1. Dynamic CT with diamox challenge: 
- Diamox (acetazolamide) causes vasodilation of cerebral arterioles for some unknown reason
- In cases of stroke, the arterioles in that distribution are already dilated, so the administration of diamox will cause a steal phenomenon and decrease perfusion to that area.

- Images from {this paper} by Eastwood et al in AJNR. 

- See the low perfusion in L MCA before diamox, and even less perfusion in L MCA after diamox (small arrowhead pointing to relatively decreased perfusion to L basal ganglia) 

2. Risk of air embolus with craniotomy-- higher risk with surgery where the surgical field is >5 cm above the R atria (i.e. sitting craniotomy) 

- Dural veins have no valves, and thus air is more likely to travel to lungs

- Dural veins are less collapsible 

- When the field is above the heart, there is a greater likelihood of air being "sucked into" the venous system 

3. Flying after craniotomy: 

- Postop pneumocephalus can hypothetically turn into tension pneumocephalus with the decreasing ambient air pressures associated with higher altitudes, however this study of 21 patients with posttraumatic/postoperative pneumocephaus who had to be airlifted found.... "The volumes of pneumocephalus ranged from 0.6 to 42.7 ml, with mean volume of 9.3 ml and median volume of 4.2 ml. No patient sustained a temporary or permanent neurologic decline as a result of air transportation. Three patients with continuous monitoring of intracranial pressure (ICP) were not observed to have any sustained pressure elevations during flight" 

4. X-stop vs decompressive surgery: no difference in outcomes or complications, higher rate of re-operation in x-stop, according to this meta-analysis of 5 prospective trials. 

5. Roof of 4th ventricle: superior cerebellar peduncle and anterior medullary velum. 

6. Review of cisterns: sagittal 

Chiasmatic = suprasellar 

Cerebellomedullary = cisterna magna

cistern of great vein = quadrigeminal 

7. Review of cisterns: axial 

What is labelled here as "crural" I learned by the name of "perimesencephalic"; I've heard that same space referred to as part of the ambient. I've even heard the quadrigeminal cistern referred to as part of the ambient, and I've heard the term perimesencephalic refer to all of the above labeled.
8. Relationship of lamina terminalis to anterior commissure: 
On CT:

{source}

Green: anterior cerebral artery

Purple: supposedly the anterior commissure as the LT is supposed to be too thin to see on CT 

9. {An amazing resource} of cistern anatomy, contents, imaging

10. Gas induction: 

- Good for kids, as it can be hard to get an IV in an awake kid

- Also helps you oxygenate-- as kids struggle, they increase their oxygen demand and make it harder for you to mask them; at least with a mask induction they get 100% oxygen at the same time as induction.