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Test II Review
| What is Known as a large collateral system? | The circle of willis |
| What supplies the anterior or frontal portion of the brain? | ACa and AComm A |
| What supplies the anterior and lateral or the frontal, temporal and parietal portions of the brain? | MCA |
| What supplies the posterior or occipital portions of the brain? | PCA and Pcomm A |
| What can transcranial Doppler be used to detect? | Intracranial stenosis, aneurysms, brain death, monitor for emboli in surgery, AV malformations, sickle cell anemia and Vasospasm |
| What are the 4 windows used in TCD? | Transtemporal Suboccipital aka transforaminal Submandibular Transorbital |
| What MHz probe is used for TCD? | 2MHz |
| What is the angle of isonation? | 0 degrees |
| Limitations of TCD | Recent eye surgery Inability to penetrate the transtemporal window Wrong vessel identification |
| What type of measurements are used in TCD ? | Time averaged men velocity or time averaged maximum velocity Pulsatility index |
| Uses are TCD | Vasospasm Brain Death Sickle Cell Anemia Interoperative Monitoring Evaluation of stenosis evaluation of aneurysms and AVMs |
| What is an AV malformation? | An abnormal connection between arteries and veins, usually in the brain or spine. |
| What is a vasospasm? | Is a condition that develops days after a rupture of an intracranial aneurysm. The increased pressure will cause vessels to spasm and increase velocities. |
| What is considered “cross over” for collateral pathways? | antegrade flow in ACA from crossover collateralization (flow from the contralateral ACA by the way of the A comm A) |
| Velocities over 120 cm/s | |
| What will give the greatest risk of poor outcome and reduced cerebral perfusions? | Velocities over 200 cm/s |
| What kind of patient runs a great risk of vasospasm? | A patient with subarachnoid hemorrhage (SAH) |
| Most SAHs are the result of a _________________ | Hemorrhagic stroke |
| What can happen due to an increase in intracranial pressure? | Vasospasm |
| Can you make the determination of brain death over one scan? | No you need serial scans |
| Why do you need serial scans for brain death? | Scans show changes over time and will display a loss of diastolic component and eventually only forward flow with reduced velocity |
| What type of flow will you see in a patient being evaluated for Brain death? | A loss of diastolic component and eventually only forward flow with reduced velocity |
| What is sickle cell anemia? | A blood disorder that will cause blood to become thick and will cause strokes. |
| What is the benefit of using TCD for sickle cell anemia? | It helps to determine the need for transfusion to reduce the risk of stroke |
| What does inter-operative monitoring determine? | Determines if surgical procedures need to be changed due to emboli |
| What are the results of microemboli in the traveling in the blood stream | High Intensity Transient Signals |
| What does HITS stand for? | high Intensity transient Signals |
| What is the common sign for the MCA/ACA junction when imaging the transtemporal window? | The waveform appears to be a mirror image |
| What imaging window do you use when you see the MCA/ACA junction? | transtemporal Window |
| What is considered “external to internal” regarding collateral pathways? | Retrograde flow in ophthalmic artery -this can be seen with ipsilateral ICA occlusion (path: supra orbital and frontal connections - ECA>ICA) |
| What kind of collateral pathways can be seen with ipsilateral ICA occlusion? | External to Internal |
| What is considered “posterior to anterior” in collateral pathways? | Flow reversal in the P comm A (This is increased flow in the PCA) |
| Types of collateral pathways | Cross over, external to internal and posterior to anterior |
| COW largest collateral connection: ECA-ICA connections via the __________** | Ophthalmic and Orbital Artery |
| COW largest collateral connection: Occipital branch of the ECA with the ___________ | Atlantlic branch of the vertebral |
| COW largest collateral connection: Deep cervical and ascending cervical branch of the subclavian to the __________ | Branches of lower vertebral artery |
| Factors and conditions that may alter blood flow: | Hematocrit, metabolism, blood gasses |
| Causes of Cerebral Artery Vasospasm: | 4 CHAT 1.Cerebral aneurysm rupture (most common cause) 2.Head Trauma 3.Arteriovenous malformation 4.Tumor Manifestations |
| What is the gold standard for identifying a cerebral vasospasm caused by a Subarachnoid hemorrhages? | Angiography |
| What is the gold standard for identifying Acute Ischemic Stroke? | CT/CTA or MRI/MRA |
Created by:
jcazares10
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