Cerebral aneurysms A case study

Transcription

1 August 2001 Cerebral aneurysms A case study Heather L. Hinds, Harvard Medical School Year III

2 Our Patient 57yr old woman History of migraines Presents with persistent headache several months duration different from her usual headache Need to rule out intracranial abnormality 2

3 Menu of tests for initial cerebral imaging Computed tomography (CT) Fast and readily available Excellent for detection of acute hemorrhage Magnetic resonance imaging (MR) Higher soft tissue resolution/contrast Multiplanar capability (Plain film Shows the skull, but reveals few brain abnormalities) 3

4 Our Patient 57yr old woman History of migraines Presents with persistent headache several months duration different from her usual headache Test of choice: HEAD CT 4

5 Normal Head CT Check: Blood, acute High attenuation (bright) Midline Is symmetry preserved? Ventricles Cisterns Sulci Grey/white matter Soft tissues Bones Sinuses RIGHT R Frontal lobe Gr R Occipital lobe BIDMC PACS system W LEFT L Lateral Ventricle W = white matter Gr = grey matter 5

6 Our Patient s Head CT (no contrast) Film Findings: Spherical mass Smooth margined High attenuation Slight mass effect Located just anterior to the Circle of Willis RIGHT Frontal lobe LEFT No acute hemorrhage, edema, infarct Midbrain Cerebellum BIDMC PACS system 6

7 DDx: Cerebral mass Tumor Hematoma Abscess Arterio-venous malformation (AVM) Aneurysm 7

8 Work-up: Cerebral mass Computed tomography (CT) + IV contrast Magnetic resonance imaging (MRI) 8

9 Our Patient s Head CT (with contrast) RIGHT LEFT Frontal lobe RIGHT Frontal lobe LEFT cerebellum cerebellum BIDMC PACS system BIDMC PACS system 2 brightly enhancing round lesions suggestive of cerebral aneurysms 9

10 Lets review the anatomy of the Circle of Willis Communicating system of vessels that supplies blood to the brain Anterior portion fed by the internal carotid arteries Posterior portion fed by the vertebral arteries 10

11 Circle of Willis in our Patient RIGHT LEFT RIGHT LEFT ACA Frontal lobe MCA basilar tail PCA cerebellum BIDMC PACS system BIDMC PACS system Film findings: C/W cerebral aneurysms. 11

12 Menu of tests for evaluating suspected: Cerebral aneurysms Computed tomography (CT) + contrast Magnetic resonance imaging (MRI) Magnetic resonance angiograpy (MRA) Cerebral angiography Patient Plan: Come to the ER for immediate MR imaging! 12

13 Our Patients sagittal MR (T1 sequence) T1 sequence Fat is bright (high signal) CSF is dark (low signal) Sagittal section corpus callosum midbrain Mass characteristics Low signal emission flow void moving blood is dark Position adjacent to ICA BIDMC PACS system internal cerebellum carotid artery 13

14 Our Patients Axial MR (T2 sequence) T2 sequence: CSF is bright ( high signal ) RIGHT LEFT RIGHT LEFT BIDMC PACS system BIDMC PACS system Round lesions with flow void confirmed 14

15 Menu of tests for evaluating suspected: Cerebral aneurysm Computed tomography (CT) + contrast Magnetic resonance imaging (MRI) Magnetic resonance angiograpy (MRA) Cerebral angiography 15

16 Magnetic Resonance Angiography (MRA) MR technique for imaging vessels Uses MR pulse sequences ( Time of Flight ) that can turn flowing blood into a strong signal ( white blood ) Does not require contrast; non-invasive Can convert a stack of contiguous MR slices into a 3D angiographic model Excellent visualization of the Circle of Willis and aneurysm characterization Note: Traditional angiography is the Gold Standard 16

17 MRA - Circle of Willis Our Patient RIGHT LEFT Anatomic Diagram ACA MCA b a s i l a r PCA internal carotid BIDMC PACS system vertebral arteries internal carotid Internal carotid artery aneurysms 17

18 Our patients diagnosis Right giant suprasellar internal carotid artery (ICA) aneurysm (2.6cm) Left supraclinoid internal carotid artery aneurysm (13mm) Patient was booked for definitive treatment in 5 days 18

19 Treatment options Broadly include; 1. Surgical clipping 2. Angiographic embolization 19

20 Lets review a little on Cerebral aneurysms Dilatations or outpouchings of the arterial wall Saccular ( berry ) or fusiform (dilated and elongated) Mycotic, neoplastic, traumatic Saccular aneurysms form secondary to a weakness in the media and elastica of the arterial wall typically occur at vessel bifurcations/branchings 20

21 Saccular aneurysms Frequency: 3.6-6% of the population 15-20% multiple aneurysms Most common locations: Circle of Willis Anterior communicating artery 30-35% Posterior communicating artery 30-35% Bifurcation of the middle cerebral artery 20% Basilar tip 5% 21

22 Saccular aneurysm Risk factors Female gender Family history Polycystic kidney disease (ADPKD) Connective tissues disorders Smoking (cardiovascular risk factors?) Treatment options: Conservative or aggressive? > 5-9mm increased risk of rupture Treatment options Surgical clipping of the neck of the aneurysm Aneurysm occlusion (angiography) Choice for this patient Proximal vessel occlusion 22

23 Unfortunately, our Patient returned. 4 days later, patient complained of headache and vomiting Arrived at the ER unresponsive Concern: Subarachnoid Hemorrhage (SAH) 80% of SAH are due to rupture of saccular aneurysms 23

24 Our patients CT without contrast Acute blood is bright (high attenuation) RIGHT LEFT RIGHT LEFT 4th ventricle BIDMC PACS system High attenuation blood is present in dilated ventricles BIDMC PACS system 24

25 Our patients CT without contrast BIDMC PACS system BIDMC PACS system Blood again seen in dilated ventricles Enlarged aneurysm with surrounding edema causing mass effect 25

26 Impression Subarachnoid hemorrhage following rupture of a right internal carotid artery aneurysm Acute blood in cisterns and ventricles Dilatation of ventricles (hydrocephalus) Mass effect on right lateral ventricle Midline shift Interventional radiological treatment was pursued. 26

27 Lets review anatomy to understand how a ruptured aneurysm bleeds into the subarachnoid space 27

28 pmccaff/syllabi/sppa362/362unit3.html 28

29 Brain ventricles Cavities in the brain filled with CSF Open to subarachnoid space via foramen in the 4th ventricle Foramina of Luschka Foramen of Magendie 29

30 Plan: Transcatheter embolization Guglielmi Coiling Method Wall off the aneurysm from the circulation by filling it with platinum wire coils. Benefits Utilizes standard angiography techniques Less invasive than surgical clipping (craniotomy) Can reach distal/inaccessible aneurysms Risks Occlusion of parent artery by renegade coils Perforation of aneurysm Little information available on long term outcomes 30

31 Our patient s Cerebral artery angiogram during embolization Femoral artery catheterization route to the internal carotid Inject contrast Continue moving catheter through the internal carotid towards the Circle of Willis Internal carotid artery External carotid artery Right common carotid BIDMC PACS system 31

32 Our Patient s Cerebral artery angiogram during embolization Locate aneurysm Estimate volume Thread a microcatheter through the main catheter to the aneurysm site Deliver fine, wound platinum coils through the microcatheter via a guide wire Release coils into aneurysm Pack until full BIDMC PACS system Internal carotid artery 32

33 Our patients cerebral angiogram during embolization Internal carotid artery BIDMC PACS system Aneurysm partially filled with coils 33

34 Projected outcomes Guglielmi coil treated cerebral aneurysm Best for aneurysms 4-10mm, narrow necks Best for aneurysms difficult to access using surgical approaches Best for patients for whom surgery is contraindicated Problems: incomplete occlusion (rebleeding), potential complications (rupture, artery occlusion/coil migration) Long term outcomes still unclear Surgically treated cerebral aneurysm Classic approach - surgical clipping of aneurysm neck Better occlusion of aneurysm Carefully controlled randomized trials need to be done. 34

35 Our Patient was already unresponsive at the time of the angiographic embolization and died shortly thereafter 35

36 Take home message Rule out intracranial abnormality? Exam of choice: typically CT ALWAYS do non-contrast CT to identify acute blood Follow with contrast study, if indicated Cerebral mass? MR to characterize further Putative aneurysm? Cerebral artery angiography is the Gold Standard MRA offers a convenient alternative; also CTA Treatment of aneurysm? Surgical clipping or thrombosis Considerations: Aneurysm location, size and neck shape Patient stability 36

37 References Dovey, Z., Misra, M., Thornton, J., Fady, T., Charbel, M.D., Debrun, G.M., Ausman, J.I. Guglielmi detachable coiling for intracranial aneurysms. Arch Neurol 2001; 58: Grossman, R.I., Yousem, D.M. Neuroradiology: The requisites. St. Louis: Mosby; Naidich, T.P., Righi, A.M. Neurovascular imaging. Radiol Clin North Am 1995; Reeder, M.M., Felson, B. Gamuts in radiology: Comprehensive lists of roentgen differenetial diagnosis. Cincinnati: Audiovisual Radiology of Cincinnati, Inc.; Schnitzlein, H.N., Murtagh, F.R. Imaging Anatomy of the Head and Spine. Baltimore: Urban & Schwarzenberg; Van Gijn, J., Rinkel, G.J.E. Subarachnoid haemorrhage: diagnosis, causes and management. Brain 2001; 124: Wardlaw, J.M., White, P.M. The detection and management of unruptured intracranial aneurysms. Brain 2000; 123:

38 Acknowledgements Dr. Gillian Lieberman Dr. Chad Brecher Dr. Nicole Thobe Dr. Steven Reddy Pamela Lepkowski Larry Barbaras and Cara Lyn D amour 38