Neuroradiology Part II Flashcards Preview

Pathophysiology - Neurology > Neuroradiology Part II > Flashcards

Flashcards in Neuroradiology Part II Deck (18)
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1
Q

What are the most common areas in the cortex and cerebellum for parenchymal hemorrhage secondary to hypertension?

A

Basal ganglia, thalamus, dentate nucleus of cerebellum (distal branches of SCA and PICA)

2
Q

What are the most common sites for contusions?

A

Inferior frontal lobes

Anterior temporal lobes

3
Q

Where does axonal injury during shearing usually occur?

A

Gray-white junctions of cortex, corpus callosum (splenium and body), dorsal brainstem

4
Q

How can a small intraparenchymal cortical hemorrhage be differentiated from a subarachnoid hemorrhage?

A

Intraparenchymal hemorrhages are usually surrounded by a small mount of vasogenic edema in the brain

Subarachnoid hemorrhages are not actually in the brain but are around it, and the areas of enhancement in the CT will be in the sulci and cisterns

5
Q

What does dense artery sign + loss of gray/white distinction + gyral swelling and sulcal effacement mean and what do these indicate when taken together?

A

Dense artery sign - intraluminal thrombus -> area enhances on CT due to thrombous

Gray-weight distinction loss -> increased water content of cortex making it more hypodense -> seen in first few hours of infarct

Gyral swelling / sulcal effacement - late manifestations of acute infarct (12-24 hours) from brain swelling

6
Q

What is the hallmark of acute infarct diagnosis? When can this be seen radiologically?

A

Restricted diffusion -> water normally diffuses freely in equilibrium in brain, but when cytotoxic edema occurs due to loss of Na/K pump, diffusion is restricted

-> can be seen within minutes with MRI diffusion weighted imaging (DWI) -> T2-type image where CSF appears black

7
Q

Will T2 MRI become positive very quickly in acute infarct?

A

No -> there is no significant net increase in water content following infarction, and thus normal T2 will appear unchanged until about 6-8 hours post infarct when enough water has actually gotten into the brain to make it appear bright

Early restricted diffusion makes cells swell as water enters them from the interstitium, but there is no major increase in brain water

8
Q

What is the radiologic hallmark of multiple sclerosis?

A

Periventricular plaques which are areas of oligodendrocyte loss and reactive gliosis. Lesions may also exist in corpus callosum. Will appear hypointense on T1 and hyperintense on T2

9
Q

Will lesions in MS enhance with contrast? How else can they be seen?

A

These WILL enhance with contrast if they are actively inflamed and thus the BBB is damaged at those spots (vasogenic edema), but not all lesions will enhance

They can also be seen on T2 DWI because active plaques demonstrate restricted diffusion

10
Q

What are the most common spots to find lesions of MS?

A

Corpus callosum, callosal / septum pellucidum interface, periventricular white matter, middle cerebellar peduncles

11
Q

How does metastatic disease present in brain imaging?

A

Focal, solid, or ring-enhancing masses with surrounding vasogenic edema / mass effect (vasogenic edema spreads with finger-like extensions)

12
Q

Where in the brain does metastatic cancer typically spread to, and what are the most common types of cancer to spread there?

A

80% will spread to gray / white junction of cerebrum

15% will spread to cerebellum

Lung, breast, and melanoma are most common cancers to spread there

13
Q

How many metastases will be seen in brain cancer metastasis?

A

50% will have solitary metastasis
20% have 2 metastases
30% will have >=3 metastases

14
Q

What is the differential diagnosis for chronic thoracic back pain and mild leg weakness in a middle-aged female?

A
  1. Spondylitis / degenerative arthritis
  2. Injury / fracture
  3. Tumor causing cord or nerve root compression

Order MRI of spine

15
Q

What is the DDx for a mass found outside of spinal cord but inside of dura (intradural / etrameduullary)?

A
  1. Meningioma
  2. Nerve sheath tumor - Schwannoma or neurofibroma
  3. CNS primary drop-metastasis
  4. Hematogenous metastasis
16
Q

What is the “classic” MRI presentation of spinal Schwannoma?

A

Foraminal “dumbbell” growth within interventricular foramen, with masses on either side of the opening

-> lesion appears well-delineated and T2 hyperintense

17
Q

How does bacterial discitis / osteomyelitis appear on MRI?

A

Signal abnormality of between vertebral endplates and disc , with vivid enhancement due to edema / fluid in the interdisc space. Oftenwith narrowing and destruction of disc area

Abscess is often present

18
Q

How is definitive diagnosis of osteomyelitis made, and what is often seen in the surrounding tissue?

A

Inflammatory changes in the paraspinal soft tissue

-> must biopsy with needle to isolate organism