymal nodules and in SEGA, best determining criter is increase size, typically > 1cm
Choroid plexus papillomas:
- Most likely to be in 4th ventricle in adults, and lateral ventricles in pediatric pts
-Avidly enhancing, cauliflower lobulated mass, a/w cysts and hemorrhage.
- See with older pts, 4th ventricle, doesn't really enhance
- Neurological compromise comes from CSF obstruction, not really herniation b/c slow growing
- Peripheral, calcified, not as much vasogenic edema as other lesions, cortical
-Most common pimary CNS neoplasm, Ages 40-70
- Lots of hemorrhage and necrosis (unike primairy CNS lymphoma)
PRIMARY CNS Lymphoma:
- Usually large B-cell,
- CT is hyperattenuation, homogenous enhancement on MRI, and restricted diffusion
- MOST COMMON Location = periventricular region/corpus callosum, basal ganglia, thalami. In the DDX for butterfly tumor, not as much ass effect for size of lesion.
- Typically temporal
-P/w intractable seizures, young males, not too much enhancement, hetergenous flair signal
-a/w cortical dysplasia
- bubbly lesion
Pleomorphic Xanthrocytoma (PXA):
-lOW GRADE NEOPLAS, IN CHILDREN/YOUNG ADULTS
-typically superficial (subpial) and temporal lobe
-Not too much surrounding edema
-Differentiate from DNET by looking at associated cortial dysplasia which is seen in DNET not PXA.
- Cyst and NODULE in temporal lobe, usually,
- Most common cause of temporal lobe epilepsy in children
- NEOPLASM = Elevated Choline to NAA (normal is for NAA to be higher), which means rapid cell turnover and loss of health neuroglial tissue
- LIPID PEAK = Higher grade neoplasm, possibly due to associated necrosis.
- Most common parasitic infx
-Mulitple peripherally enhancing ring lesions, hx of seizure and recent travel
-From porl tapeworm Taenia solium
-TX: ALBENDAZOLE and STEROIDS
- In immunocompromised
-A meningeal dz, but presens w/ ha, seizures, blurry vision
-If its in the parenchyma it is BASAL GANGLIA, MIDBRAIN,
-tx: amphotericin or fluconazole
- MULTIPLE lesions with distributions such as:
- CORTICOMEDULLARY JUNCTION, CEREBELLUM, BASAL GANGLIA
SPECTROSCOPY FINDINGS IN INFXN:
- Decreased NAA, choline, creatine, INCREASED CAA and Succinate
- On DWI won't see restricition of the BASAL GANGLIA, bilateral, diffuse, asymmetric and has leptomeningeal enhancement
- Progressive dementia and myoclonic jerks (abnl movements)
-BILATERAL THALAMI, also see insula and basal ganglia involvement.
Leptomeningeal Enhancement DDX:
- young PTS: DROPPED METS FROM MEDULLOBLASTOMA, CHOROID Plexus papilomas
- ADULTS: Lung and breast
- Can also think of arachnoiditis (empty sac sign, recent surger) and GuillanBarre syndrome which is smooth pial enhancement of cauda equine and conus medullaris in pt with recent history of viral illness.
2ND Most common in adults = ASTROCYTOMA
Most common in KIDS = ASTROCYTOMA
- Spans 4-7 VB segments, infiltrative and enhances a lot, +/- cysts.
- ECCENTRIC AN INFILTRATVIE, INDISTINCT MARGINS? ---> THINK ASTROCYTOMA!
- CYST WITH A NODULE IN ADULTS (think JPA in kids)
- See in posterior fossa & spine
- THINK VHL! = AD disorder Chr 3p mutation
-VHL pts have 2 or CNS hemangioblastomas or 1 Hemangioblastoma + visceral lesion or retinal hemorrhage (young to middle aged pts)
-Most common intramedullary tumor in ADULTS
- higher grade than myxopapillary type
-CERVICAL CORD most common site
-MARGINAL and non-tumoral cysts, peri0tumoral edema, peripheral hemorrhage (HYPOintense T2 rim)
- SUPER T2 bright and AVIDLY enhances, much like chondrosarcoma
Rathke Cleft Cyst:
- Cyst w/ a nodule in suprasellar region
-Usually HYPERINTENSE to fluid on T1 and T2 hypointense (this can vary, however)
- ISOINTENSE TO GREY MATTER on all sequences without cystic component.
-First 2 decades of life, males
- Gelastic seizures
- T2 HYPERINTENSE + AVID ENHANCEMENT, T1 is hypo or hyper.
- In the cavernous sinus.
PINEAL GLAND TUMORS
GERM CELL TUMOR = Most Common (GERMINOMA)
- Young males (under 20)
- Can p/w increased ICP, Hydrocephalus, parinaud;s
- If in suprellar region, then p/w if infiltration of infundibular recess, can get central diabetes insipidus.
- On CT, they ENGULF the calcified pineal gland and enhance homogenously
- Peripheral calcs on CT
- AVID contrast enhacement,
- Can't rely on T1/T2 characteristics
- T2 Hyperintense, delayed enhancement, < 10mm
- BIMODAL AGE 10-15YRS and 60 yrs
- Autoimmunity can cause
- Large pear shaped suprsellar mass that compresses the pituiatry gland
- Can be caused by medications
Spinosum - Middle Meningeal Artery
Foramen Ovale - Mandibular nerve, acc. meningeal artery
Pterygopalantine Fossa - Pterygopalantine ganglion, desc. palantine artery, maxillary division of trigeminal neerve
Superior Orbital Fissure = Opthalmic (V1), III, Trochlear (IV), abducens (VI) Superior/inferior opthalmic veins
-expansile, cystic petrous bone
-BRIGHT ON T1!
-p/w blue retrotympanic mass (just like dehiscent jugular bulb)
-In adults, Prussaks Space
-In Kids, congenital is in Cochlear promonotory
-T1 HYPO, and RESTRICTED DIFFUSION, no internal enhancement.
-p/w white retrotympanic mass
- a/w Peristent stapedial artery which is a/w absent foramen spinosum.