University of Missouri Radiology Department
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March, 2010




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Web Publication No 6.
 
Ricky Ogles MD, Ahsan Humera MD, Fallahian Amir MD, Kenneth Rall MD
 
Clinical Presentation:

A 70 years old female presented in the emergency department with the complaints of deteriorating vision in the right eye with no symptom in the left.

 
The MRI showed :
1a 1b 1c

Caption picture 1a
Axial T2 weighted image of the brain showing T2 hypointense round mass in the right suprasellar region. It is showing Vortex appearance within it.

Caption picture 1b
Axial T1 weighted image showing T1 hypointense round mass in the right supra sellar region.

Caption picture 1c
Axial T1 weighted post contrast image showing marked enhancement of the mass.

     
   
1d    

Caption picture 1 d
MR angiogram showing dilated aneurysm in the right supra clinoid location and another aneurysm in the left cavernous portion.

 
   
Pic2    

CT angiogram showing a  right ophthalmic aneurysm measuring approximately 2.6 cm x 2.2 cm in its largest dimension on axial views.  There also is a left cavernous ICA aneurysm that is approximately 9 mm in diameter.
There appears to be some decreased flow through the right A1 segment,and the MCA appears to be patent at this time. 

 
 
Pic3a 3b  

3a conventional angiogram left internal carotid injection showing aneurysm in the left cavernous portion of internal carotid artery about 9 mm in size.

3b
Conventional angiogram right internal carotid injection is showing a large aneurysm measuring 2.6 x 2.2 cm arising from left internal carotid artery, there is no filling of the right anterior cerebral artery from this injection.

 
Diagnosis:

Bilateral Internal Carotid Artery Aneurysms right more than the left.

 
Discussion:

A cerebral aneurysm is weakness in the wall of acerebral or which causes a localized dilation or ballooning of the blood vessel. Approximately 85% of cerebral aneurysms develop in the anterior part of the Circle of Willis. The most common sites include the anterior cerebral artery and anterior communicating artery (30-35%), the bifurcation, division of two branches, of the internal carotid and posterior communicating artery (30-35%), the bifurcation of the middle cerebral artery (20%), the bifurcation of the basilar artery, and the remaining posterior circulation arteries (5%).

Cerebral aneurysms are classified both by size and shape. Small aneurysms have a diameter of less than 15 mm. Larger aneurysms include those classified as large (15 to 25 mm), giant (25 to 50 mm), and super giant (over 50 mm). Saccular aneurysms are those with a saccular outpouching and are the most common form of cerebral aneurysm. Intracranial aneurysms are multiple in 10-30% of all cases.  About 75% of patients with multiple intracranial aneurysms have 2 aneurysms, 15% have 3, and 10% have more than 3.
Before a larger aneurysm ruptures, the individual may experience such symptoms as a sudden and unusually severe headache, nausea, vision impairment, vomiting, and loss of consciousness, or the individual may be asymptomatic, experiencing no symptoms at all. Ruptured aneurysm presents with severe headache (Worst headache of the life of the patient). One complication of aneurysmal subarachnoid hemorrhage is the development of vasospasm. Approximately 1 to 2 weeks following the initial hemorrhage, patients may experience 'spasm' of the cerebral arteries, which can result in stroke.

The most common presentation of intracranial aneurysm is subarachnoid hemorrhage. In North America, 80-90% of nontraumatic SAHs are caused by the rupture of an intracranial aneurysm. Vasospasm is the leading cause of disability and death from aneurysm rupture. Of patients with SAH, 10% die before reaching medical attention and another 50% die within one month. Fifty percent of survivors have neurological deficits. Ruptured aneurysms are most likely to rebleed within the first day (2-4%), and this risk remains very high for the first 2 weeks (about 25%) if left untreated.

Studies demonstrate that the geometric relationship between an aneurysm and its parent artery is the principal factor that determines intra-aneurysmal flow patterns. In lateral aneurysms, such as those that arise directly from the ICA, blood typically moves into the aneurysm at the distal aspect of its ostium and exits at its proximal aspect, producing a slow-flow vortex in the aneurysm center.

 
Treatment

Currently there are two treatment options for brain aneurysms: surgical clipping or endovascular coiling. If possible, either surgical clipping or endovascular coiling is usually performed within the first 24 hours after bleeding to occlude the ruptured aneurysm and reduce the risk of rebleeding.

Surgical clipping was introduced by Walter Dandy of the Johns Hopkins Hospital in 1937. It consists of performing a craniotomy, exposing the aneurysm, and closing the base of the aneurysm with a clip chosen specifically for the site. The surgical technique has been modified and improved over the years. Surgical clipping has a lower rate of aneurysm recurrence after treatment.

Endovascular coiling was introduced by Guido Guglielmi at UCLA in 1991. It consists of passing a catheter into the femoral artery in the groin, through the aorta, into the brain arteries, and finally into the aneurysm itself.

 
REFERENCES
  1. Brisman JL, Song JK, Newell DW (August 2006). "Cerebral aneurysms". N Engl J Med 355 (9): 928–39. doi:10.1056/NEJMra052760. PMID 16943405.
  2. Appel, Jacob M. Health care hard to recognize, tough to define, Albany Times Union, Nov. 12, 2009 .
  3. Greenberg MS. SAH and aneurysms. In: Greenberg MS, ed. Handbook of Neurosurgery. 5th ed. New York: Thieme Medical Publishers; 2001:754-803.
  4. Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning. Neurosurgery. Jan 1980;6(1):1-9. [Medline]
 
 
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