Brainstem glioma

Brainstem gliomas are usually non pilocytic, low grade astrocytomas.

On imaging studies they are most commonly solid and infiltrating, with variable contrast enhancement.

Tumors intrinsic to the brainstem are biologically more aggressive than pilocytic astrocytomas arising in the optic pathways or cerebellar hemispheres, with most patients dying within two years. Occasionally cystic pilocytic astrocytomas may arise in this region.

History: 3 year-old boy with walking difficulty.

Diagnosis: Low grade astrocytoma, WHO I

ACR Code: 152.3631

Chodorma

Large T2 hyperintensity mass in clivus with enhancement after contrast administration on T1 weighted image.

History: 34 year-old male with difficulty walking.

Diagnosis: Chordoma, clivus.

ACR Code: 121.327

-- A chordoma is a primary malignancy arising from remnants of the notochord, most commonly seen in sacrum and the clivus.

-- MRI will show heterogenous, bright signal on T2 weighted images. There is usually post-contrast enhancement.

-- Differential diagnoses include myeloma, aneurysmal bone cyst, giant-cell tumor, metastatic renal cell cancer, etc.

CJD

There are bilateral T2 hyperintensities in the basal ganglia and caudate on the FLAIR and T2 weighted images.

Bright signals are seen in bilateral basal ganglia and caudate on diffusion weighted images which are dark on corresponding ADC map, indicative restricted diffusion from cytotoxic edema.

Post-contrast T1 weighted images show no significant enhancement.

History: 72 year-old male with progressive dementia and myoclonus.

Diagnosis: Creutzfeldt-Jacobs Disease.

ACR Code: 148.2079

-- Creutzfeldt-Jakob disease (CJD) is a rare and fatal neurodegenerative disease, possibly caused by a peion infection. Patients are usually aged between 50 and 75 and typical clinical features include a rapidly progressive dementia associated, myoclonus and a characteristic electroencephalographic pattern. Neuropathological examination reveals cortical spongiform change, hence the term `spongiform encephalopathy'.

-- MRI usually shows characteristic basal ganglia abnormal T2 hyperintensities with restricted diffusion pattern.

-- Differential diagnosis is relatively short, including CJD, familial striatal degeneration, Leigh disease, and Wilson's disease .

Cystic Hematoma

Non-contrast CT images show a cystic lesion with surrounding edema in the left high parietal region. This represents involutional changes from prior acute hematoma (next image).

Previous (2 weeks earlier) non-contrast head CT images demonstrate high left parietal region acute hematoma after trauma. Blood is also seen within right lateral ventricle occipital horn.

History: 32-old male with trauma to the head.

Diagnosis: Cystic hematoma.

ACR Code: 132.434

De Morsier Syndrome

The axial FLAIR image as well as the coronal T1 and T2 weighted MR images demonstrate absence of the septum pellucidum and hypoplasia of the optic chiasm. The coronal T2 weighted image demonstrates small/hypoplastic optic nerves.

History: 4 year-old female suspected for developmental delay.

Diagnosis: Septo-optic dysplasia

ACR Code: 1613.1354

-- The septum pellucidum may be completely (64%) or partially (36%) absent which results in a squared-off appearance of the frontal horns of the lateral ventricles.

-- Up to 50% of patients may have schizencephaly. Others include dysgenesis of the corpus callosum, olfactory, aplasia, gray matter, heterotopia, and cerebellar dysplasia.

-- Septo-optic dysplasia is often considered in the spectrum of holoprosencephaly as representing the most minor form of holoprosencephaly.

Dysembryoplastic Neuroepithelial Tumor

Abnormal T1 hypointensities are noted in the left temporal tip region which demonstrate no significant enhancement on the post-contrast image.

Abnormal T2 yhperintensity lesion in the left temporal lobe with mild enhancement on the coronal image.

History: 3 year-old girl with seizures.

Diagnosis: Dysembryoplastic neuroepithelial tumor (DNET) with nodullar oligodendroglial hypercellularity and focal cortical dysplasia.

ACR Code: 1348.3638

-- An uncommon, slow-growing superficial hemispheric lesion found mainly in young adults.

-- Due to the slow growth, the cortical location (usually in the temporal lobe) and the frequent presence of cysts, skull remodelling with erosion of the inner and middle table is frequently found.

-- The most common clinical presentation is partial complex seizure disorder.

Dysembryoplastic Neuroepithelial Tumor (DNET)

Pre- and post-contrast enhanced head CT images demonstrate hypodensity lesion in the right middle cranial fossa. No apparent enhancement is seen.

FLAIR and T1 weighted ( pre- and post-contrast) images of the brain demonstrate ill-defined large T2 hyperintensity and T1 hypointensity lesion in the right temporal lobe without significant enhancement on post contrast image (coronal image).

History: 4 year-old boy with partial complex seizures.

Diagnosis: DNET.

ACR Code: 1348.3638

1. Young patients with intractable seizures – almost always partial complex

2. Well-circumscribed supratentorial cortical lesions

a. Temporal or frontal lobes most common sites

b. Multinodular architecture (mucinous or gelatinous cysts) with glioneuronal elements and foci of cortical dysplasia is also a common finding

3. Benign, nonaggressive

DNET Imaging Findings:

1. Isointense on T1WI, hyperintense on T2WI (often "bubbly" appearance). Usually don't enhance (20% do).

2. Remodelling of overlying calvarium common (45%).

3. Calcification in 20-25%, gyral thickening/dysplasia.

4. Differential diagnosis:

a. Ganglioglioma

b.     Oligodendroglioma

Epidermoid

Large, mixed signal intensity extra-axial mass in the lateral left posterior fossa.

T1 weighted pre- and post contrast images show no enhancement

Diffusion weighted image with corresponding ADC map image Demonstrate restricted diffusion of this lesion.

History: 38 year-old male with headache.

Diagnosis: Epidermoid inclusion cyst.

ACR Code: 134.3622

Erdheim-Chester disease

T1 images show bilateral infiltration of retroconal fat.

Abnormal T2 hyperintensity signals in pons and cerebellum

Post ccontrast images show intense enhancement.

History: 46 year-old male with gait disturbance.

Diagnosis: Non-Langerhans cell histiocytosis (Erdheim-Chester disease).

ACR Code: 158.389

It is a rare histiocytic disorder of adults characterized by an infiltrate of lipid-laden macrophages, multinucleated giant cells, inflammatory infiltrate of lymphocytes and histiocytes, that can involve many organs.

The central nervous system involvement of the hypothalamic / pituitary axis can lead to diabetes insipidus, intra-&-extra axial cerebral infiltration, retro-orbital fat infiltration.

They demonstrate as T2 hyperintensity signals which enhance after Gd contrast administration. There is no significant mass effect.

The most common neurologic manifestation is central diabetes insipidus and gait disturbance.

GBM from a PXA

Ring enhancing right frontal lobe mass with adjacent parenchymal edema and associated mass effect.

History: 38 year-old male with seizures.

Diagnosis: Pathology findings indicate that the lesion fulfills criteria for glioblastoma multiforme. It is astrocytic, mitotically active, and has exuberant vascular proliferation. Also present are focal eosinophilic granular bodies as are common in pleomorphic xanthroastrocytoma (PXA). While the lesion is thus unequivocally malignant, it is possible that is arose in a PXA.

ACR Code: 1318.3634

PRES with diffusion abnormality

CT images show low density areas in bilateral occipital lobes

T2 hyperintensity signals in bilateral occipital lobes

Those areas show restricted diffusion on the dffusion weighted images and the corresponding ADC map images

History: 23 year-old male with cocaine abuse presented with hypertension crisis.

Diagnosis: Posterior reperfusion encephalopathy syndrome (PRES).

ACR Code: 133..7615

Nonaneurysmal Perimesencephalic Bleed

History: 42 year-old female with sudden onset of headache

Diagnosis: Nonaneurysmal Perimesencephalic Bleed

ACR Code: 152 .729

-- The most common cause of any form of subarachnoid hemorrhage is trauma. In the case of spontaneous subarachnoid hemorrhage, 95% of the cases are a result of a ruptured aneurysm.

-- A small percentage of subarachnoid hemorrhages have no aneurysm found on angiohraphy. They occur spontaneously, and are usually localized to the perimesencephalic cisterns.

-- The usual outcome for this type of hemorrhage is excellent. This type of bleed is thought to be caused by a ruptured vein or capillary.

Hydranencephaly

Multiple non-contrast head CT images show the supratentorial space is mostly filled by fluid. Only a small amount of brain tissue is present in the occipital regions, cerebellum hemsphere, as well as the inferior frontal region.

Only the basal ganglia and inferior frontal lobes are seen. The falx cerebri is present both posteriorly and anteriorly.

Similar finding are seen on the transcranial ultrasound images.

History: Abnormal intrauterine ultrasound findings.

Diagnosis: Hydranencephaly

ACR Code:138.1459

-- Hydranencephaly is a rare condition in which the brain’s cerebral hemispheres are absent and replaced by sacs filled with cerebrospinal fluid.

-- The disorder is caused by an in utero event, most likely either ischemia or infection. Hydranencephaly can be caused in experimental animals by tying off both carotid arteries in the first half of the second trimester.

-- Hydranencephaly is considered to be an extreme form of porencephaly (a rare disorder characterized by a cyst or cavity in the cerebral hemispheres).

Basilar tip thrombosis

Non-contrast head CT images show areas of hypodensities involving the bilateral basal ganglia, right greater than left, as well as the right medial occipital lobe in the PCA distribution.

History: 54 year-old male with visual change and dizziness.

Diagnosis: Basilar tip thrombosis at the level above SCA causing bilateral PCA distribution infarction. However, the left PCA territory is spared due to a fetal poterior communication artery on the left side. The findings were confirmed by angiography.

ACR Code: 1753.72145

Central neurocytoma

Pre- and post-contrast T1 and T2 weighted images of the brain demonstrate a complex cystic mass lesion arising from the lateral wall of the right lateral ventricle with mild post-contrast enhancement.

History: 42 year-old male with recurrent headache.

Diagnosis: Central neurocytoma.

ACR Code: 1613.3619

-- The central neurocytoma arises from neuronal precursor elements rather than from glial cells. Most patients are young adults and can present with symptoms of ventricular obstruction.

-- It usually appears as a well-defined, lobulated intraventricular mass growing near the foramen of Monro or septum pellucidum.

-- Enhancement is typically mild to moderate and calcifications and cystic changes are common. Uncommonly, there have been cases of more aggressive tumor with dissemination.

Bilateral Accustic Shwannomas in NF-2

T1 weighted axial images with and without contrast through the internal auditory canals demonstrating bilateral 8th nerve masses with extension into the porous acousticus of the internal auditory canal bilaterally.

History: 21 year-old male with NF-2 presented with hearing loss.

Diagnosis: 8th nerve Shawnnoma, bilateral.

ACR Code: 154.3641

-- Bilateral acoustic neuromas are a common finding in patients with neurofibromatosis Type II (NF-2). Other intracranial abnormalities which are associated with NF-2 include meningiomas as well as ependymomas and occasionally neuromas involving the other cranial nerves.

-- The imaging characteristics of acoustic neuromas may be variable, but they generally present as focal enlargement of the 8th cranial nerve, often with extension into the porous acousticus of the internal auditory canal. The lesions most characteristically demonstrate diffuse and homogeneous enhancement on post Gadolinium enhanced scans.

ACOM Aneurysm

Axial noncontrast head CT shows hyperdense material in the basal cisterns and sylvian fissures, consistent with subarachnoid hemorrhage.

AP right common carotid arteriogram shows a rounded contrast collection in the region of the anterior communicating artery, consistent with aneurysm.

History: 42 year-old female with sudden onset of severe headache.

Diagnosis: Anterior communicating artery aneurysm.

ACR Code: 1731.7368

-- ACOM aneurysms are among the most common, representing approximately 1/3 of intracranial aneurysms. 15-20% of pts will have multiple aneurysms.

-- Large ACOM aneurysms may present with an optic chiasmal syndrome (bitemporal hemianopsia).

-- Although any size aneurysm may rupture, those measuring greater than 3-5 mm are at higher risk.

-- Complications include communicating hydrocephalus, rebleeding (20%), vasospasm (>7d) +/- infarct. 1/3 of pts die immediately, 1/3 have long term deficit, and 1/3 have near normal outcome.