Neuroradiology Boards Questions

The following are True/False questions:

1. 

1?T

2 F

3 ?F

2. 

1 F

2 F 30-70% calcify

3 F

4 T 0.2%

3. 

1 T

2 T

3 T

4 F

4. 

1 F batwing

2 F everted

3 T

4

5. 

1 F infra 65%

2 F

3 F thin

4

5 T but rare <1%

6. 

1 T with low attenuation on CT in periventricular white matter

2 F but cisterns are

3 F isotope persists in lateral ventricles up to 2d

4

7. 

Answer:

c. severe paroxysmal hypertension

Associations:

Loss of function: postural hypotension with faintness or syncope, anhydrosis, hypothermia, bladder atony, obstipation, dry mouth, dry eyes, blurring of vision from lack of pupillary and ciliary regulation, sexual impotence in males.

Hyperfunction: episodic hypertension, diarrhea, hyperhydrosis, and either tachycardia or bradycardia

Severe paroxysmal hypertension may be due to pheochromocytoma.

8. 

Answer:

1. true

2. false

3. true

4. false

Medulloblastoma, lymphoma, and pituitary adenoma, meningioma, mets; mucin producing and hemorrhagic, as hyperdense lesions. -- probably secondary to calcification, hemorrhage, or dense protein.

Medulloblastoma on NCCT are hyperdense, well circumscribed lesions. They have occasional calcification and cystic degeneration.

The classic teaching is that lymphoma is typically hyperdense on NCCT and enhances to a moderate degree. This can be a little more variable in the HIV population.

On CT , a microadenoma is hypodense compared to normal gland. Macroadenomas have the same signal characteristics but have a higher propensity for hemorrhage and infarction because of the marginal blood supply.

Acoustic neuromas can be seen on CT with contrast because it diffusely enhances. Intracanilicular acoustics are difficult to ID on CECT. Basically, CT is best for ID bone erosion.

9.

Answer:

5. True

6. True

7. False

8. False

9. False

The pterygopalatine fossa is a small pyramidal space situated below the orbital apex. It is extremely important, as it communicates with multiple fissures, canals, and foramina, including:

The pterygopalatine fossa contains the pterygopalatine ganglion and the distal portion of the internal maxillary artery.

It is obvious that once a malignant neoplasm reaches the pterygopalatine fossa, it may easily spread to a wide variety of anatomic locations.

10.

Answer:

10. false

11. false

12. false

13. true

80% of parotid tumors are benign, 80% of benign are pleomorphic adenomas, 80% are in the superficial lobe of the parotid, 80% of pleomorphics are in the parotid, 80% of pleomorphics if left untreated stay benign.

The portion of the parotid that extends deep to the plane of the facial nerve is the deep lobe. The superficial lobe extends from just under the skin. These lobes don't really exist but are arbitrary distinction for surgical purpose. If the tumor is in the superficial lobe, the facial nerve is dissected out deep to the mass and the tumor is resected superficial to the facial nerve. Are most commonly seen in middle aged women.

Warthin's tumor are nearly exclusive to the parotid and are the most common multiple and bilateral tumors in the gland. These lesions are entirely benign. Warthins are most commonly seen in elderly men.  They are the second most common benign tumor of the parotid-- 10%.  These lesions are usually round to oval encapsulated masses.

11.

Answer:

14. false

15. true

16. true

17. true

NF-1 is von Recklinghausen's disease. To dx must have two or more of the following findings--

>6 cafe au lait spots,

>2 lisch nodules of the iris,

> one plexiform neurofibroma,

axillary freckling,

> one bony dysplasia,

pseudarthrosis of long bone,

optic glioma,

1st degree relative with NF.

Acoustic neuroma is associated with NF-2.

The orbit frequently displays a characteristic unilateral defect of the greater and lesser wings of the sphenoid attributed to underlying mesodermal dysplasia. Other cranial abnormalities include bone defect along left side of the lambdoid suture, hypoplastic maxillary and ethmoid sinuses. The mandible and maxilla may be affected by overlying soft tissue abnormalities.

Macrocranium is seen in 75%.

12.

Answer:

18. true

19. true

20. false

21. false

22. true

Schizencephaly is a abnormality of neuronal migration in the 5-7th week. It is a cleft seen coursing from the ependyma to the pial surface. The disorder is secondary to failure of the germinal matrix to form.

Heterotopia is usually in the gray matter which is located in the wrong place due to arrest in neuronal migration. This usually occurs in the 7th to 16th week when migration of the neuroblasts from the perivent to the pia is thwarted. Ectopic gray matter is usually in the subependymal or subcortical location.

Holoprosencephaly is a congenital abnormality where separation of the right and left cerebral hemispheres is incomplete. Alobar type is the most severe and demonstrates almost no separation of the cerebral hemispheres and ventricles. There is one large horseshoe shaped vent with no interhemispheric fissure. The BG and thalamus are fused.

Etiologies of unilateral cranial enlargement-- Dyke-Davidoff-Masson syndrome, hemimegalencephaly (neuronal migrational anomaly), NF, Klippel-Trenaunay Syndrome, Proteus Syndrome. Can get polygyria associated with hemispheric size, or agyria associated with less severe hemispheric enlargement. MR demonstrates distorted thickened cortex with ipsilateral ventricular dilatation.

Chiari malformation is dx when cerebellar tonsils are below the foramen magnum. ? no etiology stated.

13.

Answers:

23. True

24. False?

25. False

26. True

27. False

28. false

29. false-

The important thing to know is that the posterior cerebral artery supplies the thalamus via thalamic perforators. However, there is also cross flow to contralateral as well as ipsilateral sides. Therefore, with PCA occlusion you can infarct no thalamus, ipsilateral thalamus, contralateral thalamus, or ipsilateral and contralateral thalamus. Most commonly, the ipsilateral thalamus is infarcted and only rarely the contralateral thalamus. The PCA does not supply the cerebellum. It supplies occipital as well as posterior temporal and parietal lobes as well as choroid plexus and ependyma of the third and lateral ventricles. The frontal lobe is the domain of the ACA.

Midbrain perforating arteries arise from the basilar and proximal PCA. Infarctions of these arteries can affect CN III, IV, causing oculomotor deficits; the cerebral peduncles- affecting motor strength, medial lemniscus- altering sensation; the red nucleus and substantia nigra- affects coordination and motor control; reticular activation substance- affect level of consciousness.

The PCA have small premamillary thalamoperforate, and thalamogeniculate branches supplying the hypothalamus, midbrain, inferior thalamus. Infarctions of these vessels may affect memory and emotion- anterior thalamus, endocrine- hypothalamus, language- pulvinar, pain sensation- thalami, sight- lateral geniculate, motor control- subthalamic nuclei.

The next branches of the PCA are the medial and lateral posterior choroidal arteries that supply the trigone of the lateral vents. They supply the tectum, choroid plexus of the 3rd vent, and the thalami. The lateral posterior choroidal arteries supply the choroid of the lateral and third vents and the posterior thalamus , the fornix.( fornix lies anterior and inferior to the corpus callosum)

The PCA continues branching off the anterior and posterior temporal arteries and posterior pericallosal artery before terminating into the parietooccipital branches and calcarine arteries. PCA infarct affects vision- calcarine, memory- post-inferior temporal lobe, smell- hippocampus, emotion-splenium.

One named branch off the ACA is the recurrent artery of Heubner which supplies the head of the caudate and anteroinferior internal capsule.

The peduncles are fed by the artery of Percheron which comes off the basilar.

14.

Answer:

30. false

31. false

32. true

33. false -- it would be Tolosa-hunt

34. prob true-- may be autoimmune, ? false -semantics.. cause is basically unknown

Orbital pseudotumor is a common cause of unilateral exophthalmos. Clinical features include restriction of ocular motility, chemosis, lid swelling, pain. They usually have rapid onset and respond to steroids. There is a chronic progressive form which responds poorly to steroids. and is treated with chemo and XRT. In the acute case, it is an inflammatory condition that may be an autoimmune condition involving the lacrimal gland, extraocular m, connective tissue surrounding the dura of the optic nerve, the orbital fat, epibulbar connective tissue, and sclera. May present as a lacrimal mass.

Tolosa-Hunt syndrome is an inflammatory condition similar to orbital pseudotumor that involves the cavernous sinus and orbital apex. This presents with painful opthalmoplegia.

15.

Answer:

35. false

36. true

37. false

38. false

39 true

Findings on MR may be seen within a few hours. Swelling is observed on T1 and proton density w/o changes of signal. 8hrs, high signal develops on T1 and PDWI. 16hr, low signal on T1. Arterial enhancement which is slow flow is detected in approximately 50% of ischemic lesions. Arterial enhancement is more sensitive than T2 in the first few hr of stroke. Reappearance of flow void occurs around 7-11days. this suggests establishment of collateral flow or lysis of embolus.

Noncortical infarctions have parenchymal enhancement between 4-7 days whereas cortical infarctions enhance after 6 days. Enhancement of the infarct may last 6-8weeks.

On CT, 6hr-faint loss of gray-white border, 12-24hr, indistinct low density, feeble mass effect, >24hr, more mass effect, 3-5days, peak mass effect. Parenchymal enhancement is rarely seen before 3 days. If see earlier enhancement, either because of excellent collaterals, or embolus has moved distally. Mass effect resolves at around 2-4 weeks.

16.

Answer:

40. True

41. True

42. True

43. True???

44. True

Diabetes classically gives a pupillary-sparing third-nerve palsy because it does not involve the parasympathetic fibers which control pupillary constriction.

An unruptured posterior communicating artery aneurysm classically gives an isolated and complete third-nerve palsy with a dilated pupil.

17.

Answer:

45. True

46. True

47. True??? false

48. True ???

49. True

50. false

51. False (shouldn’t enhance)

Pineal cysts typically ring enhance on MRI. Supratentorial PNETs are distinctly uncommon. We are therefore not including this. If you include pineoblastomas as a PNET, the answer is easy with PNET being true as well.

Pineal region masses include germinoma aka dysgerminoma or seminoma which have marked enhancement and are almost exclusively male, pinealblastoma and pineocytoma. Pineocytoma enhance vividly.

Other lesions in this area include pineal and tectal gliomas, cavernous hemangioma, meningioma, and benign cyst. Pineal cyst can be large. Pineocytoma can be hard to differentiate from a cyst because it can also have cystic components. Key is long-term f/u. Because pineal cyst are surrounded by limbs of internal cerebral veins, have to be careful not to misread vascular enhancement as solid mass enhancement.

Chemodectoma is a glomus tumor and can be found from the glomus jugular-tympanicum to the base of the bladder.

Colloid cysts can ring enhance but are usually located in the anterior aspect of the 3rd vent near the foramen of Monro.

18.

Answer:

52. False--all, NOT most

53. True

54. False -- true for macroadenomas

55. False

56. false

By definition all microadenomas are less than 1 cm

There are many microadenomas discovered as incidental findings at autopsy therefore most are not prolactin-secreting.

Pituitary adenomas are the most common intrasellar tumor, representing 10-15% of all intracranial neoplasms. Prolactinomas account for 40-50% of hormonally active adenomas; less commonly, adenomas may produce growth hormone (20%) or ACTH (20%). T1-weighted images are best for visualizing the pituitary because the bright signal of the surrounding CSF on T2-weighted images obscures the gland. Hemorrhage into macroadenomas is not uncommon.

Treatment with bromocriptine increases the likelihood of hemorrhage which has been reported in more than half of the bromocriptine treated adenomas. ? Hemorrhage into the gland not into the fossa.

19.

Answer:

57. True

58. True

59. False

60. False

Most pediatric cerebellar astrocytomas arise in the midline

A PNET is usually seen in the midline arising from the superior vellum of the 4th ventricle in kids. In young adults they are more eccentric.

20.

Answers.

61. False

62. False

63. True

64. False

65. False

Hemosiderin rings are low density on CT.

Hemosiderin rings are dark on T1 and T2.

21.

Answers:

66. true

67. True

68. True

69. True

70. True

A dermoid cyst is a midline mass but is rare in the suprasellar cistern. Its capsule is thick with peripheral calcification. The presence of fat or calcium in it can distinguish it from a large ventricle. However,  a dermoid cyst can mimic an enlarged vent. The midline vermis or the 4th vent are the most frequent infratentorial locations.

Cysticercosis is one of the most common parasitic diseases that affect the brain. A large cyst or cluster of cysts within the 4th ventricle may simulate dilatation of that ventricle. Cysticercosis is acquired by ingestion of a parasite which is in insufficiently cooked pork. The cysticerci are located in brain parenchyma, subarachnoid space, and the ventricles (rarely intraspinal). The parenchymal cysts have a propensity for cortical and deep gray matter; whereas subarachnoid cysts can produce hydrocephalus and mass lesions, particularly in the suprasellar cistern, cerebellopontine angle cistern, and the Sylvian cistern. There are four stages of the cyst. In stage I, the larvae are alive and the cyst has clear fluid. Edema is minimal and the cyst is surrounded by a thin capsule. On MR, the fluid of the cyst is isointense on all pulse sequences and the eccentric scolex (which appears as a mural nodule) can be identified. CT shows a circumscribed cyst with density similar to CSF (the scolex is more dense). Visualization of the scolex is pathognomonic of cysticercosis. When the larvae die, the cysts incite an inflammatory response.

The hypothalamic polycystic astrocytoma has incomplete necrosis which sometimes leads to a polycystic appearance. Supratentorial astrocytomas in children frequently involve the thalamus.

If a suprasellar arachnoid cyst invaginates into the 3rd ventricle, it can be mistaken for an enlarged 3rd ventricle on the basis of aqueductal stenosis.

Most cerebellar astrocytomas arise in the midline and can be cystic. Cystic astrocytomas with a mural nodule account for 50% of cerebellar astrocytomas in children.

22.

Answers:

71. True

72. True

73. false

74. False

75. True

An encephalocele arises from failure of dorsal induction, which normally occurs at 3-4 weeks gestational age. However, basal (sphenoidal) encephaloceles arise as a result of abnormal ventral induction (2 months gestational age). An encephalocele is extracranial extension of leptomeninges and brain tissue (meningocele is extracranial extension of leptomeninges alone). Encephaloceles are much more common than meningoceles and typically occur along the midline.

Nervous system anomalies which are frequently associated with encephaloceles: Dandy-Walker malformation and Chiari III malformation (occipital), dysgenesis of the corpus callosum (parietal), dysgenesis of the corpus callosum, callosal lipomas and globe anomalies such as micropthalmia/anopthalmia (frontoethmoidal), and agenesis of the corpus callosum and optic nerve dysplasias (basal).

A skull defect can give rise to a meningoencephalocele - 70% are occipital, 10% parietal, and 9% frontal (in the U.S.). Southeast Asian women have a propensity for nasofrontal or sphenoethmoidal meningoencephaloceles.

Meckel-Gruber syndrome consists of renal cysts which are macroscopic like MDK, microcephaly, polydactyly, and meningoencephaloceles.

Amniotic band syndrome also gives multiple irregular asymmetric off-midline encephaloceles (among abnormalities found in amniotic band syndrome is distal syndactyly).

I couldn’t find any association with pyelectasis.

23.

Answers:

76. False

77. False

78. True

79. False

80. True

Amyloid angiopathy = Deposition of amyloid in the media and adventitia of small and medium-sized vessels of the superficial layers of the cerebral cortex and leptomeninges with sparing of the deep gray nuclei. Amyloid accumulates Congo red dye and exhibits yellow-green birefringence when examined with polarized light. Hemorrhages are usually lobar, involving frontal and parietal lobes including subjacent white matter. Subarachnoid and subdural hemorrhages have also been reported. There is a propensity for recurrent hemorrhages or multiple simultaneous hemorrhages. The hemorrhages are rarely found in the cerebellum, white matter, basal ganglia, and brain stem. The major risk factor is aging, but doesn’t correlate with hypertension. It is not associated with systemic amyloidosis.

24.

Answer:

81. False??

82. False

83. True

84. False

85. False

L4 radiculopathy should present as hip pain radiating to the anterior thigh (not lateral), knee, and medial calf. Sensation is impaired over the medial calf and the territory of the saphenous nerve. One gets an absent knee jerk although overlapping innervation may make it difficult to detect. Muscle weakness is difficult to establish owing to the heavy overlap of root innervation. The quadriceps, abductor longus, gluteus medius, and tibialis anterior muscles may be weak.

25.

Answer:

86. False

87. False

88. False

89. false

90. False

Less than 70-80% of childhood gliomas are from the brain stem. Juvenile pilocytic astrocytomas are the most common infratentorial neoplasm in the juvenile age group. Pilocytic astrocytomas are not usually lobular.

Less than 80% of low grade gliomas will degenerate if you include things like pilocytic astrocytoma.

The peak incidence of gliomas is in the seventh decade.

26.

Answer:

91 True -fetal origin of PCOM

92. True

93. True

94. true

95. true

Carotid-basilar anastomoses are persistent embryological anastomoses.

Possible carotid ---> basilar anastomoses:

27.

Answers:

96. False

97. True

98. false

99. false

100. False

An osteoma is a bony mass which occasionally results in mucocele and/or pneumocephalus as the posterior wall of the frontal sinus is breached.

A medial wall blow-out fracture involves the lamina papyracea of the ethmoid bone

Traumatic CSF rhinorrhea most commonly is secondary to fractures through the frontoethmoidal complex and middle cranial fossa. The most common cause of CSF rhinorrhea is trauma.

Can arise from postoperatively when the cribriform plate is violated. Usually get post ethmoidectomy.

Pneumocephalus is found in 20% of pt with CSF leaks. Blood clot forms around the fracture initially, but when the clot resolves, CSF leak begins. Usually the CSF leak stops within the 1st week, 99% w/in 6wks. Post trauma CSF leaks most often involve the frontal, ethmoid sinus, and cribriform plate. Less frequently, the sphenoid sinus, petrous and other calvarial sites are involved.

Internal orbital wall blowout involves fracture of ethmoid or maxillary sinus Medial wall fracture are characterized by the passage of air thru the fracture defect into the orbit giving orbital emphysema. The air gains access w/ increased intranasal pressure such as nose blowing. Medial blow out fracture characteristically involves the medial floor and the medial orbital wall, and medial wall of the maxillary antrum. Clinical signs of blow out include enopthalomos, diplopia, limited upward and outward gaze.

28.

Answer:

101. false

102. false

103. prob true

104. false

105. false

Internal carotid artery injection is about 6ml/s for a total of 8cc. External carotid artery injection is 3ml/s for 5cc.

In general, 3.06g limit for (non) iodinated contrast is instilled intrathecally. Therefore, 10cc of 300mg/ml concentration or 12cc of 240mg/ml concentration is injected for lumbar or cervical myelography.--from package insert of Omnipaque. If doing a cervical myelography via a lumbar approach, the max dose should be given.

Iodinated contrast agents are potentially nephrotoxic with decreases in creatinine clearance. The effect on creatinine clearance seems to be less with nonionics. The potential for renal damage is greatest in pt with predisposing renal disease/illness.

According to a review article in Radiology 8/96, there is less nephrotoxicity w/ nonionic contrast in pt with baseline elevated creatinine.

29. 

Answers:

106. True

107. False

108. false - uncommonly calcifies

109. False

110. False

Dermoids are midline lesions containing fat, squamous epithelium, hair follicles, sweat glands, and sebaceous glands. The capsules are thick with peripheral calcification. They rarely arise in a suprasellar location. They are more frequent in the posterior fossa than supratentorially.

[Astrocytoma] A GBM is common in the posterior fossa of an adult. They are associated with a large amount of edema and mass effect. Central necrosis is a hallmark. Posterior fossa astrocytomas uncommonly calcify--<10%.

Medulloblastomas have a 10-21% incidence of calcifications in adults and in kids is 10-15% and listed as uncommon. 10-20% are cystic in children (adults, it is cystic 60-80%).

A hemangioblastoma is stereotypically a cystic mass with a solid mural nodule (55%) which is highly vascular and has serpentine signal voids of feeding vessels. 40% are solid.

Acoustic neuroma (Schwannoma is a more accurate term) occurs most commonly along the 8th cranial nerve. On MR they are usually isointense to slightly hypointense compared with pontine tissue (all pulse sequences). They enhance. Edema is present in one third. Hemorrhagic and cystic changes are unusual.

30.

Answers:

111. True

112. True

113. True

114. True

In shaken baby syndrome retinal hemorrhages are observed with subdural (particularly interhemispheric) hematomas and/or subarachnoid hemorrhage. Contusions and diffuse cerebral swelling are also noted. The abused child can have epidural, subdural, subarachnoid, and intraventricular hemorrhages as well as DAI.

Traumatic subdural hematomas in the child (from any traumatic cause) are bilateral in 80%.

31.

Answers:

115. True

116. True

117. False

118. True

119. False

Von Hippel-Lindau syndrome is autosomal dominant and consists of cerebellar hemangioblastomas and retinal angiomatosis (67%), pheochromocytoma, cysts of kidneys, pancreas, liver, and epididymis, and a high incidence of renal cell carcinoma.

Turcot’s is associated with CNS tumors, especially supratentorial glioblastomas.

Gardner’s consists primarily of colonic polyps, osteomas, and soft tissue tumors.

The intracranial manifestations of tuberous sclerosis include periventricular subependymal nodules, cortical and subcortical peripheral tubers, white matter lesions, and subependymal giant cell astrocytomas.

In sickle cell disease the incidence of cerebrovascular occlusive disease is 5-17%. Infarction is most likely related to stasis and ischemia in the vasa vasorum which leads to intimal and medial hyperplasia and subsequent narrowing and occlusion of internal carotid or proximal anterior and middle cerebral arteries.

32.

Answers:

120. True

121. true

122. False

123. False

124. False

Lipoma is associated with a tethered conus which is associated with mild dysraphism.

The mechanism for development of spinal dysraphism is lack of folding of primordial neural tissue into a tube. No bone is induced directly over the neural tissue. Get meningocele, myelocele, myelomeningocele are tissue that go through a boney spinal defect. when fat, meninges, cord roots protrude through the defect its called a lipomyelomeningocele. Lipomyelomeningocele is associated with tethered cord, Chiari II, and syringohydromyelia.

Dandy Walker is partial or complete absence of the vermis with dilatation of the fourth ventricle.

mylolipoma is a benign tumor of the adrenals.

Myelolipoma is lipoma(s) of the filum terminale. This is another form of spinal dysraphism and tethering of the spinal cord. These lesions have fat on CT or MR.

33.

Answers:

125. False

126. True

127. True?? is it really a typical feature?

128. False

129. False

Hemangioblastoma is the most common primary neoplasm of the adult posterior fossa and arise most frequently in the cerebellum. It is associated with von Hippel-Lindau disease. It does not typically present with hemorrhage although there may occasionally be hemorrhage in the nodular component. They are very vascular with very intense staining on angiography, and prominent flow voids on MR. It is solid in one third but commonly appears cystic +/- mural nodule. It almost never calcifies. A spinal hemangioblastoma can present with subarachnoid hemorrhage. Common symptoms include HA, ataxia, N/V, vertigo. 40% can have Polycythemia vera from erythropoietin production.

Perinaud’s syndrome is loss of upward gaze which is seen with pineal tumors.

34.

Answers:

130. True

131. False

132. True

133. False

134. False

The ophthalmic artery goes through the optic canal on the undersurface of the optic nerve.

Luscious French tarts sit naked in anticipation of sex.

Lacrimal, Facial, Trochlear IV, Superior III, Nasociliary, Inferior III, Abducens VI, opthalmic V1, Superior vein

35.

Answers:

135. True

136. True

137. True

138. True

139. True

140. True

The dermoid is unlikely but possible in the suprasellar area.

The germinoma is the most frequent tumor of the hypothalamic area. It is most commonly pineal but 20% are suprasellar. The peak age is early puberty but it can be seen in a 4 y/o. M=F with suprasellar germinomas while 90% of pineal germinomas are in males. The most common presentation of a suprasellar germinoma is the hypothalamic syndrome (diabetes insipidus, emaciation, precocious puberty). They are relatively radio-resistant but long time survival rates are high. There is a marked tendency for them to spread through CSF pathways -In the suprasellar region, the finding of an infiltrating suprasellar mass that is intrinsically hyperdense would favor germinoma over astrocytoma.

A hypothalamic hamartoma usually presents before the age of 3 y/o with precocious puberty. It is isointense to gray matter on all sequences with no enhancement. It is a rare tumor.

Craniopharyngioma is a common childhood tumor. It accounts for 50% of pediatric sellar and suprasellar tumors (90% suprasellar). In children, they tend to be cystic and enhance. 90% will be at least partially calcified. They extend into the anterior, middle, or posterior cranial fossa in 25% of cases.

Optic glioma is classified as a juvenile pilocytic astrocytoma and represents 2/3 of all primary optic nerve tumors. The mean age of presentation is 8.5 years ( 5yo in presence of NF1 and 12yo in absence of NF).

36.

Answers:

141. True

142. True

143. True

144. True

145. False

146. False

The differential diagnosis of pulsatile tinnitus:

Cholesteatomas may be primary (congenital) or secondary (acquired). Primary cholesteatomas arise from epithelial rests and, in the middle ear compartments, most often occur in the epitympanum. The petrous apex is another important location. Secondary cholesteatoma is an acquired, postinflammatory lesion which develops from ingrowth of squamous epithelium through the eardrum. The accumulation of squamous and keratin debris within the middle ear gradually causes erosion of the petrous bone and ossicles. Pars flaccida cholesteatomas are much more common than pars tensa lesions; the former typically herniate into Prussak’s space in the lateral attic.

Cholesterol granulomas are postinflammatory lesions of the petrous apex that generally occur in pneumatized petrous apices. They cause varying degrees of expansion of the petrous apex, and their signal characteristics (hyperintensity on T1- and T2-weighted MR images) help distinguish them from primary cholesteatomas.

37.

Answers:

147. True

148. False

149. True

150. True

151. False

An epidural hematoma is collection of blood along the subperiosteal inner table. It is associated with skull fracture in 90%. It is biconvex, and since it is subperiosteal, it is limited by the sutures (exception is when a fracture crosses a suture). Sources of blood are the meningeal vessels (arteries (60%) or veins), dural sinuses, diploic veins, and marrow sinusoids. The meningeal vessels are displaced from the inner table.

Collection of blood along the subperiosteal outer table is called a cephalohematoma. An epidural hematoma can decompress through a fracture to cause a cephalohematoma or subgaleal hematoma.

Subdural hemorrhages are due to tears of bridging veins. There is dissection of the subdural space with dural vessels remaining close to the inner table. SDH may be due to minor trauma or no trauma with such things such as bleeding diatheses. A SDH is usually crescentic and, since it is not subperiosteal, crosses regions of sutures.

38.

Answer:

152. False

153. False

154. True

155. False

156. True

Herpes encephalitis is more common in adults. In children it is secondary to HSV II which can cause a variety of findings: calcification, microcephaly, microphthalmia, retinal dysplasia, and encephalitis, as well as severe sequelae in survivors.

HSV I is the most common cause of herpes encephalitis in adults. It usually involves the temporal lobes asymmetrically, the insula, the orbitofrontal region, and the cingulate gyrus. One third is primary and 2/3 is reactivation. There is often hemorrhage (either gross or petechial). Zoster causes a granulomatous angiitis in immunocompromised patients.

39. 

Answer:

157. True

158. True

159. True

160. False

Meningiomas are hypo to iso on T1 to gray matter and iso to hyperintense on T2 to gray matter. Intraventricular meningiomas typically occur around the choroid in the trigone of the lateral ventricle esp the left lat vent.

40.  

Answer:

161. False (F: M = 4:1)

162. true

163. False

164. True

Anencephaly is associated with spinal dysraphism and polyhydramnios.

Spinal and non CNS abnormalities and polyhydramnios is common. Anencephaly is characterized by absence of the cranial vault, cerebral hemispheres, diencephalic structures and their replacement by amorphous vascular-neural mass.

41.

Answer:

165. True

166. True

167. True

168. True

42. 

Answer:

169. True

170. False (skin is a barrier)

171. True

43. 

Answer:

172. False

173. True

174. True

175. False

Sturge-Weber calcification occurs in the superficial parenchyma. In TORCH, toxoplasmosis and CMV do it.

44.

Answer:

176. false

177. True

178. False

179. True

The most typical appearance of a posterior fossa ependymoma on CT is that of an iso- to hyperdense 4th ventricular mass with punctate calcifications, small cysts, and moderate contrast enhancement. Nearly 50% will show multifocal, small calcifications; larger calcifications are occasionally seen,

Posterior fossa astrocytoma is eccentric in location. Hemangioblastoma is hemispheric. In younger pt with Hemangioblastoma consider VHL.

45. 

Answer:

180. false

181. false

Most common location for a meningioma is supratentorial. In descending order, the common locations include : parasagittal dura, convexities, sphenoid wing, CPA, olfactory groove, planum sphenoidale.

Spread along CSF pathways suggests subarachnoid seeding which doesn't include meningiomas.

46.  

Answer:

182. True

183. True

184. false

185. False

186. False

Von Hippel-Lindau disease is an autosomal dominant disorder characterized by retinal angiomas, cerebellar and spinal cord hemangioblastomas, angiomas of the liver and kidney, pheochromocytomas, and cysts of the pancreas, kidney, and liver. Renal cell carcinomas also arise more frequently in these patients.

Sturge-Weber disease is a congenital disorder characterized by angiomatosis involving the face, the choroid of the eye, and the leptomeninges. Calcifications occur in the cerebral cortex underlying the meningeal angiomatosis and are the most frequent CT finding. The calcifications are gyriform in shape, and are most frequently seen in the temporoparietooccipital regions.

Tuberous sclerosis is characterized by multiple subependymal hamartomas Giant cell astrocytoma refers to enlarging subependymal nodules that tend to be situated near the foramina of Monro; they are seen in 5-10% of patients with tuberous sclerosis.

Phakomatoses refer to a group of hereditary diseases of the neuroectoderm characterized by cutaneous manifestations. Included are NF, TS, VHL, Sturge Weber. Also included in the phakomatosis is meningiomatosis which is hamartomatous proliferation of meningeal cells via the intraparenchymal blood vessels in the cerebral cortex AND neurocutaneous melanosis which is characterized by cutaneous nevi and melanotic thickening.

Ataxia telangiectasia; immunodeficiencies, tumours, bronchiectasis.

47.

Answer:

187. True

48. 

Answer:

188. true

189. false

190. false

191. true

192. true

Mets which have a propensity for hemorrhage include melanoma, renal cell, choriocarcinoma, and thyroid ca. While bronchogenic ca doesn't have a propensity for hemorrhage, hemorrhagic lesions may be seen b/c lung ca is so common.

49. 

Answer:

193. false

194. true

195. false

196.false prob

197. true

Vasogenic edema results from breakdown of the blood brain barrier. Cytotoxic edema begins as intracellular swelling secondary to any type of insult to the cell membrane usually due to ischemia.

In stroke, treatment of edema is done with water restriction and agents that raise serum osmolality such as mannitol.

With edema secondary to tumor, treatment is based on lowering intracranial pressure. Treatment with daily doses of dexamethasone or methylprednisone reduces cerebral edema and improves surgical prognosis. This may not control symptoms of obstructed ventricular system, so a ventriculostomy may need to be placed.

HSV encephalitis is Rx with IV antiviral therapy- acyclovir which has been noted to shorten the course of infection.

CNS lymphoma is treated with high dose methotrexate, glucocorticoids alone or in combo with cyclophosphamide, doxorubicin, vincristine followed by XRT.

No effective treatment for MS is known. Therapy is directed towards reducing the acute episode, prevent relapses or progression, and relief of Sx. In acute flare, glucocorticoid treatment may lessen the severity, but recovery is not improved or the extent of disability is not altered. Can give ACTH. Immunosuppressive agents like azathioprine, and cyclophosphamide have claimed to reduce the # of relapses but there is no consensus. Also tried is total lymphoid radiation, alpha and beta interferon, diet alteration.

50.  

Answer:

198. true

199. true

200. true

Pineal region masses include pineoblastoma which is a PNET, germinoma, teratoma. Also included are pineocytoma, choriocarcinoma, embryonal cell, glioma.

51. 

Answer:

201. false

202. false

203. false

The frontal horns and the body of the two lateral vents are separated by the septum pellucidum. The two layers containing CSF are consistently seen in infants. In the majority, they fuse but if they don't it is a cavum septum. It's posterior extension is the cavum verge. The septum pellucidum has neural connections with the cerebral hemispheres.

52.  

Answer:

204. True

205. True

206. False

207. False

208. False

Angiomas of the retina are found in Von Hippel-Lindau.

Rhabdomyoma of the heart is found in tuberous sclerosis. By intrarenal tumors they probably mean angiomyolipoma, which is also found in TS.

Wyburn-Mason syndrome may be forme fruste of S-W-D have facial vascular nevus in nerve V, retinal angioma, and midbrain AVM.

53.  

Answer:

209. False

210. False

211. True

212. True

213. True

Cornelia De Lange with radial ray anomalies.

Progeria is dwarf with premature aging, scleroderma and endocrine abnormalities.

54.

Answer:

214. True

215. True

216. False

217. true

The facial nerve is superior and anterior in the IAC. So the facial nerve is superior to crista falciformis and ant to Bills bar.

                                    sup

                    VII            l         VIII sup-vestibular

                VIII cochlear l             VIII inf vestibular

                                  inferior

55. 

Answer:

218. True

219. False

220. False

221. True

homonymous hemianopsia-- same side visual defect.

Neuroradiology Section

Select the single best answer:

56.

Answer:??

57.

Answer: a

58. 

Answer: a

59. 

Answer: a

60. 

Answer: b

61. 

Answer:???

62. 

Answer: c. location of the hematoma

The best indication of the aneurysm that bled is finding a hematoma associated with it. Other findings include:

ACA aneurysm- blood in the interhemispheric fissure, lat vent

MCA-- hematoma in the Sylvian fissure

PCA or ICA- blood in the 4th vent.

MR is useful to find hemorrhage in the wall of the aneurysm that bled. Angio findings associated with rupture include: proximity to spasm, irregularity of aneurysm, tendency for larger aneurysm to bleed, mass effect around aneurysm, tapering of the apex of aneurysm.

63. 

Answer: b. left internal carotid artery dissection

For an internal carotid dissection to do this, there must also be emboli since the lesions are separated in space (3rd cranial nerve nucleus, left parietotemporal region). Sx for extracranial dissection can present with neck and face pain, HA, Horner's syndrome, cranial nerve involvement, ischemic symptoms. With cervical internal carotid dissections, get Raeder's syndrome- ptosis, miosis, HA, and preserved ipsilateral face sweating because of preserved sympathetic fibers. Dissection can occur after blunt trauma, abrupt head turning, sports injury, direct puncture.

Right PICA syndrome includes right-sided ataxia, loss of pain and temperature sensation on the right side of the face, loss of pain and temperature sensation in the left upper and lower extremities, difficulty swallowing, loss of taste on the right, vertigo, and nystagmus.

HSV-1 causes encephalitis. Sx include alteration of pt state of consciousness with lethargy, drowsiness or stupor. Pt can have confusion, disorientation, hallucinations. Pt can have N/V, HA. Can get aphasia, involuntary movements, ataxia, sensory defects, loss of retentive memory.

64. 

Answer: a. Wallenberg syndrome secondary to left vertebral dissection

Wallenberg Syndrome is lateral medullary syndrome. When infarction is in the vertebral artery distribution, the lateral medulla is most often affected +/_ the posterior inferior cerebellum. Lateral medullary infarction can result from occlusion of vertebral artery, PICA, sup, middle, inf  lateral medullary arteries. In 70-80% of cases, get after ipsilateral vertebral artery occlusion. Get pain, numbness, impaired sensation over ipsilateral face, arm, trunk, leg AND contralateral impaired pain, thermal sense over half of body. Get ataxia of limbs, falling to side of lesion, nystagmus, Horner's, dysphagia, hoarseness, paralysis of palate, vocal cords, and diminished gag.

Deviation of the tongue to the right is from 12th nerve palsy on the right which can result from medial medullary syndrome -- occlusion of the vertebral or branch of the vertebral or lower basilar artery.

Weber's syndrome is a result of PCA infarct Weber's is a third nerve palsy with contralateral hemiplegia. Involves infarction of the third nerve and cerebellar peduncle.

65. 

Answer: e. ipsilateral PICA

The Wallenberg stroke syndrome is loss of temperature and pain sensation on the contralateral side of the body and loss of sensation of the face on the ipsilateral side. There is also ataxia, loss of swallowing and taste sensation on the ipsilateral side, hoarseness, vertigo, nystagmus, and ipsilateral Horner’s syndrome.

66. 

Answer: d

Toxoplasmosis is by far the most common infection of the brain parenchyma in AIDS pts. Crypto is at least as common but affects the meninges. In CMV see ependymitis. CMV is a common infection in the general population.

The most common infection seen in AIDS is HIV encephalitis.

67. 

Answer: prob b , ??c

Craniopharyngioma can be seen in children and adults. They arise from metaplasia of the squamous epithelial remnants. Calcification, nodular enhancement. Account for 6-7% of all intracranial pediatric tumors. Angiographically, these tumors are avascular.

Chiasmatic and hypothalamic gliomas can present in the suprasellar cistern. Enhancement is variable. Seen in pt w/ and w/o NF-1. Less common than astrocytomas of cerebral hemisphere, brainstem, or optic pathway.

Germinoma have a propensity for children and young adults. They arise from primitive germ cells. They uniformly enhance.

Metastatic neuroblastoma frequently mets to skeleton, marrow, liver, nodes, skin. Can metastasize to the orbit. 50% of pt with neuroblastoma are less than 2 yo. At least 15% of cancer deaths in kids are due to neuroblastoma. In requisites, cerebral neuroblastomas are now called cortical PNETs. Usually they are in the frontal parietal, and occipital lobes.

CNS tumors account for more deaths during childhood than any other malignancy except leukemia. Primary intracranial neoplasm accounts for 15% of neoplastic disease during childhood.

Supratentorial primary tumors include cerebral astrocytoma (37%), optic glioma (13%), craniopharyngioma (12%), ependymoma (5%) and miscellaneous.

68.

Answer: c. responds rapidly to steroid and radiation therapy

Grave disease may result in thyroid ophthalmopathy, which is the most common cause of bilateral exophthalmos in an adult. Pathologically, there is deposition of mucopolysaccharides and infiltration by lymphocytes in the muscle bodies and retroorbital fat. Imaging reveals bilateral enlargement of the muscle bodies, with sparing of their tendinous muscle insertions on the globe. This is in contrast to orbital pseudotumor (myositis), wherein the tendinous insertions are involved

Orbital pseudotumor is a common cause of unilateral exophthalmos. Clinical features include restriction of ocular motility, chemosis, lid swelling, pain. They usually have rapid onset and respond to steroids. There is a chronic progressive form which responds poorly to steroids. and is treated with chemo and XRT. In the acute case, it is a inflammatory condition that may be an autoimmune condition involving the lacrimal gland, extraocular m, connective tissue surrounding the dura of the optic nerve, the orbital fat, epibulbar connective tissue, and sclera. May present as a lacrimal mass.

Tolosa-Hunt syndrome is a inflammatory condition similar to orbital pseudotumor that involves the cavernous sinus and orbital apex. This presents with painful opthalmoplegia.

69.  

Answer: a. atria of lateral ventricle

Intraventricular meningiomas occur around choroid plexus in the trigone of the lateral ventricle (left > right). 15% are in the 3rd ventricle and 5% are in the 4th ventricle. While associated with neurofibromatosis (type II), most patients with intraventricular meningiomas don’t have neurofibromatosis.

70.

Answer: a. normal variant

Optic nerve meningiomas typically show tram-track calcification.

71. 

Answer: b. subacute infarction

Only infarcts have sharp borders (representing the margin of vascular territory). All the other lesions produce mass effect, edema, or are infiltrative.

72. 

Answer: b. metastasis

A metastasis is the most common posterior fossa tumor in an adult. However, infarct is the most common posterior fossa mass in an adult. Lung and breast are the most common metastatic sources (followed by melanoma, RCC, and thyroid). Hemangioblastoma is the most common primary tumor of the posterior fossa in an adult.

73.

Answer: d. longitudinal fracture of the petrous bone

Longitudinal fractures 75% (parallel to the long axis) of the petrous bone are associated with conductive hearing loss secondary dislocated ossicles and to fluid in the middle ear. Cranial nerve 7 is involved in 10-20% of injuries (this is less common than in transverse fractures.). No neurosensory hearing loss.

Transverse fractures 25% (perpendicular to the long axis) are less common - complications include sensorineural deficits (CN 8) and cranial nerve 7 injury (40-50%).

74. 

Answer: b. carotid artery dissection

Internal carotid occlusion is out. Carotid dissection is clearly the best. Jill Hunter thought if this was not single best answer format that vertebral artery dissection might also cause these symptoms.

Dissection of the cervicocerebral arteries cause stroke in kids and young adults. Trauma is the most frequent cause. Horner's syndrome occurs in over half the cases.

Dissection can involve the carotid or vertebral. Sx include neck and face pain, HA, Horner's, CN involvement, ischemic symptoms that can occur days to weeks from dissection. Ptosis, miosis, HA with preservation of ipsilateral facial sweating (Raeder's syndrome) can occur with cervical ICA dissection. Sympathetic fibers for sweat go with ECA and those controlling the dilator pupillae and superior palpebral muscles follow the ICA .

75. 

Answer: f. spinal cord shock

The answer has to be spinal cord shock secondary to the fact that all of the other choices represent permanent damage.

76.

Answer: b. glioma

Gliomas constitute 30% of supratentorial neoplasm in children. Supratentorial ependymomas constitute 20-40% of childhood ependymomas. PNETs constitute 5% of childhood supratentorial neoplasms.

77.

Answer: c. multiinfarct dementia

Changes described above likely represent changes of small vessel ischemic disease and therefore multi infact dementia.

78. 

Answer: c. cochlea

Otosclerosis (aka otospongiosis) represents the deposition of spongy vascular new bone within the otic capsule. It is another cause of sensorineural hearing loss that is usually bilateral and seen most frequently in young to middle aged women. In the early stages one identifies a lytic lucent erosion of the labyrinthine margins of the oval window, the round window niche, and the cochlea. The cochlea is therefore the best choice. The middle and basal turns are most frequently involved showing areas of demineralization.

The acoustic pathway is divided into sensory (cochlear) and neural (retrocochlear) components. Congenital or inflammatory lesions of the cochlea (cochlear otosclerosis) cause a sensory hearing loss. Retrocochlear hearing loss has multiple etiologies; acoustic schwannoma is the classic tumor responsible for neural hearing loss.

79. 

Answer: a. longitudinal fracture of temporal bone or b. transverse

In the patient with post traumatic conductive hearing loss and facial nerve palsy typically associated with a transverse fracture of the temporal bone - transverse fractures are only one fifth as common as longitudinal fractures and are perpendicular to the petrous ridge. Sensorineural hearing loss due to both parts of CN VIII being affected is a complication. Facial nerve can be involved in both but more typically in transverse fractures (40-50%).

Longitudinal fractures usually spare the inner ear with disruption of the ossicular chain. Longitudinal fractures are parallel to the petrous ridge. The facial nerve is affected in 10-20%, but the eighth cranial nerve typically remains intact, resulting in a conductive hearing loss.

These represent the classical teaching and like all other things is far from the reality with oblique fractures being the most common.

transverse fracture ( sag), longitudinal fracture ( coronal)

80.

Answer: b

In the cavernous sinus lie the CNIII- which is in the superolateral portion, CNIV- which lies just below III, V-1, V-2, VI- which lies just lateral to the carotid.

The optic nerve is not in the cavernous sinus.

The most medial - the  abducens-VI.

81.

Answer: a. astrocytoma

Astrocytoma comprises 60% of intramedullary tumors in a child.

Hemangioblastomas account for only 3% of intramedullary spinal cord tumors, and 30% of these are seen with von Hippel-Lindau syndrome. Purely intramedullary lesions are associated with cyst/syrinx formation in two-thirds of cases - the presence of a holocord cyst, with only small areas of enhancement, should raise the possibility of hemangioblastoma.

Ependymoma comprises 30% of intramedullary tumors in a child. They are the most common primary tumors to arise in the lower spinal cord, conus medullaris, and filum terminale. One subtype of ependymoma, the myxopapillary form, is particularly common in the conus and filum; it is a mucin-producing tumor, which is prone to bleeding - sometimes presenting as unexplained subarachnoid hemorrhage.

Hemangioma is the most common benign lesion of the vertebral body in a child. Cobb’s syndrome (rare) is cutaneous malformations, vertebral hemangiomas, and hemangiomas of the spinal cord.

82.

Answer : probably b. medulloblastoma

Hemangioblastoma is the most common infratentorial tumor in an adult.

Medulloblastomas (one of the PNET tumors) are one of the most common posterior fossa masses in the pediatric population, accounting for more than one third of posterior fossa neoplasms and 50% of cerebellar tumors in children  These tumors are usually seen in the midline arising from the superior velum of the fourth ventricle. Patients usually have hydrocephalus. On nonenhanced CT the lesions are hyperdense well-circumscribed masses. Subarachnoid seeding may be present.

Barkovich claims that there are slightly more cerebellar astrocytomas in most series.

"Depending on the series, medulloblastoma or cerebellar astrocytoma is the most common primary neoplasm of the pediatric posterior fossa."

Pilocytic astrocytomas are the most common infratentorial neoplasm in children - 20% are in the brainstem and 40% are cerebellar.

Ependymoma is usually associated with the 4th ventricle. They have a greater incidence of calcification (40-50%) than other posterior fossa pediatric neoplasms.

83. 

Answer: a. cavernous sinus

Lesions in the optic canal can affect the optic nerve and the ophthalmic artery.

Lesions in the brainstem can affect: cranial nerves I-IV if they arise from the midbrain or above, V-VIII if they arise from the pons, and IX-XII if they arise from the medulla.

84. 

Answer: b. myolipoma

Spinal dysraphism basically means a group of spinal anomalies with the common feature of imperfect union of midline structures. Tethered cord is a spinal cord that is held in an abnormally low position by a fibrous band, bone spur, or mass.

Diastematomyelia is a longitudinal split in the spinal cord, conus medullaris, or filum terminale associated with bony abnormalities including spina bifida. It also is associated with tethering of the conus medullaris (below L2 in 76%).

Hydrosyringomyelia is a cavity in the spinal cord. Most are associated with congenital spinal and hindbrain abnormalities.

Thickening of the filum terminale (= tethered spinal cord syndrome) is associated with midline bony defects.

Myelolipoma is lipoma(s) of the filum terminale. This is another form of spinal dysraphism and tethering of the spinal cord. These lesions have fat on CT or MR.

Spinal lipomas are masses of fat and connective tissue that are at least partially encapsulated and have definite connection to the spinal cord and meninges. They are considered in three major groups: intradural lipomas, lipomyelomeningoceles, and lipomas of the filum terminale. In patients with lipomyelocele there is no substantial meningocele component and the lipoma usually extends into the canal through an occult spina bifida. The lipoma is attached to the dorsal surface of the neural tissue and is covered by intact skin. The spinal cord may assume different shapes and associated tethering may be present.

Fibrolipomas frequently occur in the filum terminale, and may be considered a normal variant if not associated with tethering of the spinal cord or neurologic dysfunction. These developmental lesions arise secondary to the persistence of caudally located pleuripotential cells that differentiate into fat. Fibrolipomas of the filum may be intradural or extradural, or both; extradural lesions tend to be diffuse.

85. 

Answer: b. pseudoaneurysm of the internal carotid artery

aneurysm = focal dilatation of an artery

pseudoaneurysm = organized hematoma from a vessel that has bled.

86. 

Answer: b. L5

The spinal cord contains 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal paired spinal nerves. C1 exits above the C1-2 interspace, so C2 exits between C1 and C2, etc. The vertebral bodies in the lumbar spine are tall and the nerve roots leave the thecal sac right under the pedicle above the interspace. Therefore, herniations in the lumbar region strike the root exiting below the interspace. However, a far lateral disc herniation could impinge on the root exiting above the interspace (L4 in this case - also the answer to the question on the 1994, 1996 boards which asked about a far lateral herniation) and a very large herniation could impinge on both the root above and the root below.

87. 

Answer: c. 18F-deoxyglucose PET scan

Radiation necrosis is usually a late effect of treatment. The late injury may be focal or diffuse. XRT necrosis favors the tumor site. CT or MR may demonstrate a mass lesion associated with edema (low attenuation on CT or high signal on T2) which usually enhances.

Diagnosis of XRT necrosis is made by surgical biopsy but may be suggested by PET. Residual or recurrent tumor has increased activity on PET (XRT necrosis has low activity). The overall accuracy of PET is 85%.

88. 

Answer: d. fungal encephalitis

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease with viral etiology (papovavirus). It is associated with immunosuppression. It can occur anywhere in the brain (usually in the subcortical white matter, but can involve the cortex - in contrast to HIV encephalitis which is characteristically periventricular). It can be solitary or multifocal. It is low intensity on T1 and high intensity on T2. Usually there is no enhancement.

Lymphoma is not uncommonly seen in immunosuppressed patients (AIDS, post-transplant, etc.). There is a marked predilection for the basal ganglia, cerebellar hemispheres, thalamus, brain stem, corpus callosum, and subependymal region. Primary CNS lymphoma occurring in AIDS patients is a highly aggressive malignancy which is frequently necrotic and surrounded by vasogenic edema. The central necrotic portion is hypodense on CT and the periphery enhances with contrast. In contrast, lymphoma occurring in patients who do not have AIDS is more typically a solid, hypercellular tumor and is therefore often hyperdense on noncontrast CT scans. Following gadolinium or iodinated contrast, enhancement is typically uniform. Primary CNS lymphoma virtually never calcifies.

Mucormycosis [fungal encephalitis]  affects patients with abnormalities of host defenses, particularly patients with diabetes and ketoacidosis. The fungus is usually inhaled and rapidly destroys nasal mucosa. It may then spread into paranasal sinuses (with or without bone destruction), orbit, skull base, or may extend through the cribriform plate and involve the anterior cranial fossa. There is a high frequency (50% in some series) of intracranial extension. With intracranial extension, there are low density abnormalities in the anterior cranial fossa (these may in fact be present in any part of the brain). One can also see mass effect and enhancement.

Herpes virus Type I is responsible for encephalitis in adults. One-third of cases are due to primary infection (usually <18 y/o) and 2/3 are due to reactivation. Herpes attacks the temporal lobes, insula, orbitofrontal region, and cingulate gyrus. MR examination done during the first five days of infection shows high signal on PD and T2 in the temporal and inferior frontal lobes with increasing mass effect. Linear, subarachnoid, and gyriform enhancement may be seen.

89. 

Answer: a. mycotic aneurysm

A mycotic aneurysm is often secondary to endocarditis with septic emboli to the vasa vasorum and secondary destruction of the vessel wall - all that is left is the intima. The aneurysms may be saccular or fusiform. The aneurysms tend to be peripheral in the MCA distribution.

Polyarteritis nodosa is a multisystem disease with necrotizing inflammation of muscular arteries. There is CNS involvement in 45% (usually late). There are no specific findings.

Berry aneurysms, or saccular aneurysms, are congenital weaknesses in the media and elastica of the arterial wall. They occur at branching points where the parent vessel is curving.

Takayasu’s arteritis tends to involve large vessels coming off the arch. Aneurysms are not a typical feature. Generalized vasculitis may lead to infarcts.

90. 

Answer: a. it most commonly involves the atrium of the lateral ventricle

Intraventricular meningiomas typically occur around the choroid plexus in the trigone of the lateral ventricle and have a distinct propensity for the left lateral ventricle. They calcify in 45-68% of cases. Blood supply to an intraventricular meningioma is usually via choroidal vessels.

91. 

Answer: b. choroid plexus papilloma

The most common posterior fossa lesions in kids are pilocytic astrocytoma and PNET (medulloblastoma) which each account for 1/4-1/3. Brainstem glioma and ependymomas are the next most common (each about 1/6). While choroid plexus papillomas occur most frequently in kids (35% of cases occur in kids less than 5 y/o) and are in the 4th ventricle, they account for only 3% of childhood tumors.

Medulloblastoma (30-40% of posterior fossa neoplasms in children and cerebellar astrocytoma are the most common. Ependymoma represents 15% of posterior fossa neoplasms.   Choroid plexus papilloma almost always arises in the lateral ventricles in children (In adults, the 4th ventricle is the most common location.). These are uncommon tumors with a median age of 26 months. Symptoms are generally due to hydrocephalus. The answer most likely is choroid plexus papilloma.

92. 

Answer: b. septic emboli

Mycotic aneurysms are peripheral to the 1st bifurcation of a major vessel in 64% and are often located near the surface of the brain, especially over the convexities. (e.g., often just distal to MCA trifurcation in the inferolateral Sylvian fissure.)

Polyarteritis nodosa may involve all organs, but mainly the kidney (85%), heart (65%), and liver (50%).

Intravenous amphetamine can yield a CNS vasculitis and subsequent microaneurysms, but this is rare.

93. 

Answer: a. cervical spine

Symptoms of autonomic dysreflexia occur with spinal cord lesions above T5 (level of greater splancnic nerve) secondary to alpha-adrenergic response below the spinal cord lesion uncontrolled by central centers. Therefore, there is a rapid rise in blood pressure, pallor below the level of the lesion, flushing and diaphoresis above the level of the lesion, headache, coma, and potentially death. Activation of the carotid sinus baroreceptors can cause bradycardia.

94. 

Answer: b. epidural hematoma

A lucid interval is seen in 40% of patients with epidural hematoma.

General guidelines following head trauma:

DAI injury is due to shearing and is most commonly seen in the gray-white junction, the corpus callosum, and basal ganglia.

95. 

Answer: a. holoprosencephaly

Holoprosencephaly represents a failure of normal development of the forebrain. Complex facial and craniocerebral abnormalities are associated. There are three classifications: alobar, semilobar, and lobar.

In the alobar form, the cerebral hemispheres are absent. A crescent-shaped monoventricle is present with a thin rim of cortical tissue. The thalami are fused. The septum pellucidum and interhemispheric fissure are absent.

In all three types, the septum pellucidum and olfactory bulb are absent. In the alobar and semilobar forms, midline facial anomalies are common.

Meningoencephalocele is a disorder of midline closure commonly seen in the occipital region. It represents herniation of the meninges-containing CSF through a congenital defect in the skull vault. In an encephalocele, contents include brain tissue. The most common site is the occipital region.

96. 

Answer: a. cavernous sinus

The lesion has to be before/anterior to the optic chiasm. CNIII supplies extraocular muscles except lateral rectus VI and superior oblique IV. The nucleus is in the midbrain just posterior to the red nucleus and anterior and superior to the aqueduct. It goes thru the interpeduncular cistern to between the PCA and superior cerebellar arteries lateral to the PCOM. Thru the cavernous sinus thru the superior orbital fissure. The optic nerve goes back to the lateral geniculate in the pulvinar of the thalamus and back thru the geniculocalcarine tract.

This must involve the prechiasmatic optic nerve and the 3rd nerve. This could be at the orbital apex or in the cavernous sinus.

97.  

Answer: b. retrograde flow via the ophthalmic artery

The intracranial extracavernous internal carotid artery gives rise to several important branches:

The ophthalmic artery is an important source of collateral flow in cases of cervical ICA occlusion.

98. 

Answer: b

Multiple sclerosis is a demyelinating disease of unknown etiology which most frequently affects young adults. The classic lesions seen on MR are plaques, which occur commonly in the periventricular white matter, internal capsule, corpus callosum, pons, and brachium pontis. They are best seen on long TR sequences.

99. 

Answer: a. recurrent subarachnoid hemorrhage

Intracranial aneurysms are the most common atraumatic cause of subarachnoid hemorrhage. Only about 10% occur in the posterior fossa, the majority of these arising in the basilar tip. At least 20% are multiple. By definition, aneurysms larger than 2.5 cm are termed giant. Although the vast majority of berry aneurysms occur in isolation, certain diseases predispose to their formation. These include autosomal dominant polycystic kidney disease (6% incidence of aneurysm), AVM, fibromuscular dysplasia, coarctation of the aorta, and collagen vascular disease.

100. 

Answer: a. aging hematoma

101. 

Answer: Drusen, c

Retinoblastoma typically presents as leukokoria or strabismus. It is the most common tumor of the globe in children. Bilateral involvement (30% of cases) is associated with the heritable form of retinoblastoma, is usually multifocal, and tends to be diagnosed in younger children (average = 8 months, 98% in kids less than 3 y/o) than unilateral involvement (average = 25 months). The presence of bilateral retinoblastoma should prompt the search for a pineal cell neoplasm (trilateral retinoblastoma). Unilateral disease is often unifocal and sporadic. Metastases are extremely infrequent. Enucleation is curative (ocular preservation is attempted if less than half of the retinal surface is affected and no adjacent structures are affected.)

Melanoma are usually hyperintense on T1 and hypointense on T2. It is associated with retinal detachment, subretinal proteinaceous effusions.

Choroidal osteoma is benign tumor in young women. The lesion is usually unifocal, demonstrate ossification, and are juxtapapillary. Punctate calcification in the posterior globe on the temporal side of the nerve is usually seen. The ddx includes amelanotic melanoma, choroidal hemangioma, mets, scars, resolving hemorrhage.

Drusen is made of a mucoprotein matrix. It occurs in 2% of the population. Can be familial and typically bilateral. It is located at the junction of the optic nerve and globe. CT demonstrates punctate calcifications. Normal course may be progressive enlargement.  Drusen can give pseudopapilledema.

Neuroradiology Section

The following are matching answers:

102.

1 e

2  a

3 d

4 c

103. 

1. a

2. b

3. d

104. 

1 a

2 b

3 c

4  d

105.

106. 

Answer:

5. b

6. a

7. c

Huntington's is characterized by chorieform movements with rapid onset dementia. It's autosomal dominant, predominantly involving males. The hallmark is atrophy of caudate nucleus and subsequently the putamen. The later stages involves temporal and frontal lobes.

Parkinson's is a movement disorder associated with cogwheel type rigidity. The disease involves the substantia nigra. In later stages, it involves the corpus striatum and globus pallidus.

Dilantin causes atrophy of the cerebellum.

107. 

Answer:

8. c

9. b

10. a

11. c

Orbital cellulitis in kids and adolescents is most often associated with paranasal sinuses. Increased pressure in the sinus is transmitted to the orbit and causes preseptal edema. Septic thrombophlebitis leads to cellulitis and may lead to orbital cellulitis.--- ethmoid and frontal.  Acute ethmoiditis can result in infection traversing the thin plate of bone causing orbital cellulitis.

Mucocele are most common in the frontal and ethmoid sinuses with sphenoid sinus the least common. The most frequent location for a mucocele is the frontal sinus (60%)..

Retention cyst are a result of obstruction of small sermucinous glands usually in the maxillary sinus..

One manifestation of allergic sinusitis is sinonasal polyposis. The lesion although benign may demonstrate fairly aggressive bony distortion.

The most common location of polyps is the nasal cavity. The best answer offered is the ethmoid sinus.

108. 

Answer:

12. a

13. d

14. prob c ,could also be a, d

15. b

Macrocrania is associated with craniosynostosis. Microcrania is associated with trisomy 13. Universal craniosynostosis leads to microcrania.

Premature sagittal suture closure produces a long narrow skull termed dolichocephaly or scaphocephaly.

Brachycephaly is when the skull is short in AP diameter and can be seen in coronal craniosynostosis.

Apert's syndrome leads to secondary craniosynostosis and hypertelorism.  Hypertelorism is greater interorbital distance. Bilateral coronal craniosynostosis can cause hypertelorism.

Arnold -Chiari malformation leads to increased intracranial pressure. In neonates and infants, increased pressure leads to sutural diastasis. In pt with closed sutures, get increased inner table markings and sellar erosion.

109. 

Answer:

16. a

17. b ,d

18. c

19. g

20. f

110. 

Answer:

21. a

22. d

23. b

24. b

25. e

2/3 of mycotic aneurysms rupture within the first 3 weeks of diagnosis of endocarditis. For aneurysms in general, 20-50% rebleed within the first 2 weeks of subarachnoid hemorrhage.

Most contusions in trauma occur in the frontal and anterior temporal lobes secondary to the rough surface of the anterior and middle cranial fossa and sharp border of the planum sphenoidale.

Hypertensive bleeds tend to occur in the basal ganglia.

Venous angioma:

111.

Answer:

26. a, c and d

27. b and e

28. ???

Buccinator and stapedius are innervated by facial nerve.

The mylohyoid and anterior belly of the digastric are supplied by the mylohyoid branch of the inferior alveolar  nerve from V3 and combine with the extrinsic tongue muscles to form the floor of the mouth and are supplied by CN 12.

112.

Answer:

29. d

30. a

31. b.

32. c.

33. d

Neurofibromatosis occurs in approximately 1 in every 3300 live births.

113. 

Answers:

34. d , ?a

35. b

36. c

37. c (in vertebral.)

38. ???

Dissection usually affects the extracranial great vessels but can occasionally occur in intracranial vessels. Symptoms differ in that extracranial dissection can present with neck and face pain, headache, Horner’s syndrome, cranial nerve involvement, and ischemic symptoms that occur days to weeks after the dissection. The association of ptosis and miosis with headache and preservation of ipsilateral facial sweating (Raeder’s syndrome) can occur with cervical internal carotid dissection, because the sympathetic nerve fiber for sweat follow the external carotid artery whereas those controlling the dilator pupillae and superior palpebral muscle follow the internal carotid artery.

114. 

Answer:

39. a

40. b

41. d

AICA is IAC. The internal auditory artery can arise from the basilar artery or more frequently from the AICA. It enters the internal auditory canal with cranial nerves 7 and 8.

The anterior choroidal artery freely anastomosis with the posterior choroidal artery - as a result it supplies the choroid of the inferior temporal horn and atrium. The posterior choroidal artery supplies the choroid of the posterior temporal horn, atrium, and body of lateral ventricle.

Posterior and anterior choroidal branches supply choroid

The inferior colliculus typically is supplied by the PCA, less commonly by the posterior lateral choroidal artery. It drains via the precentral vein. ("The superior vermian branch of the superior cerebellar artery supplies tiny branches to the inferior colliculus"?)

115. 

Answer:

 42. a

43. b

 44. c

Jugular tumors may invade adjacent nerves in the jugular foramen and around the jugular - thus involving cranial nerve 10 and causing hoarseness.

The glomus tympanicum tumor is a paraganglioma arising at the cochlear promontory of the middle ear cavity. It presents with pulsatile tinnitus and/or a vascular tympanic membrane. Since it is a highly vascular tumor, intense enhancement occurs after CT or MR contrast administration (or signal voids on MR before contrast administration). The tympanic branch of the ascending pharyngeal artery is the major source of blood supply to the glomus tympanicum and is therefore often enlarged when a tumor arises there.

116. 

Answer:

45. c

46. b

Hyperdense lesion centrally (this is actually quite tough) most likely represents a two week old hematoma. Contrast enhancement around the periphery of the hematoma usually develops at 7-9 days after the bleed.

Thick wall is excellent for glioma and should lead you away from things like abscess (classical teaching is 5 mm or thicker is glioma).

Infarcts begin to enhance after the first week after the insult. This is due to improved collateral circulation.

Nice mnemonic for contrast-enhancing ring lesions = MAGIC DR.

117. 

Answer:

47. a

48. b

 49. c

The Dandy-Walker malformation consists of cystic dilatation of the 4th ventricle, agenesis of the cerebellar vermis, and marked enlargement of the posterior fossa. Hydrocephalus develops in 75% of patients; dysgenesis of the corpus callosum occurs in 20-25% of patients.

118.

Answer:

50. a

51. b

119. 

Answer:

52. b

53. a

54. d

55. a

56. b

The Arnold Chiari malformations are divided into four types:

Type I - tonsillar invagination through the foramen magnum into the spinal canal with variable degrees of cerebellar displacement (tonsillar ectopia). There is normal position of the 4th ventricle. Syringohydromyelia is an associated finding. Two components are necessary for the diagnosis - tonsilar herniation and syringohydromyelia.

Type II - dysgenesis of the hindbrain with caudally displaced 4th ventricle and caudal elongation of the medulla and vermis. Concurrent anomalies include: myelomeningocele, mesencephalic beaking (tectal beaking), enlarged massa intermedia, accessory anterior commissure, absence of the corpus callosum (which manifests as elevated third ventricle), and partial absence of the falx. Abnormalities of the bony vault include Luckenschadel (or lacunar) skull (appears as "soap bubble" lucencies in the upper calvarium - it is a dysplasia of bone and underlying dura and can be seen with any cause of meningocele and myelomeningocele) which regresses after about 6 months of age, scalloping of the petrous bone and clivus (older children), and enlargement of the foramen magnum (older children).

Type III - is a rare lesion that consists of herniation of cerebellum into a high cervical or occipital encephalocele.

Type IV - consists of extreme cerebellar hypoplasia without associated displacement.

120.

Answer:

57. a

58. c

59. d

Cerebellar pilocytic astrocytoma often infiltrate the 3rd ventricle and present with hydrocephalus.