Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Diagnostic Imaging of Intracranial Aneurysms

Diagnostic Imaging of Intracranial Aneurysms

  • Login to see the comments

Diagnostic Imaging of Intracranial Aneurysms

  1. 1. C.N.S. Intracranial Aneurysms
  2. 2. Mohamed Zaitoun Assistant Lecturer-Diagnostic Radiology Department , Zagazig University Hospitals Egypt FINR (Fellowship of Interventional Neuroradiology)-Switzerland zaitoun82@gmail.com
  3. 3. Knowing as much as possible about your enemy precedes successful battle and learning about the disease process precedes successful management
  4. 4. Aneurysm 1-Presentation 2-Incidence 3-Diagnosis 4-Types
  5. 5. 1-Presentation : a) Sudden onset of severe headache b) Mass effect c) Thromboembolic events
  6. 6. a) Sudden onset of severe headache : -Sudden onset of severe headache +/- neurological signs + /- reduced level of consciousness with scan findings of : 1-Subarachnoid Hemorrhage 2-Parenchymal Hemorrhage (usually with associated SAH ) 3-Intraventricular Hemorrhage (most often secondary to bleeding in the general subarachnoid space , occasionally primary)
  7. 7. b) Mass effect : 1-Cranial nerve palsies (especially 3rd nerve palsy with PCOM aneurysms) 2-Horner’s syndrome 3-Brainstem dysfunction 4-Hydrocephalus c) Thromboembolic events
  8. 8. 2-Incidence : -Incidence in general population is 2-3 % -Overall risk of rupture = 0.5-1.5 % per annum , variable according to size and position of aneurysm , sex , smoking , etc
  9. 9. 3-Diagnosis : a) CT & CTA b) MR & MRA c) Catheter Angiography
  10. 10. a) CT & CTA : -Extra-axial mass in subarachnoid space -Enhances if patent -May be thrombosed and / or have calcification (especially giant aneurysms) -CTA demonstrates site and morphology of aneurysm and may allow planning of treatment (neurointervention versus surgery) without need for catheter angiography
  11. 11. Nonenhanced CT scan of a middle-aged man with headaches, the patient had a giant aneurysm of the LT ICA in its intracavernous segment, this aneurysm is densely calcified and is easily depicted
  12. 12. CTC shows a basilar tip aneurysm
  13. 13. Coronal reformatted MIP images from a CTA demonstrates a 5 mm aneurysm (straight arrow) of the anterior communicating artery (arrowhead)
  14. 14. RT MCA aneurysm seen on both CTA and MRA), A, Coronal section on CTA reveals aneurysm in RT MCA bifurcation, B, MRA also displays aneurysm with less definition, C, 3D reconstruction of CTA better defines saccular appearance of this aneurysm
  15. 15. A, Catheter angiography lateral view, following left ICA injection, shows aneurysm originating from supraclinoid portion of ICA, B, CTA axial source image reveals lobulated aneurysm (arrow)
  16. 16. CTA obtained on day 6 after occurrence of aneurysmal subarachnoid hemorrhage shows severe spasm of the right MCA (arrows) and a midline hematoma surrounding a thrombosed aneurysm of the anterior communicating artery
  17. 17. b) MR & MRA : -Patent aneurysm will show flow void -Giant or partially thrombosed aneurysms can show complex flow patterns with heterogeneous signals on standard sequences -Not reliable for treatment planning
  18. 18. T1 of a middle-aged woman with progressive headaches, aphasia, and right- sided hemiparesis, a large intracerebral mass with a significant amount of surrounding edema is depicted, the lesion is a giant internal carotid artery aneurysm
  19. 19. T2 of a middle-aged woman with progressive headaches, aphasia, and right- sided hemiparesis, the lesion is a giant internal carotid artery aneurysm, note the flow void, the blood breakdown products within the layers of mural thrombus, and calcification within the aneurysm that produces a marked hypointense signal, significant surrounding edema is depicted
  20. 20. T2 shows 7-mm basilar artery terminus aneurysm (arrow)
  21. 21. MRA shows basilar tip aneurysm (arrow) and very small (1.5 mm) P1 segment aneurysm (arrowhead)
  22. 22. Coronal T2 through the chiasmatic cistern , the optic chiasm is displaced to the left (arrow) and the anterior cerebral arteries elevated by a large right carotid-ophthalmic aneurysm , this patient present with visual disturbance and examination revealed an ipsilateral temporal quadrantanopia
  23. 23. (a) Axial T2 and (b) oblique frontal intra-arterial digital subtraction angiography showing a giant aneurysm of the intrapetrous right carotid artery , this patient presented complaining of deafness and was treated by balloon occlusion of the carotid artery
  24. 24. c) Catheter Angiography : -Invasive with 0.1-0.5 % inherent stroke risk -Still considered gold standard but may soon be superimposed by CTA
  25. 25. Left oblique cerebral angiogram in a patient with multiple intracranial aneurysms shows an anterior communicating aneurysm and a middle cerebral artery aneurysm
  26. 26. (a) Axial CT showing acute SAH with intra parenchymal and intraventricular hemorrhage , (b, c) DSA by right (b) and left (c) ICA injection 2 days after the hemorrhage shows no evidence of vasospasm and only faint filling of a small saccular aneurysm of the anterior communicating artery on b (arrow) , (d, e) A repeat study was performed 4 days later and shows the aneurysm filling from the left side (e) and intense vasospasm of right (d) and left (e) anterior cerebral arteries
  27. 27. (a) Left carotid angiography showing a saccular ACOM aneurysm 24 h after rupture , (b) the aneurysm rebleed before treatment and a second angiogram 8 days later (immediately prior to coil embolisation) shows a daughter lobule at the fundus
  28. 28. (a) Very large aneurysm arising from the lCA distal to the ophthalmic artery origin ; pointing upwards and medially , aneurysms at this site are variously described as carotid-ophthalmic , paraclinoid or global ICA aneurysms , the neck is very wide and this lesion was treated by parent artery occlusion , (b) T1 showing the aneurysm filling the chiasmatic cistern with the chiasm displaced to the right , (c) T1 shortly after left ICA balloon occlusion , the aneurysm sac is substantially thrombosed
  29. 29. ICA DSA showing a small superior hypophyseal aneurysm arising from the supraclinoid artery and pointing medially , the aneurysm arises at the level of the superior hypophyseal artery , but this vessel is rarely visible on angiography
  30. 30. Oblique frontal angiograms of a large aneurysm of ICA , (a) before and (b) 6 months after coil embolisation , aneurysms at this site often have wide necks which increases the risk of recurrence after coil embolisation , a microcatheter has been positioned in the central part of the aneurysm sac in (a) , at follow-up (b) there is a small neck remnant (arrow) which will be monitored by further intra-arterial angiography
  31. 31. Lateral intra-arterial DSA showing a small aneurysm at the origin of the anterior inferior frontal artery , the angiogram was performed soon after SAH
  32. 32. Left MCA arising at the bifurcation , the orbitofrontal artery arises from the superior trunk (arrow) and its origin is intimately related to the aneurysm neck , an early branch of the M2 arteries such as this may be difficult to separate , on imaging , from the aneurysm neck
  33. 33. Basilar artery (BA) termination aneurysm on frontal (a) and oblique (b) intra-arterial DSA , this aneurysm points upwards and to the right side , lateral deviation of the aneurysm sac is due to asymmetry of the inflow , the bifurcation of the BA , in this case , is low relative to the dorsum sella and the P1 arteries are therefore directed vertically , the right P1 is obscured and oblique views (b) are used to show the relationship of the aneurysm neck to the posterior cerebral artery origins , note that both PCOMs fill and the proximity
  34. 34. Oblique lateral intra-arterial DSA following vertebral artery (VA) injection , there is a small saccular aneurysm arising from the PICA , the neck of the aneurysm is clearly separate from VA ; arising from the apex of the initial downward turn of the lateral medullary section of PICA , the aneurysm points upwards and medially
  35. 35. 4-Types : a) Saccular aneurysm b) Fusiform aneurysm c) Dissecting aneurysm d) Mycotic aneurysm e) Oncotic aneurysm f) Traumatic pseudoaneurysm
  36. 36. a) Saccular Aneurysm : 1-Incidence 2-Etiology 3-Radiographic Features 4-Complications 5-Multiple aneurysms 6-Giant aneurysm
  37. 37. 1-Incidence >> -Present in approximately 2% of population , multiple in 20% , 25% are giant aneurysms (>25 mm)
  38. 38. -Increased incidence of aneurysm in : a) Adult dominant polycystic kidney disease (ADPKD) b) Aortic Coarctation c) FMD d) Structural collagen disorders (Marfan syndrome , Ehlers-Danlos syndrome) e) Spontaneous dissections
  39. 39. 2-Etiology : -Degenerative vascular injury (previously thought to be congenital) > trauma , infection , tumor & vasculopathies
  40. 40. 3-Radiographic Features : a) CT & CTA b) MR & MRA c) Catheter Angiography
  41. 41. a) CT & CTA : -See before b) MR & MRA : -See before
  42. 42. c) Catheter Angiography : -Number of aneurysms : multiple in 20% -Location , 90% in anterior circulation -Size -Relation to parent vessels -Presence and size of aneurysm neck
  43. 43. 4-Complications : a) Rupture >> -SAH -Parenchymal hematoma -Hydrocephalus b) Vasospasm >> -Occurs 4 to 5 days after rupture -Causes secondary infarctions -Leading cause of death / morbidity from rupture
  44. 44. c) Mass effect >> -Cranial nerve palsies -Headache d) Death >> 30 % e) Rebleeding >> -50% rebleed within 6 months -50% mortality
  45. 45. 5-Multiple Aneurysms : -In the presence of multiple aneurysms , one may identify the bleeding aneurysm using the following criteria : a) Location of SAH or hematoma adjacent to or around bleeding aneurysm b) Largest aneurysm is the one most likely to bleed c) Most irregular aneurysm is the one most likely to bleed d) Extravasation of contrast (rarely seen) e) Vasospasm adjacent to bleeding aneurysm
  46. 46. 6-Giant aneurysm : a) Definition : -Aneurysm > 25 mm in diameter b) C/P : -Mass effect (cranial nerve palsies , retro-orbital pain ) -Hemorrhage
  47. 47. c) Radiographic Features : 1-Large mass lesion with internal blood degradation products 2-Signet sign : eccentric vessel lumen with surrounding thrombus 3-Curvilinear peripheral calcification 4-Ring enhancement : fibrous outer wall enhances after complete thrombosis
  48. 48. 5-Mass effect on adjacent parenchyma 6-Slow erosion of bone : *Sloping of sellar floor *Undercutting of anterior clinoid *Enlarged superior orbital fissure
  49. 49. b) Fusiform (Atherosclerotic) Aneurysm : 1-Etiology & Incidence 2-Radiographic Features 3-Complications
  50. 50. 1-Etiology & Incidence : -Elongated aneurysm caused by atherosclerotic disease -Most located in the vertebrobasilar system -Often associated with dolichoectasia (elongation and distention of the vertebrobasilar system)
  51. 51. 2-Radiographic Features : -Vertebrobasilar arteries are elongated , tortuous and dilated -Tip of basilar artery may indent 3rd ventricle -Aneurysm may be thrombosed : CT: Hyperdense T1W: Hyperintense
  52. 52. 3-Complications : a) Brainstem infarction due to thrombosis b) Mass effect (cranial nerve palsies)
  53. 53. c) Dissecting Aneurysm : 1-Etiology 2-Radiographic Features
  54. 54. 1-Etiology : -Following a dissection an intramural hematoma may organize and result in a saclike out pouching -Causes : Trauma > vasculopathy ( SLE , FMD ) > spontaneous dissection -Location: Extracranial ICA > vertebral artery
  55. 55. 2-Radiographic Features : Elongated contrast collections extending beyond the vessel lumen Angiography is sometimes required for imaging of vascular detail (dissection site)
  56. 56. Patient presenting with SAH) due to rupture of a dissecting aneurysm of the right intracranial vertebral artery (VA) (arrow) , this is a common site for a dissecting aneurysm to cause SAH
  57. 57. (a) Diffusion shows lesion of restricted diffusion on the left side (arrow), which was consistent with acute posterior choroidal-artery infarction, (b) T2, (c) MRA and CTA (d) show a dilatation of the left posterior cerebral artery, with a double lumen, that is, a true circulating lumen (lower arrows) and a false noncirculating lumen (upper arrows) divided by an intimal flap (b, arrowheads), suggesting a dissecting aneurysm, (e) Angiography confirmed an aneurysm of the posterior cerebral artery , (f) shows the coiling of the aneurysm
  58. 58. d) Infectious (Mycotic Aneurysm) : 1-Causes : -Bacterial endocarditis , IVDA (intravenous drug abuse) 80 % -Meningitis , 10 % -Septic thrombophlebitis , 10 %
  59. 59. 2-Radiographic Features : -Aneurysm itself is rarely visualized by CT -Most often located peripherally and multiple -Intense enhancement adjacent to vessel -Conventional angiography is the imaging study of choice
  60. 60. Coronal CT angiography showing a large irregularly shaped presumed mycotic middle cerebral artery aneurysm
  61. 61. e) Oncotic aneurysm : -Is an aneurysm caused by neoplasm -A benign left atrial myxoma may predominantly embolize and cause a distal oncotic aneurysm
  62. 62. Oncotic IAA in a 14-year-old girl with Maffucci syndrome and a skull base chondrosarcoma, (a) Axial T2 through the circle of Willis shows bulbous dilatation of the right ICA (arrow) where it abuts the skull base chondrosarcoma (arrowheads), (b) Axial CTA at the same level shows the aneurysmally dilated right ICA (straight arrow), mildly aneurysmal left ICA (curved arrow), and normal-caliber basilar artery (arrowhead)
  63. 63. f) Traumatic Pseudoaneurysm : -Aneurysms due to trauma are most commonly pseudoaneurysms which don’t contain the typical three histologic layers of the vessel wall, usually the vessel wall exhibit abnormal luminal narrowing proximal to the aneurysm -Similar to mycotic aneurysms, traumatic pseudoaneurysms tend to occur distally -Arteries close to bony structures (such as the basilar & vertebral artery) are prone to dissecting aneurysms
  64. 64. (a) Preoperative T1+C shows a 3-cm tuberculum sellae meningioma encasing the ACOM, (b) Preoperative RT ICA angiogram shows elevation of the right A1 portion and occlusion of the left A1 portion, but no aneurysms (c) RT ICA angiogram, 1 month after surgery, shows a newly developed 3- × 5-mm aneurysm of the ACOM, (d) RT ICA angiogram, 2 months after surgery, shows a 6- × 8-mm aneurysm that enlarged progressively

×