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Neuro > Magnetic resonance imaging diagnosis of brain tumors in dogs > Flashcards

Magnetic resonance imaging diagnosis of brain tumors in dogs Flashcards

1
Q

Differential diagnosis for masses associated with the pituitary gland or nearby optic chiasm.

A
  • Pituitary adenoma or adenocarcinoma
  • Germ cell tumor
  • Craniopharyngioma
  • Ependymoma
  • Meningioma, lymphoma, granular cell tumor…
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2
Q

T/F. Contrast-enhancement of extra-axial tumors is almost universal.
(Bentley 2015)

A

True (bc pachymeninges are outside of the BBB).

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3
Q

A dural tail is a linear enhancement of (thickened / thin) dura mater adjacent to an (extra / intra) axial mass on (T1 / T2W) post-contrast images.
(Bentley 2015)

A

A dural tail is a linear enhancement of THICKENED dura mater adjacent to an EXTRA-AXIAL mass on T1W POST-contrast images.

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4
Q

T/F. The dural tail sign occurs in brain tumors only.

A

False. It has occurred in fungal and protozoal granulomas too.

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5
Q

T/F. Broad-based dural contact and the dural tail sign may confirm that a lesion is extra-axial.
(Bentley 2015)

A

True, but do not allow a definitive diagnosis.

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6
Q

T/F. Meningiomas do not typically cause mass effect.

A

False, they do.

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7
Q

What is the second most common solitary meningeal-based contrast-enhancing mass lesion?
(Bentley 2015)

A

Histiocytic sarcoma.

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8
Q

T/F. The absence of extra-neural disease does not rule out histiocytic sarcoma.
(Bentley 2015)

A

True.

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9
Q

Can meningiomas be cystic or polycystic?
(Bentley 2015)

A

Yes, around one-quarter of them are, in contrast with histiocytic sarcoma.

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10
Q

Name 3 non-neoplastic extra-axial cystic lesions.
(Bentley 2015)

A

Arachnoid diverticula, epidermoid cyst, ependymal cyst.

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11
Q

T/F. Fungal lesions frequently have sharply defined borders.
(Bentley 2015)

A

False. They frequently have indistinct or poorly defined borders.

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12
Q

T/F. 90% of meningiomas have sharply defined borders.
(Bentley 2015)

A

True. Smooth or irregular, but sharply defined.

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13
Q

T/F. Around 3/4 of meningiomas are infratentorial, especially front-olfactory.
(Bentley 2015)

A

False! Supratentorial!

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14
Q

T/F. Granular cell tumors are usually plaque-like meningeal growths.
(Bentley 2015)

A

True! They are also T1-hyperintense.

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15
Q

Meningiomas are usually T1-_______ and T2-_______.
(Bentley 2015).

A

T1-iso or HYPOintense, and T2-iso or HYPERintense.

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16
Q

If the lesion is T2-hypointense, what should we include in the list of ddx?

(Bentley 2015)

A

Benign hematoma or hemorrhage.

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17
Q

Can granulomas be a differential diagnosis for a solitary contrast-enhancing meningeal mass?
(Bentley 2015)

A

Yes!

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18
Q

What is the most important differential diagnosis for solitary enhancing intra-axial lesion?
(Bentley 2015)

A

Glioma.

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19
Q

Where are choroid plexus tumors more common?
(Bentley 2015)

A

In the fourth ventricle.

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20
Q

What are the 2 types of choroid plexus tumors?
(Bentley 2015)

A

Papillomas and carcinomas.

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21
Q

Which one of the 2 types of choroid plexus tumors can display ‘drop metastasis’?
(Bentley 2015)

A

Carcinomas. They can even cause meningeal carcinomatosis.

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22
Q

T/F. As CPTs are more abundant, any mass replacing the normal choroid plexus is more likely to be a CPT than ependymoma.
(Bentley 2015)

A

True, especially if sited in the fourth ventricle.

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23
Q

T/F. If a normal choroid plexus can be identified as a small contrast enhancing area on T1W images, separate from a solitary ventricular mass, that mass is probably a CPT.
(Bentley 2015)

A

False, is NOT a CPT. Ependymoma most likely.

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24
Q

T/F. Ependymomas are derived from the ependymal cell lining of the ventricle system and spinal cord central canal, and are common in domestic animals.
(Atalay Vural 2006)

A

False. They are rare.

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25
Q

CPTs are T1-______ much more often than other brain tumors.
(Bentley 2015)

A

Hyperintense.
Can also be iso or hypointense.

26
Q

CPTs are typically T2-_________ with/without peri-humoral edema.
(Bentley 2015)

A

HYPERintense, WITH edema (non-specific features).

27
Q

Meningiomas are rarely or infrequently T1-________.
(Bentley 2015)

A

HYPERintense, contrary to CPTs.

28
Q

Name 2 non-neoplastic differential diagnoses for a solitary ventricular mass.
(Bentley 2015)

A
  1. Choroid plexus cyst
  2. Cholesterol granuloma
  3. Epidermoid cyst
29
Q

Is it common to see mass effect associated with gliomas?
(Bentley 2015)

A

Yes, it’s seen in over 90% of astrocytomas and oligodendrogliomas.

30
Q

T/F. Astrocytomas usually distort ventricles.
(Bentley 2015)

A

False. Oligodendrogliomas do.

31
Q

T/F. Lymphoma and GC may infiltrate without mass effect.
(Bentley 2015)

A

True.

32
Q

Strong/weak contrast-enhancement significantly predicts neoplasia over inflammatory and vascular.
(Bentley 2015)

A

STRONG.

33
Q

T/F. Gliomas are generally T1-HYPOintense and T2-HYPERintense.
(Bentley 2015)

A

True. Frequently heterogeneous in T2.

34
Q

The causes of T1-hyperintensity within tumors are narrow, and include m_______ and h______.
(Bentley 2015)

A

Melanoma and hemorrhage.

35
Q

T/F. Hemorrhage or T2W gradient echo (GRE) signal voids occur in 70-80% of gliomas.
(Bentley 2015)

A

False. 30-40%.

36
Q

Name 3 other lesions with hemorrhage or GRE signal voids.
(Bentley 2015)

A
  • Hemangiosarcoma.
  • Hemorrhagic CVA.
  • Melanoma.

Others: hemangioma, hamartoma, cerebellar medulloblastoma.

37
Q

Peri-lesional edema is more common in glioma or in CVA?
(Bentley 2015)

A

Glioma.

38
Q

Where are oligodendrogliomas usually located?
(Bentley 2015)

A

Prosencephalon.

39
Q

T/F. The majority of caudal fossa gliomas are astrocytic.
(Bentley 2015)

A

True.

40
Q

Within gliomas, surface contact and ventricular distortion are more common for …
(Bentley 2015)

A

Oligodendroglioma.

41
Q

Name 4 tumors that can metastasize as solitary enhancing intra-axial lesions.
(Bentley 2015)

A
  • Hemangiosarcoma
  • Round cell tumor
  • Carcinoma
  • Melanoma
42
Q

What are the 3 most common neoplastic ddx for a solitary meningeal-based mass?
(Bentley 2015)

A

Meningioma
Histiocytic sarcoma
Choroid plexus tumor

43
Q

What are the 3 most common neoplastic ddx for solitary ventricular mass?
(Bentley 2015)

A

Choroid plexus tumor
Ependymoma
Meningioma

44
Q

What are the 3 most common neoplastic ddx for solitary enhancing intra-axial lesions?
(Bentley 2015)

A

Glioma, metastasis, primary CNS lymphoma

45
Q

T/F. All the solitary enhancing intra-axial lesions can appear non-enhancing, the difference is the order in the ddx list.
(Bentley 2015)

A

True! Low-grade glioma, cerebellar meduloblastoma, and gliomatosis cerebri are going to be more likely.

46
Q

T/F. Minimal contrast-enhancement is characteristic of glioma.
(Bentley 2015)

A

False! Gliomatosis cerebri.

47
Q

T/F. Ischemic strokes are a major differential diagnosis for non-enhancing lesions.
(Bentley 2015)

A

True. Strong enhancement occurs in only 5% of vascular lesions.

48
Q

T/F. Contrast-enhancement rules out hemorrhagic cerebrovascular accident.
(Bentley 2015)

A

False. It is possible during peripheral revascularization.

49
Q

The 2 MRI sequences critical in distinguishing neoplasms from infarcts are d_____ w_____ i_____ and a_____ d____ c____ maps.
(Bentley 2015)

A

Diffusion weighted imaging (DWI)
Apparent diffusion coefficient maps.

50
Q

Hyperintensity on apparent diffusion coefficient is significantly more common for glioma/infarcts.
(Bentley 2015)

A

Glioma, as is mass effect.

51
Q

W____-shaped lesions predict cerebrovascular accidents.
(Bentley 2015)

A

Wedge-shaped.

52
Q

T/F. Inflammatory lesions including GME and distemper are always enhancing.
(Bentley 2015)

A

False, they can be non-enhancing.

53
Q

What are the 3 most common neoplastic ddx for a solitary non-enhancing intra-axial lesion?
(Bentley 2015)

A

Low-grade glioma, gliomatosis cerebri, cerebellar medulloblastoma.

54
Q

What are the 4 most common neoplastic ddx for multifocal lesions (intra and extra)?
(Bentley 2015)

A

Lymphoma, metastasis, gliomatosis cerebri, and choroid plexus carcinoma.

55
Q

Although lymphoma can produce any of the 5 patterns considered, which 2 are not typical?
(Bentley 2015)

A

Non-enhancing lesions and ventricular involvement.

56
Q

Lymphoma has no characteristic MRI appearance, but the most repeatable characteristic is _________ _________.
(Bentley 2015)

A

Contrast enhancement.

57
Q

T/F. MRI might be within normal limits with lymphoma, gliomatosis cerebri, or multifocal oligodendroglioma.
(Bentley 2015)

A

True.

58
Q

T/F. Lymphoma and glioma are archetypal examples of diffuse infiltration of neoplastic cells with negligible mass effect.
(Bentley 2015)

A

False. Lymphoma and gliomatosis cerebri.

59
Q

T/F. Diffuse multifocal meningeal enhancement, with or without other lesions, can increase the suspicion of round cell tumors and inflammatory disease.
(Bentley 2015)

A

True.

60
Q

Name some non-neoplastic causes for multifocal lesions.
(Bentley 2015)

A

Inflammatory (GME, NLE, NME)
Infectious (fungal, neosporosis, viral, tick-borne)
Thiamine deficiency

61
Q

Post-ictal changes may overlap in appearance with infiltrating neoplasia, occurring uni or bilaterally in the __________ lobe and elsewhere.
(Bentley 2015)

A

Pyriform-temporal lobe.

62
Q
A

Neuro (12 decks)

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