Neuro Picture Cards Jess Flashcards
On non-contrast CT brain what is this sign and what does it represent?
Obscuration of the Lentiform Nucleus
“Lentiform Nucleus Sign” / “Blurred Basal Ganglia”
- Important sign of infarction in MCA territory
- One of the earliest and most frequently seen signs
- The basal ganglia are almost always involved in MCA-infarction
On non-contrast CT brain what is this sign and what does it represent?
Insular Ribbon sign
- hypodensity and swelling of the insular cortex –> loss of grey-white matter differentiation in the area
- very indicative and subtle early CT-sign of infarction in MCA territory (may be ONLY sign on CT, so important to search for it)
- Region is vulnerable to ischemia because it is the furthest removed from collateral flow.
- DDx: herpes encephalitis.
On non-contrast CT brain what is this sign and what does it represent?
[Hyper] Dense MCA sign
- Result of thrombus or embolus in the MCA
- Thrombus is more dense (eg. 100HU) than flowing blood (eg. 40HU). May take hours for clot to develop hyperdensity. In case of embolism, material already dense so can be visible early.
- Highly specific but poorly sensitive sign of MCA occlusion
- In NINDS Trial: poorer prognosis but NOT reduced benefit of t-PA
On non-contrast CT brain what is this sign and what does it represent?
Hypo attenuating brain tissue
- Suggestive of infarction when seen in vascular territory and when involves both grey and white matter
- In first 6 hours after onset onset of stroke symptoms it is highly specific for irreversible ischemic brain damage and correlates with: larger infarct volumes, more severe symptoms, less favorable clinical courses and a higher risk of hemorrhage.
- Lack of hypoattenuation in early stroke is a good sign!
Mechanism: cerebral ischaemia –> inadequate ATP supply –> failure of ion-pumps –> cytotoxic edema develops –> seen as hypoattenuation
(An increase of brain water content by 1% will result in a CT attenuation decrease of 2.5 HU).
On non-contrast CT brain what is this sign and what does it represent?
Hemorrhagic infarct
Hyperintensity on non-con CT.
15% of MCA infarcts are initially hemorrhagic.
Hemorrhage is most easily detected with CT, but it can also be visualized with gradient echo MR-sequences.
Once you have diagnosed the infarction, you want to know which vessel is involved by performing a CTA.
Name the location of these bleeds (seen on non-con CT head). What are all three associated with?
Left: Basal ganglia / thalamus
Middle: Pons
Right: Cerebellum
All associated with chronic, poory controlled hypertension.
Draw the Circle of Willis
(viewed from inferior aspect)
Include:
ICAs, ACAs, MCAs, PCAs, Vertebral and basilar arteries, cerebellar arteries, ophthalmic ateries, and the major connections.
