FRCR 2A Central nervous system SBA

A. The vermis is always absent or very hypoplastic with Dandy-Walker.
B. The falx cerebelli is absent.

A. Correct. As stated in the question, DAI is associated with axonal disruption leading to coma and poor outcome.
B. MR is the test of choice to evaluate the white matter as CT can miss non hemorrhagic and subtle hemorrhagic shear injuries.
C. Involvement of the corpus callosum is common.
D. This describes patients with epidural hematomas not DAI.

"A. Persistent trigeminal artery arises from the cavernous segment of the internal carotid artery and courses posteriorly following either a parasellar or intrasellar course anastomosing with the basilar artery.
B. Persistent trigeminal artery occurs in 0.02% to 0.6% of cerebral angiograms.
C. Correct. Persistent trigeminal artery is associated with an increased incidence of other vascular anomalies including aneurysms. Intracranial aneurysms are found in approximately 14% of cases of persistent trigeminal artery.
D. Persistent trigeminal artery is the most common persistent carotid-basilar anastomosis. Persistent hypoglossal artery is the second most common persistent carotid-basilar anastomosis with a prevalence of 0.027% to 0.26%.

A. Moyamoya is seen in sickle cell disease secondary to stenosis/occlusion within the distal internal carotid artery and proximal aspects of the middle and anterior cerebral arteries. These findings are secondary to ischemia in the vasa vasorum with subsequent intimal and medial hyperplasia
B. Vascular dysplasia sometimes occurs in neurofibromatosis type 1. This most commonly consists of intimal proliferation with resultant stenosis/occlusion involving the carotid, middle cerebral and anterior cerebral arteries. Moyamoya pattern is seen in 60-70% of these patients.
C. Correct. Tuberous sclerosis is a neurocutaneous syndrome characterized by subependymal nodules, cortical hamartomas, giant cell astrocytomas, neuronal migration anomalies and many additional findings outside the central nervous system. There is no known association with moyamoya.
D. Radiation therapy can produce arterial injury including medial hyperplasia, intimal fibrosis, and endothelial degeneration. These can then produce vascular stenosis/occlusion resulting in a moyamoya pattern of collateral circulation.

A. Spinal lipomas are frequently associated with all forms of spinal dysraphism, especially those with a low conus and tethered cord
B. Correct. The Chiari I malformation is associated with syringo-hydromyelia in 20-60% but not with meningomyelocele or other forms of cord tethering.
C. A thick filum terminale is the rule with tethered cords.
D. Diastematomyelia is characterized by a sagittal clefting of the spinal cord or filum terminale. A low lying or tethered cord is present in about 40%.

A. This is a feature of the Juvenile AVM also termed type III in Spetzler classification.
B. Patients, most commonly elderly males, present with gradual onset of lower extremity weakness. Myelopathy as opposed to hemorrhage is identified on imaging studies in combination with subtle dilatation of spinal surface vasculature.
C. Correct. SDAVF is the most common. There is usually a single feeding radicular artery draining into pial surface veins. In most cases, treatment is endovascular unless the anterior spinal artery arises from the same level.
D. Males are more commonly affected than females with age of onset somewhere in the fifth to sixth decade.

"A. Correct. Hamartomas of the tuber cinereum do in fact produce precocious puberty secondary to secretion of luteinizing hormone-releasing hormone by the lesion.
B. Hamartomas of the tuber cinereum produce gelastic seizures. This may result from connections between the lesion and the limbic system.
C. Hamartomas of the tuber cinereum do not enhance as a rule. These lesions are immediately anterior to the mamillary bodies and may be broad based or pedunculated in configuration.
D. Hamartomas of the tuber cinereum are typically isointense to gray matter on T1WI and usually hyperintense to gray matter on T2WI.

A. Spread is to nodes more superiorly in the neck.
B. Intracranial involvement is typically from retrograde perineural spread through the skull base foramina
C. Correct. Nasopharyngeal carcinoma is common in young adult men in Southeast Asia, and is thought to be caused by EBV in this group.
D. Tumors mildly enhance and are hyper-intense on T2.

A. Preseptal cellulitis generally causes painless swelling and there is no restriction of ocular motion.
B. Orbital cellulitis is usually confined to the extraconal space except in severe cases.
C. Opportunistic infections in AIDS more commonly involve the globe.
D. Correct. Orbital abscesses most commonly result from infection in the adjacent ethmoid sinus.

Findings: Bilateral enlargement of the vestibular aqueduct.

A. Cock's deformity is the second most common cohlear malformation occurring at 4-5 weeks gestation. The cochlea and vestibule form a common cavity. The semicircular canals may or may not be involved.
B. Correct. Enlarged vestibular aqueduct syndrome is the most common cause of congenital sensorineural hearing loss. The midportion of the normal vestibular aqueduct should measure 1.5 mm or less in diameter. The incidence of associated cohlear abnormality is near 100%. The condition is bilateral in approximately 90% of cases.
C. Michel's aplasia is used to describe total aplasia of inner structures. This is due to a defect in otic placode development during the third gestational week.
D. Mondini malformation is the most common cochlear congenital anomaly. Occurring during the 7th to 8th gestational weeks, it consists of incomplete development of the cochlea. While the basal turn is relatively normal, the middle and apical turns often form a common cavity.

"A. Myelomeningocele has a defect in the posterior elements (dysraphism) with a cyst. This is an open neural tube defect. The spinal cord is tethered to the cyst. No cyst is seen is this case. This lesion is typically seen in the setting of the Chiari II malformation with hydrocephalus and low-lying cerebellum.
B. In a lipomyelocele there is a dysraphic defect. The spinal cord is tethered to a lipoma within the spinal canal. In a lipomyelomeningocele, there is a cyst associated with the lipoma and enlargement of the spinal canal. This is not an open neural tube defect. Patients may become symptomatic later in life due to the tethered cord; complications include scoliosis, bladder dysfunction, and leg weakness and pain.
C. Dermoid cysts of the spine typically occur in the sacrum. In addition to lipid material, they typically show mixed fluid signal on MR. If a dermoid ruptures into the subaracnoid space, it results in chemical (aseptic) meningitis. Dermoids can also be associated with dermal sinuses. The large dysraphic defect in this case is atypical for dermoid.

Findings: Bilateral increased signal intensity within the dorsal columns of the cervical spinal cord on T2WI extending over multiple spinal segments.

A. Incorrect: ADEM can enlarge the spinal cord but is usually seen in the cerebrum. Its appearance can mimic MS.
B. Myelopathy is a rare complication of systemic lupus erythematosis occurring in approximately 1 % of patients. It is thought that the underlying process is vacuolar degeneration caused by ischemia related to vasculitis or an autoimmune phenomenon. As in this case, it may present as increased signal intensity on T2WI extending over multiple spinal segments. However, given the rarity of this entity and absence of a history of SLE, an alternative diagnosis should be sought.
C. Foix Alajouanine syndrome is a myelopathy associated with a spinal dural arteriovenous fisula. The entity tends to occur in males in their 40’s and 50’s. It begins with insidious onset of lower extremity weakness or sensory deficits and may progress to paralysis if untreated. The underlying pathology is chronic venous hypertension secondary to the vascular malformation. MR findings include a normal or enlarged spinal cord with increased signal intensity on T2WI. The spinal cord may enhance and prominent vessels are often seen on the dorsal surface of the spinal cord. These findings most commonly occur within the lower thoracic spinal cord or conus medullaris.
D. Correct. Subacute combined degeneration is secondary to vitamin B12 deficiency and produces a myelopathy predominantly affecting the cervical and upper thoracic spinal cord. Paresthesias of the hands and feet, lower extremity weakness, and loss of position and vibratory sensation are presenting symptoms. Pernicious anemia is the most common cause of subacute combined degeneration in the US. It results from inability to absorb B12 from the GI tract secondary decreased levels of intrinsic factor. Intrinsic factor is produced by the gastric parietal cells which are lost in pernicious anemia. The intrinsic factor/B12 complex binds to the mucosa of the terminal ileum where the B12 is absorbed. Therefore, diseases involving the terminal ileum such as Crohn’s disease and tropical sprue may also produce subacute combined degeneration. Gastrectomy and resection of the terminal ileum are additional causes. The MR findings are increased signal intensity within the dorsal columns bilaterally. Many entities may produce increased signal intensity within the dorsal columns on T2WI but the history in this case should lead to the correct diagnosis.

A. Correct. This is the most common vascular malformation in the spine. These lesions typically present with paraplegia. MR shows spinal cord edema, with variable visualization of enlarged vessels. Angiography demonstrates an enlarged draining vein on the surface of the cord. Patients present with progressive lower extremity weakness due to venous hypertension.
B. These uncommon lesions are similar to parenchymal AVM’s seen in the brain. They usually present after hemorrhage.
C. These unusual lesions are extensive AVM’s which are both intra and extra dural. They are extensive lesions which involve skin, muscle and bone in addition to spinal cord.
D. Aneurysms are rare in the spine, with only scattered case reports.

A. Frontal and ethmoid sinuses are more common.
B. Mucoceles have an enhancing rim whereas tumors have more solid enhancement.
C. Mucoceles typically have increased T1 signal on MR.
D. Mucoceles are associated with an expanded enlarged sinus.

"A. Correct. Tolosa Hunt syndrome is an idiopathic inflammatory process involving the orbital apex and/or the cavernous sinus. It is histologically identical to orbital pseudotumor. Commonly presenting with retroorbital pain and multiple cavernous sinus cranial nerve palsies, it is rapidly responsive to steroid therapy.
B. Wegener's granulomatosis is a necrotizing granulomatous inflammatory process which may involve the orbit and paranasal sinuses. It is either transiently responsive or nonresponsive to steroid therapy. Antineutrophil cytoplasmic antibodies (ANCA. are sensitive indicators of the entity.
C. Posttransplant lymphoproliferative disorder occurs in a small percentage of patients following organ transplantation. It likely is incited by Ebstein Barr virus infection which leads to a proliferation of the B cell population. In these immunosuppressed patients, this proliferation is unopposed secondary to a deficiency in the T cell population. A spectrum of disease results which ranges from adenopathy and lymphoid tissue hypertrophy to lymphoma.
D. Sarcoidosis is a granulomatous disease of unknown etiology. CNS involvement occurs in a minority of cases. It can present in a number of ways including dural based mass, leptomeningeal mass/enhancement, and intraaxial mass. Orbital involvement including uveitis and orbital masses can also occur.

AKA Idiopathic Orbital Inflammatory Disease

Pathology
Most common painful orbital mass in adults

Clinical Issues
Proptosis and globe displacement
Uveitis, sclerotenonitis, retinal detachments
Cranial nerve palsies (III, IV, V, VI) with Tolosa-Hunt syndrome
Steroids effective in most patients
Radiotherapy for nonresponsive or refractory cases or when steroids contraindicated

Diagnostic Checklist
IOID is diagnosis of exclusion; exclude infectious orbital cellulitis, CCF in acute cases
Atypical onset or recurrences should prompt biopsy for confirmation

"A. Meningoceles and myelomeningoceles are the most commonly encountered neural tube defects.
B. Caudal Regression Syndrome is commonly seen in infants of diabetic mothers. Diastematomyelias are associated with other spinal anomalies including Chiari II and myelomeningoceles.
C. This is actually the definition of diplomyelia which is a much more rare anomaly.
D. Correct. Diastematomyelia involves a split of the cord into two separate components. As mentioned, the division may be the result of bone, cartilaginous or fibrous septation. The separate halves so to speak may be enclosed in a single dural sac or the split may involve the dura as well.

  

A. Correct. LeFort Fractures basically occur along weakness planes in the facial skeleton. These include the two structures mentioned above.
B. The LeFort type I injury specifically does not involve the orbits with the blow and fracture line occurring at the level of the maxilla. The fracture includes the entire palate, maxillary and alveolus teeth and portions of the pterygoid plates. The zygoma is not included in the classification of LeFort fractures.
C. This describes the Type I injury.
D. This describes the Type III injury.

A. The pathologic lymph nodes are at level 2.

A. Correct. Extra-adrenal paragangliomas may occur in the spine, most commonly at the cauda equina. They present as smooth, lobulated intradural, extramedullary enhancing masses. Serpentine flow voids are common and represent draining veins. As these are highly vascular masses, a hemosiderin cap or intrathecal blood products may be seen. 

A. Correct. The most important lesion to exclude in the differential of a parasellar / sellar / suprasellar mass is aneurysm. The peripheral calcifications and location in the cavernous sinus are most concerning for an aneurysm of the cavernous internal carotid artery. This was confirmed by subsequent CTA. 

A. Correct. The epidural space is the most common location for prostate carcinoma to result in cord compression. 

C. Correct. Sagittal suture synosotosis is most common. Sagittal 60%, coronal 20-30%, metopic 1-2%, lambdoid 1%.

A. The association between hypertension and aneurysm formation and rupture has been controversial, although the balance of evidence suggests that hypertension is a risk factor. Though this is a possible answer, the proven association with ADPCK is the better answer in this case.

A. Septooptic dysplasia is associated with various genetic mutations as well as intrauterine cocaine exposure and valproate toxicity. It is not associated with Intrauterine CMV infection.

A. The lesion is intraconal but distinct from the optic nerve from which opric gliomas arise. This is most readily apparent in image three.

B. The data on the epidemiology of olfactory neuroblastomas come from an analysis of 311 cases in the Surveillance, Epidemiology, and End Results (SEER) database over a 30-year period. In this study, the mean age at presentation was 53 years, with most cases occurring in patients between 40 and 70 years. There was a moderate male predominance, with a 55:45 male:female ratio. Nasal obstruction due to the presence of a mass is the most common symptom with olfactory neuroblastoma and is present in the majority of cases. Other manifestations of local disease include epistaxis, nasal discharge, and/or pain. Examples of symptoms due to local extension of tumor include:

A. Transependymal CSF flow correlates with positive outcome after ventricular shunting. However, T2 hyperintense transependymal flow can be difficult to distinguish from periventricular and deep white matter ischemic change which correlates with poor surgical outcome.
B. Patients with gait apraxia and recent clinical onset have more favorable response to shunting than patients in whom memory impairment predominates or in those who have long-standing symptoms.
C. Correct. Increased CSF flow rates correlate with a good response to shunting.
D. A flow void through the aqueduct reflects increased CSF velocity which is correlated with good outcome after ventricular shunt placement.

C. Correct.

"B. Correct.

A. Correct.

A. Calcifications are seen in greater than 90% of patients
B. Signal on MR is increased on T1 and decreased on T2
C. The involved globe is normal in size. This helps differentiate retinoblastoma from other entities that involve calcification of the globe including retinopathy of prematurity, Coat’s disease and phthisis bulbi which are all associated with a small globe.
D. Retinoblastomas are the most common ocular malignancy of infancy

A. Correct. The most common location of paragangliomas in the head and neck is at the level of the carotid body. 

A. Correct. Rasmussen’s encephalitis is a disease of children of 6 to 8 years. Focal motor seizures are followed by progressive loss of ipsilateral motor function associated with cognitive decline. Cerebral atrophy is a late finding in the disease. 

A. Correct. Meningiomas are the most common extra axial neoplasms of the brain that arises from the dura and are associated with an enhancing dural tail which is seen in 72 percent of patients with meningiomas. 

A. Lupus cerebritis should be considered in a female of reproductive age with a complicated neurologic presentation. Subcortical infarcts as seen on the FLAIR imaging are seen in this entity. 

A. Though MS can present with a splenial lesion as well as lesions in the centrum semiovale, the presentation of this patient is not consistent with MS. Patients with MS present with various neurologic deficits but not to the ED in coma.

A. Correct. The lesion has the hallmarks of a craniopharymgioma on MRI, cyst formation, calcification and enhancement in the suprasellar compartment. 

"A. Correct. Paragangliomas are common at the level of the Jugular foramen. They have a characteristic salt and pepper appearance on MR imaging due to the vascularity of the lesion. 

  

A. Correct. Langerhans cell histiocytosis commonly presents with a vertebral plana appearance as seen here. 

A. Correct. The most common intradural extramedullary lesion of the spine is a meningioma or schwannoma. The best choice here is meningioma. They account for 25 percent of spinal canal neoplasms. 

A. Correct. There is a depressed orbital floor fracture appreciated on the right with fat herniating through the defect with probable hemorrhage in the right maxillary sinus as evidenced by opacification of the sinus on bone window evaluation. The inferior rectus is also somewhat enlarged likely related to post traumatic edema/hematoma. 

A. Glioblastoma multiforme is the most common primary supratentorial neoplasm in adults. However, it is uncommon in the posterior fossa. Brainstem glioma, which is usually a lower-grade astrocytoma, is the most common glial neoplasm found in the posterior fossa in adults.

"

A. Correct. Both subdural empyemas and chronic subdural hematomas may show rim enhancement.

"

"

"A. Sarcoidosis can result in glottic or supraglottic soft tissue thickening, but should not cause dilatation of the pyriform sinus.
B. Laryngoceles present as fluid or air-filled cystic mass in the paraglottic fat.
C. Squamous cell carcinoma can cause thickening of the aryepiglottic fold but should result in narrowing of the pyriform sinus.
D. The imaging findings are characteristic for right vocal cord paralysis.

Laryngocele

"A. Craniopharyngiomas are not associated with precocious puberty and typically enhance or have cystic change or calcification.
B. The sagittal images show a nonenhancing mass at the posterior aspect of the suprasellar cistern between the pituitary stalk and mammillary bodies in the region of the tuber cinereum. In association with the clinical history of precocious puberty this is most consistent with a hypothalamic hammartoma (tuber cinereum hammartoma.)  
C. The pituitary gland appears mildly prominent though no discrete pituitary mass is seen and an adenoma would not account for the nonenhancing mass in the suprasellar cistern.
D. No history of visual disturbance was given to suggest an optic glioma and the mass lies inferior to the optic chiasm.

A. Patients with cerebral atrophy do not have an increased head circumference.
B. There are no findings of a subdural fluid collection. Most patients with subdural effusions from meningitis will not be asymptomatic.
C. The subarachnoid spaces are enlarged greater than 5mm. There are no findings of a subdural fluid collection. This process is usually self-limited and will correct as the arachnoid villi mature.
D. There are no findings of a subdural fluid collection. Subdural hematoma will generally not be identical in signal to CSF. There are no other findings of direct cranial trauma.

A. Molar tooth brainstem is seen with Joubert syndrome not agenesis of the corpus callosum. The vermis is small and dysplastic and the superior cerebellar peduncles are big.
B. Fused thalami are seen with holoprosencephaly not agenesis of the corpus callosum.
C. Cobblestone cortex is not associated with agenesis of the corpus callosum. It is seen with several forms of congenital muscular dystrophy. Former term was Type 2 Lissencephaly.
D. Probst bundles are seen with agenesis of the corpus callosum. These are densely packed white matter tracks that run parallel to the interhemispheric fissure. These are the fibers that would have crossed in the corpus callosum if present.

"A. NF1 patients may get optic gliomas and neurofibromas.
B. Although NF2 patients may get spinal cord tumors (ependymoma), an intra-axial tumor in the cerebellum would not be expected.
C. TS patients may develop giant cell astrocytomas near the foramen of Monro. Spinal cord and cerebellar tumors would not be expected.
D. Hemangioblastomas in the cerebellum (solid and cystic tumors as in this case) and tumors in the spinal cord (hemangioblastomas) fits VHL as the best choice here.

Terminology
Autosomal dominant familial syndrome with hemangioblastomas (HGBLs), clear cell renal carcinoma, cystadenomas, pheochromocytomas

Imaging
2 or more CNS HGBLs or 1 HGBL + visceral lesion or retinal hemorrhage
HGBLs vary from tiny mass to very large with even larger associated cysts

Pathology
Posterior distribution of HGBLs = result of tumor development during embryogenesis

Clinical Issues
Phenotypes based on absence or presence of pheochromocytoma
Earliest symptom in VHL often visual
Nearly 75% of symptom-producing tumors have associated cyst, peritumoral edema
HGBLs → multiple periods of tumor growth (usually associated with increasing cyst size) separated by periods of arrested growth

Diagnostic Checklist
Follow NIH screening rules
Look for ELS tumors in VHL patients with dysequilibrium, hearing loss, or aural fullness

"A. Pang Type II lesions have a single dural sac and subarachnoid space. All cases of diastematomyelia have only 4 nerve roots. Diplomyelia has 8 nerve roots.
B. Intersegmental laminar fusion is virtually pathognomonic of diastematomyelia being found in approximately 60% of cases.
C. 85% are found between T9 and S1.
D. Sagittal images may completely miss the lesion. Coronal and/or axial images best demonstrate the abnormality.

Terminology
Synonyms: SCM, split cord malformation, ""diastem""
Sagittal division of spinal cord into two hemicords, each with one central canal, dorsal horn, and ventral horn

Imaging Findings
Location: Thoracolumbar cleft (85% between T9 and S1) > > upper thoracic, cervical clefts
Hemicords usually reunite above and below cleft
Osseous spur often visible; fibrous spurs are frequently occult
Vertebral segmentation anomalies
Split cord; one or two dural tube

Clinical Issues
Cutaneous stigmata high on back indicates diastematomyelia level (> 50%); ""fawn's tail"" hair patch most common

A. Myelination is first seen in the posterior portion of the posterior limb of the internal capsule and then in the anterior limb of the internal capsule.
B. Myelination occurs first in the splenium and then in the genu of the corpus callosum.
C. Central white matter myelinates prior to the peripheral white matter.
D. T1 weighted images are most useful in assessing myelination milestones during the first 6 months of life. T2 weighted images become more useful between 6 to 18 months of age.

"A. Benign lymphoepithelial lesions associated with HIV most commonly occur in the parotid glands. When the submandibular glands are involved, disease is usually also present in the parotid glands.
B. 80% of neoplasms involving the sublingual glands are malignant. The two most common types are adenoid cystic and mucoepidermoid carcinomas.
C. Warthin tumor is a benign parotid tumor. In contrast, adenoid cystic carcinoma is a slow-growing tumor that has a propensity for perineural spread and late recurrence.
D. Benign mixed tumor (pleomorphic adenoma) accounts for 80% of parotid neoplasms.  

Pathology
Most common parotid space tumor (80%)
80% BMT arise in parotid glands

Diagnostic Checklist
Large asymptomatic masses arising from deep lobe of parotid are almost always BMT
Define facial nerve plane & identify deep parotid lobe component as this may be missed clinically
Infiltrative margins, multicentricity or hypointense T2 signal should suggest alternative diagnosis

"A. Hemorrhage is rare in osmotic demyelination syndrome.
B. Osmotic demyelination syndrome is commonly iatrogenic related to rapid correction of hyponatremia.
C. The pons is a site commonly involved with osmotic demyelination, occurring in about 50% of cases. This was previously referred to as central pontine myelinolysis.
D. Hippocampal and peripheral cortex involvement is uncommon. The basal ganglia, thalami and white matter are more commonly involved in extrapontine osmotic demyelination.

"A. Subarachnoid hemorrhage is an uncommon occurrence in hypertensive hemorrhage. Hypertensive hemorrhage is typically parenchymal.
B. Acute hemorrhage typically contains deoxyhemoglobin which is hypointense on T2 weighted MR images.
C. Hypertensive hemorrhage most commonly occurs in the basal ganglia (putamen) followed by the thalamus and cerebellum or pons.
D. Hypertensive hemorrhage is more common in elderly adult males.

"A. The basal ganglia are usually spared in herpes encephalitis.
B. Cerebellar involvement by herpes encephalitis is unusual.
C. The occipital cortex can be involved by herpes encephalitis but less commonly than the temporal lobes.
D. The temporal lobes, inferior frontal lobes (subfrontal area and cingulate gyri) and subinsular cortex are typical locations of herpes encephalitis.

"A. Headache is the most frequent symptomatic clinical presentation secondary to obstructive hydrocephalus. Other clinical symptoms such as nausea, vomiting or visual disturbance occur less often. A significant proportion of patients are asymptomatic.
B. The most common location is at the foramen of Monro (anterior third ventricle).
C. Colloid cysts are most often dense at CT imaging.
D. Peripheral enhancement may be found at MR though there is no central enhancement.

"A. Neurenteric cysts are congenital in etiology.
B. Dermoid cysts are congenital in etiology.
C. Epidermoid cysts may be congenital (60%) or acquired (40%) in etiology. Epidermoid cysts can arise after a lumbar puncture if viable epidermal elements are introduced into the spinal canal.
D. May be secondary congenital arachnoid proliferation in nerve root sleeve or post traumatic rupture of perineurium and epineurium.

Terminology
Acquired intraspinal mass arising from iatrogenically implanted epithelial elements

Pathology
Epithelial cells iatrogenically introduced into thecal sac during lumbar puncture

"A. In general, diskitis-osteomyelitis complex will be centered on the disk space and have adjacent endplate involvement, findings not described in this case.
B. Calcification below the anterior arch of C1 (longus coli muscle insertion), prevertebral soft tissue swelling, in conjunction with a patient with neck pain and odynophagia is a classic description of calcific tendinitis of the longus coli muscle.
C. A destructive peridiscal arthritis in a dialysis patient would be centered about the disk space, and could contain disc space calcification.
D. This would be an erosive arthritis centered on a disc space in a patient with known gout.

"A. This is the classic imaging finding associated with Guillian-Barre syndrome.
B. This would be an unusual finding.
C. In GBS, the nerve roots may enhance and be mildly enlarged/thickened, but not clumped. Clumping is a better finding for arachnoiditis.
D. This would be an unexpected finding with GBS.

"A. Children tend to present with TIAs and strokes.
B. Supraclinoid segment internal carotid artery occlusion or stenosis is characteristic.
C. Correct.
D. The lenticulostriate vessels hypertrophy and serve as collateral vessels with moya moya syndrome.

Terminology: Progressive narrowing of distal ICA and proximal circle of Willis (COW) vessels with secondary to collateralization

Imaging:
Best diagnostic clue: Multiple punctate dots (CECT) and flow voids (MR) in basal ganglia (BG)
""Puff of smoke"" (moyamoya in Japanese) = cloud-like lenticulostriate and thalamostriate collaterals on angiography
Best imaging tool: MR C+/MRA

Clinical Issues
Bimodal age peaks: 6 and 35 years
Most frequent cause of stroke in Asian children
Presentation (children): TIAs, alternating hemiplegia (exacerbated by crying), headache
Presentation (adults): TIAs, cerebral infarct, or hemorrhage
Treatment: Indirect (children) or direct bypass (more common adults)

A. Arise from the vestibular division of the eighth cranial nerve.
B. Correct.
C. Acoustic schwannoma is the most common CP angle mass.
D. Bilateral in NF-2, not NF-1.

A. Patients present with solitary metastases in approximately 50% of cases.
B. Metastases, in contrast to primary brain tumors, usually have well-defined borders and moderate vasogenic edema, often disproportionate to the size of the lesion.
C. Cortical metastases often have little associated edema and are therefore difficult to detect on T2WI. Administration of contrast is essential to detect cortical lesions.
D. Metastases typically occur at the gray-white matter junction because of the small caliber of the vessels in this region.

"A. The biconcavity seen at the superior and inferior end plates of osteoporotic vertebral bodies in sickle cell disease resembles the appearance of the fish spine leading to the term “fish” vertebrae. The intervertebral disc spaces have a widened appearance similar to that of the “fish mouth.”
B. Calcium pyrophosphate crystals deposit in the cartilaginous endplate and intervertebral discs causing disc space narrowing and calcification as well as sclerosis of the adjacent vertebral body endplate margins.
C. Early phases of discitis and osteomyelitis are characterized by signal alteration and enhancement in the disc space and adjacent vertebral endplates. Without treatment, disc space and bony destruction will occur.
D. Loss of sensation and proprioception causes repetitive traumatic injury. This leads to sclerosis, osteophytosis and fragmentation of vertebral body endplates and to narrowing of the intervertebral endplates.

A. 16*0.625 mm implies 10 mm coverage and is less than 20 mm coverage (16*1.25 mm) and therefore less anatomical coverage is obtained per tube rotation.
B. A 0.625 mm detector element (z-axis collimation) will provide better resolution of fine detail structures than a 1.25 mm detector element due to the decrease in partial volume averaging with the thinner detector element.
C. Detector configuration has no effect on the amount of beam hardening in a given image.
D. In fact, the radiation dose is slightly higher with thin (0.625 mm) detector configuration compared to thick (1.25 mm) detector configuration and therefore may yield higher dose.

A. Within the first 6 hours after onset of acute infarction, edema can be seen as obscuration of the contrast difference between gray and white matter in the cortex and insular ribbon and at the junction of the lentiform nucleus and internal capsule.
B. Mass effect peaks between 3 and 5 days and usually resolves in 2 to 4 weeks.
C. Variable nonstandard window width (approximately 8) and level (approximately 32) settings on PACS accentuate the gray white matter contrast difference facilitating the detection of early edema.
D. Enhancement is uncommon in the first 3 days after ictus. Early enhancement may indicate spontaneous or iatrogenic clot lysis and reperfusion into an area of infarcted brain.

"A. Prominent atrophy of the caudate nuclei is the most prominent imaging finding in Huntington disease. This is an autosomal dominant inherited neurodegenerative disease characterized by movement disorder and dementia.
B. Degeneration of the substantia nigra is associated with Parkinson Disease.
C. Iron deposition in the globus pallidus is associated with Hallorvorden-Spatz disease. The globus pallidus is also susceptible to injury by carbon monoxide and other toxins.
D. Prominent atrophy of the anterior temporal lobes is seen in Alzheimer disease.

"A. Abscess of the spinal cord is rare.
B. The intervertebral disc is frequently involved by pyogenic bacterial infection, but mycobacterial infections usually spare the intervertebral disc.
C. Mycobacterial infections most commonly present as osteomyelitis of several adjacent vertebral bodies, with sparing of the intervertebral disc.
D. Tuberculous meningitis may occur in acutely ill patients. However, spondylitis (Pott's disease) is more common.

Tuberculous spondylitis (TS): Pott disease

A. Slice thickness increases have a small effect on dose reduction that diminishes as the change increases.
B. Bismuth eye shields have been found to not produce significant artifacts by most investigators.
C. Increased kVp results in increased patient dose approximately by the square of the kVp.
D. Reduction in mAs reduces patient dose in direct relation to the reduction if all other parameters are maintained the same.

"C. Of the TORCH infections, cytomegalovirus has the strongest association with the development of polymicrogyria. Occasionally, toxoplasmosis or rubella infections may result in polymicrogyria. Herpes simplex type 2 is not a TORCH infection, that is herpes simplex type 1.

A. Primary CNS Lymphoma can produce lesions with reduced ADC values, however it generally enhances homogeneously in the immunocompetent patient (suggested by previously well history). Thin walled enhancement would also be unlikely with lymphoma and it is not the best answer.
B. Multiple thin walled ring enhancing lesions with edema and reduced ADC values are most suggestive of abscess, which is the best answer. This was confirmed on subsequent stereotactic aspiration.
C. Multifocal bilateral noncontiguous tumors would be unlikely. They would not likely have a uniform wall thickness without a mural nodule. They would not have reduced ADC values.
D:  Metastatic neuroblastoma is nearly always extradural and calvarial based. Intraaxial lesions are rare and would not likely enhance in a thin ring like fashion.

A. Asymmetric fat in the petrous apex would result in T1 hyperintensity and intermediate to high signal on T2WI. However, asymmetric fat should not cause expansion of the petrous apex.
B. Petrous apicitis would have low signal intensity on T1WI and would not cause a smooth, expansile appearance to surrounding bone.
C. Congenital cholesteatoma could cause smooth expansion of the petrous apex, but would have low signal on T1 weighted imaging.
D. Cholesterol granuloma causes smooth expansion of the petrous apex and is hyperintense on both T1 and T2 weighted images.

"A. The mass lesion is centered in the muscles of mastication and mandibular ramus. It displaces the parapharyngeal fat posteromedially. A carotid space mass should be centered in the carotid sheath and displace the parapharyngeal fat anteromedially.
B. The mass lesion does not arise from the parapharyngeal space. Rather, it displaces the parapharyngeal space fat posteromedially.
C. The mass lesion is centered in the muscles of mastication and mandibular ramus. It displaces the parapharyngeal fat posteromedially.  
D. A parotid space mass should be centered in the parotid gland and displace the parapharyngeal fat medially.

"A. 90% of optic nerve gliomas present in patients under the age of 20. The whole nerve is usually enlarged. Enhancement may vary from minimal to intense, but is usually less intense than enhancement of meningiomas and does not typically demonstrate a ""tram-tracking"" appearance.
B. Enhancement of the optic nerve sheath with a ""tram-tracking"" or ""doughnut"" appearance is relatively specific, although not pathognomonic, for optic nerve sheath meningioma.  
C. Optic neuritis causes enhancement of the optic nerve with minimal enlargement of the nerve/sheath complex. Intracranial demyelination is also often evident.
D. Clinically, orbital psuedotumor causes painful proptosis. On imaging, enhancement is usually not confined to the optic nerve sheath.

A. A well-defined thin-walled cystic lesion extending from the sublingual space into the submandibular space is a characteristic imaging appearance for a diving or plunging ranula.  
B. A dermoid tumor contains soft tissue and fat in its matrix and therefore would have a heterogenous appearance demonstrating hyperintensity on T1WI and hypointensity on fat-saturated sequences.
C. First branchial cleft cysts occur in the parotid gland, preauricular region or posterior submandibular space. This lesion arises in the sublingual space with extension to the anterior submandibular space.
D. Patients with submandibular abscess would present with painful neck swelling clinically. On imaging, single or multiple fluid collections would demonstrate peripherally enhancing walls.

"C. Acute subarachnoid hemorrhage usually is seen as increased signal (failure of CSF suppression) within the basilar cisterns and sulci on FLAIR sequences. Care must be taken so that pulsation artifact is not mistaken for acute hemorrhage.

"C. Correct.

  

Warthin Tumor

Imaging Findings
Best diagnostic clue: Sharply-marginated parotid tail mass with striking parenchymal inhomogeneity
Cystic component in 30% with thin, uniform walls & CT density of 10-20 HU
Minimal enhancement of solid components

Pathology
2nd most common benign parotid tumor
20% multicentric, unilateral or bilateral, synchronous or metachronous

Diagnostic Checklist
Consider CECT to help identify cystic areas within Warthin tumor to help differentiate from small BMT

"A. This is membranous choanal atresia.
B. The choana is narrowed and is obliterated with a soft tissue plug.
C. This is a narrowing of the anterior nasal opening.
D. The choana would be narrowed, but would have a patent air filled passage.

Imaging Findings
Best diagnostic clue: Narrow posterior nasal cavity, medial bowing and thickening of the lateral wall of the nasal cavity and enlargement of the posterior vomer
50-60% unilateral, 40-50% bilateral (BL)
Choanal airspace < 0.34 cm in newborn
Vomer > 0.34 cm in children less than 8 years
Purely bony atresia in 29%
Mixed bony-membranous malformation in 71%

Pathology
Most common congenital abnormality of nasal cavity
75% with bilateral atresia have other congenital anomalies

Clinical Issues
Bilateral: Severe respiratory distress in newborn
Unilateral: Chronic purulent rhinorrhea, mild airway symptoms in older child

Piriform Apeture Stenosis
Anterior nasal bony stenosis
Look for central megaincisor and midline intracranial anomalies

  

Findings: There is symmetric bilateral restricted diffusion in the striatum and paramedian frontal cortex with sparing of the thalamus, internal capsule and globus pallidus.

A. The abnormality involves portions of two vascular territories, anterior and middle cerebral arteries, and would therefore be atypical for acute infarction.
B. These findings are characteristic of Creutzfeldt-Jakob disease (CJD). DWI has been reported to be more sensitive than T2W or FLAIR imaging for the early diagnosis of CJD.
C. Deep venous thrombosis typically results in edema and possibly early reversible restricted diffusion in the thalamus bilaterally. The thalamus is relatively spared in this case.
D. While these findings could also be seen in hypoxic-ischemic encephalopathy (HIE), the clinical history of progressive cognitive decline and myoclonic jerks does not support this diagnosis.

"A. There is an acute hematoma in the right frontal lobe with changes of chronic microhemorrhage remote from the acute hematoma in both hemispheres at the gray-white matter junction. These findings are most consistent with a diagnosis of cerebral amyloid angiopathy in an elderly patient. There was no clinical history of trauma and there are no other post-traumatic abnormalities such as scalp hematoma or subarachnoid hemorrhage.
B. There is acute hemorrhage in the right frontal lobe with relatively little edema as would be expected with a metastasis. The patient also has no clinical history of a primary tumor.
C. Hemorrhagic transformation of acute infarction typically has a delayed onset of 24-48 hours after ictus secondary to reperfusion following lysis of obstructing vascular thrombus. This patient presented acutely with a right frontal lobe hemorrhage.
D. These findings are most consistent with a diagnosis of cerebral amyloid angiopathy in an elderly patient.

"Findings: There is ossification of the posterior longitudinal ligament over 4 contiguous levels and to a lesser extent of the anterior longitudinal and transverse ligaments, best seen on the CT exam. Ossification is difficult to confirm on MRI, but is suggested by the presence of fatty marrow elements on the T1-weighted image. The T2-weighted sagittal MRI best demonstrates narrowing of the spinal canal and cord compression.

A. A sequestered disc herniation would involve a single disc level. The abnormality shown extends over multiple contiguous vertebral levels.
B. There is ossification of the posterior longitudinal ligament (OPLL) over 4 contiguous levels, best seen on the CT exam. Ossification is difficult to confirm on MRI in the absence of fatty bone marrow elements. However, MRI best demonstrates narrowing of the spinal canal and cord compression.
C. The density of the abnormality on CT is not characteristic of a hematoma. It is characteristic of dense calcification or ossification and is confined to the posterior longitudinal ligament.
D. Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by flowing paravertebral ossification over at least 4 contiguous levels and primarily involving the anterior longitudinal ligament. This case demonstrates involvement of 4 contiguous levels but primarily involves the posterior longitudinal ligament.

Imaging Findings
Best diagnostic clue: Flowing multilevel ossification posterior to vertebral bodies, with relatively minimal degenerative disc disease, absent facet ankylosis
Location: Midcervical (C3-C5) > mid-thoracic (T4-T7)
Characteristic ""upside down T"" or ""bowtie"" configuration on axial images

Pathology
Epidemiology: 2-4% prevalence in Japan; much less common elsewhere
Bulky posterior ligamentous ossification with normal cortical bone, marrow

Clinical Issues
Symptomatic myelopathy almost universal if canal diameter < 6 mm; rare if > 14 mm
↑ Risk for developing progressive myelopathy if > 60% canal stenosis, ↑ cervical range of motion

Diagnostic Checklist
Overly ""thick"" hypointense PLL on MRI strongly suggestive of OPLL
Requires high index of suspicion, careful observation to diagnose on plain radiographs

A. The scutum is blunted and the tympanic membrane is thickened and retracted implying a chronic process.
B. Blunted scutum, opacified Prussak space, thick retracted TM good clues in this case.
C. The majority of cholesteatomas are acquired, not congenital.
D. Better location would be on the cochlear promontory.

Findings: A large intra- and extra-dural mass is present at the level of C3/4. The mass extends into the right neural foramen, which is enlarged. The mass is extramedullary and there is compression of the spinal cord. The mass shows intense heterogenous contrast enhancement.

Findings: There is an epidural mass at the L4/5 disc space with compression of the right L5 nerve root in the subarticular recess.

A. The right L4 nerve root has already entered the neuroforamen and is not compressed by the disc herniation.
B. The disc herniation is on the right side and is not compressing left nerve roots.
C. The disc herniation is compressing the right L5 nerve root as it traverses the subarticular recess.
D. The right S1 nerve root leaves the thecal sac inferior to the disc herniation. It is not compressed by the disc herniation.

A. The posterior fossa mass has features suggestive of medulloblastoma. Ependymomas are usually more heterogenous often containing cysts and calcification. They are less common than posterior fossa medulloblatomas in children.
B. Midline cerebellar mass posterior to the fourth ventricle that is densely cellular given the appearance on the diffusion and the T2 weighted sequence is consistent with a medulloblastoma. Evaluation of the entire neural axis should be performed prior to institution of therapy.
C. These lesions are usually located laterally, are cystic and have an enhancing mural nodule. Usually older age group than kids with medulloblastoma.
D. More common in the atria of the lateral ventricle in a young child. Most common in children less than 1 year of age. These lesion densely enhance and present with hydrocephalus.

A. The posterior fossa mass has features suggestive of medulloblastoma. Ependymomas are usually more heterogenous often containing cysts and calcification. They are less common than posterior fossa medulloblatomas in children.
B. Midline cerebellar mass posterior to the fourth ventricle that is densely cellular given the appearance on the diffusion and the T2 weighted sequence is consistent with a medulloblastoma. Evaluation of the entire neural axis should be performed prior to institution of therapy.
C. These lesions are usually located laterally, are cystic and have an enhancing mural nodule. Usually older age group than kids with medulloblastoma.
D. More common in the atria of the lateral ventricle in a young child. Most common in children less than 1 year of age. These lesion densely enhance and present with hydrocephalus.

"C. The most likely diagnosis is hydranencephaly. There is an absent cerebrum with a CSF filled cranial vault. The falx cerebri and posterior fossa structures are intact. These are the findings of hydranencephaly. Alobar holoprosencephaly would have fused midline structures, absence of the falx, and a cerebral mantle around a monoventricle. Severe hydrocephalus would demonstrate a thin peripheral cortical mantle compressed against the inner table. Bilateral open-lip schizencephaly would have MCA distribution transmantle gray matter lined clefts, i.e. some cortical mantle would be evident.

A. Germinoma tends to be more homogeneous, high CT attenuation prior to contrast, and strong enhancement post contrast.
B. This pineal region mass is heterogeneous with cystic areas as well as calcification and fat attenuation. These features are typical of teratoma. Teratoma is the second most common pineal tumor in children of all ages with peak incidence in the second decade.
C. Pineoblastoma may be heterogeneous, have “exploded” calcifications, and hemorrhage – however they do not contain fat.
D. Pineal cysts are typically of CSF signal and attenuation in the absence of hemorrhage. They would not have a solid component with fat and calcification.

A. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria measures the degree of stenosis using the maximum internal carotid artery stenosis (C. compared to a parallel(non-curved)segment of the distal, cervical internal carotid artery (A. with the formula  [1- C/A] X 100%.

"B. An indirect CCF is due to arteriovenous fistulization of one or both cavernous sinuses by branches of the carotid arteries. CCF is often found in post-menopausal white females. Symptoms may include pulsatile tinnitus, decreasing visual acuity, ocular proptosis, and scleral and corneal injection. The most constant observation on cross sectional imaging is an enlarged superior ophthalmic vein (SOV), which often engorges due to the increased flow from the fistula into the SOV via the cavernous sinuses. This patient's CCF was cured by bilateral cavernous sinus coil embolization.

Direct

Indirect

"B. Choroid plexus papilloma is the most common tumor seen in the lateral ventricle in children. It is often associated with hydrocephalus. This is usually a benign tumor which can be cured with surgical resection.

A. Pars flaccida is the most common.
B. Pars flaccida displaces the middle ear ossicles medially and extends inferiorly.
C. Pars flaccida blunts the scutum.
D. The lateral semicircular canal is the canal most commonly affected with fistulization.

"A. A laryngocele is caused by an obstruction of the ventricular saccule resulting in an outpouching of the laryngeal ventricle. Ball valve phenomenon.

Internal laryngocele: Dilated, air- or fluid-filled laryngeal saccule
Located in paraglottic space of supraglottis
Synonym: Simple laryngocele

Mixed laryngocele:Extends from paraglottic space through thyrohyoid membrane to low submandibular space (SMS)
Synonym: Mixed laryngocele
Contains internal (intralaryngeal) & external (extralaryngeal) components

"D. Echo Planar Imaging (EPI) is the fastest of all sequences, with the k-space matrix filled in one or two excitation events (50 to 100 ms). Usually a ""phase encode blip"" in concert with gradient inversions along the readout axis allow the k-space matrix to be filled in a zig-zag pattern. This sequence is typically used in brain imaging.

B. Metastases replace normal hematopoietic and fatty marrow resulting in decreased vertebral body signal intensity on T1-weighted MR images.

Radiation causes fatty involution.
Typical hemangioma bright on T1 and T2.

Modic Changes
Type I: Hypointense on T1WI, hyperintense on T2WI (marrow edema).
Type II: Hyperintense on T1WI, isointense on T2WI (conversion to fatty marrow).
Type III: Hypointense on T1WI and T2WI (bone sclerosis).

A. Contrast should flow freely away from the needle tip gradually filling the thecal sac and outlining the cauda equina. If contrast pools at the needle tip or along the posterior or lateral thecal sac without free-flow, a subdural or mixed injection should be suspected.

C. A band-like, horizontally elongated focus of increased T2 and decreased T1-weighted signal intensity immediately beneath the fractured endplate is a specific feature of benign osteoporotic compression fractures, seen in ~80% of cases.

"D. Tarlov cysts, although often asymptomatic, are capable of producing clinical symptoms such as a progressive painful radiculopathy, paresthesias, and bladder and bowel dysfunction.

More common in lower lumbar spine and sacrum
Outer wall with epineurium lined by arachnoid
Inner wall lined with pia mater
Fibrocollagenous tissue also present

"C. In this tomographic MR image, the x-direction has the applied phase encode gradient (PEG) applied, which determines the location of the protons based upon subtle differences in phase. While chemical shift can manifest phase differences (at 1.5 T the chemical shift of the ""second kind"" is due to ""out of phase"" to ""in phase"" reversals every 2.25 seconds, equal to 1/220 Hz), spin-echo sequences (as opposed to gradient recalled echo sequences) have a relatively long TE; and therefore, there is no major chemical shift manifested, as shown in the figure.

"A. The ophthalmic artery is the first branch to arise from the internal carotid artery beyond the dural ring.

"D. This embryologic venous structure drains the choroid plexus and normally regresses by the 11th week (50-mm embryo). The most caudal part normally joins the internal cerebral veins to form the vein of Galen.

Clinical Issues
Age: Neonatal presentation most common
Prognosis related to volume of shunt and timing/success treatment
Brain damage or multisystem organ failure at presentation are contraindications to treatment
Initial transarterial embolization (TAE. at 4-5 months
Frequent neurological and MRI F/U after TAE
Up to 60% neurologically normal after treatment

C. This large named cortical vein typically drains the parietal region and empties into the  superior sagital sinus.

"B. The artery of Adamkiewicz is left-sided approximately 75% of the time.

Dominant thoracic anterior radicular = artery of Adamkiewicz
Left side origin (73%)
T9-12 origin (62%)
Lumbar origin (26%)
T6-8 (12%)

"C. Correct.

Early: Critical disturbance in CBF
Severely ischemic core has CBF < 6-8 mL/100 g/min (normal ~ 60 mL/100 g/min)
Causes oxygen depletion, energy failure, terminal depolarization, ion homeostasis failure
Represents bulk of final infarct → cytotoxic edema, cell death

Determines cerebral blood volume (CBV) and/or flow (CBF), mean transit time (MTT)
↓ CBV = infarcted core, ↑ MTT = ischemic penumbra

D. In communicating hydrocephalus, there is no obstruction to flow within the ventricular system. Rather, there is impaired absorption of CSF by the arachnoid granulations. Common causes of communicating hydrocephalus include hemorrhage, infection, and metastatic neoplasm.

"

Findings: There is a monoventricle with a thinned diminished cortical mantle, with fusion of the thalami, and lack of a septum pellucidum or interhemishperic separation.

A. With hydranencephaly, there is lack of a cortical mantle, preservation of the brainstem, thalami, and cerebellum, and preservation of the dura, including the falx.
B. The lack of midline septation and identifiable usual ventricular structures, and the lack of an obstructive mass rules out this possibility.
C. Correct. All of the features typical of alobar holoprosencephaly are present.
D. While there may be some dysgenesis of the corpus callosum and falx with this disorder, the ventricular structures, while dilated are all present.  No posterior fossa “cyst” with cerebellar vermain hypoplasia and fourth ventricular dilatation is seen.

A. Incorrect.
B. Correct. The pitch is 1.5 for the helical scan with 7.5 mm table motion per rotation and 5 mm collimated slice. This is a gap-like technique and would result in a dose of 1/pitch or 1/(1.5) or 0.67 of that of a procedure with a pitch of one, or of an axial series of contiguous slices.
C. Higher pitch implies reduced dose.
D. Reconstructed slice spacing does not affect dose.

"A. Unlike most of the neurocutaneous syndromes, Sturge Weber syndrome (SWS) occurs sporadically. There is an approximately equal male-female distribution.
B. Neuronal migration anomalies are not a feature of SWS. They may be seen in a variety of conditions including schizencephaly, holoprosencepahly, and in utero CMV infection.
C. Lisch nodules (iris hamartomas) are a feature of NF1. The ocular findings of SWS include choroidal angioma, glaucoma, and buphthalmos.
D. Correct. Dyke Davidoff Masson syndrome consists of unilateral calvarial thickening, elevation of the ipsilateral petrous ridge and sphenoid wing and ipsilateral enlargement of the frontal sinus. This is secondary to a cerebral insult that occurs in utero or early in life. The leptomeningeal angiomatosis of SWS is associated with underlying cerebral hemiatrophy and thus the association with Dyke Davidoff Masson syndrome.

A. Correct. Malignant otitis externa is a Pseudomonas aeruginosa infection of the external auditory canal seen most frequently in elderly poorly controlled diabetics. The infection is typically very aggressive and difficult to control. Extension to involve the skull  base, nasopharyngeal masticator space, middle ear cavity and adjacent structures is common. Lower cranial nerve palsies and venous sinus thrombosis may also be seen.
B. Nasopharyngeal carcinoma is unrelated to malignant otitis eterna. There are three types of nasopharyngeal carcinoma: squamous cell, nonkeratinizing, and undifferentiated. The nonkeratinizing and undifferentiated types are the most common and account for the majority of cases. Undifferentiated nasopharyngeal carcinoma is especially prevalent in young Southeast Asian adults and persons of Southeast Asian descent. Non Asian nasopharyngeal carcinoma patients tend to be older (40-60 years) and have a higher incidence of nonkeratinizing and squamous cell carcinomas.
C. Grisel syndrome is C1-2 rotary subluxation associated with recent head and neck surgery or upper respiratory tract infection. The mechanism is controversial.
D. Squamous cell carcinoma is unrelated to malignant otitis externa but can occur in the external auditory canal.  Squamous cell carcinoma of the external auditory canal is usually preceded by chronic ear infection. It occurs most commonly in females and has a mortality rate of approximately 50%.

A. The accepted measurement for Chiari I malformation in the average adult is tonsillar ectopia of greater than 5 mm below the foramen magnum.
B. This is a correct statement.
C. The incidence of syringomyelia in these patients is much higher, as much as 53%.
D. Meningomyelocele is a feature of Chiari II, not Chiari I.

"A. This is the classic pattern for multiple sclerosis. Flame shaped lesions (Dawson’s fingers) are seen in the periventricular white matter of the cerebral hemispheres. Spinal cord involvement and optic neuritis may also occur, but the cerebral white matter disease is dominant in most cases.
B. This is also a classic pattern for multiple sclerosis.
C. The brainstem is spared in Devic’s disease. This is the pattern seen in osmotic demyelination (central pontine myelinolysis) related to rapid correction of hyponatremia.
D. Correct. Devic’s disease involves optic neuritis and transverse myelitis. Lesions may occur simultaneously or separated in time. Demyelinating lesions are not found in the cerebral white matter. CSF does not demonstrate the monoclonal bands typical of MS.

Osmotic Demylenation

A. This is the second most common location at about 35%.
B. Correct. This is the most common location at 50%.
C. Third most common location at 15%.
D. The least common of those mentioned.

A. An eleveated choline to creatine ratio is a marker for tumor. It is an indicator of high membrane turnover.
B. Myonositol is not elevated in high grade tumors. Isolated reports exist of elevated myonositol with low grade tumors.
C. Lactate is a marker of necrosis which is an indicator of a higher grade lesion.
D. A markedly elevated NAA, is seen in canavan's disease.

"C. The pial enhancement on the surface of the brain, ipsilateral cerebral hemisphere atrophy, and ipsilateral enlargement of the choroid plexus are consistent with Sturge-Weber.

D. The midline location at the base on the tongue makes a thyroglossal duct cyst the best choice.

D. The images demonstrate a peripherally enhancing epidural lesion arising from the left L5-S1 disc space consistent with a recurrent disc extrusion.

"A. There is a contrast filled pseudomeningocele in the epidural space and neural foramen associated with avulsion of the ventral and dorsal nerve roots on the ipsilateral side. The normal ventral and dorsal nerve roots are seen arising from the spinal cord on the contralateral side.

A. Microadenomas form in the adenohypophysis.
B. By definition measure less than 10 mm.
C. In symptomatic patients, the most common hormone produced is prolactin (30-40%).
D. Microadenomas usually enhance less rapidly compared to the pituitary gland.

A. Correct.

A. Acute infarction usually becomes visible on diffusion weighted imaging within 12 hours. Abnormal DWI signal is often apparent within 30 minutes of clinical stroke onset.
B. Acute infarction has maximum signal intensity on DWI after approximately 2  days. The signal intesity is due to a combination of T2 prolongation and restricted diffusion.
C. The abnormal DWI signal associated with acute infarction will usually resolve after 2 weeks. However, abnormal signal may persist longer in some cases.
D. Changes of encephalomalacia will usually be apparent after several months. Abnormal DWI signal has usually resolved long before these changes appear.

A. Pilocytic astrocytoma is a low grade neoplasm which typically has a cystic component and enhancing mural nodule.
B. Contrast enhancement is typically absent in subependymomas. These tumors often extend from the medulla into the fourth ventricle.
C. This lesion seldom shows contrast enhancement. It appears as linear bands of increased signal in the cerebellum. It is associated with Cowden disease.
D. Colloid cysts may have increased pre-contrast T1 signal but usually do not enhance. These lesions are found in the third ventricle and may result in acute hydrocephalus.

A. Mastoid opacification may be related to acute or chronic inflammation. It is a non-specific finding.
B. The tympanic membrane may be thickened due to acute or chronic inflammation or prior surgery. This finding is non-specific.
C. Soft tissue density in the middle ear cavity has multiple causes, including cholesteatoma, otitis media, glomus tumor and vascular anomalies.
D. Osseous erosion is the most specific of these findings for cholesteatoma. A non-dependent soft tissue mass associated with osseous erosion represents cholesteatoma 90% of the time.

"A. Level I encompasses the sublingual and submandibular region.
B. Level II involves the anterior jugular chain above the level of the hyoid.
C. Level V is the posterior jugular chain.
D. Level VI is the peri-thyroidal region.

A. Arachnoiditis is considered a late cause of Failed Back Surgery Syndrome (FBSS).
B. Recurrent disk herniation is a late cause of FBSS.
C. Epidural Abscess is an early cause of FBSS.
D. Epidural fibrosis is a late cause of FBSS.

D. MR spectroscopy in the MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokes) would demonstrate elevated lactate and decreased NAA peaks. Elevated alanine and elevated creatine peaks are not characteristic of the MELAS syndrome.

A. While cystic cavitation can occur, this is very infrequent.
B. Contrast enhancement, even in active lesions, is infrequently seen.
C. A skip-type pattern involving no more than two vertebral bodies per focus of abnormality is usually seen in cases of MS.
D. They are peripheral, involving the white matter.

"A. Chiari I is associated with tonsillar herniation and a syrinx cavity.
B. Chiari II is associated with myelomeningocele and hydrocephalus and presents at birth.
C. Chiari III is associated with encephaloceles
D. Primary cerebellar agenesis is characteristic of Chiari IV

A. Deletions of chromosomes 1p and 19q are associated with oligodendroglioma and indicate a more favorable prognosis.
B. Von Hippel-Lindau disease results from a mutation of a gene on chromosome 3. This conditon is associated with hemangioblastoma.
C. The mutation for neurofibromatosis type I involves a gene on chromosome 17. This condition is associated with plexiform neurofibromas and optic gliomas.
D. Neurofibromatosis type II is associated with a gene mutation on chromosome 22. This condition results in multiple ependymomas, meningiomas, and Schwannomas of the cranial nerves.

"A. Vacuolar myelopathy is a late complication of HIV disease felt to be result of infiltration of the spine with HIV infected mononuclear cells that secrete neurotoxins.
B. B12 deficiency causes subacute combined degeneration which can appear identical to vacuolar myelopathy on imaging.
C. Thiamine deficiency causes Wernicke’s encephalopathy, not vacuolar myelopathy.
D. Vacuolar myelopathy is a late complication of HIV disease. With the advent of HAART therapy, the incidence has been significantly reduced.

A. The ipsilateral true vocal cord is resected in vertical hemilaryngectomy.
B. Invasion of the cricoid cartilage is a contraindication to all types of larynx conservation surgery. The cricoid cartilage is necessary for postoperative airway stability.
C. Tumors with limited involvement of the paraglottic space may be resected with supracricoid partial laryngectomy.
D. The thyroid cartilage may be resected with supracricoid partial laryngectomy.

"A. They are hypervascular lesions.
B. This lesion is most common in adolescent males.
C. This is the site of origin of this lesion.
D. The primary vascular supply is the ascending pharyngeal artery off of the external carotid.

A. Usually, extension beyond the nasal cavity is characteristic.
B. This describes the typical appearance of this neoplasm when it spreads into the intracranial compartment.
C. Approximately 15-20% of tumors will have metastatic disease to the neck or elsewhere upon initial discovery.
D. Since this is a neural crest-type tumor, the octreotide imaging should is positive.

A. A lingual thyroid is usually at the base of tongue in the midline.
B. A lingual thyroid avidly enhances, just like a normal thyroid gland.
C. Lingual thyroid is the only function thyroid tissue in 75% of cases.
D. Pertechnetate is the radionuclide of choice for nuclear medicine imaging.

Findings: There is a large enhancing mass in the left lateral ventricle. There is moderate hydrocephalus. Flow voids are seen within the lesion on the T2 image.

A. This is a tumor associated with tuberous sclerosis. It occurs near the foramen of Monro and may produce hydrocephalus. It is generally found in adolescence or early adulthood. Other intracranial findings of T.S. include subependymal nodules and cortical tubers.
B. This is the most common intraventricular tumor in infants. Imaging findings include enlarged choroid plexus in the trigone of the lateral ventricle and hydrocephalus. Enlarged feeding choroidal vessels may be seen as flow voids. Carcinoma of the choroid plexus can also occur and has similar imaging findings, although it is about 10 times less frequent. Choroid plexus papilloma is rare in adults, where it is usually found in the fourth ventricle.
C. Meningiomas may occur in the lateral ventricle, although this is very rare. Meningioma is extremely rare in infants and should not be considered as the most likely lesion. When meningiomas are found in children, they are usually associated with a genetic disorder such as neurofibromatosis type 2.
D. Ependymoma usually occurs in the fourth ventricle in young children. Supratentorial ependymomas are less common and are usually solid parenchymal masses. Subependymoma is a distinct histologic lesion. It is a benign mass found in the lateral ventricle in older adults.
E. Teratomas may present as congenital tumors. They are more common in older children in the pineal region. Only five cases of intraventricular teratoma have been reported in the literature (see reference), making this diagnosis highly unlikely. Teratomas have heterogenous appearance on imaging, often containing lipids or calcium.

Findings: There is a crescentic fluid collection overlying the left cerebral convexity. It is isodense to the brain. The fluid collection lies between the cerebral cortex and the skull. It is producing mass effect on the left hemisphere.

A. Subarachnoid hemorrhage is seen as increased attenuation within the sulci. It is frequently associated with hydrocephalus due to obstruction of CSF flow by clot. The most common causes are trauma and aneurysmal rupture. The fluid collection in this case displaces brain rather than lying within the sulci.
B. Epidural hematomas are the result of trauma. They present as a lens-shaped fluid collection with a convex inner border, rather than the concave inner border seen here. Acute epidural hematomas usually are high in attenuation. This finding requires emergent neurosurgical consultation, as rapid arterial bleeding can result in brain herniation and death. Bleeding from a lacerated middle meningeal artery is the most common cause. This hematoma is usually associated with a skull fracture overlying the hematoma. Epidural hematomas from venous hemorrhage are less common.
C. Cerebral infarction shows decreased attenuation of gray and white matter on unenhanced CT. Severe mass effect can develop within several days of a large hemispheric infarction and may cause brain herniation and death. The fluid collection in this case is extra-axial and does not represent infarction.
D. Meningiomas are extra-axial masses, which may be isodense to brain on non-contrast CT. However, they are commonly increased in density due to the presence of calcifications. They are usually focal rounded masses rather than the crescentic lesion seen here. En plaque meningiomas can have a crescentic morphology but are usually found adjacent to the sphenoid bone rather than in the frontal or parietal bones as in this case.
E. Correct. This subdural hematoma is isodense to brain. Acute subdural hemorrhage is usually increased in attenuation. Most subacute (7-28 days) subdural hematomas are isodense to brain, with chronic subdurals being low in attenuation. Careful attention to the location of cortex between the fluid collection and brain is required to make this diagnosis. Contrast administration may be helpful in difficult cases by demonstrating enhancing vessels between the brain and the subdural fluid collection.