Neuroimaging of Intracranial Aneurysms for Surveillance and Posttreatment Follow-up

Targeted CE per ARRT’s Discipline, Category, and Subcategory classification:

Computed Tomography: 2.75
Procedures: 2.75
Head, Spine, and Musculoskeletal: 2.75

Magnetic Resonance Imaging: 2.75
Procedures: 2.75
Neurological: 2.75

Registered Radiologist Assistant: 2.75
Procedures: 2.75
Neurological, Vascular, and Lymphatic Sections: 2.75

Vascular-Interventional Radiography: 2.75
Procedures: 2.75
Vascular Diagnostic Procedures: 2.75

Outline

1. Introduction
2. Evolving Trend toward Endovascular Treatment
3. Imaging Techniques for Aneurysm Evaluation
   1. Noninvasive Neuroimaging: Noncontrast CT and MRI
   2. Noninvasive Neurovascular Imaging: CT Angiography and MR Angiography
   3. Three-Dimensional Time-of-Flight MRA
   4. Contrast-Enhanced Time-Resolved MRA
   5. MR Vessel Wall Imaging
   6. Digital Subtraction Angiography
4. IA Characterization and Reporting
5. Contemporary Treatment Modalities
   1. Clip Ligation
   2. Endovascular Coiling and Adjunct Techniques
   3. Flow Diversion
   4. Intravascular Flow Disruption
6. Follow-Up Strategies for Untreated and Treated IAs
7. Unexpected Findings at Postprocedural Follow-Up Imaging
   1. Device Migration or Dislodgement
   2. Thromboembolic Events
   3. Side Branch or Perforator Infarction
   4. Aneurysm or Vessel Rupture
   5. Delayed Intraparenchymal Hemorrhage
   6. Iatrogenic Cerebrovascular Injuries
8. Unexpected Findings at Mid- to Long-Term Follow-Up Imaging
   1. Recurrent or Residual Aneurysm Filling
   2. In-Stent Stenosis
9. Conclusion

Objectives

Upon completion of this course, students will:

1. describe the reported incidence of intracranial aneurysms (lAs)
2. list the first and second most common incidental findings on brain MR images
3. describe the vessel from which lAs most commonly arise
4. describe the percentage of spontaneous subarachnoid hemorrhage cases caused by lA rupture
5. list the factors that affect the rupture risk of lAs
6. describe the 5-year lA rupture risk based on patient age
7. describe patients who have the highest risk of rehemorrhage within the first 24-48 hours
8. identify the initial diagnostic study of choice for identifying subarachnoid hemorrhage (SAH)
9. describe the accuracy of noncontrast CT in detecting acute SAH within the first 6 hours
10. identify the diagnostic study that is recommended in cases of high suspicion for SAH following negative noncontrast CT
11. list the MRI sequences with increased sensitivity for subarachnoid blood in the acute to subacute settings
12. describe the detection rate of CT angiography based on lA size
13. list the factors that limit detection of lAs at CT angiography
14. identify the preferred imaging modality for lA screening in asymptomatic patients
15. describe the MRA sensitivity for detecting lAs larger than 3 mm
16. list factors that can limit the efficiency of MRA for lA detection
17. identify the imaging modality used as a problem solver in clinically challenging cases
18. identify the imaging modality used for diagnosis of both unruptured and ruptured lAs
19. describe the incidence of permanent neurologic complications in DSA cases
20. identify the imaging modality that is used to identify lA features important for determining treatment strategy
21. identify the treatment that can mitigate stroke risk in the setting of intra-aneurysmal thrombus or calcification
22. list the lA characteristics for which clip ligation is the preferred treatment
23. list the benefits of clip ligation
24. describe the most common lA treatment modality
25. list the benefits of coil embolization
26. describe the year the first flow diverter was approved by the U.S. Food and Drug Administration
27. describe aneurysm occlusions rates 5 years after flow diversion
28. describe the timepoint when retreatment should be considered after flow diversion
29. describe the year the first intrasaccular flow disruptor was approved by the U.S. Food and Drug Administration
30. list the reasons why 3D TOF MRA is a preferred modality for aneurysm surveillance imaging
31. describe the lA recurrence rate following microsurgical clipping with complete occlusion
32. describe the lA recurrence rate following endovascular coiling therapy
33. identify the imaging modality that should be used for follow-up imaging to avoid metallic implant artifact
34. describe the percentage of cases that experience coil migration
35. list the imaging modalities used to identify coil loop herniation or displacement
36. Compare the rates of technical failures between flow diverters and self-expanding stents
37. describe the most common complication arising from neuroendovascular procedures
38. list the factors that affect the risk of thromboembolism following treatment
39. describe the prevalence of symptomatic thromboembolism during interventional coiling and flow diversion
40. list the factors that affect the likelihood of side branch perforator thrombosis following flow diverter placement
41. describe a devastating complication of clipping, coiling, and flow disruption device deployment
42. describe a rare complication of flow diversion treatment
43. list interventional devices that are sources of hydrophilic polymer coating